Random_18 Flashcards

Question

Malignant potential * multiple hereditary exostosis * Ollier disease * Muffucci syndrome NO malignant potential * McCune-Albright syndrome

Answer 1

PET has limited sensitivity for which tumors? * HCC * prostatic carcinoma

Answer 2

Pre-pneumonectomy pulmonary function assessment * Routine PFTs * If pre-op FEV1\>2L -- no further w/u necessary * If pre-op FEV1\<2L * --\> Quantitative lung perfusion study * % x total FEV1 * minimum acceptable predicted postoperative FEV1 is *_800 ml_*

Answer 3

Since the male breast lacks lobules, invasive *_lobular_* carcinoma is very unlikely in male patients.

Answer 4

The asterion is where three cranial bones meet: ## Footnote Parietal bone, Occipital bone, and Mastoid portion of the Temporal bone.

Answer 5

Medullary thyroid carcinoma * Medullary thyroid carcinoma is a rare type of thyroid cancer that arises from the parafollicular C cells and accounts for 5–10% of thyroid malignancies. * Parafollicular C cells originate from neural crest cells and mainly secrete calcitonin. * Medullary thyroid carcinoma can occur in sporadic and hereditary forms. Approximately 25% of medullary thyroid carcinomas are seen with pheochromocytoma and parathyroid tumors in the multiple endocrine neoplasia syndromes (MEN 2A and MEN 2B). * Metastatic liver lesions from medullary carcinoma are hypervascular and show arterial enhancement and may have a targetoid appearance in venous phase on contrast-enhanced MRI

Answer 6

Classification of extremity shortening * rhizomelic * proximal shortening - humerus and femur etc * achondroplasia & thanatophoric dwarfism * mesomelic * middle narrowing - radius-ulna, tibia-fibula * rare * acromelic * distal shortening * asphyxiating thoracic dystrophy (Jeune syndrome) * chondroectodermal dysplasia (Ellis-van Creveld syndrome)

Answer 7

DDx for trident acetabulum * Jeune syndrome (asphyxiating thoracic syndrome) * Ellis-van Creveld syndrome * thanatophoric dysplasia Legend: A - achondroplasia -horozontal acetabuli (decreased acetabular angles) and short iliac bones rounded tops - tombstone iliac bones = achondroplasia B - trident acetabulum = Jeune syndrome (asphyxiating thoracic syndrome); if trident acetabulum + telephone receiver femur = thanatophoric dysplasia

Answer 8

Achondroplasia * autosomal dominant - homozygous - lethal; heterozygous - clinical manifestations * craniofacial disprportion * small skull base, small foramen magnum - brainstem compression * vertebral bodies short in AP dimension, tall discs, short pedicles, and interpedicular distances narrower in the more inferior lumbar spine - prone to spinal stenosis * shortened long bones with metaphyseal flaring * iliac bones are short in height and acetabular roof is horizontal * tombstone appearance

Answer 9

A: Achondroplasia - interpedicular distances become narrower inferiorly B: Thanatophoric dysplasia - vertebral bodies demonsrate platyspondyly. Short ribs wih narrow AP diameter of the chest and protuberant abdomen

Answer 10

Mucopolysaccharidoses * The vertebral bodies are oval in shape and often have an anterior beak in the anterior cortex. * midportion of the vertebral bodies in Morquio syndrome * inferior portion in Hurler syndrome. * Beaking is most prominent in the lumbar vertebral bodies. * There can be focal kyphosis (gibbous deformity). * The clavicles and ribs are commonly thickened. * The ribs are narrower posteromedially, giving them a ‘‘canoe-paddle’’ appearance. * The appearance of the pelvis is essentially opposite of that in achondroplasia. The iliac wings are tall and flared and the acetabuli are shallow (increased acetabular angles). * femoral heads are dysplastic, and femoral necks are gracile and demonstrate coxa valga (loss of angle between the neck and the the shaft of the femur). * hands have a characteristic appearance that includes proximal tapering of the metatarsal bones

