Diagnostic imaging

Question 1

For thoracic radiographs, a ___-___% change in diagnosis was found when only 2 views were obtained. ____ and ___ views are more sensitive.

Answer 1

• 12-15%
• VD and right lateral

Question 2

For target lesions, the PPV for malignancy is ___% when a single nodule is found in liver or spleen on ultrasound. The PPV is ___% if more than one lesion is found.

Answer 2

PPV 1 target lesion: 74%
PPV >1 target lesion: 81%

Question 3

Contrast-enhanced US improves detection of small blood vessels compared with power doppler imaging because ____________.

Answer 3

reduced motion artifact

Question 4

Second generation contrast-enhanced US agents contain _______ or ______ within microbubbles. The microbubbles are generally ____, resulting in an intravascular agent that has the flow pattern similar to ___________ and therefore can demonstrate the presence of ________ and can assess arterial, portal, and late phases in the liver.

Answer 4

• perfluorocarbon or sulfur hexafluoride
• <2.5um
• red blood cells
• blood vessels

Question 5

In both the liver and spleen, a nodule that remains _____ in both early vascular phase and late vascular phase in contrast-enhanced US is more commonly seen with malignant lesions.

Answer 5

hypoechoic

Question 6

In both the liver and spleen, a nodule that becomes ____ to surrounding parenchyma in both early vascular phase and late vascular phase is most often benign.

Answer 6

isoechoic

Question 7

For elastography, hard tissues are typically displayed in _____ to _____ colors and soft tissues are displayed in _____ to ____ colors. Tissue stiffness tends to ____ with disease.

Answer 7

• hard: yellow to red
• soft: green to blue
• increase

Question 8

The most common complications of percutaneous lung biopsy are _______ and ______.

Answer 8

pulmonary hemorrhage and pneumothorax

Question 9

Hemorrhage associated with ultrasound-guided sampling occurs in ____% and is self-limiting in all but ___%

Answer 9

• <6%
• 1%

Question 10

The first generation contrast-enhanced US agents were ______________.

Answer 10

air within microbubbles

Question 11

A paper evaluating ultrasound-guided biopsy and FNA of abdominal structures was performed. Of the 233 biopsy specimens, ___% were considered to be of adequate quality for histologic interpretation. ___% of 70 specimens obtained by fine-needle aspiration correlated with the final diagnosis made during surgical exploration or at necropsy.

Answer 11

• 97%
• 84%

Question 12

Thin - slice images in CT will have an ______ that can be offset by increasing mAs setting.

Answer 12

increased noise

Question 13

Keeping the scan field of view only as large as anatomy to be imaged will improve _________.

Answer 13

spatial resolution

Question 14

CT has decreased _______ compared to radiographs but superior __________ due to reduction in superimpostion.

Answer 14

• decreased spatial resolution
• superior contrast resolution

Question 15

Accuracy for detecting tracheobronchial lymphadenopathy for CT was ___% compared to ____% for radiographs. Sensitivity was _____% for CT and ____% for radiographs.

Answer 15

CT
- accuracy: 93%
- sensitivity: 83%

Radiographs
- accuracy: 57%
- sensitivity: 0%

Question 16

In people, the high sensitivity of CT also results in detection of more benign lesions with nodules ______ infrequently developing into metastasis.

Answer 16

< 5 mm

Question 17

Ground-glass pulmonary lesions are also referred to as ________.

Answer 17

subsolid nodules

Question 18

About ___% of dogs (mostly with OSA) with ground glass lesions went on to develop radiographically visible metastasis in one pilot study.

Answer 18

75%

Question 19

Up to ___% of ground glass pulmonary lesions are caused by transient inflammation or hemorrhage.

Answer 19

70%

Question 20

Pure ground-glass lesions ______ have a high probability of malignancy. Those ____ are considered benign.

Answer 20

• > 8mm
• <4mm

Question 21

CT angiography can improve detection of small tumors, such as ____, and may be a more accurate assessment of _____ and _______ masses.

Answer 21

• insulinoma
• thyroid and cranial mediastinal masses

Question 22

CT is used for RT planning because it provides a map of ________ information that is used by most planning computers to calculate dose distribution.

Answer 22

electron density

Question 23

CT is more sensitive than radiographs in the detection of pulmonary metastasis and allows for detection of nodules as small as _____ in diameter compared with ______ for radiography

Answer 23

• 1mm
• 7-9 mm

Question 24

A study of _____ showed no difference in evaluation of peritumoral lesions between CT and MRI.

