Secret deck

Question 1

What dose of barium contrast medium is recommended in cats to achieve adequate filling of the stomach?

Answer 1

10 mL/kg Morgan VRU 1981

Question 2

In regards to Upper GI studies in cats, how does the position of the stomach vary with respiration?

Answer 2

Deep inspiration caused stomach to shift caudally a distance of 1 vertebral body Morgan VRU 1981

Question 3

What influences gastric emptying in the cat during upper GI studies?

Answer 3

Dependent on the volume of contrast medium If received over 10 mL/kg –> more complete emptying and minimal residual streaking at 30 min

Question 4

Does laparoscopic assisted gastropexy alter GI transit times in the dog?

Answer 4

No Balsa JVIM 2017

Question 5

GI transit times with Barium in the dog

Answer 5

• Gastric - 30 to 120 min
• Time to reach duodenum 15 min
• Time to reach jejunum - 30 min
• Time to reach ileum - 60 min
• Time to reach ICJ (aka SITT) - 90 to 120 min
• SI empty - 3-5 hours

Question 6

GI transit times with Barium in the cat

Answer 6

• Gastric - 30 to 60 min (within 30 min if use 10ml/kg)
• SITT - 30-60 min

Question 7

Dose of Barium in large dog (>20kg)? Small dog (<20kg)?

Answer 7

• 30% w/v (dilution of normal 60%-100% w/v)
• Large - 5-7 mL/kg
• Small - 8-12 mL/kg

Question 8

What is this most consistent with?

Answer 8

Settling - irreversible process caused by barium coming out of suspension

Question 9

What position is best for esophageal contrast studies?

Answer 9

Sternal position - faster transit time and increased stimulation of primary peristaltic waves for both liquid and kibble compared to lateral recumbency

Bonadio JVIM 2009

Question 10

What are the 4 measured parameters of pharyngal function in the dog? How are these parameters affected in dogs with cricopharyngeal achalasia?

Answer 10

1. Maximum caudal contraction of the pharynx
2. Opening of the cranial esophageal sphincter
3. Closure of the cranial esophageal sphincter
4. Re-opening of the epiglottis

Opening and closing of the cranial esophageal sphincter was significantly delayed during both liquid and kibble swallows in dogs with cricopharyngeal achalasia.

Pollard VRU 2000

Question 11

Which cranial nerves govern the oropharyngeal phase of swallowing?

Answer 11

1. Trigeminal
2. Facial
3. Glossopharyngeal
4. Vagus
5. Hypoglossal

Question 12

How is the pharyngeal constriction ratio calculated?

Answer 12

Area of pharynx at MAXIMAL constriction/area of pharynx at rest

Pollard VRU 2007

Question 13

How does the pharyngeal constriction ratio differ between normal dogs and dogs with weak pharyngeal contraction?

Answer 13

Normal dogs have smaller PCR than dogs with weak pharyngeal contraction

Pollard VRU 2007

Question 14

How does PCR change with diminished pharyngeal contractility?

Answer 14

As pharyngeal contractility diminishes, the PCR approaches 1

Question 15

What are the most common imaging findings in cats undergoing video fluoroscopy?

Answer 15

1. Hiatal hernia
2. Esophageal stricutre
3. Esophageal dysmotility

Question 16

T/F: oropharyngeal and cricopharyngeal causes of dysphagia were not identified in the cat

Answer 16

True

Question 17

Which view has the highest sensitivity for identifying pneumothorax?

Answer 17

Right lateral HB projection had the highest rate of detection and gradation of severity for pneumothorax

Question 18

Which radiographic view is best for detection of pneumoperitoneum?

Answer 18

Left lateral view - gas accumulates dorsally near fluid-filled fundus

Question 19

What type of stent is this? What are its indications?

Answer 19

Balloon-expanding metallic stent (BEMS) - premounted onto a balloon dilation catheter and balloon inflation deploys the stent at the target. The BEMSs are typically made of stainless steel and used in veterinary IR for palliation of nasopharyngeal stenosis or stenting of the right ventricular outflow tract

Question 20

What type of stent is this? What are its indications?

Answer 20

Self-expanding metallic stent (SEMS)

Common indications for SEMSs in veterinary IR include tracheal, vena caval, and urethral stents

Question 21

What are the types of self-expanding metallic stents (SEMS)?

Answer 21

1. Woven SEMS:
   
   • Stainless steel or nitinol
   • Forshorten (compressed stent longer than deployed stent)
   • Reconstrainable for correction of improper positioning if less than 60-70% of the stent has been deployed
2. Laser-cut SEMS:
   
   • Nitinol
   • Do not forshorten
   • Are not reconstrainable

Question 22

What is the difference between these 2 stents (can come in both BEMS and SEMS)?

Answer 22

D - Covered form or stent graft; help to constrain tissue proliferation and luminal restenosis, but may act as a nidus for infection

E - Bare-metal form

Question 23

Answer 23

B - cutting balloon dilator

C - conventional balloon dilator

Question 24

What are the phases of excretory urography?

Answer 24

1. Arteriogram
2. Nephrogram
3. Pyelogram
4. Cystogram

Question 25

What are contraindications for IVP?

Answer 25

1. Dehydration 2. Previous contrast reaction 3. Oliguria/anuria 4. Multiple myeloma

Question 26

What phases of IVP are these kidneys in?

Answer 26

A - before B - nephrogram C - pyelogram

Question 27

T/F: 4 mL/kg sufficiently distends bladder to eliminate wall thickening due to incomplete filling, but does not eliminate mucosal irregularity due to cystitis

Answer 27

True Wall should not be \>2mm in thickness at this degree of distention

Question 28

Describe normal appearance of equine myelogram in neutral, flexed, and extended positions

Answer 28

NEUTRAL * Dorsal column is wider and more uniform than ventral column * Dorsal column widens at the caudal aspect of each foramina * Ventral column usually narrows and is slightly elevated at intervertebral disc spaces FLEXION: * Dorsal contrast column remains the same * Ventral column becomes even narrower at the disc spaces EXTENSION: * Dorsal column remains the same * Ventral column becomes slightly wider C5

Question 29

Sensitivity and specificity of myelography for identifying CVM in horses

Answer 29

Sensitivity of myelogram is low and specificity is moderate no matter the criteria used Sensitivity and specificity appear higher for C6-7 than mid-cervical sites

Question 30

What are described measurements for myelography in CVM horses? What is the accuracy of each?

Answer 30

1. 50% reduction of the dorsal contrast column at the intervertebral disc space * Recently been shown to have false positive results * 70% reduction of the dorsal column necessary to avoid false positives 2. \>20% reduction in dural diameter * more accurate in neutral views 3. 2 mm reduction in the dorsal contrast column signify significant compression * Not recommended

Question 31

At C6-7, what percent reduction in dorsal contrast column height and dural diameter have a high sensitivity and specificity?

Answer 31

At C6-7, reduction of the dorsal contrast column height by 70% or reduction in dural diameter by 25% have a high sensitivity and specificity

Question 32

What are the most common sites of compression in CVM horses?

Answer 32

* C3-4 \> C6-7 \> C5-6 \> C4-5 * Rarely detected at the other sites in the cervical spine * 29% of compressive horses had it in multiple sites Papageorges 1987

Question 33

Which stent is recommended by Weisse for urethral stenting due to obstruction by tumor? Due to recurrent stricture?

Answer 33

Obstruction - Self-expanding metallic stent (SEMS), laser cut, uncovered Stricture - SEMS, laser cut, covered

Question 34

Calculate the tracheal stent size needed given that your raw radiographic measurement (not corrected for magnification) measures 13mm in the cervical trachea and 10mm in the intrathoracic trachea. The marker measures 11mm in length. The length of the trachea requiring stenting is ~85mm.

Answer 34

# Choose a 14mm diameter stent (to be 2-3mm greater in diameter than the maximal measure) A 14 x 58 mm stent expanding between 9mm and 12mm (calculated from radiograph) will be approximately 85mm in length once expanded

Question 35

What fatal complications is automatic tru-cut biopsy of the liver associated with in cats?

Answer 35

Fatal hypotension and bradycardia within 15 minutes of biopsy

Question 36

How do different anesthetic protocols affect uptake of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) by the brain in PET/CT imaging?

Answer 36

* Standard uptake value (SUV) for the frontal and occipital lobes was significantly higher than in the brainstem in all dogs regardless of protocol * Dogs receiving medetomidine/tiletamine-zolazepam also had significantly higher whole brain SUVs than the propofol/isoflurane group

Question 37

What is the radiopharmaceutical uptake caused by?

Answer 37

Peroneal nerve block This occurs in approximately 50% of blocked limbs and can mimic a tibial lesion on the lateral view in approximately 20% of blocked limbs. Associated with higher dose of anesthetic.

Question 38

How does acepromazine influence count density in horse limbs?

Answer 38

* Intravenous administration of acepromazine increases peripheral blood flow causing an earlier onset of the vascular phase during the three-phase bone scan; increased count density of vascular phase * Acepromazine did not increase the count density of the bone phase scintigrams

Question 39

In regards to trans-splenic portoscintigraphy, are there any distinguishing features differentiating between single intrahepatic and single extrahepatic shunts?

Answer 39

No distinguishing features

Question 40

What is the morphology of this shunt?

Answer 40

Portoazygous - Tc bolus traveled dorsally, running parallel to the spine and entering the heart craniodorsally

Question 41

What is the morphology of this shunt?

Answer 41

Splenocaval - bolus ran from the area of the portal vein/splenic vein junction in a linear fashion toward the caudal vena cava entering the heart caudally

Question 42

What are the 3 identified shunt morphologies with trans-splenic portography?

Answer 42

1. Porto-azygous 2. Spleno-caval 3. Internal thoracic

Question 43

What is the most common distribution of feline thyroid disease?

Answer 43

Bilateral asymmetric

Question 44

T/F: multifocal thyroid disease will develop in a few cats that have ectopic thyroid disease or thyroid carcinoma

Answer 44

True. Ectopic thyroid disease and thyroid carcinoma are relatively uncommon in hyperthyroid cats

Question 45

Which thyroid scintigraphy measurement has the highest sensitivity for diagnosis of hyperthyroidism in cats?

Answer 45

T/S ratio had the accurary

Question 46

Which thyroid scintigraphic parameter is the best parameter to predict the functional volume and metabolic activity of the feline adenomatous thyroid gland?

Answer 46

Percent thyroidal uptake of Tc (TcTU)

Question 47

List differentials for generalized osteosclerosis in the cat?

Answer 47

* Osteopetrosis * FeLV * Lymphoblastic leukemia, lymphoma * C-cell tumor * Myeloproliferative disorders * Chronic renal failure

Question 48

Does head and neck position have an effect on nasopharyngeal size in horses? If so, which results in the smallest diameter?

Answer 48

* Significant influence of head and neck position on pharyngeal diameter, with head position having the major effect; neck position was less important, but still significant * Smallest pharyngeal diameter was found at the dorsal, flexed position

Question 49

What head and neck position in the horse results in the largest nasopharyngeal diameter?

