Diagnostic

Question 0

Dissection types?

Answer 0

Stanford A: involves the ascending aorta
Stanford B: involves only the descending aorta

De-Bakey type 1: ascending and descending
De-Bakey type 2: only ascending aorta
De-Bakey type 3: only descending aorta

Question 1

TB: CXR pattern with primary? Reactivation?

Answer 1

Primary: segmental consolidation, hilar adenopathy or a miliary pattern.

Reactivation: Upper lobe infiltrate with cavitation and scarring.

Question 2

Aneurysmal dilation of the aorta?

Answer 2

> 5 cm in diameter in the ascending aorta,
4 cm in the descending thoracic aorta,
3 cm in the abdominal aorta as measured by cross-sectional imaging (CT, MRI, or TEE).

The average normal aortic width is 3.5 cm in the ascending aorta, 2.5 cm in the aortic arch, and 2 cm in the descending thoracic aorta.

Question 3

Abnormal small bowel diameter on abdominal radiograph?

Differentiating SBO from ileus?

Answer 3

3 cm

Ileus is more diffuse.

SI dilation in setting of SBO occurs upstream from site of mechanical obstruction.

Question 4

Sentinel loop?

Answer 4

Aka localized ileus. When a single dilated air-filled loop of bowel is located near an intra-abdominal inflammatory process.

Question 5

Ogilvie’s syndrome?

Answer 5

Idiopathic colonic ileus (no underlying cause such as an electrolyte disturbance or neurological disorder).

Question 6

The radiographic principle of small bowel obstruction— dilation of bowel proximal to the obstruction and collapse of distal bowel—often does not pertain to LBO. There are three reasons?

Answer 6

First, large bowel that is distal to an obstruction often does not collapse due to retention of fecal matter.

Second, the distribution of air in the segments of the colon is determined more by anatomical location than by whether it is proximal or not there is an obstruction. For example, the transverse colon has an anterior location and tends to fill with air on a supine radiograph, whereas the descending colon is posterior and therefore fills with fluid, which makes the assessment of dis- tention difficult.

Third, the rectum is the most dependent por- tion of the bowel and is usually fluid-filled and not radi- ographically visible irrespective of whether it is distended or collapsed.

Question 7

Cecal volvulus?

Answer 7

Cecal volvulus: 25–40% of cases of large bowel volvulus, younger pts 40-60, due congenital incomplete fixation of the cecum to the posterior peritoneum.

Question 8

Sigmoid volvulus?

Answer 8

Sigmoid volvulus: accounts for 60–75% of cases of large bowel volvulus, occurs in older individuals who have developed an elongated redundant sigmoid colon with a narrow mesenteric base.

Question 9

The key radiographic finding that distinguishes a distal large bowel obstruction from adynamic ileus?

Answer 9

Disproportionate distention of the cecum with LBO because it is the segment of the colon with the greatest diameter and in accordance with Laplace’s law regarding distensible tubular structures, the bowel segment with the greatest diameter has the greatest wall tension and therefore tends to become most distended.

Question 10

How to exclude LBO in chronically bed-bound patients with recurrent adynamic ileus?

Answer 10

A simple imaging technique in which patient is placed in a prone position so that the rectum will fill with air if it is not obstructed. Visualized by a cross-table lateral radiograph of the rectal area.

Question 11

Toxic megacolon on abdominal XR?

Answer 11

AXR shows colonic distention, loss of haustral markings, and mucosal nodules due to focal bowel wall edema, hemorrhage, and pseudo-polyps (areas of intact mucosa surrounded by areas of deep ulceration).

Question 12

How long is free air seen following abdominal surgery?

Answer 12

3-7 days (may persist for 2-3 weeks)

Question 13

Intussusception

Answer 13

MCC of intestinal obstruction in children between the ages of 6 months and 2 years.

Radiographic findings are different from those of mechanical SBO.

Triad: pain, vomiting, bloody stools (“currant jelly”).

Children: ileocolic most often post viral infection. Adults usually have lead point.

Question 14

Fracture search pattern?

Answer 14

ABCs
Alignment
Bone
Cartilage/joint space
Soft tissues

Question 15

T/F: The posterior fat pad of the elbow is not normally visible.

Answer 15

True

Question 16

T/F: Elbow fat pad signs can also caused by nontraumatic elbow effusions such as infectious and inflammatory arthritides?