Answer 11

Renal artery aneurysm * Classification of aneurysms * True aneurysm * most common cause - atherosclerosis * other causes - Ehlers-Danlos syndrome, Marfan's dz, polyarteritis nodosa, fibromuscular dysplasia * False aneurysm * traumatic or iatrogenic * Almost always *_extraparenchymal_* in location, but may rarely be cortically based if a small tertiary or higher order renal artery branch is involved. * Unenhanced CT shows a mass-like lesion with *_internal high attenuation*_ (blood clots). There may or may not be _*peripheral calcification_* depending on the age of the aneurysm; chronic aneurysms tend to calcify. * Enhanced CT shows variable contrast blush within the sac. Contrast may blush brightly if there is no thrombus, or may dissect within the interstices of the thrombus. In addition, there may be peripheral cortical hypoenhancement if there is infarction of the artery. * Rx: * Up to 2 cm in size: Usually followed by imaging on annual or biannual basis. * Greater than 2 cm in size: Surgery is recommended with aneurysmectomy.

Answer 12

Hilgenreiner line = a line drawn through the bilateral triradiate car- tilages, touching the inferior medial aspect of each acetabulum. A second line (acetabular roof line) = drawn connecting the inferior medial and superolateral aspects of the acetabulum, outlining the acetabular roof Between the above 2 lines = actabular angle * normally \< 30 degrees at birth * decreases to 22 degrees at 1 y/o * note: acetabular angle and alpha angle are complementary angles (acetabular angle + alpha angle = 90 degrees; alpha angle should \> 60 degrees, acetabular angle should \< 30 degrees) Vertical line of Perkins = perpendicular to Hilgenreiner line and traverses the superolateral corner of the acetabulum * When the femoral head is ossified and visible, it should lie medial to the Perkins line Shenton arc = continuous smooth arch connecting the medial cortex of the proximal metaphysis of the femur and the inferior edge of the superior pubic ramus. * In DDH and dislocation, the arc is discontinuous Figure: Developmental dysplasia of the hip on the right. The femoral heads are not yet ossified. The right metaphysis is displaced lat- erally compared to the Perkins line, and the Shenton arc is not continuous. The acetabular angle is greater than 30 degrees.

Answer 13

Alpha angle = between lines drawn along the straight part of the iliac bone and the acetabular roof. Normally, the alpha angle is greater than 60 degrees (55 degrees in newborns). With a shallow acetabulum, this angle is decreased. a normally developed acetabular roof. The femoral head is bisected by the vertical line drawn along the iliac crest, denoting a nondislocated femoral head.

Answer 14

Immature acetabulum without dislocated femoral head. The acetabulum is shallow and has an alpha angle of 48 degrees. The femoral head is not dislocated.

Answer 15

Poorly developed acetabulum and dislocated femoral head. The acetabulum is very shallow and has a small alpha angle. The femoral head (H) is lateral to the iliac line, indicating that it is completely dislocated from the acetabulum.

Answer 16

DDx for abormally increased acetabular angle * DDH * neuromuscular disorder abnormally decreased acetabular angle * Down syndrome * skeletal dysplasias, e.g., achondroplasia

Answer 17

Typical age for: * Slipped capital femoral epiphysis * 12-15 y/o * Legg-Calve-Perthes disease * 5-8 y/o

Answer 18

## Footnote Proximal focal femoral deficiency shown on radio- graph as hypoplastic right femur. Note elevated position of right knee compared to left.

Answer 19

DDx of hip pain in children * septic arthritis * osteomyelitis * SCFE * Legg-Calve-Perthes disease * toxic synovitis * JRA * LCH * Ewing sarcoma * Osteosarcoma * Osteoid osteoma

Answer 20

Legg-Calve-Perthes disease A, Radiograph of the left hip, with frog-leg positioning, shows crescentic subchondral lucency (arrow), consistent with necrosis. The femoral epiphysis is irregular and sclerotic and shows loss of height compared to the normal left femoral head. B, T1-weighted coronal MR image shows loss of the normal fatty signal in the right femoral epiphysis (arrow). There is also mild loss of height.