Answer 49

Largest pharyngeal diameter was found at the extended midway position

Question 50

Are intra- and intervertebral ratios good for differentiating normal from CVM in Dobermans? How do the ratios change with location along the cervical spine (general)?

Answer 50

* No difference in either the intervertebral or intravertebral ratio between normal vs. affected dogs * In all dogs (normal and CVM), ratios decreased progressively along the cervical spine, being smallest at C6–C7 and C7

Question 51

What signalment parameters are associated with small intra- and intervertebral ratios in Dobermans?

Answer 51

* Increasing age * Males

Question 52

Left cranial vena cava * Pathophysiology * Clinical significance

Answer 52

Most commonly encountered anatomic variant, but not clinically significant * Failure of left anterior cardinal vein regression * Can occur alone or with a normal right cranial vena cava * Left cranial vena cava enters the right atrium caudally (see image) * Has no detrimental effect but assumes importance during surgery as catheterization of left jugular can cause catheter to take unexpected path * Transpositional venous anomalies often seen in patients with transpositional arterial anomalies (i.e., left cranial vena cava and persistent right aortic arch)

Question 53

What are the standard views for evaluation of the foot in cows?

Answer 53

* Dorsal 65 proximal-palmarodistal and a lateral 30 dorsal-mediodistal oblique * Allow the pedal bone and distal sesamoid bone, as well as the distal interphalangeal joint, to be displayed and evaluated in 2 different planes DOI: https://doi.org/10.1016/j.cvfa.2013.11.003

Question 54

Where was the injection made? Label the anatomy.

Answer 54

Right atrium Left image 1. Right auricle 2. Right ventricle 3. Pulmonary sinus of Valsalva 4. MPA 5. LPA 6. RPA Right image a. Pulmonary v. b. Left atrium c. Left ventricle d. Sinus of Valsalva e. Ascending aorta f. Brachicephalic trunk g. Left subclavian a.

Question 55

Where was the injection made? Label the anatomy.

Answer 55

Injection made in vena cava Left image: 1. Right atrium 2. Right ventricle 3. Pulmonary sinus of Valsalva 4. MPA 5. Right auricle Right image: a. Left atrium b. Left ventricle c. Left auricle d. Aorta e. Brachiocephalic trunk f. Left subclavian

Question 56

Where was the injection made? Label the anatomy.

Answer 56

Injection made in vena cava 1. Vena cava 2. Right atrium 3. Right auricle 4. MPA 5. Right ventricle 6. MPA

Question 57

Label the anatomy

Answer 57

1. Left atrium 2. Left ventricle 3. Ascending aorta 4. Descending aorta 5. Brachiocephalic trunk

Question 58

Label the anatomy

Answer 58

Question 59

Answer 59

Question 60

Answer 60

Question 61

Answer 61

Question 62

What are the two commonly used balloon-dilator catheters for pulmonic stenosis as described in Weisse?

Answer 62

1. TYSHAK * Thin, minimally compliant * Relatively low maximal burst pressure * Low profile * Most sizes can accomodated a 0.035" guide wire * Commonly selected for BPV in dogs 2. Z-MED * Thicker --\> require larger introducer size * Greater maximal burst pressure

Question 63

What are the 3 types of esophageal stents?

Answer 63

1. Biodegradable (BDS) made of PDS suture 2. SEMS 3. Self-expanding plastic stents (SEPS) They are either uncovered, partially covered, or fully-covered. The advantages of a covered stent is a lower rate of re-obstruction, especially with strictures, but a higher rate of migration, due to the failure of tissue in-growth. Esophageal stents have a dumb-bell shape at each end, to aid in preventing migration, and the covered stents, since they are intended for short-term use, have a string around each end so that they can be removed endoscopically with a grasping instrument.

Question 64

What stent is recommended for tracheal stenting?

Answer 64

Mesh, self-expanding metallic stents are most commonly used for tracheal stenting procedures,as balloon-expandable and laser-cut stents have been ssociated with unacceptable risks of migration and fracture, respectively

Question 65

Label the anatomy of the digital flexor tendon sheath.

Answer 65

Question 66

Which tendon of the shoulder is this?

Answer 66

Supraspinatous

Question 67

Answer 67

Infraspinatous

Question 68

Answer 68

Question 69

Answer 69

Biceps tendon

Question 70

Answer 70

Question 71

Answer 71

Question 72

Features of insulinoma on different modalities (CEUS, CT, and MRI)

Answer 72

1. CEUS * Variable enhancement patterns, but generally increases conspicuity of the nodule 2. CT (variable reports) * Hyperattenuating to normal pancreas in arterial phase * Variable in venous and delayed phases 3. MRI * T2w fat-saturation hyperintense * Post-gad T1w fat-saturation isointense

Question 73

Which equine intercarpal ligaments were visible with CT arthrogram

Answer 73

* Medial and lateral palmar intercarpal ligaments * Radiocarpal ligament * Transverse intercarpal ligaments * Palmar carpal ligament

Question 74

In dogs, mean ratio of kidney length to the second lumbar vertebra length is dependent on what?

Answer 74

Skull type - brachycephalic dogs had the highest median LK/L2 ratio and dolichocephalic dogs the lowest. Mesaticephalic dogs were in the middle

Question 75

Using the right lateral view, what is the mean ratio of kidney length to the second lumbar vertebra length for different skull types?

Answer 75

* Brachycephalic dogs - LK/L2 ratio of 3.1 * Dolichocephalic dogs - 2.8 * Mesaticephalic dogs 2.97

Question 76

T/F: A mean ratio kidney to L2 length of \>3.5 was found only in mesaticephalic dogs on the ventrodorsal view

Answer 76

True

Question 77

How did the mean ratio of kidney length to L2 length correlate with body weight?

Answer 77

* Small dog = larger ratio

Question 78

In the Latimer et al. paper regarding lung lobe torsions in juvenile dogs (\<12 mo), which lung lobes were affected most commonly and in what order?

Answer 78

* Left cranial lung lobe * Right middle lung lobe * Right cranial lung lobe This paper consisted of mostly pugs, which are predisposed to L Cr LLT. The two non-pugs in this paper did not have torsions of L Cr.

Question 79

In D'Anjou et al., was there a predilection for site of lung lobe torsion and weight?

Answer 79

Yes. * Large dogs - Right middle lung lobe * Small dogs - Left cranial lung lobe * Cats (n=2) - right cranial and right middle

Question 80

What is the most-likely diagnosis?

Answer 80

Lung lobe torsion * Vesicular gas pattern * Abrupt tapering of bronchus * Mild pleural effusion

Question 81

In Lang et al. (1986), which radiographic view was most sensitive for detecting pulmonary metastasis?

Answer 81

* R lateral \> Left lateral \> VD * Recommend two-viewers review all met checks or, if only one reviewer, a 3-view study should be used

Question 82

What side do these cranial lobar vessels belong to in this left lateral radiograph?

Answer 82

Right pulmonary vessels - The pulmonary vessels in the right cranial lung lobe are more conspicuous in a left lateral than in a right lateral radiograph. This is caused mainly by the dorsal displacement of the right cranial lobe that occurs when the patient is in right lateral recumbency resulting in the right cranial lobar vessels being superimposed on the left cranial lobar vessels. Thrall 6 ed.

Question 83

Which is left and right?

Answer 83

Question 84

T/F: An enlarged left atrium causes bronchial collapse resulting in coughing

Answer 84

FALSE. No association between moderate‐to‐severe left atrial enlargement and left bronchial collapse (Singh and Johnson, JVIM)

Question 85

How does 40mcg/kg dexmedetomidine IM influence the size of the cardiac silhouette on different views in cats?

Answer 85

Dexmedetomidine was associated with a small but significant increase in cardiac silhouette size: * Right lateral (vertebral heart score) * VD/DV (percentage width) Enlargement may be persistent at a minimum of two hours postdexmedetomidine reversal

Question 86

Radiographic appearance of non-cardiogenic pulmonary edema

Answer 86

* Mixed * Symmetric * Peripheral * Multifocal * Bilateral * Dorsal lung Can be asymmetric and unilateral

Question 87

A Bulldog presents for dyspnea after a collapse episode and you suspect NCPE. On radiographs, you see asymmetric, unilateral, and dorsal pulmonary interstitial to alveolar pattern. What is the most likely cause of this distribution of NCPE?

Answer 87

Post-obstructive pulmonary edema When the distribution was unilateral, pulmonary infiltration involved mainly the right lung lobes

Question 88

What criteria can be used to assess the pulmonary veins in dogs with MMVD (Oui et al., 2015)?

Answer 88

Normal dogs: * Pulmonary arteries and veins are similar in size * Cranial lobar vessel diameter smaller than 4th rib (lateral) * Right caudal PV \<1.22x width of 9th rib (VD) Right caudal pulmonary vein can be enlarged without distention of cranial pulmonary vein

Question 89

What is the most likely diagnosis?

Answer 89

Laryngeal paralysis --\> air-filled laryngeal ventricles (Stadler VRU 2011, Figure 3)

Question 90

Magic angle

Answer 90

* 55 degrees relative to B0 * Short TE (PD, STIR, T1w) * Occurs in neutral and angled limbs * Increasing the TE to \>40ms in spin echo sequences and \>80ms in TSE sequences, eliminates the magic angle effect in tendons * Other paper says that magic angle is reversed at TE 140ms, but 120 ms had the best balance bt image quality and magic angle artifact Werpy

Question 91

T/F: Due to the configuration of the fibers, ligaments more susceptible to magic angle effect than tendons

Answer 91

True - ligament fibers have a more complex organization than tendons

Question 92

MRI features of coccidioides granulomas

Answer 92

* Difficult to determine location (intra- vs. extra-axial location) * Variable MR features, many of which overlap with neoplasia * Variably enhancing, may be marked * Often poorly defined borders --\> this will differentiate between meningiomas, which have sharp margins Bentley VRU Newer paper out of AZ (Spoor VRU 2019) describes a different appearance - bilateral, symmetric T2w hyperintensities, faint/wispy enhancement in the caudate nucleus, frontal lobe, and rostral internal capsule. Impressive brain atrophy once the infection resolved.

Question 93

CT and MRI features of carotid body paragangliomas (Mai VRU 2015)

Answer 93

* Centered on carotid body * CT * hypoattenuating to adjacent muscles * strong, heterogeneous enhancement * MRI * hyperintense to muscles in T1- and T2-weighted MRI * strong, heterogeneous enhancement * Invasion of adjacent structures - most common was basilar portion of skull; others included regional vessels, tympanic bulla, cranial cavity

Question 94

Carotid body paragangliomas * Common presenting complaint * Signalment

Answer 94

* Most common reason for imaging was a palpable cervical mass or respiratory signs (i.e., dyspnea or increased respiratory noises * Most commonly affected breed was Boston terrier (n = 5) * Predominately male castrated * Median age was 9 years [range 3–14.5].

Question 95

7‐year‐old male neutered domestic short‐haired cat had depression for 5 months and acute blindness

Answer 95

Pituitary apoplexy

Question 96

A dog presents for hindend weaknes. On MRI you see heterogeneous STIR hyperintensity in the hindlimb muscle and the majority of the STIR‐hyperintense region does not enhance indicating poor perfusion. What is the most likely diagnosis?