Answer 16

True

Question 17

Essex-Lopresti

Galeazzi

Monteggia

Answer 17

Essex-Lopresti fracture-dislocation: comminuted fx of radial head with DRUJ.

Galeazzi fracture-dislocation: radial shaft fx with DRUJ.

Monteggia fracture-dislocation: ulna shaft fx and dislocation of the radial head. **Radial head dislocation often overlooked.

Question 18

Three distinctive elbow injuries in children?

Answer 18

Supracondylar fractures: anterior humeral line

Lateral condylar fractures: radiocapitellar line

Medial epicondylar avulsion fractures: CRMTOL

Question 20

Anterior Humeral Line?

Answer 20

The anterior humeral line is a feature of alignment seen on the lateral view. A line drawn along the anterior cortex of the humeral shaft should intersect the middle third of the capitellum. The capitellum is the rounded ossification center of the distal humerus that articulates with the radial head.

Question 21

Radiocapitellar line?

Answer 21

The second elbow alignment feature is the radiocapitellar line. A line drawn along the shaft of the radius should intersect the middle of the capitellum. This alignment should be present in both the AP and lateral views.

Useful in detecting the second most common fracture about the elbow in children, a lateral condylar fracture.

Intact with supracondylar fractures.

Question 22

Medial epicondyle avulsions?

Answer 22

The fat pad sign is not present in most cases because the injury is extra-articular.

Question 23

How to Interpret Elbow Radiographs in Children?

Answer 23

1. Two views properly performed: AP and Lateral (elbow flexed to 90 and not rotated)
2. Fat pad signs: may need to lighten image to see
3. Three features:
   A. Anterior humeral line
   B. Radiocapitellar line
   C. Ossification centers—correct location and
   sequence of appearance based on child’s age
4. Three injuries
   A. Supracondylar fracture (Anterior humeral line)
   B. Lateral condylar fracture (Radiocapitellar line)
   C. Medial epicondylar avulsion fracture
   (also, radial head fracture in older children)

Question 24

Frequency of Carpal Injuries?

Answer 24

Scaphoid ~60%
Triquetrum ~20%
Perilunate injuries ~20%
Other ~1%

Also consider:

• Distal radial fxs
• fxs at the bases of the MC.
• DRUJ (ulnar styloid posterior to triquetrum on lateral)

Question 25

Wrist fxs by age?

Answer 25

In children, the growth plate and distal radial metaphysis are the weakest elements and so growth plate (Salter-Harris) fractures and meta- physeal torus (buckle) fractures are most common. In young adults, the distal radius is relatively strong, and so scaphoid fractures and other carpal injuries are more likely. In the elderly with osteoporosis, the distal radius is again the most vulnerable part.

Question 26

Colles fracture?

Answer 26

Distal radial metaphyseal fx with dorsal displacement of fx fragment (fx w/in 1.5" of the distal end of the radius)

Question 27

Smith fracture?

Answer 27

Distal radius fx with volar displacement of distal fragment.

Question 28

Posterior Shoulder Dislocations? AP view findings?

Answer 28

1. Diminished overlap of the humeral head and glenoid fossa (nl glenohumeral overlap is 6 mm or less between the edge of the humeral head and the anterior rim; widened with posterior dislocation) 2. Humeral head fixed in internal rotation (external rotation view cannot be obtained). The humeral head is impacted against the posterior rim of the glenoid fossa, and this prohibits external rotation of the shoulder. The humeral head in internal rotation has a spherical appearance because the greater tuberosity is seen “en-face.” These two findings, internal rotation of the proximal humerus plus diminished overlap with the glenoid fossa, give the proximal humerus in a posterior dislocation its characteristic appearance—a “light bulb on a stick.” (Others see an ice cream cone with a scoop of ice cream.) 3. Trough line: Impacted fracture of the anterior surface of the humeral head that occurs when it impacts upon the posterior rim of the glenoid fossa. Seen as a vertical line parallel to the glenoid rim. Aka: “reverse Hill-Sachs deformity” because it is analogous to the Hill-Sachs deformity (an impacted fracture of the posterior aspect of the humeral head seen with an anterior shoulder dislocation).

Question 29

If humeral head fx, must rule out dislocation. Get axillary or Y view.

Answer 29

True

Question 30

What is the most common fracture associated with an anterior shoulder dislocation (not including Hill Sachs deformities)?

Answer 30

Avulsion of the greater tuberosity at the attachment of the supraspinatus tendon. Occurs in 5-19% (increased incidence in older pts).