Answer 21

## Footnote Legg-Calve-Perthes disease Chronic changes in a node-fragmented, shortened capital femoral epiphysis with metaphyseal ‘‘cyst’’ (arrowhead). Note widening of femoral head and neck (coxa magna; arrows). There has been left surgical acetabular reconstruction to create acetabular coverage of the enlarged left femoral head.

Answer 22

## Footnote Slipped capital femoral epiphysis. Radiograph shows complete slip of left epiphysis (E) in relation to left metaphysis (M).

Answer 23

Rickets. Radiograph of bilateral knees shows metaphyseal cupping, fraying, and irregularity.

Answer 24

Types of scoliosis * idiopathic scoliosis * most common * S-shaped * upper (thoracic) curvature convex to the right * congenital scoliosis * due to abnormal vertebral segmentation * associated with more abrupt short-segment curves than idiopathic cases * neuromuscular scoliosis * due to neurologic impairment or muscular dystrophy * C-shaped

Answer 25

Management of scoliosis * Curves less than 7 degrees are considered normal. * Curves less than 25 degrees are often treated by applying an external brace. * Rapidly progressive curves or curves greater than 40 degrees are typically treated surgically.

Answer 26

* joint effusion * epiphyseal overgrowth * widening of the intercondylar notch * accelerated bone maturation

Answer 27

Ankylosis of the apophyseal joints

Answer 28

## Footnote Juvenile rheumatoid arthritis of knee. Sagittal, con- trast-enhanced, T1-weighted MR image shows markedly enhanced and thickened synovium. There is an associated joint effusion.

Answer 29

## Footnote Juvenile rheumatoid arthritis: radiographic findings in several patients. A, Radiograph of the hands shows marked narrowing of intercarpal joints, erosions of several carpal bones (arrowheads), and narrowing of the third metacarpophalangeal joints (arrows). The findings are bilateral and symmetric.

Answer 30

Still disease * acute form of JRA * fever, rash, hepatosplenomegaly and LAD * skeletal involvement is rare in these children

Answer 31

## Footnote Hemophilia. T2-weighted, sagittal MRI through the radial-capitellar joint shows markedly thickened and low- signal synovium (arrows), consistent with hemosiderin deposi- tion. There is associated irregularity of the capitellar joint surface.

Answer 32

## Footnote Recurrent hematoma formation can also lead to the forma- tion of pseudotumors, which usually occur in the soft tissues but can cause pressure necrosis and lucency of adjacent bone.

Answer 33

* cortical thinning * trabecular coarsening * bony remodeling * skull - hair-on-end appearance * bone infarcts * fish spine * cardiomegaly * splenomegaly or splenic infarct or autosplenectomy * gallstones * extramedullary hematopoiesis * osteomyelitis

Answer 34

Radial dysplasia. Radiograph of upper extremity shows absent radius and short dysplastic ulna in a patient with Fanconi anemia. The thumb is also absent.

Answer 35

Blount disease Radiograph demonstrates bowing of the tibia in association with irregularity and fragmentation of the medial tibial metaphysis

Answer 36

MSK manifestations of NF-1 ## Footnote The bones may demonstrate overgrowth, bowing, areas of sclerosis, and numerous cortical defects. Characteristic findings include pseudoarthrosis formation, commonly within the tibia, and twisted-appearing (ribbonlike) ribs. The vertebral bodies may demonstrate posterior scalloping due to either dural ectasia or multiple neurofibromas. There is often kyphoscoliosis.

Answer 37

Venous malformation - phlebolith Lymphatic malformation - fluid-fluid levels

Answer 38

Venous malformation of the thigh. A, Axial T2-weighted MR image shows serpentine areas of high signal within the musculature throughout the right thigh. B, Axial contrastenhanced T1-weighted MR image shows the serpentine areas to enhance diffusely with contrast, consistent with slowmoving venous blood. C, Photograph of cutaneous manifestations of venous malformation in the forearm in another patient.Note purplish, raised skin lesions.