Answer 96

Ischemic myopathy

Question 97

Which MRI sequence is best for evaluating facial neuropathy?

Answer 97

VIBE (sensitivity 86-96% and the specificity 87-92%) Conventional T1-weighted images yielded a sensitivity of only 39-65% and a specificity of 94-96%

Question 98

T/F: MRI was not a sensitive detector of vestibulocochlear nerve abnormalities

Answer 98

True

Question 99

A pelvic width reaching ____ was observed in several dogs and cats with clinically normal renal function that were not receiving IV fluids

Answer 99

3 mm (D'Anjou VRU 2011) Mean pelvic width increased in polyuric animals or animals receiving IV fluids; increased further with pyelonephritis

Question 100

What width of the renal pelvis has been suggested as a cut-off for predicting animals with urinary outflow obstruction?

Answer 100

13mm

Question 101

What measurements are considered normal, indicative of hyperplasia, or indicative of neoplasia regarding parathyroid US per Wisner VRU 2005?

Answer 101

* \>4mm = adenoma or carcinoma * 2-4mm = hyperplastic * \<2mm = normal

Question 102

The strength of a sound wave depends on:

Answer 102

* Amplitude * Intensity

Question 103

Amplitude

Answer 103

* Maximum variation along the y-axis * In diagnostic US, positive compression amplitude exceeds the negative rarefaction amplitude (asymmetric, non-sinusoidal waveform)

Question 104

Intensity

Answer 104

* Concentration of energy (power) per unit of area (W/cm²) * Inversely related to wave width * Intensity of the beam is greatest where the beam is narrowest (i.e., focal point) * Higher intensity beam = increased risk of adverse biological effects

Question 105

Wavelength (λ)

Answer 105

* Distance between 2 areas of compression (rarefaction) * Determines penetration power and image resolution along the beam * large λ = low frequency * small λ = high frequency

Question 106

Frequency (f)

Answer 106

* Number of cycles per unit of time (Hz) * Inversely related to wavelength

Question 107

How do image resolution and penetration vary with changing frequency?

Answer 107

* Low frequency (large wavelength) = high penetration, but low resolution * High frequency (small wavelength) = low penetration, but high resolution

Question 108

\_\_\_\_\_ and _____ are dependent on the propagation medium, but ____ is not dependent on the propagation medium

Answer 108

**Wavelength** and **speed** are both depended on the propagation medium, but **frequency** is not dependent on the propagation medium

Question 109

Acoustic velocity depends on:

Answer 109

* Density - increased density ---\> slower speed * Stiffness - increased stiffness --\> faster speed * More important than density * Compressibility - increased compressibility = slower speed * Inverse of stiffness

Question 110

Rank soft tissues, air, and bone in order of acoustic velocity (propagation speed) from fastest to slowest

Answer 110

Bone (4,080 m/sec) \> soft tissue (1,540 m/sec) \> air (331 m/sec)

Question 111

Focusing the beam improves _____ resolution

Answer 111

* Lateral (narrower beam) * Elevational (less important)

Question 112

Advantages of harmonic imaging

Answer 112

* Increased lateral resolution * Increased signal to noise ratio * Decreased artifacts: * Reverberation * Refraction * Scatter * Noise * Side lobes

Question 113

As the angle (insonation angle) between the transmitter and interface approached ____ degrees, the accuracy of the estimation of velocity decreases

Answer 113

90 degrees. Only the sound waves parallel to the beam contributes to Doppler effect. In general, use an insonation angle \<60 degrees to give accurate estimate of velocity. May have increased artifact if the angle is less than 30 degrees

Question 114

Strain elastography

Answer 114

* Aka compressive elastography * Stress is applied by repeated manual compression of the transducer and the amount of lesion deformation relative to the surrounding normal tissue is measured and displayed in color * Largely dependent on the examiner’s experience, and significant interobserver variability has been found

Question 115

Shear-wave elastrography

Answer 115

* Uses an acoustic radiation force impulse created by a focused ultrasound beam, which allows measurement of the propagation speed of shear waves within the tissue to locally quantify its stiffness * Kilopascals or meters per second * Highly reproducible * Potential for an increase in artifacts caused by reflection and refraction

Question 116

The Doppler frequency shift is defined as: * A. The difference between the Doppler frequency and the imaging frequency * B. The difference between the transmitted and received frequencies * C. The time between the transmitted and received pulses * D. The rate at which the transducer emits pulses

Answer 116

B. The difference between the transmitted and received frequencies. The Doppler effect causes the transmitted Doppler frequency to be altered when it encounters a moving reflector. The frequency is increased if the reflector is moving toward the beam and decreased if the reflector is moving away from the beam. The difference that occurs between the transmitted frequency and the altered frequency that is reflected back is known as the frequency shift.

Question 117

While performing a Doppler study, the measurement of the Doppler angle of incidence was underestimated. What error will result from this mistake? * A. The frequency shift will be underestimated. * B. No Doppler frequency shift will be detected. * C. Mirror imaging of the Doppler spectrum will occur. * D. The velocity estimation will be inaccurate. * E. Aliasing of the Doppler spectrum will occur

Answer 117

D. The velocity estimation will be inaccurate.

Question 118

Power Doppler

Answer 118

* Uses the amplitude of Doppler signal to detect moving matter * Independent of velocity and direction of flow, so there is no possibility of signal aliasing * Independent of angle, allowing detection of smaller velocities than color Doppler * Higher sensitivity than color Doppler, which makes a trade-off with flash artefacts

Question 119

In the cat, normal measurements of: * Esophageal wall * Cardia wall * Pyloric wall * Pyloric muscularis layer * Length of duodenal submucosal thickening

Answer 119

* Esoph - 4.9 mm * Cardia - 5 mm * Pyloric wall - 4.4 mm * Pyloric mucosal layer - 2.5 mm * Length of duodenal SM thickening - 4.7 mm

Question 120

In Zwingenberger JVIM 2011, muscularis thickening on ultrasound correlated with cellular infiltration of what layers? Lymphadenopathy was associated with infiltration of what layers?

Answer 120

* Muscularis thickening - mucosal and submucosal * Lymphadenopathy - mucosal and submucosal OR mucosal, submucosal and muscularis

Question 121

T/F: In cats with infiltrative bowel disease, disease confined to the mucosa and lamina propria was not associated with ultrasonographic changes

Answer 121

True

Question 122

What is this artifact and why does it occur?

Answer 122

* Twinkle * Occurs behind a strongly reflective interface, such as those produced by urinary tract stones or parenchymal calcifications, and appears as a quickly fluctuating mixture of Doppler signals with an associated characteristic spectrum of noise * Narrow-band signal error generated by highly echogenic interfaces seems to be the primary cause * Enhanced with rough surfaces

Question 123

In vivo, which factors influence the appearance of Twinkling artifact

Answer 123

* Gain * Surface roughness * Stone size

Question 124

Ultrasonographic appearance of lipiduria in cats

Answer 124

* Suspended +/- gravity independent echoes * No artifact

Question 125

Clumping of suspended echoes in lipiduric cats is associated with \_\_\_\_\_\_\_\_

Answer 125

* Type of lipid - diacylglycerol (DAG)

Question 126

Label the anatomy in this Gelding

Answer 126

* Arrows - ureters * Arrowheads - deferent ducts

Question 127

Label the anatomy in this mare

Answer 127

* Arrows - ureters * Arrowheads - vagina

Question 128

Label the anatomy in this Stallion

Answer 128

* Arrows - ureters * Arrowheads - ampullae

Question 129

In horses, what is the normal ureteral wall thickness and diameter of ureter (contracted vs. expanded)?

Answer 129

* Ureteral wall thickness 1.0 - 2.4mm * Ureteral diameter contracted - up to ~9.5mm * Ureteral diameter distended - up to 19mm

Question 130

Normal urinary bladder thickness in horses

Answer 130

1 to 5 mm

Question 131

Differences in enhancement pattern of the spleen between non-sedated dogs, dogs sedated with butorphanol, and dogs sedated with dexmedetomidine?

Answer 131

* Normal and butorphanol dogs were the same * Initial phase - rapid, intense enhancement of small arteries * Venous phase - heterogeneous enhancement of splenic parenchyma gradually becoming more homogeneous * Wash-out phase - gradual, homogeneous decrease in intensity * Dexmedetomidine * Slower distribution of contrast medium * Whole organ was diffusely hypoechoic during the first 30s * Enhancement was weak and homogeneous throughout

Question 132

T/F: Butorphanol does not cause subjective or objective effects during normal contrast-enhanced ultrasound of the spleen

Answer 132

True

Question 133

Increased GB volume and reduction in GB ejection fraction were seen in which of the following groups: * Normal * Mobile sludge * Immobile sludge * Mucocele

Answer 133

Seen in all dogs with sludge or mucocele, but the mucocele group was most severely affected

Question 134

T/F: Biliary stasis occurs not only in dogs with gallbladder mucocele but also in dogs with biliary sludge

Answer 134

True

Question 135

CEUS adrenal gland enhancement patterns in normal dogs versus dogs with PDH

Answer 135

Normal: * Initial enhancement of an artery within the medulla parallel to the long-axis of the gland * Centrifugal enhancement of small arteries branching off the central artery * Diffuse, homogeneous, intense enhancement * Gradual washout - homogeneous loss of intensity PDH * rapid, chaotic, and simultaneous perfusion of US contrast agent into both the adrenal medulla and cortex * Three enhancement patterns * In all PDH dogs, regardless of these vascular patterns, there was a uniform distribution of the contrast agent during the late washin phase and the entire gland became iso-enhanced, followed by slow and progressive washout, similar to that of the remaining adrenal parenchyma

Question 136

What are the 3 early wash-in enhancement patterns in the adrenal glands of dogs with PDH?

Answer 136

* Type 1 * only the central longitudinal artery of the medulla was seen, but it was barely visible * dogs with \<24ug/dl on ACTH * Type 2 * perfusion of the adrenal gland by the contrast agent was so fast and disordered that the central longitudinal artery was not detectable, even in the initial washin stages * ACTH-stimulated cortisol levels \> 24ug/dl * Type 3 * nodular pattern - presence of abnormal vessels forming nodular lesions together with homogeneous, but chaotic enhancement of the contrast agent within the whole adrenal parenchyma

Question 137

Normal CEUS pattern of small intestine in healthy cats

Answer 137

* Initial rapid enhancement of **serosal and submucosal** layers * Followed by a more gradual enhancement of the entire wall * At peak enhancement, there was a lack of demarcation between wall layers * Late phase, there was a gradual wash out of signal from the intestinal wall. The wash out of the submucosal layer occurred last

Question 138

T/F: kVp, but not mAs influences the energy (quality) or the x-ray beam

Answer 138

True. kVp is the only factor to control quality (aka energy) of the x-ray beam

Question 139

T/F: Both kVp and mAs control quantity of the x-ray beam

Answer 139

True.

Question 140

What are heat units? How is this calculated?