Question 31

What is a pseudo-dislocation of the shoulder?

Answer 31

In a patient with a proximal humerus fracture, a hemarthrosis can distend the joint capsule and displace the humeral head from the glenoid fossa. AP: inferior displacement can mimic dislocation of the glenohumeral joint. Y-view or axillary view may be needed to show that the humeral head is still in alignment within the gle- noid fossa.

Question 32

Pediatric ossification centers?

Answer 32

Capitellum: 1y Radial head: 3y Medial epicondyle: 5y Trochlea: 7y Olecranon: 9y Lateral epicondyle: 11y

Question 33

Maisonneuve fracture?

Answer 33

Unstable fx of medial malleolus and/or disruption of the distal tibiofibular syndesmosis along with a fracture of the proximal fibula shaft.

Question 34

Relative Frequencies of Various Fractures About the Knee in Adult ED Patients?

Answer 34

``` Patella 40% Tibial plateau 32% Fibular head 9% Distal femur 8% Tibial spine 7% Tibial tuberosity 2% Osteochondral junction (articular cartilage) fracture 1% ```

Question 35

The Most Frequently Overlooked Radiographically Apparent Fractures in an ED?

Answer 35

``` Tibial plateau 16% Radial head 14% Elbow—child 14% Scaphoid 13% Calcaneus 10% Patella 6% Ribs 4% ```

Question 36

Blood supply to the femoral head?

Answer 36

Circumflex artery encircles base of femoral neck just outside the insertion of the joint capsule. Ascending cervical ascends along femoral neck. Epiphyseal arteries supply femoral head.

Question 37

Proximal femur fxs?

Answer 37

Femoral neck: subcapital, trans cervical and basicervical. Intertrochanteric Subthrochanteric

Question 38

When does bone scan become positive for fracture?

Answer 38

3-5 days following injury.

Question 39

Sonographic signs of a foreign body are:

Answer 39

A bright echogenic focus representing the foreign body itself, An acoustic shadow deep to the foreign body, A hypoechoic rim surrounding the foreign body due to soft tissue edema and exudate.

Question 40

Four signs of unilateral facet dislocation?

Answer 40

Bowtie: Abrupt rotation causes the articular masses to lie adjacent to one another rather than overlap. Compare to the subjacent vertebrae. Abrupt narrowing of the “laminar space”–space between the posterior cortex of the lateral mass and the spinolaminar junction. Anterior slippage of vertebral body (anterolisthesis) up to 50% of vertebral body width. “Fanning” of the spinous processes.

Question 41

Radiographic Signs of Hyperflexion Sprain

Answer 41

* Anterior slippage of vertebral body (anterolisthesis) * Kyphotic angulation between vertebral bodies • Widening of posterior intervertebral disk space • Anterior subluxation of facet joints • Separation (lack of parallelism) of facet joint surfaces • Increased distance between spinous processes (“fanning”) • Vertebral body wedge compression fracture (when an anterior compressive force accompanies hyperflexion)

Question 42

Spondylosis?

Answer 42

Degenerative changes of the spine seen in pts > 40y, MC'ly after age 65. Includes: - VB flattening (platyspondylia), - Osteophyte formation, - Ligamentous calcification, - Facet joint or intervertebral disk space narrowing causing spondylolisthesis.

Question 43

Is degenerative spondylolisthesis mechanically stable?

Answer 43

Yes bc intervertebral ligaments are intact. On flexion/ex radiography, there may be some movement between the vertebral bodies (

Question 44

Midbrain aka

Answer 44

Mesencephalon

Question 45

Ddx for HA on CT?

