TEST PAPER 6 Flashcards

Question

25. An asymptomatic military recruit showed a well-defined 2 x 2 cm solitary pulmonary nodule in the right lower zone on a plain chest radiograph. On dose inspection, the nodule showed faint calcification. CT performed for further characterisation showed areas of fat density on pixelometry. What is the diagnosis? A. Tuberculoma B. Aspergilloma C. Hamartoma D. Carcinoid E. Haemangioma

Answer 1

25. C. Hamartoma Hamartoma is a benign neoplasm composed of mesenchymal tissues such as cartilage, fat, connective tissue, smooth muscle and calcification. Hamartoma are common benign tumours. Typical CT findings consist of a well-defined, smooth, round or lobulated nodule or mass with fat density in nearly two-thirds of cases, and popcorn like calcification or central calcification in a quarter.

Answer 2

26. E. Biliary cystadenoma Biliary cystadenomas are benign neoplasms originating in bile ducts, most commonly seen within the right lobe of liver. They rarely affect the extrahepatic biliary system. Women are affected more than men and typically present with chronic, vague abdominal pain. Biliary cystadenomas can reach up to 35 cm in size and are usually demonstrated as large multiloculated anechoic masses on ultrasound. A CT scan typically demonstrates a water density mass that shows enhancement of its walls and septations following administration of contrast, differentiating these from simple cysts. An echinococcal cyst (hydatid cyst) is a parasitic infection causing cystic transformation in the liver

Answer 3

27. B. Malakoplakia Malakoplakia is a rare chronic inflammatory disease primarily affecting the bladder, with decreasing incidence with increasing proximity to the kidney. Small smooth papules, nodules or plaque-like mural defects of the affected urinary tract are characteristic. Malakoplakia can be associated with immunosuppression, diabetes mellitus, renal transplants or long-term corticosteroid use. Leukoplakia is characterised by soft-tissue flakes that can be passed in the urine during micturition. Haemorrhagic cystitis and emphysematous cystitis can occur with E. coli infections but are associated with intraluminal blood clots and gas deposits, respectively. Bladder outflow obstruction results in a thick walled bladder with trabeculations.

Answer 4

28. C. Chondrosarcoma The radiographic description is aggressive and the stippled calcification is suggestive of a chondroid matrix. The most likely diagnosis is therefore a chondrosarcoma. These may be primary or develop from an enchondroma or osteochondroma. Although chondromyxoid fibroma would be a possibility in this age group, it is an exceedingly rare benign chondral lesion that would normally have well-defined, thickened sclerotic margins. Chondrosarcomas are quite common tumours that may have relatively benign radiographic appearances. They are normally metaphyseal, located centrally within the skeleton and may exhibit endosteal scalloping. The diagnosis should also be considered in patients with increased pain or growth in centrally located enchondromas or osteochondromas. Surgical resection is the treatment of choice and the 5-year survival rate is approximately 75%.

Answer 5

29. C. Sarcoidosis Causes of optic canal enlargement (more than 6.5 mm in diameter) Common causes: * Glioma of the optic nerve * Meningioma of the optic nerve sheath * Metastasis * Neurofibromatosis with or without optic neurofibroma or glioma Uncommon causes: * Aneurysm of the ophthalmic artery or cavernous portion of internal carotid artery * Arteriovenous malformation with ophthalmic artery involvement * Carcinoma of ethmoid or sphenoid sinus * Granuloma (e.g. tuberculosis, sarcoidosis) * Increased intracranial pressure * Mucocoele of sphenoid sinus * Mucopolysaccharidoses (especially Hurler syndrome) * Pituitary adenoma or craniopharyngioma extending anteriorly * Pseudotumour of orbit * Retinoblastoma with intracranial extension

Answer 6

30. C. AP radiograph of the cervical spine The standard child protection skeletal survey for suspected non accidental injury includes the following: Skull * AP, lateral and Townes view (the latter if clinically indicated). * Skull X-rays should be taken even if a CT scan has been or will be performed. Chest * AP including the clavicles. * Two oblique views to show ribs (‘left and right oblique’). Abdomen * AP including the pelvis and hips. Spine * Lateral: may require separate exposures of the cervical, thoracic and thoraco-lumbar regions. * AP views of the cervical spine are rarely diagnostic at this age and should only be performed at the discretion of the radiologist. Limbs * AP of both upper arms * AP of both forearms * AP of both femurs * AP of both lower legs * PA of hands * DP of feet Where an abnormality is suspected, these views should be supplemented by the following: * Lateral views of any suspected shaft fracture * AP and lateral coned views when a fracture is suspected

Answer 7

31. D. Meconium aspiration Meconium aspiration is the most common cause of neonatal respiratory distress in full-term or post-mature infants (hyaline membrane disease is the most common cause in premature infants). Chest X-ray shows the following: * Bilateral diffuse grossly patchy opacities (atelectasis + consolidation). Unlike hyaline membrane disease, air bronchogram is not a typical feature. * Hyperinflation with areas of emphysema (air trapping). * Spontaneous pneumothorax + pneumomediastinum (25%) requiring no therapy. * Small pleural effusions (20%). * Rapid clearing, usually within 48 hours.