Answer 39

High-flow vascular malformation of the right shoulder. A, Coronal T1-weighted image shows tubular flow voids (arrows) in subcutaneous tissues of shoulder. There is no associated solid, soft-tissue mass. B, Sagittal T2-weighted image shows flow voids with surrounding high-signal edema (arrows). C, Frontal arteriogram after injection of the arch shows a tangle of arterial structures over the right shoulder, documenting arteriovenous malformation.

Answer 40

Dermatomyositis: ## Footnote imaging findings in multiple children. A, Axial T2-weighted image through the thigh shows marked abnormally increased signal throughout the anterior and posterior musculature of the thigh. Normally, the muscles are low in signal on this sequence. B, Chest radiograph shows calcifications (arrows) diffusely within the subcutaneous tissues. C, Axial CT image shows heterogeneous calcifications in the subcutaneous tissues of the lower pelvis and upper thigh.

Answer 41

Soft tissue malignancies in children Uncommon. MRI is modality of choice * infants = fibrosarcoma * older children = rhabdomyosarcoma * PNET * synovial sarcoma - can be deceptively benign-appearing with smooth, well-defined borders

Answer 42

Aggressive fibromatosis * A fibroproliferative disorder that is locally aggressive but does not metastasize. * Older children * On MRI - *_high-signal on T2_*-weighted images despite their fibrous nature * After resection, there is a tendency to recurrence along the proximal margin of the resection

Answer 43

Posttraumatic fat necrosis. ## Footnote Axial, T2-weighted MRI of the knee, obtained because of palpable soft tissue mass on physical examination, shows linear area of increased signal (arrow) immediately anterior to the anterior surface of the tibia. There is no associated soft tissue mass. Position and appearance are characteristic of posttraumatic fat necrosis.

Answer 44

Fibromatosis colli in a 1-month-old child with a right neck mass and a head tilt to the left. Longitudinal ultrasound of the right (R) and left (L) sternocleidomastoid muscles shows the right muscle to be of abnormal thickness and increased echogenicity.

Answer 45

Upper vs lower airway thoracic inlet is division * upper airway obstruction - stridor * lower airway obstruction - wheezing

Answer 46

## Footnote With croup, there is loss of the normal shoulders (lateral convexities) of the subglottic trachea secondary to symmetric subglottic edema. Normally, the subglottic trachea appears rounded, with ‘‘shoulders’’ that are convex outward. In croup, the subglottic trachea becomes long and thin, with the narrow portion extending more inferiorly than the level of the pyriform sinuses. Figure: Normal frontal radiograph of the airway. The subglottic airway demonstrates rounded shoulders (white arrows) that are convex outward. Note the appearance and location of the pyriform recess (black arrow on right pyriform recess).

Answer 47

Normal epiglottis. Lateral radiograph showing thick-appearing epiglottis (arrow). Incidentally, note appearance of enlarged adenoid tonsils (A).

Answer 48

Exudative tracheitis. Lateral radiograph showing irregular plaquelike filling defects and airway wall irregularities (arrows) within trachea. Again, note the normal appearance of the nonthickened epiglottis in this patient.

Answer 49

de·lin·quent (typically of a young person or that person's behavior) showing or characterized by a tendency to commit crime, particularly minor crime.

Answer 50

Giant cell tumor of tendon sheath / GCTTS * usually benign * may represent neoplasm or reactive mass * aka pigmented villonodular tumor of tendon sheath (PVNTS) * most often occur in hands * X-ray - 10-20% bony erosions, calcifications uncommon * U/S - homogeneously hypoechoic * MRI - similar to PVNS due to hemosiderin accumulation; T1 low and T2 low * Rx - local excision * DDx * ganglion cyst * PVNS * desmoid tumor * fibroma * fibrosarcoma

Answer 51

## Footnote Retropharyngeal abscess. A, Lateral radiograph showing marked thickening of the retropharyngeal soft tissues (arrows), which are wider than the adjacent vertebral bodies. Note the anterior convexity of soft tissues. B, Contrast-enhanced CT shows a low attenuation region with enhancing rim (A), suggestive of a drainable abscess.