Answer 45

``` Aneurysms SAH Mass/tumor Abscess Hematoma (ICH, EDH, SDH) AVM Venous sinus thrombosis Sinusitis ```

Question 46

Systematic Approach to Head CT Interpretation?

Answer 46

Symmetry: Compare L & R sides of the cranium Midline: shift Brain tissue: Gray/white differentiation, parenchyma lesions CSF spaces: Ventricles, basal cisterns, cortical sulci, fissures Soft tissues: Scalp swelling Subdural windows: blood collections adjacent to the skull Bone windows—Skull, orbits and sinuses, intracranial air

Question 47

Indications for CT Scanning Prior to LP in Patients Suspected of having Meningitis?

Answer 47

1. Focal neurological deficit 2. AMS: GCS score 60 years 8. Other d/o that req CT: SAH, IC hemorrhage, brain abscess

Question 48

When does post stroke edema peak?

Answer 48

3-5d

Question 49

Time-Attenuation Curves for CT perfusion

Answer 49

Time-attenuation curves show the progressive opacification of brain tissue following a bolus of intravenous contrast. (A) Normal tissue demonstrates normal timing of opacification = normal time-to-peak (TTP), and normal quantity of opacification – area under the time attenuation curve = normal cerebral blood volume (CBV). (B) Potentially reversible ischemia (ischemic penumbra) – Opacification is delayed (increased TTP), but the total quantity of opacification is main- tained (normal CBV). (C) Irreversibly ischemic tissue – Opacification is very delayed (incensed or absent TTP) and diminished (very low CBV).

Question 50

PWI?

Answer 50

A region of delayed perfusion (increased TTP), but normal diffusion on DWI = perfusion/diffusion (PWI/DWI) mismatch and defines an area of potentially reversible ischemia, aka, an ischemic penumbra. Regions of diffusion-weighted signal abnormality (DWI bright= cytotoxic edema) are irreversibly ischemic – the ischemic core.

Question 51

GB Wall thickening (3 mm is upper limit of normal)?

Answer 51

``` Cholecystitis Cirrhosis Hypoprotinemia CHF Hepatitis Portal hypertension Lymphatic obstruction GB CA Adenomyomatosis ```

Question 52

How to distinguish portal and hepatic veins on US?

Answer 52

Portal has fibro-fatty and therefore echogenic walls. Hepatic veins do not.

Question 53

Spleen size - upper limit?

Answer 53

13 cm

Question 54

It is important to appreciate that C1, which is a sensory nerve, exits above the C1–C2 interspace so that the C2 nerve exits between C1 and C2, and so on.

Answer 54

It is important to appreciate that C1, which is a sensory nerve, exits above the C1–C2 interspace so that the C2 nerve exits between C1 and C2, and so on.

Question 55

Vertebral Artery segments?

Answer 55

V1: Originates from the SCA. V2: Enters the foramen transversarium at ~C6, and travels superiorly before exiting at C1–C2. V3: Post exit at C1-C2 and pre entry into the cranial compartment. V4: Intracranial component.

Question 56

The external fibers of the annulus are connected to the bone of the vertebral bodies by?

Answer 56

Sharpens fibers

Question 57

The spinal cord has two segments of enlargement. Where?

Answer 57

In the cervical region from approximately C4 to approximately T1 and in the lower thoracic region from approximately T9 to T12. These enlargements correspond to the locations in the cord that supply the spinal nerves for the upper and lower extremities.

Question 58

Terminal ventricle or 5th ventricle?

Answer 58

Small dilation of the central canal of the cord in the conus region which is seen in 2% to 3% of children under age 6 years.

Question 59

Myelography

Answer 59

In general, a 3.06-g limit of iodinated contrast medium instilled intrathecally in the lumbar or cervical region is followed. Thus, one is able to administer 10 mL of contrast material with a 300 mg/mL concentration or approximately 12 mL at a 240 mg/mL concentra- tion. These are the usual doses used for lumbar puncture myelog- raphy. In children, manufacturers recommend no more than 2.94 g of iodine intrathecally and a concentration no greater than 210 mg/mL. The contrast is instilled with intermittent fluoroscopy to deter- mine the correct amount of contrast to be administered.

Question 60

Is thyroid nodule size predictive of malignancy?

Answer 60

Nodule size is not predictive of malignancy, because the likelihood of cancer in a thyroid nodule has been shown to be the same regardless of the size measured at US.

Question 61

US features associated with an increased risk of thyroid CA?

Answer 61

``` Calcifications, Hypoechogenicity, Irregular margins, Absence of a halo, Predominantly solid composition, More talk then wide, Intranodule vascularity. ``` Note: The feature with the highest sensitivity, in the range of 69.0%–75.0%, is solid composition; how- ever, this feature has a fairly low PPV in that a solid nodule has only a 15.6%–27.0% chance of being malignant. The feature with the highest PPV, 41.8%–94.2%, is the presence of micro-calcifications; however, micro-calcifications are only found in 26.1%–59.1% of cancers (low sensitivity).

Question 62

US features of peri-thyroid LNs associated with the highest risk of cancer?

Answer 62

``` Heterogeneous echotexture, Calcifications, Cystic areas, A rounded LN or one causing mass effect, A LN measuring > 7 mm in the short axis. ```

Question 63

Atlantodental interval?