Answer 8

32. A. Pneumoconiosis with progressive massive fibrosis On chest radiographs, large opacities (progressive massive fibrosis) may be seen in complicated coal worker pneumoconiosis, as in complicated silicosis. The large opacities result from nodule coalescence and are observed commonly in the middle lung zone or peripheral one-third of the lung on axial chest images and in the upper lung zone on longitudinal images. The large opacities gradually migrate towards the hilum, leaving emphysematous lung tissue between the fibrotic tissue and the pleural surface.

Answer 9

33. D. Mirizzi syndrome The sonographic findings of an impacted gallstone within the neck of bladder causing proximal biliary dilatation are diagnostic for Mirizzi syndrome. Mirizzi syndrome is caused by impaction of a large gallstone in the cystic duct, cystic duct remnant or gallbladder neck. The impacted stone causes external compression of the CBD, resulting in proximal dilation of the biliary tree. A choledochocoele is cystic dilatation of the CBD within the lumen of the duodenum. Caroli disease is a congenital disorder characterised by saccular dilatations of intrahepatic ducts. Caroli disease, in association with congenital hepatic fibrosis, polycystic kidney disease and others, is known as Caroli syndrome.

Answer 10

34. E. The bladder dome is the most common site of injury. Extraperitoneal bladder rupture accounts for 80% of bladder ruptures. A flame-shaped extravasation of contrast is a classic finding and can be seen to extend into the perivesical fat and into the retropubic space of Retzius, anterior abdominal wall, upper thigh or scrotum. The most common site of injury is close to the anterolateral aspect of the bladder base. It us usually caused by puncture from pelvic fractures.

Answer 11

35. A. Pyknodysostosis Pyknodysostosis is a congenital abnormality that should be considered in the differential diagnosis of osteosclerosis. The patients are typically short, have hypoplastic mandibles, widened cranial sutures, Wormian bones, brachycephaly, clavicular dysplasia, thick skull base and hypoplasia or non pneumatisation of the paranasal sinuses. The distinguishing feature is aero-osteolysis with sclerosis. The distal phalanges appear as if they have been put in a pencil sharpener - they are pointed and dense.

Answer 12

36. C. Ill Clinical classification of neck nodes Level I: Above hyoid bone Level Ia: Previously called submental nodes Level Ib: Previously called submandibular nodes Level II: from skull base to level of lower body of hyoid bone Posterior to back of submandibular gland Anterior to back of sternocleidomastoid muscle Level IIA: anterior, lateral, medial or posterior to internal jugular vein Inseparable from internal jugular vein (if posterior to vein) Previously classified as upper internal jugular nodes Level IIB: Posterior to internal jugular vein with fat plane separating nodes and vein previously classified as upper spinal accessory nodes Level III: Prom level of lower body of hyoid bone to level of lower cricoid cartilage arch, anterior to back of sternocleidomastoid muscle, previously known as mid-jugular nodes. Level IV: From level of lower cricoid cartilage arch to level of clavicle Level V: Posterior to back of sternocleidomastoid muscle from skull base to level of lower cricoid arch Level VI: Between carotid arteries from level of lower body of hyoid bone to level superior to top of manubrium Level VII: Between carotid arteries below level of top of manubrium

Answer 13

37. B. PET CT is useful in differentiating lung cancer from PMP. It is clinically and radiologically important to differentiate progressive massive fibrosis from lung cancer. MR! is a preferable option because lung cancer appears as high signal lesion on T2 weighted images, whereas progressive massive fibrosis appears as a low-signal abnormality when compared with the signal of muscle on both Tl weighted and T2-weighted images. On post-contrast MR, progressive massive fibrosis appears peripherally enhanced more frequently than not. Histopathologic analysis should still be performed for diagnosis. PET may show intensive uptake of FDG in the fibrotic mass in progressive massive fibrosis; hence differentiation from cancer may be difficult.

Answer 14

38. B. Klatskin tumour Klatskin tumours are cholangiocarcinomas that involve the confluence of hepatic ducts and account for up to 70% of cholangiocarcinomas. Dilation of the intrahepatic ducts is the most frequent abnormal finding on ultrasound. Lobar atrophy may be very subtle on ultrasound but may be identified by secondary findings such as extension of dilated ducts to the liver surface and lobar ductal crowding. The tumour itself may be very' difficult to identify on ultrasound but may present as an isoechoic or hyperechoic mass. Primary sclerosing cholangitis is a fibrotic process that affects the biliary tree causing multifocal strictures and may lead to biliary cirrhosis. Mirizzi syndrome is dilation of the proximal common bile duct and intrahepatic ducts secondary' to external compression of a large gallstone impacted in the cystic duct/gallbladder neck.

Answer 15

39. B. Intraperitoneal bladder rupture Intraperitoneal bladder rupture occurs in around 20% of bladder ruptures. It can be caused by a sudden increase in intravesical pressure owing to blunt trauma and usually causes rupture to the bladder dome. Contrast can be seen in the peritoneal cavity, often outlining loops of bowel and extending up the paracolic gutters. Extraperitoneal bladder rupture is more common and is usually caused by puncture from pelvic fractures. Contrast can be seen in the retroperitoneal space, anterior abdominal wall, upper thighs or even the scrotum. It is important to distinguish between intraperitoneal and extraperitoneal rupture: intraperitoneal rupture requires surgical repair, whereas extraperitoneal rupture is managed conservatively. Contrast outside the bladder would not be seen on the pre IV contrast CT in cases of arterial damage or pelvic haematoma.