Answer 52

## Footnote Retropharyngeal cellulitis. A, Lateral radiograph showing increased thickness of the retropharyngeal soft tis- sues (arrows). B and C, Contrast-enhanced CT in axial (B) and sagittal (C) planes showing low attenuation edema (C) in retropharyngeal soft tissues. There is no focal collection with enhancing rim to suggest drainable fluid.

Answer 53

Double aortic arch * Determining the dominant arch is one of the goals of performing cross-sectional imaging. * Typically, the right arch is dominant, both larger and positioned more superiorly. In such cases, the left arch is ligated by performing a left thoracotomy. * When the left arch is dominant, a right thoracotomy is performed and the right arch ligated.

Answer 54

Pulmonary sling * the left pulmonary artery arises from the right pulmonary artery rather than from the main pulmonary artery and passes between the trachea and esophagus as it courses toward the left lung. * ONLY vascular anomaly to cross b/t trachea and esophagus --\> compression of posterior trachea and anterior esophagus is characteristic * ONLY vascular anomaly that is associated with asymmetric lung inflation on CXR * associated with congenital heart disease, anomalous right bronchus, and complete tracheal rings Fugure: Complete tracheal rings. CT shows the very small caliber and rounded appearance (arrow) of the midtrachea.

Answer 55

Right aortic arch with an aberrant left subclavian artery (RAA-ALSCA) * Airway compression typically occurs when there is a persistent ductus ligament completing the ring. * Often, there is dilatation of the subclavian artery at the origin from the right aorta (called a Kommerell diverticulum), which can contribute to airway compression. * Descending aorta may lie in the midline, immediately anterior to the vertebral bodies, if the descending aorta passes from right to left as it descends. This midline descending aorta can contribute to airway com- pression as the result of the abnormal stacking of anatomic structures in the limited space between the sternum and vertebral bodies.

Answer 56

Innominate artery compression syndrome * The innominate artery passes immediately ante- rior to the trachea just inferior to the level of the thoracic inlet. In infants, in whom the innom- inate artery arises more to the left than in adults and in whom the mediastinum is crowded by the relatively large thymus, there can be narrowing of the trachea at this level. * Spectrum from normal to severe narrowing * Symptoms decrease with time as the child grows, and surgical therapy is reserved for cases in which symptoms are severe * Lateral CXR: indentation of the anterior aspect of the trachea at or just below the thoracic inlet

Answer 57

Tracheal hemangioma * most commonly occur in the subglottic region * often associated with facial hemangioma * CXR - asymmetric subglottic narrowing * DDX * tracheal papilloma * tracheal granuloma

Answer 58

Enlarged adenoid tonsils * If AP diameter \> 12mm * commonly grow back quickly

Answer 59

Meconium aspiration syndrome * term or post-mature neonates * usually occur secondary to stress - intrapartum or intrauterine, due to hypoxia etc * mechanism * meconium obstructs small airways * meconium causes chemical pneumonitis * CXR * hyperinflation (high lung volumes) * asymmetric lung densities - ropy appearance * perihilar distribution * alternating areas of hyperinflation and atelectasis * air-block --\> pneumothorax (20-40%)

Answer 60

Transient tachypnea of the newborn * due to delayed clearance of fetal lung fluid * causes * c section * maternal diabetes * maternal sedation * hallmark - benign cause * develops @ 6 hours * peaks @ 1 day * resolves by 2-3 days * CXR * findings similar to pulmonary edema * airspace opacification * interstitial markings * prominent and indistinct pulmonary vasculature * fluid in fissures * pleural effusions * cardiomegaly

Answer 61

Neonatal pneumonia * CXR * With the exception of b-hemolytic streptococcal pneumonia * hyperinflation * patchy, asymmetric perihilar densities * pleural effusions * may be indistinguishable from meconium aspiration syndrome Figure: Neonatal pneumonia. Newborn chest radiograph shows large lung volumes and coarse, bilateral perihilar mark- ings. Note right pleural effusion (arrow). Also note umbilical venous catheter with tip into right atrium. Tip should be at the junction of the right atrium and inferior vena cava.