Answer 24

FISS

Question 25

_____ MRI images provide good spatial resolution to assess anatomy and are used with contrast to show vascular enhancement of tissues.

Answer 25

T1-weight images

Question 26

____ MRI images are water-weighted sequences that provide high-contrast images of water-dense pathology.

Answer 26

T2-weighted images

Question 27

On BOTH T1 and T2-fast spin echo sequences on MRI, ____ has a high signal intensity (bright) that can mask the margins of pathology.

Answer 27

Fat

Question 28

The use of fat suppression techniques on T1 post-contrast and T2 images is important in cancer imaging to allow for clear assessment of the extent of pathology. _______ is a fat suppression technique.

Answer 28

STIR

Question 29

___________ measures the random Brownian motion of water molecules in a voxel of tissue on MRI.

Answer 29

Diffusion-weighted imaging

Question 30

_________- provides similar results to PET/CT in people with diffuse B-cell LSA. Images are suboptimal for ________.

Answer 30

- Diffusion-weighted imaging MRI - skeletal system

Question 31

Hepatocyte-specific MR agents, such as ______, accumulate in normal hepatocytes, potentially allowing for differentiation between benign liver nodules and metastatic lesions.

Answer 31

gadoxetate disodium

Question 32

Nuclear scintigraphy has low _______, lacks ____, and is highly sensitive for _______.

Answer 32

- low spatial resolution - lacks specificity - increased metabolic activity

Question 33

Radiographs require at least ___-___% change in mineral density for bone lesions to be detected.

Answer 33

30-50%

Question 34

The most commonly used radiopharmaceutical for PET/CT is ______, which is a glucose analog.

Answer 34

F18-FDG

Question 35

FDG is transported into hypermetabolic cells and becomes trapped after phosphorylation by _____ as it is not a suitable substrate for _______. Positrons emitted from F-18 create _________ that travel 180 degrees from each other and allows for imaging.

Answer 35

- hexokinase - glucose-6-phosphatase - two annihilation photons

Question 36

_____ is a bone specific radiopharmaceutical for PET/CT that has been shown to be superior in detecting bone metastasis compared to _______.

Answer 36

- F-18 NaF - SPECT imaging with Tc99m-methyl diphosphonate

Question 37

_____ is thymidine analog used to detect proliferating tissues in PET/CT. It reflects _________.

Answer 37

F-18 FLT DNA synthesis

Question 38

PET/CT functional imaging of tumor hypoxia using dogs with nasal tumors injected with _______ has been performed for radiation boost planning.

Answer 38

Cu-ATSM

Question 39

The ________ of normal tissues must be known to accurately interpret PET images.

Answer 39

baseline metabolic rate

Question 40

_______ is a semiquantitative measure of FDG uptake that is directly proportional to metabolic activity.

Answer 40

- standardized uptake value (SUV)

Question 41

In humans, an SUV max ____ is predictive of malignancy in patients with solitary pulmonary nodules.

Answer 41

> 2.5

Question 42

What PET/CT radiopharmaceutical was shown to correlate with grade of mast cell tumors in a small group of dogs?

Answer 42

F-18 FDG

Question 43

CT assessment of sternal LNs suggest a sternal LN to second vertebrae ratio of ____ and a pre-contrast attenuation of _________ is highly predictive of malignancy.

Answer 43

- >1 - 37.5 HU or higher

Question 44

A change in change of a LN from ______ to ______, as indicated by a short axis-to-long axis ration of ____, and loss of definition of the ____ is seen more frequently in malignant LNs.

Answer 44

- oval to round - >0.7 - LN hilus

Question 45

Use of _______ contrast medium in lymphangiography results in retention of the agent in LN for up to ____ after injection, which can aid in follow-up LN assessment. Contrast voids are consistent with new metastatic lesions.

Answer 45

- iodized oil - 2 months

Question 46

__________ is superior at identifying intramedullary margins on MRI in dogs with appendicular OSA.

Answer 46

T1-weighted non-contrast images

Question 47

SPECT detects ____ emissions for Technetium 99m.

Answer 47

gamma

Question 48

Preoperative helical contrast CT was evaluated in hepatic lesions. What findings were consistent with HCC, nodular hyperplasia, and metastatic liver lesions?