Answer 140

Heat units describe maximum load (function of heat energy) that can be safely applied to an x-ray tube; heat energy determined by exposure factors * Simple generator: HU = kVp \* mA \* exposure time (sec) * For 3-phase generators - multiple by 1.35 * For constant potential generators - multiple by 1.4

Question 141

Calculate the heat units for a simple generator with settings of 70 kVp, 100 mA, and 0.1 sec exposure time

Answer 141

70 \* 100 \* 0.1 = 700 HU

Question 142

Calculate the heat units for a constant potential generator with settings of 70 kVp, 100 mA, and 0.1 sec exposure time

Answer 142

70 \* 100 \* 0.1 \* 1.4 = 980 HU

Question 143

What is the relationship between radiographic contrast and kVp?

Answer 143

* Inversely related * Low kVp = high contrast * Increased energy (kVp) photons are more likely to undergo scatter than photoelectric effect --\> compton decreases image contrast (makes it gray)

Question 144

What is this foramina?

Answer 144

Optic canal

Question 145

Answer 145

Optic canal

Question 146

Answer 146

Green - orbital fissure Pink - rostral alar foramen

Question 147

Bonus Q: What structure is indicated by the blue arrow

Answer 147

Rostral alar foramen Blue arrow - indicates the rostral clinoid process, which is the rostral border of the sella turcica

Question 148

Answer 148

Blue - round foramen Green - alar canal

Question 149

Bonus Q: What is the structure identified by the pink arrow

Answer 149

Oval foramen Pink - caudal clinoid process, which is the caudal margin of the sella turcica

Question 150

Answer 150

Internal acoustic meatus

Question 151

Answer 151

Pink - jugular foramen Green - petro-occipital fissure (aka temporo-occipital fissure)

Question 152

Answer 152

Hypoglossal canal

Question 153

What is this view? Name the tarsal bones.

Answer 153

Blue - talus Black - calcaneus Orange - central tarsal Yellow - tarsal 3 Purple - tarsal 1 and 2 Pink - tarsal 4 Lateromedial

Question 154

What is this view? Name the tarsal bones.

Answer 154

Blue - talus Black - calcaneus Orange - central tarsal Yellow - tarsal 3 Pink - tarsal 4 Craniocaudal

Question 155

What is this view? Name the tarsal bones.

Answer 155

Blue - talus Black - calcaneus Orange - central tarsal Yellow - tarsal 3 Purple - tarsal 1 and 2 Pink - tarsal 4 PLDMO

Question 156

What is this view? Name the tarsal bones.

Answer 156

Blue - talus Black - calcaneus Orange - central tarsal Yellow - tarsal 3 Purple - tarsal 1 and 2 Pink - tarsal 4 DLPMO

Question 157

What attaches at this site?

Answer 157

Superficial digital flexor tendon

Question 158

What attaches at this site?

Answer 158

Common digital extensor tendon

Question 159

What is the order of enhancement and order of peak enhancement with ocular CEUS?

Answer 159

* Initial enhancement * Choroid retina ---\> iris and ciliary body * Peak enhancement * Retrobulbar --\> ciliary body --\> iris --\> optic nerve (5 min)

Question 160

How does ocular imaging with CEUS compare to Doppler?

Answer 160

CEUS - increased visualization of small vessels particularly in iris/ciliary body

Question 161

What view is this? Label the anatomy.

Answer 161

Right parasternal long axis

Question 162

What view is this? Label the anatomy.

Answer 162

Right parasternal long axis

Question 163

What view is this? Label the anatomy.

Answer 163

Right parasternal short-axis view

Question 164

What view is this? Label the anatomy.

Answer 164

Right parasternal short axis at the level of the mitral valve 1. LVOT 2. Right ventricle 3. Mitral valve leaflets

Question 165

What view is this? Label the anatomy.

Answer 165

Right parasternal short axis view at the level of the ventricles/papillary muscles 1. Left ventricle 2. Right ventricle 3. Papillary muscles

Question 166

What is the view? Label the anatomy

Answer 166

Left apical view - four chamber 1. Right atrium 2. Right ventricle 3. Left ventricle 4. Left atrium

Question 167

What view is this? Label the anatomy.

Answer 167

Left apical view - 5 chamber 1. Right atrium 2. Right ventricle 3. Left ventricle 4. Left atrium 5. Aorta

Question 168

What is this view? Label the anatomy.

Answer 168

Left parasternal long- axis view

Question 169

What is this view? Label the anatomy.

Answer 169

Left parasternal short axis view

Question 170

FOAL

Answer 170

Umbilical vein * Should be thin-walled with an anechoic lumen * Diameter \<10mm

Question 171

FOAL

Answer 171

Umbilical arteries (1 and 3) * Round, thicker wall * Echogenic clot material * Diamter \<12mm (level of bladder) Urachus (2) * Normally a potential space between the two arteries; does not contain fluid * Combined measurement with arteries \<25mm

Question 172

CALF

Answer 172

* Anechoic structure is the umbilical vein * Lumen large near body wall (10-25mm) * Urachus should never be seen * Arteries should not extend beyond UB apex after 1 week * Walled structures with central anechoic to hypoechoic tissue

Question 173

Nephrogram: fair to good initial opacification that persists or becomes more opaque with time

Answer 173

* Adverse reaction to contrast media * Systemic hypotension * Acute tubular obstruction or necrosis * Acute renal failure

Question 174

Nephrogram: poor initial opacification that gradually fades

Answer 174

polyuric renal failure

Question 175

Nephrogram: poor initial opacification that persists

Answer 175

glomerular or generalized renal disease

Question 176

Nephrogram: poor initial opacification followed by intestification of the opacification

Answer 176

* Renal ischemia * Renal hypotension * Obstruction

Question 177

List 4 benefits of spatial compound ultrasound?

Answer 177

1. Reduced speckle 2. Reduced artifacts * Clutter * Shadowing * Echo drop-out 3. Increased contrast resolution (increased signal to noise) 4. Increased visibility of lesion margins

Question 178

What is spatial compound imaging?

Answer 178

Method to improve sonographic image quality by combining several image frames to cancel out random variation

Question 179

In Whatmough et al., VRU 2006, compound images were considered better with: * Transmit-only, receive-only, or combined transmit/receive * Sector, curvilinear, or linear transducers

Answer 179

* Combined transmit/receive * Sector and curvilinear transducers

Question 180

In Whatmough et al., VRU 2006, what properties of spatial compound imaging accounted for the higher quality compared to non-compound images?

Answer 180

* Improved border definition * Increased signal to noise ratio

Question 181

How does anisotropy affect renal cortical echogenicity in dogs? Does spatial compound imaging influence this?

Answer 181

* Echogenicity increased with a perpendicular insonation angle compared to a parallel insonation angle (cortical hyperechogenicity in the poles, greater cranially) * Spatial compounding did not change this

Question 182

Which CEUS agent has a hepatic sinusoidal phase?

Answer 182

Levovist

Question 183

Which CEUS agent has been associated with anaphylactic reactions in dogs and other small animals?

Answer 183

Optison - has a human albumin shell

Question 184

In the dog, which physes close by 5 months (~150 days)?

Answer 184

* Anconeal process * Acetabulum * Pubic symphysis

Question 185

In the dog, which physes close by 6-8 months?

Answer 185

* Calcaneus * Humeral condyle and medial epicondyle * Distal metacarpals and metatarsals * Phalanges

Question 186

In the dog, which physes close by 7-10 months?

Answer 186

* Proximal radius * Olecranon process * Cranial vertebral body

Question 187

In the dog, which physes close by 9-12 months?

Answer 187

* Distal radius and ulna * All of the proximal tibia and fibula * All of femur * Caudal vertebral body * Ischiatic tuberosity

Question 188

In the dog, which physes close by 12-18 months?

Answer 188

* Distal tibia/fibula (12-15 months) * Proximal humerus (12-18 months)

Question 189

In the dog, when does the humeral condyle (intercondylar) close?

Answer 189

6-8 weeks

Question 190

What is this lesion? What percentage of GSDs with cauda equina syndrome have this lesion?

Answer 190

* Sacral osteochondrosis - lesion in dorsal endplate * ~30% of GSDs with CES have sacral OC * Clinically normal with OC \<18mo * CES with OC \>18mo * Dogs with CES and OC were 2 years younger than CES dogs w/o OC

Question 191

Which tissues concentrate ^99mTc-pertechnetate?

Answer 191

* Thyroid * Salivary glands * Gastric mucosa * Choroid plexus

Question 192

T/F: In cats, optimal imaging of the thyroid gland is 20 min to 2 hours post-injection of ^99mTcO₄^- while imaging after 4 hours may give a false diagnosis of hyperthyroidism.

Answer 192

True

Question 193

Iodide trapping by normal thyroidal tissue is significantly enhanced by antithyroid medication and continues to be increased for _____ after withdrawal of the medication.

Answer 193

15 days ## Footnote normal cats placed on methimazole will have an elevated thyroid:salivary ratio and a false impression of hyperthyroidism could be made on TcO, thyroid scintigraphy

Question 194

What is the mechanism of action for methimazole?

Answer 194

* Inhibits the synthesis of thyroid hormones by blocking incorporation of iodine into tyrosyl groups to form thyroglobulin * Inhibits coupling of iodotyrosines to form tetraiodothyronine (T4) and triiodothyronine (T3) Methimazole does not directly affect the iodide pump which concentrates iodide in thyroid cells

Question 195

What is the sentinel clot sign as described by Specchi et al., VRU 2017? Is it accurate? How does the attenuation compare to peritoneal effusion?

Answer 195

* Highest attenuation hematoma adjacent to a bleeding organ * Accurately localized source of hemoabdomen in the majority of dogs * Clot has a higher HU (43-70) compared to hemoabdomen (20-45)

Question 196

What was a diagnostic limitation for identifying the sentinel clot sign?

Answer 196

* Too little peritoneal effusion

Question 197

Things that are T1w hyperintense

Answer 197

Double fragmented medial coronoid process (FMCP) + N * F - flow-related artifact * F - fat * M - methemoglobinemia * M - melanin * C - cholesterol * C - calcification (iron, copper, manganese) * P - proteinaceous fluid * P - posterior pituitary * N - necrosis

Question 198

Hemorrhage on MRI

Answer 198

* Hyperacute (\<7h) - It B * Acute (7h - 3d) - Id D * Early Subacute - B D * Late Subacute - B B * Chronic - D D

Question 199

Are spinal MCT more likely to be intramedullary, intradural/extramedullary, or extradural? What is the typical distribution?

Answer 199

* All were extradural * Can be epidural, paravertebral, or polyostotic (mimic MM)

Question 200

Which of the following factors were associated with survival of dogs diagnosed with MUE? * Absolute midline shift \<0.3mm * % Midline shift * High CSF total nucleated cell count (TNCC) * Age

Answer 200

* Age * High CSF TNCC Oliphant VRU 2017

Question 201

# Choose the correct statement regarding GFR measurement using 99mTc-DTPA renal scintigraphy: 1. This method provides reliable, precise measurements of GFR with inherent variability of \<0.01 ml/min/kg between scintigraphic studies of the same patient. 2. GFR calculation is not affected by manually drawn ROIs around syringes, provided both pre- and post-injection syringes are accounted for. 3. A value of + 0.4 ml/min/kg has been proposed as a suggested range of inherent variability between GFR studies of the same patient. 4. Renal scintigraphy is the gold standard method for GFR assessment because it provides consistent GFR measures for a given patient, regardless of camera used, isotope, or observer's level of experience.