Answer 63

< 3 mm in adults < 5 mm in children

Question 64

Scheuermann Disease

Answer 64

This degenerative disease is noted in children, with onset at puberty; it has a male predominance. It consists of vertebral wedging, result- ing in lower thoracic rigid kyphosis. It requires the involvement of three contiguous vertebrae with wedging of more than 5 degrees. Schmorl’s nodes are common. The etiology is thought to be stress- related through either congenitally or traumatically weakened por- tions of the cartilaginous endplates. Severe kyphosis of greater than 75 degrees may call for surgical correction.

Question 65

DISH

Answer 65

Characterized by ossification along the anterior and, to a lesser extent, lateral aspect of the spine. Osseous bridging of at least four contiguous vertebral bodies with relative absence of disk pathology. Hyperostosis at the sites of tendon and ligament attachment to bone, ligamentous ossification, and paraarticular osteophytes in both the axial and appendicular skeleton are present. The differential diagnosis of DISH includes ankylosing spondylitis, which is not as florid as DISH and is associated with sacroiliitis (usually the first manifestation of the disease). You can observe erosion of the superior and inferior vertebral margins, producing squar- ing and bridging of the vertebral bodies (bamboo spine) in anky- losing spondylitis. The facet joints are involved in ankylosing spondylitis and not DISH.

Question 66

spondylolysis

Answer 66

is a fracture through the pars interarticularis

Question 67

Foraminal stenosis

Answer 67

The width of the lateral recess in the lumbar region is measured from the posterior aspect of the vertebral body to the most ante- rior aspect of the superior articular facet. Width of 2 mm or less is considered stenotic. The nerve root buds out of the thecal sac to course in the lateral recess, then under the pedicle and out the neural foramen. Hypertrophy of the superior articular facet is the most common cause of narrowing of the lateral recess, although abnormalities of any components of the lateral recess may also compress the nerve.

Question 68

Haller cells

Answer 68

Anterior ethmoid air cells located inferolateral to the bulla, along the inferior margin of the orbit protruding into the maxillary sinus. Seen in 10% to 45% of patients. When enlarged, Haller cells may narrow the infundibulum or maxillary sinus ostium.

Question 69

Asser naggi cells

Answer 69

Most anterior ethmoid air cells located in front of the middle turbinate’s cribriform plate attachment. Lie anterior, lateral, and inferior to the frontal recess. Present in more than 90% of patients.

Question 70

Concha bullosa?

Answer 70

An aerated middle turbinate, which usually communicates with the anterior ethmoid air cells. Seen in ~34% to 53% of patients. Unless huge does not predispose to chronic sinusitis.

Question 71

The ethmoid sinus is usually the source of infection in childhood sinusitis. This may also lead to orbital cellulitis or subperiosteal abscesses in kids.

Answer 71

True

Question 72

Sinus development pneumonic

Answer 72

Embattled military fought Saddam (ethmoid, maxillary, frontal, sphenoid). E & M present at birth OMC is developed at birth Nasal mucosa in infants is redundant and is easily congested so sinusitis may not be present in crying child with nasal sxs.

Question 73

Sinus X-rays

Answer 73

Waters (brow- up anteroposterior [AP] view), Caldwell (frontal AP view), Lateral, Submental vertex view.

Question 74

FESS

Answer 74

FESS enlarges the natural ostia and passageways of the paranasal sinuses Surgery is directed toward removing potential obstacles to mucociliary clearance at the OMC. Amputation of the uncinate process, enlargement of the infundibulum and maxillary sinus ostia, and creation of a common unobstructed channel for the anterior ethmoid air cells are common practices in FESS. FESS may also include complete or partial ethmoidectomies with recurrent disease.

Question 75

Chonal atresia

Answer 75

The posterior choanal opening should be > 0.5cm wide in neonates, > 1 cm in adolescents. Can be bony or membranous. Can be due to enlargement of the vomer. May not be atretic but rather stenotic.

Question 76

OMC?

Answer 76

The ostiomeatal complex (OMC) refers to the maxillary sinus ostium, the infundibulum, the uncinate process, the hiatus semilunaris, the ethmoid bulla, and the middle meatus - the common drainage path- ways of the frontal, maxillary, and anterior ethmoid air cells.