Answer 16

40. A. Bone metastasis The ‘ivory vertebra’ sign, as described in this case, refers to a diffuse and homogeneous increase in the density of a vertebral body, which retains its size and contours. It can occur in both adults and children but is more common in the former. In adults, ivory vertebra has been associated most commonly with fractures (compression or healing), haemangiomas, lymphoma, myelosclerosis, with metastatic disease (especially prostate, breast and carcinoid), chronic sclerosing osteomyelitis, Paget disease and renal osteodystrophy. An ivory vertebra at one or more vertebral levels in an elderly man is most compatible with a diagnosis of metastatic disease, commonly as the result of prostate carcinoma. The other options are all much less common causes of ivory vertebrae.

Answer 17

41. A. Superior orbital fissure syndrome Because the upper transverse maxillary buttress forms the orbital floor, fractures of this buttress may cause various orbital complications, including inferior rectus muscle tears, globe rupture or impingement, optic nerve injury and orbital hematoma. Superior orbital fissure syndrome is caused by extension of the fracture through the superior orbital fissure, with resultant injury to cranial nerves III, IV, VI (the ophthalmic branch of the trigeminal nerve) and VI as they traverse the fissure into the orbit, thus causing ophthalmoplegia or diplopia (extra-ocular muscle paralysis) and ptosis (paralysis of the levator palpebrae superioris, which is supplied by cranial nerve III). Additional injury to the optic nerve (cranial nerve II) at the orbital apex results in orbital apex syndrome, with unilocular visual loss added to the list of signs and symptoms. Orbital apex syndrome is a surgical emergency because prompt intervention is necessary to prevent permanent blindness.

Answer 18

42. A. Hypothyroidism Causes of delayed bone age include the following: * Constitutional: Familial and IUGR * Metabolic: Hypothyroidism, hypopituitarism, hypogonadism (Turner syndrome), Cushing discase/steroid therapy, diabetes mellitus, rickets and malnutrition * Systemic disease: Congenital heart disease, renal disease, coeliac disease, Crohn’s disease, ulcerative colitis and anaemia * Syndromes: Trisomies, Noonan disease, Cornelia de Lange, cleidocranial dysplasia, Lesch-Nyhan disease metatrophic dwarfism Of these, in the absence of any other history or radiological abnormality, hypothyroidism is more likely until proven otherwise. Precocious puberty results in advanced bone age.

Answer 19

43. B. Few varying sized nodules, some with cavitation Wegener’s granulomatosis, currently called granulomatosis with polyangitis, is a probable autoimmune disease characterised by systemic necrotising granulomatous destructive angitis, with a classic triad of respiratory tract inflammation, systemic small vessel vasculitis and necrotising glomerulonephritis. Sinus disease classically includes destructive sinusitis, nasal septal ulceration, septal perforation and saddle nose deformity. Chest radiograph shows interstitial fibrosis at the bases, which is usually asymptomatic. Multiple pulmonary nodules with cavitation are the most common and characteristic manifestation. Pleural effusions and mediastinal nodal enlargement are seen. There are multiple causes of miliary nodules, described as innumerable small 1-4 mm lung nodules, described in miliary tuberculosis, fungal infection, metastasis (thyroid, renal, breast, melanoma, pancreas, trophoblastic tumour), sarcoidosis, pneumoconiosis, pulmonary haemosiderosis, varicella infection, hypersensitive pneumonitis, histiocytosis etc. Bilateral upper lobe fibrosis are classically described in TB, ankylosing spondylitis, sarcoidosis, silicosis, radiation and histiocytosis.

Answer 20

44. C. Thick-walled oedematous loops of bowel with branching lucencies peripherally in the liver The patient in this scenario has a history of atherosclerosis with end organ damage. This would make them at risk of developing ischaemic colitis. The area of bowel affected in this question is a watershed area and is most susceptible to ischaemic colitis. The other plain film findings described in this question include intramural gas and portal venous gas. These are very worrying signs and usually imply a poor outcome. Sigmoid volvulus would cause a coffee bean sign on plain film. The findings are also not suggestive of caecal volvulus or small bowel obstruction. Necrotising enterocolitis would cause intramural and portal venous gas; however, this is a condition of neonates. Dilated small bowel with gas at the porta hepatis, is classic description of gall stone ileus, with gas being in the biliary tree.

Answer 21

45. C. Transitional cell carcinoma Transitional cell carcinoma of the bladder is the most common urinary tract malignancy in the UK and appears as a lobulated, irregular bladder wall thickening that enhances more greatly than the normal bladder wall. If hydronephrosis is present, this suggests muscle invasive disease. Squamous cell carcinoma can look like this but accounts for only 4% of all bladder malignancies and is therefore less likely unless there are specific risk factors such as schistosomiasis infection, chronic cystitis, bladder calculi or long term catheterisation. Adenocarcinoma Is rare and associated with urachal remnants or bladder extrophy. Leiomyomas appears as smooth bladder wall masses. Blood clots do not enhance and are often seen to change in size and position on sequential scans.

Answer 22

46. E. Haemangioma Vertebral hemangiomas are present in 5%-11% of all autopsies and are multiple in one-third of these cases. Lesions commonly occur in the vertebral bodies of the lower thoracic and lumbar spine, and radiographic appearances are those of coarse vertical trabeculations, giving a ‘corduroy’ or ‘honeycomb’ appearance. A CT scan may also demonstrate small punctuate areas of sclerosis, giving a ‘polka-dot’ appearance. On MRI, the lesions are of a mottled pattern with a characteristic low to high signal on T1-weighted sequences and high signal on T2-weighted sequences in proportion to the amount of adipose tissue. The lesions enhance strongly on both CT and MRI because of hypervascularity.