Answer 201

3. A value of + 0.4 ml/min/kg has been proposed as a suggested range of inherent variability between GFR studies of the same patient. * GFR variability is affected by ROI drawing technique * Renal scintigraphy is gold standard method of GFT, but it is defendent on the observer's level of experience

Question 202

Which of the following statements is correct? (Lee, VRU, 2016) 1. Black blood cine acquisitions are useful to recognize MPA shunting lesion as turbulent flow causes MR signal loss. 2. In human medicine, transcatheter or surgical closure are recommended if Qs/Qp ratio is superior to 1. 3. A persistent left cranial vena cava occurs when the left-sided cranial venous cardinal system fails to evolve into the coronary sinus. 4. Echocardiography is superior to cMRI for evaluating the minimal ductal diameter of a PDA.

Answer 202

3. A persistent left cranial vena cava occurs when the left-sided cranial venous cardinal system fails to evolve into the coronary sinus. * Black blood cine acquisitions are useful; do NOT cause signal loss * Closure is recommended if Qs/Qp ration \>2.0 * MRI is accurate in determining the shunt diameter

Question 203

Which CT findings are statistically different between lipomas and infiltrative lipomas?

Answer 203

* shape * margins * presence and type of hyperattenuating components

Question 204

What CT features were statistically different between benign fatty masses (lipoma and infiltrative lipoma) compared to liposarcoma?

Answer 204

* heterogeneous lesion, with a prevailing soft tissue component * mineralization * regional lymphadenopathy

Question 205

LS neuroforaminal diameter is smallest using which techniques?

Answer 205

Oblique plane, hyperextended position

Question 206

Which ligaments appear heterogeneous in MRI of the tarsal region in non-lame horses?

Answer 206

* Proximal suspensory ligament * Accessory ligament of the DDFT * Dorsal aspect of long plantar ligament

Question 207

When interpreting MRI of the plantar tarsal region in horses, which structure has the most variable appearance? A: DDFT B: SDFT C: Suspensory ligament D: Long plantar ligament

Answer 207

C: Suspensory ligament

Question 208

^99mTc-sulfur * What is it? * What are its indications? * How is it interpreted? * What are its limitations?

Answer 208

* Colloid that localized in the reticuloendothelial system * Given as an IV injection to evaluate for PSS; in dogs with PSS, a significant portion of colloid localizes in the lung * PSS - reduced portal blood flow relative to arterial flow * Limitations * Localization in lung is non-specific for PSS - any hepatic insufficiency will cause the colloid to accumulate in the lung * Cannot be used in cats because lung uptake is normal (resident macrophages)

Question 209

Per-rectal portal scintigraphy * Which radiopharmaceutical is used? * How is it performed? * What is its course in the normal animal? PSS?

Answer 209

* Sodium Petechnetate (Na^{+ 99m}TcO₄^-) * Insert catheter in distal colon to the **level of the pelvic inlet** * Normal - flows to liver and then heart in 8-12 sec * PSS - pertechnetate is seen in the heart before the liver

Question 210

What are limitations of per-rectal portal scintigraphy?

Answer 210

* Cannot characterize shunt morphology * Will not identify dogs with microvascular dysplasia * Portal hypertension can result in poor absorption of pertechnetate from the colon * Large amount of pertechnetate is required to overcome poor absorption in the colon (typically ~15% absorption)

Question 211

Per-rectal portal scinitgraphy SHUNT FRACTION * Normal * Poor or slow absorption * Congenital PSS Bonus: Are shunt practions prognostic for response to surgical intervention?

Answer 211

* Normal - \<5 % * Poor or slow absorption - 15-20% * Congenital PSS - \>60% (usually 80-95%) Shunt fractions have no prognostic significance and will not predict how an animal will respond to surgical intervention

Question 212

What is portal streamlining in per-rectal portal scintigraphy? What are the 3 patterns of distribution?

Answer 212

* Non-uniform distribution of pertechnetate in the liver due to portal vein laminar flow patterns preventing homogenous mixing of the radiopharmaceutical * 3 patterns of distribution: * Dorsal hepatic --\> right divisional branch of PV * Central hepatic --\> central divisional branch of PV * Ventral hepatic --\> left divisional branch of PV

Question 213

What is the main advantage of trans-splenic portal scintigraphy over PRPS?

Answer 213

TSPS permits visualization of shunting vessel(s) in \>90% of cases

Question 214

What are advantages of TSPS over PRPS?

Answer 214

* Better absorption allows for a lower dose of radionuclide * Improved count statistics * Decreased personnel exposure * Allows visualization of shunting vessel(s) and classification by termination site

Question 215

Limitations of trans-splenic portal scintigraphy

Answer 215

* Possible reduced visualization of shunts located caudal to the splenic vein * Does not allow identification of microvascular dysplasia

Question 216

^99mTc-mebrofenin * What are clinical indications? * How does it differ from pertechnetate?

Answer 216

* Used for trans-splenic portal scintigraphy * High first pass extraction by the liver --\> very little should continue beyond the liver into the heart in a normal animal

Question 217

According to Lamb et al. VRU 2017, is this wooden foreign body likely to be acute or chronic?

Answer 217

Acute - gas in soft tissues was significantly associated with acute cases

Question 218

According to Lamb et al. VRU 2017, what are CT features associted with chronic wooden foreign body?

Answer 218

* Visible foreign material * Cavitary lesions * Fat stranding * Periosteal reaction of adjacent bones

Question 219

According to Lamb et al. VRU 2017, what is the sensitivity and specificity of CT for identification of wooden foreign bodies?

Answer 219

* Moderate sensitivity (more false negatives) * High specificity (few false positives)

Question 220

Based on a study evaluating use of single-shot turbo spin echo (SSTSE) MRI sequences of the spine, increased suspicion of later development of progressive myelomalacia may be suggested by: * A: Attenuation of CSF signal for \>12 times the length of L2. * B: Attenuation of CSF signal along dorsal margins of the spinal cord. * C: Attenuation of CSF signal measuring \<7 times the length of L2. * D: Lack of attenuation of CSF signal on SSTSE images.

Answer 220

A: Attenuation of CSF signal for \>12 times the length of L2. \>7.4x length of L2 is suggested cut-off Gilmour VRU 2017

Question 221

What is the optimal portal vein attenuation for maximizing GI wall conspicuity? When is the strongest mucosal surface enhancement seen in the small intestine? Stomach?

Answer 221

* 43-150 HUs * Peak SI mucosal enhancement 30 second * Peak gastric mucosal enhancement is in delayed phase (\>60s)

Question 222

What is the difference between scan field of view (SFOV) and display field of view (DFOV or FOV)? How do they influence resolution?

Answer 222

* SFOV - scanned area where the x-ray beam completely overlaps for 360 degrees; may not be selectable except for GE scanners * DFOV - area of SFOV from which an image is reconstructed; cannot exceed the SFOV * SFOV size has minimal effect on resolution, but DFOV should be kept as small as possible to improve resolution

Question 223

For a 512 x 512 matrix, will a 40cm DFOV or a 15cm DFOV have better resolution? What is the pixel length for each?

Answer 223

* Smaller DFOV has better resolution, so 15cm will be better * Pixel length = DFOV/matrix size * 40/512 = 0.78mm * 15/512 = 0.29mm * Decreasing DFOV below 10cm does not further increase image resolution because of the geometry of the detectors

Question 224

What is a matrix? How does matrix size influence spatial resolution and signal to noise ratio?

Answer 224

* The matrix is the number of pixels used to form an image * The larger the matrix, the smaller the pixels * Smaller pixels result in better spatial resolution, but decreased SNR (because larger matrix with smaller pixels means fewer x-rays pass through each voxel) * 512 x 512 is common in CT * 512 x 512 matrix = 262,144 pixels

Question 225

Calculate to voxel size for a 15cm FOV, 512² matrix, and slice thickness of 2mm

Answer 225

* Voxel size (mm3) = (FOV ÷ matrix) x slice thickness * Example: what is the voxel size for a 2 mm slice thickness imaged with a 512 x 512 matrix over a 15cm FOV? * Voxel size = (150mm2 ÷ 512) x 2 * Voxel size = 0.58mm3

Question 226

In multi-dectector helical CT, what determines the minimal slice thickness possible? What are the advantages and disadvantages of a smaller thickness?

Answer 226

* Acquired slice thickness cannot be narrower than the detector width in MDCT * Advantages: * Decreased volume averaging, so better quality of MPR * Disadvantages: * Decreased signal to noise ratio * Increased patient dose * Longer scan time * May affect tube heat capacity

Question 227

How does an objects inherent contrast affect the slice thickness it should be viewed at?

Answer 227

* Good inherent contrast (i.e., bone, nasal turbinates, lung) is viewed with a wide window setting * Poor inherent contrast (i.e., soft tissue, brain) is viewed with a narrow window setting

Question 228

What is pitch and why is it significant?

Answer 228

* The increment in the z-axis the patient moves during one full gantry rotation * Pitch is directly proportional to image blur * Ex: high pitch --\> blurry image * In MDCT, the increment in the z-axis is discussed in 2 ways: * Collimator pitch * Detector pitch

Question 229

What is the optimal pitch for a good quality reconstruction in a single slice scanner?

Answer 229

* **The optimal pitch is 1.4** * Provides compromise between coverage and detail * Maximum pitch is 2; if the pitch is \>2 --\> skipped data * A pitch smaller than 0.75-1 implies oversampling, longer scan time, and increased radiation dose to the patient

Question 230

What is the **effective dose** for CT of the head, thorax, abdomen/pelvis?

Answer 230

Effective dose * CT head: 2 mSv * CT chest: 8 mSv * CT abdomen/pelvis: 10 mSv

Question 231

What factors influence radiation dose during CT (5)?

Answer 231

Factors that influence dose include: * kVp * mAs * mAs is directly proportional to dose * halve mAs --\> halve the dose, BUT increase noise by the square root of 2 * Scan time * Pitch * indirect relationship * Double the pitch --\> halve the dose * Volume examined * Dose increase linearly

Question 232

In a region with high inherent contrast, what algorithm and window settings would you choose?

Answer 232

* High inherent contrast - bone, lung * Select a sharp algorithm (aka a high frequency algorithm) * Select wide window settings

Question 233

In a region of low inherent contrast, what algorithm and window settings would you choose?

Answer 233

* E.g., soft tissue, brain * Smooth algorithm (aka low-medium frequency algorithm) * Narrow window settings

Question 234

What are window level and window width?