Answer 48

HCC - heterogenous; hyper-, iso-, and hypoenhancement in both arterial and portal venous phases (85%) Nodular hyperplasia - homogenous; hyper- and isoenhancement in both portal venous and delayed phases (93%) Metastasis - homogenous; hypoenhancement in both arterial and portal venous phases (89%); 55% also had homogenous hypoenhancement in delayed phase

Question 49

What has been used with PET/CT for the detection of response to cytotoxic chemotherapy in dogs with non-Hodgkin's LSA?

Answer 49

F-18 FLT

Question 50

What is the MOA of nitroimidazole-like uptake for PET/CT and tissue hypoxia?

Answer 50

reduction of RNO2 radicals and RNHOH compounds in hypoxic conditions then covalent binding to macromolecules

Question 51

What is the MOA of Cu-ATSM in PET/CT and tissue hypoxia?

Answer 51

reduction of Cu(II)-ATSM complex into Cu(I)-ATSM and dissociation of Cu(I) in hypoxic conditions, then Cu(I) binding to intracellular proteins

Question 52

[124I]-cG250 and [89Zr]-cG250-F(ab’)2 recognizes _______ in PET/CT.

Answer 52

carbonic anhydrase IX

Question 53

18-F has a half-life of _____.

Answer 53

110 minutes

Question 54

_______ is a PET/CT tracer that detects in vivo activity of aromatic 1-amino acid decarboxylase of the dopaminergic system and is used to detect neuroendocrine tumors and Parkinson-related disorders

Answer 54

18F-fluoro-L-DOPA

Question 55

______ is a PET/CT tracer that is a precursor of biosynthesis of an essential element of phospholipids of the cell membrane. It is used to detect well differentiated tumors with low glucose uptake (ie, prostate cancer).

Answer 55

11C-Choline

Question 56

________ is a PET/CT tracer that is a structural analogue of 5-a-dihydrotestosterone that can be used to detect metastatic and recurrent prostate cancer.

Answer 56

F18- FDHT

Question 57

_____ is a PET/CT tracer that is a metabolic substrate for synthesis of cholesterol and lipids with renal clearance. It is used to detect prostate cancer and renal tumors

Answer 57

11C-Acetate

Question 58

What is the MOA of the PET/CT tracer, F-18 NaF?

Answer 58

Fluoride ion is switched with the hydroxyl group in the bone crystals forming fluoroapatite, thus where bone turnover is greatest, there are high deposits

Question 59

_____ is a PET/CT tracer that is an important amino acid for the protein synthesis process that does not accumulate in normal brain tissue, thus it have been most useful for detecting brain tumors

Answer 59

18C-Methionine

Question 60

The dominant signal intensities of T1-weighted images are as follows: - Fluid: - Muscle: - Fat: - Grey matter: - White matter:

Answer 60

- Fluid: low signal (black) - Muscle: intermediate signal (grey) - Fat: high signal (white) - Grey matter: intermediate (grey) - White matter: hyperintense compared to grey matter (white-ish)

Question 61

______ MRI images are good to evaluate borders between brain and CSF and BBB disruption.

Answer 61

T1-weighted images

Question 62

_______ MRI images are used to distinguish soft tissues.

Answer 62

T2-weighted images

Question 63

The dominant signal intensities of T2-weighted images are as follows: - Fluid: - Muscle: - Fat: - Grey matter: - White matter:

Answer 63

- Fluid: high signal (white) - Muscle: intermediate signal (grey) - Fat: high signal (white) - Grey matter: intermediate (grey) - White matter: hypointense compared to grey matter (dark-ish)

Question 64

How is FLAIR different than T2-weighted images? Most pathology is _______ and what is it good for?

Answer 64

- free CSF is suppressed --> black - bright - good for lesions near ventricles and sucli and sometimes improves white/grey matter distinction

Question 65

Dural tail is seen in ___% of cases of meningioma but is not specific. Bone changes, such as osteolysis and hyperostosis occur in ___%.

Answer 65

72% 20%

Question 66

Describe intensities on MRI for meningioma.

Answer 66

T1: isointensity to slight hypointensity relative to grey matter T2: isointensity to slight hyperintensity relative to grey matter Contrast (Gd): avid, homogenous enhancement

Question 67

What is the appearance of myelofibrosis and mastocytosis in bone marrow on MRI and why?

Answer 67

Leads to sclerosis so very dark marrow on both T1 and T2 series