Answer 23

47. E. Second branchial cleft cyst The vast majority (95%) of branchial cleft anomalies arise from the second cleft. At least three-fourths of these anomalies are cysts, which typically occur between 10 and 40 years of age, in contrast to fistulas or sinuses, which manifest most commonly during the first decade of life. No gender predilection has been reported. These cysts usually appear as painless, fluctuant masses in the lateral portion of the neck adjacent to the anteromedial border of the sternocleidomastoid muscle at the mandibular angle. The mass enlarges slowly over time and may become painful and tender if secondarily infected. At US, a second branchial cleft cyst is seen as a sharply marginated, round to ovoid, centrally anechoic mass with a thin peripheral wall that displaces the surrounding soft tissues. The mass is compressible and shows distinct acoustic enhancement. Occasionally, fine, indistinct internal echoes, representing debris, may be seen. The ‘classic’ location of these cysts (at either CT or MR imaging) is at the anteromedial border of the sternocleidomastoid muscle, lateral to the carotid space and at the posterior margin of the submandibular gland. The cyst typically displaces the sternocleidomastoid muscle posteriorly or posterolaterally, pushes the vessels of the carotid space medially or posteromedial and displaces the submandibular gland anteriorly. It may also be seen more medially within the parapharyngeal space after extending through the stylomandibular tunnel and middle constrictor muscle. MR imaging better depicts the deep tissue extent of a second branchial cleft cyst, which allows accurate preoperative planning. The cyst fluid varies from hypointense to slightly hyperintense relative to muscle on T1 weighted images and is usually hyperintense on T2-weighted images. Mural thickness and enhancement vary, depending of the presence and severity of any associated inflammatory process. Occasionally, a ‘beak sign’ may be seen on axial CT or MR images. This sign represents a curved rim of tissue or ‘beak’ pointing medially between the internal and external carotid arteries. It is considered a pathognomonic imaging feature of a second branchial cleft cyst.

Answer 24

48. C. Sacrococcygeal bony defect Anterior sacral meningocele may occur as part of the Currarino triad, also known as the ASP triad (anorectal malformation, sacrococcygeal osseous defect and presacral mass), a rare syndrome characterised by autosomal dominant genetic inheritance in more than 50% of cases. The presacral mass in those affected may be a teratoma, anterior sacral meningocoeles, dermoid cyst, hamartoma or enteric duplication cyst, or more than one of these types of masses may be present.

Answer 25

49. C. Anechoic mass in the midline On all radiologic images, a thyroglossal duct cyst manifests as a cyst-like mass either in the midline of the anterior neck at the level of the hyoid bone or within the strap muscles just off the midline. At US, the finding of an anechoic mass with a thin outer wall in this characteristic location easily establishes the diagnosis of a thyroglossal duct cyst. However, this ‘classic’ appearance is seen in less than half (42%) of cases. More commonly, these cysts manifest as hypoechoic masses, often with increased through-transmission. They may be either homogeneous or heterogeneous in appearance with variable degrees of fine to coarse internal echoes. There is no correlation between the sonographic appearance and pathologic evidence of infection and inflammation. Heterogeneity seen in thyroglossal duct cysts on sonograms is more likely due to the proteinaceous content of the fluid secreted from the cyst wall rather than to infection. Preoperative sonographic visualisation of normal thyroid tissue is sufficient to exclude a diagnosis of ectopic thyroid tissue and obviates routine thyroid scintigraphy.

Answer 26

50. E. RUL lung primary and SVC obstruction Obstruction of the superior vena cava results in impaired venous drainage of the head and neck and upper extremities. Clinical manifestations include facial and neck swelling, distended neck veins, headache due to cerebral oedema, dyspnoea, stridor and altered mental status. Cancer is the most common underlying cause of superior vena cava obstruction and this includes lung cancer, mediastinal tumours, lymphoma/lymphadenopathy and mesothelioma, either directly or through malignant mediastinal lymphadenopathy. Other causes include catheter-induced iatrogenic SVC obstruction, fibrosing mediastinitis and Behcet’s disease.

Answer 27

51. B. Angiodysplasia The clinical history and findings on angiogram suggest angiodysplasia. There is no history of atherosclerosis elsewhere to suggest ischaemic colitis. The major mesenteric vessels are usually patent in ischaemic colitis. The exception to this rule would be in a case of possible superior mesenteric artery obstruction. Angiodysplasia can be part of the hereditary haemorrhagic telangiectasia syndrome. The condition results from a chronic intermittent obstruction of the veins where they penetrate the circular muscle layer of bowel. Distorted dilated vascular channels replace the normal mucosal structures. Endovascular treatment is an option. The findings on angiography do not point to colon carcinoma, diverticulitis or haemorrhoids.

Answer 28

52. E. Trabeculated bladder with decreased capacity Neurogenic bladder can be caused by meningomyelocele, spinal trauma, diabetes, multiple sclerosis, polio and herpes infection. It is a heterogeneous condition: for example, it can cause incontinence owing to detrusor over-activity, difficulty in passing urine owing to detrusor underactivity or retention with overflow incontinence. Most commonly, the bladder eventually becomes trabeculated with decreased capacity, but very large atonic bladders can also be seen. The detrusor muscle is innervated by the sympathetic nerves originating from S2-S4, therefore, neurogenic bladder is a common problem in spinal trauma. Indwelling urethral or suprapubic catheters may be seen and can be associated with stone disease and infection, including pyelonephritis. Treatments that may be seen on imaging include urinary diversion and continent pouch formation.