Answer 234

* Window level - central value of the window; should be selected for the HU of the tissue of interest * Window width - range of HU values displayed

Question 235

What window level and width would you select for a lung CT? 1. C = 20, W = 320 2. C = -230, W = 320 3. C = -230, W = 2700 4. C = -600, W = 1600 5. C = -100, W = 1000

Answer 235

C = -600, W = 1600 Average lung attenuation is -950 to -550

Question 236

What window width and level would you select for CT of soft tissue? 1. C = 26, W = 1000 2. C = 100, W = 150 3. C = -50, W = 400 4. C = 45, W = 400

Answer 236

C = 45, W = 400 Averge attenuation of soft tissue is 30-70

Question 237

What window level and width would you select for brain? 1. C = 35, W = 150 2. C = 40, W = 450 3. C = -50, W = 1500 4. C = -500, W = 2000

Answer 237

C = 35, W = 150 Attenuation of brain * White matter - 20-34 * Gray matter - 37-41

Question 238

What window level and width would you select for bone? 1. C = 500, W = 700 2. C = 150, W = 1500 3. C = -500, W = 150 4. C = 450, W = \>1500

Answer 238

C = 450, W = \>1500 Attenuation of bone is \>250

Question 239

What is the optimal window level and width for imaging the pituitary gland?

Answer 239

C = 80, W = 250

Question 240

How does CT appearance of hemorrhage change with phase?

Answer 240

* Resolves from outside in * Peractue (\<3d) - hyperattenuating * Acute (\<1 wk) - hyperattenuating center, hypo- outer ring * Subacute (1-3wk) - ring contrast enhancement * Chronic (\>30d) - isoattenuating +/- contrast enhancement

Question 241

What is the CT appearance of basihyoid thyroid carcinoma (aka sublingual thyroid carcinoma)?

Answer 241

* Oval-to-bilobed masses centered on the basihyoid bone with associated bone lysis * Highly vascularized capsules with central poorly contrast enhancing areas (colloid) * Laryngeal wall infiltration +/- invasion of the laryngeal lumen * +/- metastasis to medial RPLN or lung * 15-62% depending on the study

Question 242

How do the clinical features of basihyoid thyroid carcinoma (aka sublingual thyroid carcinoma) differ from other thyroid carcinomas?

Answer 242

* Younger (7-9 yo depending on study) * Less likely to have metastatic disease * Specificly reported in Broome JVIM 2014 * Generally prolonged survival * Less aggressive biologic behavior

Question 243

What are CT features of muscular metastases? What is the most common location?

Answer 243

* Well-demarcated, oval-to-round or nodular lesions * Isodense to normal muscle in the pre-contrast images * Varying enhancement patterns: * ring-enhancing (n = 16) * heterogeneously enhancing (n = 8) * homogeneously enhancing (n = 5) * Usually multiple lesions * Epaxial/paraspinal musculature \> superficial muscles of thoracic wall

Question 244

What is the incidence of muscular metastases in oncology patients are reported in Vignoli VRU 2013?

Answer 244

* Incidence of 2.1% in dogs * Incidence of 3.1% in cats

Question 245

T/F: Metastatic nodules in the cardiac muscle can appear isodense to muscle pre-contrast and hypodense to muscle post-contrast

Answer 245

True Vignoli VRU 2013

Question 246

T/F: The computed tomographic attenuation properties of hemorrhage are determined by hemoglobin

Answer 246

True

Question 247

T/F: Oxyhemoglobin is diamagnetic and has long T1 relaxation times. This is the predominate form of hemoglobin in hyperacute hemorrhage.

Answer 247

True

Question 248

What is the recommended reconstruction algorithm and window settings to reduce CT metal artifact in a seal gunshot model to improve evaluation of adjacent bone?

Answer 248

* High frequency reconstruction algorithm * Wide to very wide window width * ECTS raw data reconstruction technique

Question 249

T/F: In a seal model for metallic gunshot head trauma, increasing the tube voltage from 120-140 kVp slightly increased the metal artifact magnitude.

Answer 249

True

Question 250

T/F: In a seal model for metallic gunshot head trauma, a proprietary PFO filter reduced metal artifact

Answer 250

False - no significant reduction in metal artifact

Question 251

What is the best diagnostic imaging method for gender determination in lizards?

Answer 251

* Contrast enhanced CT identified hemipenes in all males (100% accuracy) * Contrast was administered into cloaca FYI * Contrast radiography was second best

Question 252

What is the CT appearance of feline nasopharyngeal polyps (pre- and post-contrast)?

Answer 252

* Precontrast * Hypoattenuating to muscle, isoattenuating to soft tissue * Homogeneous * Ill-defined borders * Postcontrast * Rim enhancement, hypoattenuating to soft tissue centrally * Homogeneous * Ovoid with well-defined borders * Expansion of the bulla with wall thickening * Ipsilateral MRPLN enalrgement

Question 253

T/F: There is substantial overlap in the pre- and postcontrast CT features of malignant and nonmalignant hepatic and splenic masses therefore dual-phase CT provides limited specific diagnostic information

Answer 253

True

Question 254

In regards to a study by Jones and Lamb et al. (dual CT characteristics of hepatic and splenic masses), how did the appearance of splenic hematomas differ from nodular hyperplasia and hemangiosarcoma? Are there any similar characteristics between hematomas and hemangiosarcomas?

Answer 254

* Hematoma only had slight contrast enhancement in the early phase whereas hemangiosarcoma and nodular hyperplasia had marked enhancement * Hematoma and (~75%) hemangiosarcomas showed enhancement patterns consistent with blood accumulation

Question 255

Which CT characteristic is best at approximating the true length of canine appendicular osteosarcoma?

Answer 255

* Length of intramedullary/endosteal change * Use submillimeter slice thickness (0.625mm) Both the periosteal reaction length and contrast enhancement length over-estimated by ~10%

Question 256

Which modality is the most useful for identifying wooden foreign bodies in the canine manus?

Answer 256

* CT * Ultrasound evaluations were second, but limited by distal acoustic shadowing of the metacarpal pad * MR is third

Question 257

Which apect of MC3/MT3 in TB horses is predisposed to stress remodeling and fracture?

Answer 257

* Palmar-medial aspect of the condyle

Question 258

What **three** pathologic changes preceed condylar stress fractures of the distal end of MC3/MT3 in Thoroughbred racehorses?

Answer 258

* Subchondral bone sclerosis * Articular cartilage erosion * Cartilage cracking

Question 259

T/F: Subchondral bone changes CT and MRI are significantly correlated with grossly identified articular cartilage loss

Answer 259

True

Question 260

T/F: Signal changes in articular cartilage detected on MRI were not significantly related to cartilage ulceration on gross examination

Answer 260

True

Question 261

T/F: In TBs, condylar stress fractures typically propagate from the palmar/plantar third of the weight-bearing portion of distal MC3/MT3 to the level of the base of the sesamoids

Answer 261

True

Question 262

What are the common locations of equine OC/OCD?

Answer 262

* Tarsocrural joint * Distal intermediate ridge of the tibia (DIRT) * Distal aspect of lateral trochlear ridge of the talus * Medial malleolus of the tibia * Metacarpophalangeal joint (Fetlock) * Distal MC/MT 3 * Stifle * Lateral trochlear ridge of the femur * Distal patella * Medial trochlear ridge of femur * Intertrochlear groove * Shoulder * Caudal glenoid and humeral head

Question 263

T/F: Regarding equine OC/OCD, it is common to have bilateral or quadrilateral lesions or multiple lesions within the same joint, but uncommon to have lesions concomitant lesions in different joints

Answer 263

True

Question 264

What is T1 relaxation?

Answer 264

* Longitudinal relaxation (aka spin-lattice relaxation) * Energy released from protons into the tissue around them (lattice) as they return to resting longitudinal magnetization (z-axis) after the RF pulse is discontinued * T1 time = time it takes for 63% of T1 relaxation to occur * From short to long T1: fat \< white matter \< gray matter \< CSF

Question 265

What is T2 relaxation?

Answer 265

* Tranverse magnetization (aka spin-spin relaxation) * Occurs concurrently, but independent of T1 relaxation * Describes the process of dephasing (protons becoming out of phase from phase coherence) due to proton interactions * Faster than T1 relaxation * T2 time is the time it takes for the protons to de-phase to 37% of original value * From long to short: CSF \> gray matter \> white matter

Question 266

What is time to repetition (TR)? What is time to echo (TE)

Answer 266

Time to repetition (TR) * Time between 2 excitation pulses * Determines T1w of the sequence Time to echo (TE) * Time at which we sample the signal * Initially contrast in tissue is due to varying proton density, but over time it is due to differences in T2 relaxation

Question 267

What sequences does each letter correspond to?

Answer 267

Question 268

What are 3 parameters that define spatial resolution in MRI?

Answer 268

* Field of view (FOV) * Slice thickness * Bandwidth * Slope of gradient magnetic field * Size of the matrix Basically the voxel determines spatial resolution

Question 269

In what order are the gradients used to spatially encode an MRI signal?

Answer 269

* Slice * Phase * Frequency

Question 270

U.S. Food and Drug Administration (FDA) guidelines refer to a magnetic field of __________ as the upper limit where the field strength is of no potential concern for the general public, including persons with implanted electronic devices.

Answer 270

* 5 G (0.0005 T) * A line called the 5-G line is often drawn around the bore to show this limit

Question 271

What is the difference between the following devices? * MR safe * MR unsafe * MR conditional

Answer 271

* MR-safe devices are nonhazardous in all MR imaging environments * MR-unsafe devices are considered to be contraindicated in any MR imaging environment * MR-conditional device is MR imaging–compatible only in specific operating conditions: * main magnetic field strength * maximum magnetic field gradient * maximum specific absorption rate (SAR) * description of the testing conditions

Question 272

The FDA limit for a permissible increase in body temperature during MRI is \_\_\_\_\_\_\_\_\_

Answer 272

1 degree C

Question 273

Energy absorption due to the RF pulse is described in terms of a specific absorption rate (SAR; W/kg). How does SAR change with the following: * Magnetic field strength * Flip angle * Patient size

Answer 273

Specific absorption rate increases with: * Increasing magnet strength * ex., 3T magnet has 9x the SAR of a 1T magnet * Larger flip angle (more time needed) * Bigger patient

Question 274

What is quenching of the magnet? What are possible causes?

Answer 274

Quenching is when the superconductivity of the magnet is lost because of heating Potential causes: * Improper helium filling * Running out of helium * Large ferromagnetic objects * Pressing the emergency button * Can also happen for no apparent reason

Question 275

What is the LEAST likely diagnosis? * Aspiration pneumonia * Canine influenza * NCPE * Interstitial lung disease

Answer 275

Aspiration pneumonia

Question 276

The following are common radiographic features of canine influenza EXCEPT: * Cranioventral interstitial and alveolar pattern * Pleural effusion * Mediastinal lymphadenopathy

Answer 276

Mediastinal lymphadenopathy and widening are not features of canine influenza

Question 277

In MRI, slice selection relies on a gradient magnetic field applied during ______ whereas frequency encoding gradient relies on a gradient magnetic field applied during \_\_\_\_\_\_\_\_

Answer 277

In MRI, slice selection relies on a gradient magnetic field applied during the **RF pulse** whereas frequency encoding gradient relies on a gradient magnetic field applied during **time of sampling (echo time)**

Question 278

Most artifacts occur in the _____ encoding direction because this step takes a long time

Answer 278

Most artifacts occur in the **phase** encoding direction because this step takes a long time * Phase wrap * Motion artifacts

Question 279

How does gadolinium affect T1 relaxation time?