Answer 62

Surfactant Deficient Disease aka Respiratory Distress Syndrome aka Hyaline Membrane Disease * premature infants (50% affected) * #1 cause of death in live newborns * type 2 pneumocytes * CXR * LOW lung volumes * bilateral granular opacities that represent collapsed alveoli * prominent air bronchograms (large bronchi do not collapse) * if severe, diffuse lung opacity * *_a normal CXR at 6 hours excludes surfactant deficient disease_*

Answer 63

GBS pneumonia * LOW lung volumes * bilateral granular opacities * identical findings to surfactant deficient disease * pleural effusions * help differentiate GBS pneumonia from SDD * pleural effusion is very uncommon in SDD * pleural effusion is very common in GBS pneumonia

Answer 64

Esophageal intubation in a 6-day-old girl. ## Footnote Chest radiograph obtained after reintubation shows the endotracheal tube overlying the expected location of the midtrachea. However, there are low lung volumes, gas within the esophagus (arrows), and multiple air-filled and distended bowel loops.

Answer 65

“Page Kidney” in which the compression of the kidney by the subscapular hematoma may result in ischemia, renin release, and renin-dependent hypertension

Answer 66

L to R shunts specifically, VSD

Answer 67

PICC in children * small caliber (2F - 3F) * can be very difficult to see on CXR, must be filled with contrast to be visualized * position of the tip *_MUST be at the mid SVC_* * due to the small-caliber lines, if they are placed in the RA, can cause perforation, pericardial temponade and death!!

Answer 68

Pulmonary interstitial emphysema * marked increase in alveolar pressure --\> alveolar perforation --\> air escapes into adjacent interstitium and lymphatics * CXR * bubblelike or linear lucencies * focal or diffuse * PIE serves as a warning sign for other impending air-block complications * pneumothorax * pneumomediastinum * pneumopericardium * may prompt caregivers to switch from conventional to high-frequency oscillation * differentiating bubbly lucencies due to PIE from BPD * 1st week of life - PIE * older than 2 weeks - BPD

Answer 69

DDx for acute diffuse pulmonary opacification in neonates * blood/pus/water/cells * development of patent ductus arteriosus * pulmonary hemorrhage (surfactant therapy is a risk factor) * worsening surfactant deficiency (during first few days of life) * diffuse microatelectasis (artifact) (expiratory view) * pneumonia Figure: Expiratory chest radiograph mimicking heart failure in infant. A, Initial radiograph shows prominent size of cardiothymic silhouette, indistinctness of pulmonary vascularity, and low lung volumes. B, Repeat radiograph obtained immediately after A shows clear lungs and normal heart size.

Answer 70

Bronchopulmonary dysplasia / BPD * most common chronic lung disease of infancy * result from a combination of * mechanical ventilation * oxygen toxicity * stages: * at the end of 2nd week of life - hazy density throughout the lungs * next weeks to months - combination of coarse lung markings, bubblelike lucencies, and asymmetric aeration * eventually, focal lucencies, coarse reticular densities, and bandlike opacities * many completely resolve clinically and radiographically

Answer 71

Development of BPD in the absence of mechanical ventilation.

Answer 72

DDx for a focal lucent chest lesion in a newborn * congenital lobar emphysema * congenital pulmonary airway malformation/CPAM * cogenital diaphragmatic hernia * pulmonary interstitial emphysema

Answer 73

DDx for a focal solid chest lesion in a newborn * sequestration * bronchogenic cyst * CPAM