Answer 29

53. D. MRI of the wrist The patient’s presentation is a classic description of a hook of hamate fracture. These often occur during racquet, bat or club sports. A fracture of the hook of hamate can narrow Guyon’s canal, compressing the ulnar neurovascular bundle and causing distal neuropathy of vascular compromise. Conventional radiographs even with multiple dedicated views only have a sensitivity' of 72% for diagnosing this carpal fracture. CT with multiplanar reformatting would be a reasonable next investigation; however, in view of this patient’s neurological signs of ulnar nerve compression, MRI is the imaging modality of choice. This gives better soft-tissue definition w'hile still having a sensitivity and specificity approaching 100% for diagnosing fractures.

Answer 30

54. B. Rectal duplication cysts are high signal on T1W images. Anterior sacral meningocoele may be accompanied by other anomalies or syndromes, too, including uterine, renal and bladder malformations; Marfan syndrome; and Type 1 neurofibromatosis. Benign sacrococcygeal teratomas arc predominantly cystic; have attenuation similar to that of fluid on CT scans; and may include bone, fat and calcification. Cystic areas typically have the appearance of fluid on T1-weighted and T2 weighted MR images. Areas of fatty tissue demonstrate high signal intensity on T1 weighted images, whereas calcification and bone are depicted as areas of signal void. The coccyx is always involved, even in benign sacrococcygeal teratoma. Malignant teratomas have a predominant solid component, and haemorrhage and necrosis are common. Enteric cysts are rare and may arise in locations between the rectum and sacrum. They are classified according to their histologic basis as either tail-gut cysts or rectal duplication cysts. Duplication cysts on MR imaging demonstrates well-marginated, thin-walled lesions with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. Mucoid contents of tail gut cysts cause them to have high signal intensity on T1-weighted images. On MR images, cystic lymphatic malformations appear as areas of homogeneous high signal intensity on T2-weighted images and have the signal intensity of fluid on T1-weighted images. A fluid-fluid level can be seen in the setting of acute haemorrhage.

Answer 31

55. D. Tuberous sclerosis The US images suggest renal cysts, bilateral angiomyolipomas and splenic hamartoma. Polycystic kidney disease PCKD1 gene lies next to Tuberous sclerosis gene TSC2 and renal cysts are common in TS. TS is an autosomal, dominant, inherited neurocutaneous syndrome characterised by a variety of hamartomatous lesions in various organs. Classically, TS demonstrates a triad of clinical features (Vogt triad): mental retardation, epilepsy and adenoma sebaceum. PHACE syndrome constitutes, posterior fossa malformations-hemangiomas-arterial anomalies -cardiac defects-eye abnormalities-sternal cleft and supraumbilical raphe syndrome. Typically infants have large plaque like facial haemangiomas.

Answer 32

56. D. CD4 <200 Knowledge of the CD4 count when reporting a chest X-ray in an AIDS patient is important as opportunistic infections present at different count levels. A CD4 count lower than 200 is regarded as indicating a potentially life-threatening complication of Pneumocystis jiroveci infection. CD4 >500: No risk of opportunistic infection CD4 200-500: Candidiasis, Kaposi’s sarcoma CD4 100-200: P. jiroveci, histoplasmosis, coccidioidomycosis, PML CD4 50-100: Toxoplasma, cryptosporidiosis, cryptococcosis, CMV CD4 <50: Mycobacterium avium complex (MAC)

Answer 33

57. E. Pericolic focal hyperattenuation with a central area of fat density Epiploic appendagitis is most common in the sigmoid colon or caecum, where the appendages arc most prominent. Most cases resolve spontaneously in about 2 weeks. It is therefore an important diagnosis to make, as it does not require surgery. It can appear on ultrasound as a non-compressible pericolic hyperechoic ovoid mass immediately under the abdominal wall. The accordion sign is seen in pseudomembranous colitis on post-contrast CT. Ascites is a non-specific sign that can be seen in a variety of conditions, including liver failure, trauma and pseudomembranous colitis. Mucosal wall thickening with air-filled outpouchings is characteristic of diverticulitis.

Answer 34

58. C. The upper pole moiety is often associated with an ectopic ureterocoele. Ureteric duplication is seen in around 1%-2% of the population and is usually unilateral. The upper pole moiety inserts inferiorly and is often associated with an ectopic ureterocoele, which is more likely to obstruct, causing upper pole calyceal dilatation. The lower pole ureter inserts horizontally into the bladder, making it prone to vesicoureteric reflux, which can lead to scarring and deformity of the obstructed kidney’s lower pole. Intravenous urography may show poor or no function in the dilated obstructed upper pole. An MR or CT Urogram may also demonstrate the 'drooping lily’ sign caused by the lower pole moiety being displaced inferiorly.