Answer 279

Shortens T1 relaxation time

Question 280

What is the common localization (extradural, intradural/extramedullary, intramedullary) of spinal lymphoma? Multiple myeloma?

Answer 280

* Both are extradural * Other extradural tumors include: * OSA * Fibrosarcoma * Chondrosarcoma * Hemangiosarcoma (can also be intramedullary) * MCT * Carcinoma metastasis

Question 281

What is the localization (extradural, intradural/extramedullary, intramedullary) of peripheral nerve sheath tumors?

Answer 281

Can be any; can start as one and become any of the others

Question 282

What spinal neuroanatomical localization is associated with ipsilateral Horner's syndrome?

Answer 282

C6-T2

Question 283

T/F: Intradural/extramedullary tumors are typically painful whereas intramedullary tumor may be non-painful

Answer 283

True. Intramedullary can be painful if there is expansion of the spinal cord resulting in stretching of nerve roots or compression of the dura

Question 284

What are these vessels? This lesion (thrombus) may result in what pathology and clinical signs?

Answer 284

* A - Deep circumflex iliac artery * B - External iliac artery May result in ischemic myopathy to the hind limb with clinical signs of weakness and paresis

Question 285

This lesion is most likely to be associated with what clinical signs? Bonus: what is this condition?

Answer 285

* Left-sided facial neuropathy * Idiopathic facial neuritis

Question 286

The _____ sequence attenuates signal from fat by exploiting the differences in T1-relaxation times of lipids and water.

Answer 286

STIR sequences offer good conspicuity of fluids and tissues with prolonged T2 relaxation, but suppress any substance with short T1 relaxation, including fat, mucinous or proteinaceous fluid, subacute hemorrhage, and enhancement

Question 287

Chemical ________ exploits the chemical shift (i.e. the difference in the precessional frequencies) of fat and water protons

Answer 287

Fat saturation. * With this technique, a frequency-specific preparation pulse is applied to excite lipid protons selectively, followed by a spoiling gradient pulse that dephases the fat signal. Once the initial fat-specific pulse is produced, the signal generated by the subsequent T1-weighted pulse sequence arises only from nonfatty, short T1 tissues, such as gadolinium-enhancing tissues * Can be used with other types of weighting (T2, PD), which is not true for STIR * Eliminates chemical shift artifact

Question 288

What is the MR appearance of PNST in dogs?

Answer 288

* T2w: hyperintense to muscle, but hypointense to axillary fat * T1w: isointense to muscle * STIR: increased lesion conspicuity * CE: often subtle and heteogeneous * Authors suggest fat suppression may help * Diffuse thickening or nodule/mass (about 50/50) Remember - CT = rim enhancement with hypoattenuating center

Question 289

What position is recommended for MR of brachial plexus PNST?

Answer 289

Dorsal recumbency with symmetrically positioned forelimbs

Question 290

What imaging parameters are recommended for MR of PNST?

Answer 290

* 2 planes minimum * Transverse views provide the vest definition of the mass and nature of spinal cord compression * Sagittal plane - overview of the relationship of the brachial plexus lesion relative to the vertebral canal and thoracic cavity * Dorsal - see lesion, but not helpful beyond that * Large FOV view to see relationship of mass and vertebral column * Smaller FOV of cervicothoracic spine to look for nerve root and foraminal involvement

Question 291

* What is the sensitivity and specificity of TOF MR-angiography for identification of any PSS in dogs? * Which type of shunt (single or multiple) were identified with higher sensitivity and specificity? * What percentage of shunts were identified correctly as intra- or extrahepatic? * What percentage had accurate origin identified? Insertion?

Answer 291

* TOF MRA sensitivity 80%, specificity 100% (no false positives) * Single shunts were identified with higher sensitivity and specificity than multiple shunts * 80% correctly identified as intra- or extra-hepatic * Origin - 55% * Insertion - nearly 100% Seguin VRU 1999

Question 292

MRA was found to be a specific imaging modality for diagnosis of PSS and a sensitive indicator of the anatomic location of single congenital PSS. What is the most useful clinical application of MRA for PSS?

Answer 292

The most useful clinical application of MRA probably resides in patients where the presence of an intrahepatic shunt is suspected Seguin VRU 1999

Question 293

What are benefits of contrast-enhanced MRA over TOF MRA?

Answer 293

* Shorter acquisition time * Better image quality * Provides 3D anatomic detail of the portal vein and its tributaries * Easy to cary out Identified a single PSS in all dogs; they didn't have dogs with multiple and only had one intra-hepatic shunt

Question 294

What are pre- and post-contrast MRI findings in adult horses with septic arthritis?

Answer 294

Pre-contrast * Diffuse hyperintenstiy within bone and extracapsular tissue on FS images * Joint effusion, synovial proliferation, capsular thickening * Bone sclerosis * Cartilage and subchondral damage Post-contrast * Fibrin deposition * Synovial enhancement * Bone enhancement

Question 295

What is the most common MR finding in adult horses with septic arthritis?

Answer 295

Diffuse hyperintensity within bone and extracapsular tissue on fat-suppressed images

Question 296

What are 2 discriminating MR findings between foals with infectious arthritis and foals with non-infectious arthritis?

Answer 296

* Majority of foals with infectious arthritis had osseous lesions compatible with osteomyelitis; none of the foals with non-infectious arthritis had osseous lesions * Majority of foals with infectious arthritis had heterogeneous synovial fluid; non-infectious arthritis had homogeneous synovial fluid

Question 297

Describe the appearance of osseous lesions in foals with infectious arthritis

Answer 297

* Epiphyseal, physeal, or metaphyseal * T2w/PD, STIR hyperintense foci with a hypointense halo * 3D RSSG - entirely hyperintense; no hypointense halo

Question 298

Fatty infiltration of the vertebral bodies occurs most commonly in (***small/large***) breed dogs and tends to be ***(focal/multifocal***)

Answer 298

Fatty infiltration of the vertebral bodies occurs most commonly in **small breed dogs** and tends to be **multifocal**

Question 299

MR findings of irregular endplates, endplate hyperintensity in T2w/STIR, reduced endplate signal in T1w, and endplate contrast enhancement are compatible with: * Discospondylitis * Reactive endplates * Both

Answer 299

Both

Question 300

What are two MR features unique to discospondylitis (compared to other vertebral endplate changes)?

Answer 300

* Contrast enhancement of the paravertebral soft tissue * Contrast enhancement of the disc

Question 301

Reactive endplate changes in dogs have a predilection for ______ disc space. They are associated with __________ and affect ***(older/younger)*** patients.

Answer 301

Reactive endplate changes in dogs have a predilection for **the LS** disc space. They are associated with **intervertebral disc degeneration** and affect **older** patients.

Question 302

What is a Schmorl's node? What is the MR appearance?

Answer 302

* Schmorl's node is an intraosseous disc herniation * Appear as a well-marginated, focal endplate defect contiguous with the disc and contains material isointense to disc material * Localized centrally in the endplate

Question 303

Vertebral osteochondrosis and Schmorl's nodes both appear as an endplate defect. How does the location vary between the two?

Answer 303

* Osteochondrosis - defect in dorsal edge of dnplate with disc-isointense material filling the gap * Schmorl's node - localized centrally

Question 304

What are the 2 most common vertebral endplate changes in dogs?

Answer 304

* Discospondylitis * Fatty infiltration

Question 305

In Carrera et al., characteristic MRI features of discospondylitis are: * Involvement of ______ vertebral body(ies) and the adjacent disc * T1-w \_\_\_\_\_\_\_ * STIR \_\_\_\_\_\_\_ * Contrast enhancement of the \_\_\_\_\_\_\_\_\_\_

Answer 305

* Two adjacent vertebral bodies and the adjacent disc * T1-w hypointensity * STIR hyperintensity * Contrast enhancement of the vertebral bodies, intervertebral disk, paravertebral soft tissues and epidural space.

Question 306

In Carrera et al., variable T2w intensity was seen in the endplates of dogs with discospondylitis. The authors hypothesize that the T2w hyperintensity is associated with **(acute/chronic)** disease and T2w hypointensity is associated with **(acute/chronic)** disease.

Answer 306

In Carrera et al., variable T2w intensity was seen in the endplates of dogs with discospondylitis. The authors hypothesize that the T2w hyperintensity is associated with **acute** disease and T2w hypointensity is associated with **chronic** disease.

Question 307

The most likely diagnosis for the image on the right is? Left?

Answer 307

* Left - sacral osteochondrosis * Right - Schmorl's node (aka intravertebral disc herniation)

Question 308

How does MRI appearance differ between acute and chronic canine distemper virus infection?

Answer 308

Both have T2w hyperintensity: Acute * Cerebellum and brainstem +/- temporal lobes * Loss of of gray-white matter contrast Chronic * Bilaterally symmetric * Cortical gray-white matter junction of parietal and frontal lobes, cerebellar arbor vitae, and pons * Meningeal enhancement

Question 309

Describe the MR appearance of FIP.

Answer 309

* T2w hyperintensity and contrast enhancement of the ventricular ependymal lining, choroid plexus, and meninges * Hydrocephalus is common --\> 4th ventricle especially * +/- periventricular T2w hyperintensity * +/- cerebellar herniation * +/- syringohydromyelia * +/- CSF suppression in FLAIR

Question 310

Common signalment and MR distribution: * GME * NME * NLE

Answer 310

* GME * Young to middle-aged, toy breed dogs * Commonly affects brainstem * Predilection for white matter * Variable CE * NME * Pugs, other small breed dogs * Cerebrum * Variable contrast enhancement * NLE * Yorkshire terrier * Cerebrum and brainstem * Variable contrast enhancement

Question 311

What MR features of astrocytomas and oligodendrogliomas suggest high grade?

Answer 311

* Intratumoral hemorrhage * Contrast enhancement

Question 312

What is the typical MR appearance of ependymomas?

Answer 312

* T1w slightly hypointense to slightly hyperintense * T2w hyperintense * Usually minimal edema * Marked, heterogeneous enhancement * May have cysts or hemorrhage

Question 313

Approximately \_\_\_\_% of choroid plexus tumors arise from the fourth ventricle and lateral apertures

Answer 313

50%

Question 314

Choroid plexus tumors and ependeymomas have many overlapping MR features (variable T1w intenstiy, T2w hyperintense). In what ways do they differ?

Answer 314

* Mild to moderate edema with CP tumors (edema rare in ependymomas) * Marked, homogeneous CE with CP (marked, heterogeneous with ependymomas) CP are more common than ependymomas

Question 315

What is the MR appearance of hepatocellular carcinoma using gadodextate disodium?

Answer 315

* All are hypointense to the surrounding liver parenchyma in 3D T1w GRE images due to impaired hepatocyte function

Question 316

In which MR sequence is artifact caused by metallic material most severe?