Answer 35

59. E. Nail-patella syndrome Nail-patella syndrome is a rare autosomal dominant disorder characterised by symmetrical mesodermal and ectodermal abnormalities. Radiographic abnormalities include bilateral posterior iliac horns in 80% (diagnostic), flared iliac crests with protuberant anterior iliac spines, genu valgum owing to asymmetrical development of the femoral condyles, prominent tibial tubercles, fragmentation/hypoplasia/absence of the patella, radial head/capitellum subluxation with dislocation of the radial head dorsally, short fifth metacarpal, clinodactyly of the fifth finger, scoliosis and, occasionally, mandibular cysts. Protrusio acetabuli and bipartite patella are not disease entities as such; they are radiological descriptions of the acetabular floor bulging into the pelvis and a congenital fragmentation or synchondrosis of the patella, respectively. Diastrophic dysplasia refers to severe rhizomelic dwarfism, and Osgood-Schlatter refers to rupture of the growth plate at the tibial tuberosity secondary to an apophyseal traction injury.

Answer 36

60. B. Fatty atrophy of the right masticator muscles Denervation and fatty atrophy of the pterygoid muscles occurs due to involvement of the motor portion of cranial nerve V supplying the muscle of mastication. This nerve runs through the foramen ovale.

Answer 37

61. B. Routine urinary tract ultrasound within 6 weeks Atypical UTI includes the following: Seriously ill, poor urine flow, abdominal or bladder mass, raised creatinine, septicaemia, failure to respond to treatment with suitable antibiotics within 48 hours, infection with non-E. coli organisms. Recurrent UTI includes the following: Two or more episodes of UTI with acute pyelonephritis/upper urinary tract infection, or one episode of UTI with acute pyelonephritis/upper urinary tract infection plus one or more episode of UTI with cystitis/lower urinary tract infection, or three or more episodes of UTI with cystitis/lower urinary tract infection. Recommended Imaging Schedule for Infants Younger than 6 Months

Answer 38

62. A. Tl MR hypointense; T2 MR hyperintense; contrast enhancement on CT avid Benign mesothelioma is otherwise known as solitary fibrous tumour of the pleura. Unlike malignant mesothelioma, it has no recognised association with asbestos exposure. It is usually solitary and more commonly arises from the visceral pleura. It is asymptomatic in 50% and is a recognised cause of finger clubbing, hypertrophic pulmonary arthropathy and episodic hypoglycaemia. It is usually sessile but may be pedunculated, in which case shape and location may vary with the patient’s position. Imaging characteristics are as above, and contrast enhancement may be heterogeneous if there is myxoid degeneration and haemorrhage. About 14%-30% undergo malignant degeneration. Surgical excision is curative.

Answer 39

63. D. Dilated transverse colon with mucosal islands Toxic megacolon and perforation are major complications that account for most ulcerative colitis-related deaths. Toxic megacolon is a fulminant form of colitis where inflammation becomes transmural and ulceration leads to neuromuscular degeneration and loss of muscle tone. 347 Recommended Imaging Schedule for Infants and Children between 6 Months and 3 Years Test Responds well to treatment within 48 hours Atypical UTI Recurrent UTI Ultrasound during the acute infection Ultrasound within 6 weeks DMSA 4-6 months following the acute infection MCUG No No No No Yes No Yes No No Yes Yes No Recommended Imaging Schedule for Children 3 Years or Older Test Responds well to treatment within 48 hours Atypical UTI Recurrent UTI Ultrasound during the acute infection Ultrasound within 6 weeks DMSA 4-6 months following the acute infection MCUG The transverse colon is the least dependent part of the colon in the supine patient and therefore gas collects in this location. Dilatation occurs and perforation is likely. Radiographic findings include marked dilatation of the colon with absence of haustral markings, oedema and thickening of the colon wall, pneumatosis coli and perforation. Barium studies should not be performed because of the risk of perforation.

Answer 40

64. C. Inferior mesenteric artery As the horseshoe kidney ascends, the isthmus comes in contact with the inferior mesenteric artery and halts it, causing the renal pelves to lie inferior and anterior to their normal position. Horseshoe kidney is the most common renal fusion abnormality, which is seen in 1-4 per 1,000 individuals. It occurs when the two kidneys are attached in the midline by their lower poles. There is an increased risk of calculi and infection because of urinary stasis. The risk of trauma is also increased, as in compressive injuries of the abdomen the midline isthmus of the horseshoe is compressed against the spine. In addition, as the kidney is lower-lying than normal, it is less protected by the thoracic cage. There is a three to four times greater risk of malignancies including transitional cell carcinoma, Wilms and occasionally carcinoid.

Answer 41

65. C. Type III The Schatzker classification grades tihial plateau fractures in order of increasing severity based on the pattern of injury. Type I: Lateral tibial plateau split fracture, no depression Type II: Lateral tibial plateau split with depression; most common type Type III: Lateral tibial plateau pure depression only Type IV: Split and/or depressed fracture of medial tibial plateau Type V: Fracture of both medial and lateral tibial plateau with the metaphysis still in continuity with the diaphysis Type VI: Fracture of both tibial plateau and transverse subcondylar tibial fracture with separation of the metaphysis from the diaphysis

Answer 42

66. A. Increased size of her uterine fibroids Tamoxifen has weak oestrogen agonist effects in the uterus despite working as an oestrogen antagonist in the breast, to treat breast cancers. Uterine fibroids are oestrogen sensitive and therefore instead of regressing postmenopausally, these women may experience an increase in symptoms because of their fibroids (as many women taking hormone replacement therapy). Tamoxifen can also cause endometrial hyperplasia and an increased risk of endometrial carcinoma. Formation of multiple ovarian cysts occurs in ovarian hyperstimulation syndrome as a result of clomifene therapy (taken for infertility) and in polycystic ovary syndrome where multiple cysts are characteristically seen around the periphery of enlarged ovaries.

Answer 43

67. B. Agger nasi cell Agger nasi is a Latin term literally meaning nasal mound'. At rhinoscopy, the agger nasi appears as an eminence located on the lateral nasal wall at the leading edge of the middle turbinate; it represents the intranasal portion of the frontal process of the maxilla. As noted earlier, the agger nasi serves as the anterior limit of the frontal recess. Pneumatisation of the agger nasi (resulting in the so-called agger nasi cell) occurs in 78%-98.5% of individuals. When present, agger nasi cells are considered the most anterior of all ethmoid cells and can pneumatise posteriorly to narrow the frontal recess. Coronal and sagittal reformatted CT images are most helpful in identifying the agger nasi cell. On coronal images, the agger nasi appears as a laterally placed sinus below the frontal sinus and anterior to the middle turbinate. Sagittal images demonstrate the anterior location of the air cell. Haller cells are extramural ethmoidal air cells extending to the inferomedial orbital floor. Onodi cells are posterior-most ethmoidal cells which lie superolateral to the sphenoid sinus in close relation to the optic nerve and internal carotid artery.

Answer 44

68. C. Curvature of the interventricular septum to the right Constrictive pericarditis is most common in men aged 30-50 years. It most commonly occurs following cardiac surgery although it is often idiopathic, with other aetiologies including viruses such as Coxsackie B, tuberculosis and uraemia. The computed tomography scan may show a normal-sized heart with superior vena cava, inferior vena cava and azygos vein dilatation. There is flattening of the right ventricle and curvature of the interventricular septum to the left (rather than to the right) because of high right-ventricular filling pressures. Pericardial thickening and calcification is a feature, as are pleural effusions. Treatment involves surgical stripping of the pericardium. If untreated, protein-losing enteropathy may occur as a result of raised inferior vena cava and portal venous pressures.

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69. A. Ascending cholangitis The overwhelmingly important diagnosis not to be missed in this scenario is ascending cholangitis. This is because ascending cholangitis needs immediate treatment with broad-spectrum antibiotics and biliary drainage via either cholecystectomy or acute laparoscopic cholecystectomy. Although a sonographic-positive Murphy’s sign and pericholecystic free fluid suggest a diagnosis of acute cholecystitis, this should not distract the clinician from the presence of cholangitis, which is confirmed by the presence of fever and jaundice and is primarily a clinical diagnosis rather than a radiological one. Acute cholecystitis is not a clinical emergency and in this case is an associated finding that likely predates ascending cholangitis.

Answer 46

70. C. Histiocytic response Histiocytic response describes a macrophage reaction to any component of the arthroplasty (e.g. metal, cement, plastic spacer). The condition tends to occur within 1-5 years after surgery and the characteristic radiographic finding is smooth endosteal scalloping. There is an increased risk of fracture through the affected bone and therefore close follow-up is required. Computed tomography may show a soft tissue component and appearances can be aggressive. Stress shielding refers to areas of lucency often in the femur following THR secondary to alterations in bone loading. It predisposes the patient to both periprosthetic fractures and loosening and is more common in uncemented prostheses.

Answer 47

71. D. Odontogenic keratocyst Odontogenic keratocysts (OKC) are most commonly located in the body or ramus of the mandible. Most OKCs possess destructive potential, with a high recurrence rate after resection. OKCs develop from the dental lamina, which is found throughout the jaw and overlying alveolar mucosa and is lined by stratified keratinising squamous epithelium. Thus, the cysts can occur throughout periapical or primordial regions. Unlike follicular cysts, OKCs can expand cortical bone and erode the cortex. Fortunately, malignant transformation of these lesions is rare. The lesion is multiloculated, often with daughter cysts that extend to the surrounding bone. Multiple OKCs in a young patient should raise the possibility of basal cell nevus syndrome (Gorlin-Goltz syndrome). Associated findings with this autosomal dominant disorder include midface hypoplasia, frontal bossing and prognathism, mental retardation and calcification of the falx cerebri.

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72. C. If physiological periosteal reaction is present, it is typically asymmetric. Periosteal bone formation may be due to either physiologic or pathologic causes. Physiological periosteal new bone formation is seen in up to a third of infants during the first few months of life. They are benign, usually symmetric and involve the long bones (femur, tibia and humerus). Radiographs demonstrate one or more dense lines of periosteal reaction along the diaphyses. Pathologic bone formation generally results from an adjacent inflammatory process or a hypoxic or toxic stimulus. Common causes of pathologic periosteal reaction in children include trauma to the underlying bone. However, other causes such as hypervitaminosis A, prostaglandin therapy, cortical hyperostosis (Caffey’s disease), hypertrophic osteoarthropathy (primary and secondary), osteomyelitis, leukaemia, trauma and syphilis must also be considered. The last four are usually associated with some degree of bone destruction, whereas in the first four diseases the underlying bone is left radiologically intact.

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73. E. Adamantinoma Adamantinoma appears as a well-circumscribed, slightly expansile lesion, usually with a narrow zone of transition, a finding consistent with its indolent nature. It is often multilocular, with sclerosis and lysis seen in a ‘soap bubble’ pattern. The lesion is typically oriented longitudinally along the anterior tibia! diaphysis, with an average length of 10 cm. MR imaging is the best modality for delineating the extent of adamantinoma in the medullary cavity, soft tissues and satellite lesions. These tumours typically demonstrate intermediate signal intensity relative to muscle on T1-weighted images and intensity similar to that of fat on T2-weighted images obtained without fat saturation. Static-enhanced images demonstrate intense homogeneous enhancement within the lesion.