Answer 316

* Artifact was most severe in T2\* images * Artifact severity is similar between T2w TSE and T1w images

Question 317

For a symmetric metallic object, the maximal susceptibility artifact occurs parallel to the _____ gradient

Answer 317

For a symmetric metallic object, the maximal susceptibility artifact occurs parallel to the frequency-encoding gradient

Question 318

Which of the following factors does not reduce the metallic artifact size? * Position long-axis parallel to the main magnetic field * Higher static magnetic field strength (B₀) * Higher gradient magnetic field strength * Increase frequency-encoding bandwidth * Select larger matrix size * Decrease FOV

Answer 318

* Position long-axis parallel to the main magnetic field * **Lower** static magnetic field strength (B₀) * Higher gradient magnetic field strength * Increase frequency-encoding bandwidth * Select larger matrix size * Decrease FOV

Question 319

A 10-year-old Samoyed presents with a right sided Zurich-type (titanium) total hip arthroplasty and a clinical suspicion of lumbosacral intervertebral disc disease. What would be the best advice be regarding the utility of MRI T2w turbo spin echo and T1-weighted spin echo images at 1.5T for the imaging of the lumbosacral junction? * A: Signal voiding from the implants will likely obscure the lumbosacral region. * B: Images of the lumbosacral region should be possible but there will likely be distortion of the anatomy that will reduce the diagnostic quality of the study. * C: The implants are unlikely to impact the diagnostic quality of the study. * D: There is a moderate risk of implant movement from the main magnetic field and an alternative imaging modality should be selected.

Answer 319

C: The implants are unlikely to impact the diagnostic quality of the study. Titanium total hip implants were characteriz ed by up to 70% less signal voiding and image distortion than an equivalent stainless-steel total hip implant

Question 320

Rank the following metals from most likely to cause artifact to least likely: * Steel objects * Surgical stainless steel * Lead * Titanium

Answer 320

Steel \> surgical steel \> titaniun \> lead

Question 321

What is the common MR appearance of thiamine deficiency in cats?

Answer 321

* Bilaterally symmetric, T2w and FLAIR hyperintensity * Non-contrast enhancing * Locations * Lateral geniculate nucleus * Caudal colliculus * Facial nuclei * Medial vestibular nucleus * Resolve with supplementation

Question 322

Which MR sequences provide the most diagnostic information regarding acute (\<48h) head trauma in dogs?

Answer 322

T2w and FLAIR

Question 323

What MR features of acute head trauma in dogs were associated with high mortality rate, major persistent neurological deficits, or need for surgical intervention?

Answer 323

* Caudal fossa involvement * Marked midline shift

Question 324

Following acute head trauma, fontanelle herniation is associated with a **(good/poor)** outcome

Answer 324

Good

Question 325

What is the most common location of intracranial hemorrhage following acute head trauma in dogs? Where is the largest accumulation of hemorrhage?

Answer 325

* Most common location - subdural * Largest accumulation - epidural

Question 326

How does hemoglobin change over time?

Answer 326

* Hyperacute (\<7h) - oxyhemoglobin * Acute (7h to 3d) - deoxyhemoglobin * Early Subacute (3d to 7d) - central methemoglobin * Late Subacute (7d to 3w) - central and peripherla methemoglobin * Chronic (\>3w) - hemosiderin

Question 327

Rank the following from highest ADC value to lowest ADC value: * Meningioma * Glial cell tumor * Acute non-hemorrhagic infarct * Chronic non-hemorrhagic infarct * Pituitary tumor

Answer 327

Smallest ADC --\> highest ADC * Acute non-hemorrhagic infarct * Pituitary tumor * Glial cell tumor * Chronic non-hemorrhagic infarct * Meningioma There is a wide range and overlap of ADC value within the disease groups --\> unlikely that singular quantitative ADC values can be used to determine the histological type of canine intracranial disease

Question 328

* What is the most common location of GIST? * What ultrasonographic finding was associated with GIST? * Where is the most common site of metastasis?

Answer 328

* Common location - Cecum * Abdominal effusion seen with GIST more commonly than other smooth muscle tumors * Mets to liver

Question 329

Which of the following MRI system specifications offers the greatest potential for high image quality and fast image acquisition. * A: 1.5T superconducting magnet, gradient amplitude 33 mT/m, gradient slew rate 170 T/m/s * B: 1.5T superconducting magnet, gradient amplitude 34 mT/m, gradient slew rate 150 T/m/s * C: 1.5T superconducting magnet, gradient amplitude 45 mT/m, gradient slew rate 200 T/m/s * D: 1.5T superconducting magnet, gradient amplitude 33 mT/m, gradient slew rate 125 T/m/s

Answer 329

C: 1.5T superconducting magnet, gradient amplitude 45 mT/m, gradient slew rate 200 T/m/s

Question 330

This image of a stifle is an example of application of a look up table (LUT) during acquisition, rather than post-processing. The resulting artifact is known as: * A: Clipping * B: Saturation * C: Uberschwinger * D: Quantum mottle

Answer 330

A: Clipping

Question 331

Regarding radiographic diagnosis of pleural effusion, no significant difference in diagnosis and grade of pleural effusion were seen between views, although the _______ had both the highest rate of detection and grade of severity.

Answer 331

left lateral HB

Question 332

Which radiographic views were best for best for detection and gradation of pneumothorax?

Answer 332

* Right and left lateral horizontal beam * Left lateral vertical beam RIGHT LATERAL HB IS BEST!!!

Question 333

What layers of the hoof capsule are represented by the markers on thefollowing radiograph? (Goulet et. al, VRU, 2016) * A: Stratum externum * B: Stratum medium and stratum internum * C: Stratum internum * D: Stratum internum and Dermis parietis

Answer 333

D: Stratum internum and Dermis parietis

Question 334

At what number of days pre-partruition can you first identify fetal mineralization radiographically in cats? (10.2460/javma.2003.223.1614) * A: 10-14 days * B: 18-22 days * C: 25-29 days * D: 35-39 days

Answer 334

C: 25-29 days Cat gestational length: 58-67 days

Question 335

At what number of days pre-partruition can you first identify fetal mineralization radiographically in dogs? * A: 10-14 days * B: 18-22 days * C: 25-29 days * D: 35-39 days

Answer 335

B: 18-22 days Dog gestational length: 58-68 days

Question 336

What is the ratio of iodine to osmotically active particles for the following iodinated contrast agents? * Diatrizoate (Gastrografin) * Iopamidol (Isovue) * Ioxoglate (Hexabrix) * Iotralan (Isovist)

Answer 336

* Diatrizoate (Gastrografin) * Ionic monomer * Iodine to osmotic particles= 3:2 * Iopamidol (Isovue) * Non-ionic monomer * Iodine to osmotic particles= 3:1 * Ioxoglate (Hexabrix) * Ionic dimer * Iodine to osmotic particles= 6:2 (aka 3:1) * Iotralan (Isovist) * Non-ionic dimer * Iodine to osmotic particles= 6:1

Question 337

What are two non-ionic, dimer iodinated contrast agents?

Answer 337

* Iotralan * Iodixanol

Question 338

What is the ionic, dimeric iodinated contrast agent?

Answer 338

Ioxoglate (Hexabrix)

Question 339

What sonographic findings are suggestive of feline cholangitis?

Answer 339

* Hyperechoic liver parenchyma * Hyperechoic gallbladder contents * Increased pancreatic size

Question 340

T/F: Most cats with cholangitis had sonographically normal liver size, echogenicity, and normal biliary systems

Answer 340

True

Question 341

What is the most common US abnormality in dogs with renal lymphoma?

Answer 341

Pyelectasia Other abnormalities * loss of corticomedullary distinction * renomegaly * renal deformity * renal nodules/masses hypoechoic or hyperechoic * often bilateral

Question 342

Which factors were associated with survival of dogs with PV thrombosis? Non-survival?

Answer 342

Survival * Treatment with anticoagulant therapy Non-survival * Acute PVT * Multiple thromboses * SIRS

Question 343

What are the most common radiographic findings in dogs with intrathoracic histiocytic sarcoma?

Answer 343

* Lymphadenopathy (TB and sternal \> cranial mediastinal) * Pulmonary masses * Right middle is most common location * Can have multiple pulmonary nodules

Question 344

What is the least common radiographic finding in dogs with intrathoracic histiocytic sarcoma?

Answer 344

Pleural effusion

Question 345

What four factors are associated with survival in dogs with non-tonsillar oral SCC?

Answer 345

* intraoral location * listed in descending survival time: rostral \> caudal \> rostral and caudal) * tumor recurrence (no \> yes) * relative portal size (less than 100 cmz/mz \> greater than or equal to 100 cmz/m2) * age at diagnosis * less than or equal to 6y \> greater than 6y

Question 346

In dogs with pharyngeal neoplasia, which lymph nodes were most frequently affected with metastasis? What CT appearance suggests metastasis?

Answer 346

* Medial retropharyngeal LNs * CT appearance * marked enlargement * rounded shape * heterogeneous enhancement

Question 347

T/F: CT features of pharyngeal neoplasms in the dog overlap and therefore CT cannot differentiate types of neoplasia

Answer 347

True

Question 348

What is the function of a gamma camera collimator?

Answer 348

Collimator filters photons --\> only allows gamma photons that travel perpendicular to the collimator to be accepted. Those travelling at an angle will hit the septum (usually lead), be absorbed and, therefore, not contribute to the image.

Question 349

* What type of gamma camera collimator is this?

Answer 349

* Parallel hole * Most common

Question 350

What type of gamma camera collimator is this?

Answer 350

Diverging hole - allows a minified image

Question 351

What type of gamma camera collimator is this?

Answer 351

Pin-hole = single-hole collimator for magnifying images of small objects

Question 352

What type of gamma camera collimator is this?

Answer 352

Converging hole - magnifying the image

Question 353

What is the importance of septal thickness for a gamma camera collimator? What type of thickness/energy would you need for ^99mTc? What about ¹³¹I?

Answer 353

* Septal thickness must increase as photon energy increases to ensure maximum absorption of photons that hit the septae at an angle * Parallel hole collimators are classified as * Low energy = thin septae (0.3mm) = ^99mTc (150 keV) * Medium energy = 1mm = ¹³¹I (400 keV) * High energy = thick septae (2mm) = ¹⁸F

Question 354

A Low-Energy All-Purpose (LEAP) collimator is an example of what type of gamma camera collimator

Answer 354

Parallel hole collimator

Question 355

How are resolution and sensitivity of a NM image affected by increased patient to collimator distance for the following collimators: * Parallel hole Collimator * Pinhole Collimator

Answer 355

Influence of increased patient to collimator distance: * Parallel hole * Decrease resolution * No effect on sensitivity * Pinhole * Resolution and sensitivity decrease

Question 356

Ultrasound of equine forelimb: * Where is the image acquired? * Label the anatomy

Answer 356

* Level of proximal MC3

Question 357

Ultrasound of equine forelimb: * Where is the image acquired? * Label the anatomy

Answer 357

* Level of proximal P1

Question 358

Ultrasound of equine forelimb: * Where is the image acquired? * Label the anatomy

Answer 358

* Middle third of P1

Question 359

Label the anatomy

Answer 359