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74. E. Ground-glass and solid components to the nodule A variety of features of solitary pulmonary nod ides suggest a benign aetiology. If computed tomography scans have been performed pre and post-contrast administration, assessment of the degree of enhancement can be performed. Enhancement of less than 15 Hounsfield units strongly favours benignity, whereas enhancement of greater than 15 Hounsfield units could represent malignancy or an inflammatory process. A peripheral rim of enhancement implies benignity but can occur with cavitating tumours such as squamous cell carcinoma. A flattened nodule (axial: craniocaudal diameter ratio of >1.78:1) is also indicative of a benign aetiology, as is central calcification. Partly solid nodules (i.e. solid and ground glass components) are more likely to represent malignancy, in particular bronchioloalveolar cell carcinoma.

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75. A. Yersinia Yersinia enterocolitica is the most common cause of non-stenotic ulcers of the small bowel. It is a Gram-negative organism that causes fever, right iliac fossa pain and diarrhoea. It most commonly affects the terminal ileum. As a human pathogen, Y. enterocolitica is most frequently associated with acute diarrhoea, terminal ileitis, mesenteric lymphadenitis and pseudoappendicitis. It may be complicated by abscess formation and has been associated with reactive arthritis. Tuberculosis and lymphoma are also differential diagnoses; however they arc less common than yersinial infection. Occasionally, they can only be differentiated by direct visualisation and biopsy rather than by imaging characteristics.

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76. C. Detachment of a large submucosal fibroid following embolisation Uterine artery embolisation is an increasingly popular treatment that is used for the treatment of troublesome uterine fibroids; however, complications have been reported. Fibroid passage is one such complication; this is defined as detachment of the treated uterine fibroid. An increased risk of fibroid passage is seen in fibroids abutting the endometrial cavity (e.g. submucosal fibroids). Fibroid passage can precipitate severe pain, infection or recurrent bleeding. In this case, fibroid passage has caused cervical obstruction and pyometra. Cervical carcinoma and a large endometrial polyp can both cause cervical stenosis and consequent pyometra, but they are both much less likely in this circumstance.

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77. D. Homolateral Lisfranc fracture dislocation Lisfranc injury is a fracture dislocation of the tarsometatarsal joints in a dorsolateral direction. The second metatarsal is held in a mortise formed by the medial and lateral cuneiform bones. Transverse metatarsal ligaments, both on the plantar and dorsal surfaces, connect the second to fifth metatarsals proximally. There is no transverse ligament between the first and second metatarsal. The plantar ligaments are stronger; hence most dislocations occur dorsally. If there is medial dislocation of the first metatarsal and lateral dislocation of the remaining metatarsals, it is considered a divergent type of Lisfranc injury. If the alignment of the first metatarsal is normal, or if it displaces laterally along with the remaining metatarsals, it is considered the homolateral type. On AP radiography of the foot, the medial aspect of the second metatarsal and middle cuneiform bone should align and, on the oblique view, the medial aspect of the third metatarsal and the lateral cuneiform bone should align. March fracture is another name for stress fracture, which commonly occurs at the distal shafts of the second and third metatarsals. They may appear on plain radiograph as a lucent line or their presence may be noted secondary' to faint periosteal reaction or callus formation. If not visible on plain films and clinical suspicion persists, MR] or radionuclide scan may be helpful. Lover's fracture is another term for fracture of the calcaneus. Jones fracture occurs in the proximal shaft of the fifth metatarsal. It has a high rate of non-union and is found within 1.5 cm of the fifth metatarsal tuberosity.

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78. C. Tornwaldt’s cyst Tornwaldt’s cyst or pharyngeal bursa is an epithelial cyst that is related to the embryogenesis of the notochord. The incidence of Tornwaldt’s cysts has been reported in 4% of autopsy specimens and from 0.2% to 5% on MR observation. They occur in the posterior wall of the nasopharynx. Although Tornwaldt’s cysts are present in all age groups, the peak incidences have been reported to occur in various age groups. The three major symptoms are persistent, noticeable nasal discharge; obstinate occipital headaches; and halitosis and an unpleasant taste in the mouth. According to researchers who have used MR imaging to study Tornwaldt’s cyst, this lesion has characteristic high signal intensity on T1-weighted and T2-weighted images.

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79. E. Mastocytosis Multifocal histiocytosis has a triad (only 10% of patients) of calvarial lesion, exophthalmos and diabetes insipidus. About 40% of patients with Hand-Schüller Christian disease (multifocal histiocytosis) have destructive lesions affecting the alveolar margins on the mandible. The surrounding radiolucent matrix gives the appearance of floating teeth. Other conditions such as leukaemia, multiple myeloma and Burkitt lymphoma can also give the appearance of floating teeth. Mastocytosis can cause focal or diffuse sclerotic lesions and does not give the appearance of floating teeth.

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80. A. Raised serum calcium levels The aetiology of alveolar microlithiasis is uncertain, and the condition is characterised by multiple tiny intra-alveolar opacities known as calcospherites. The peak age of those affected is 30-50 years, although onset is at a young age, with antenatal onset having been reported. On biochemical profiling, serum calcium and phosphate levels are both normal. There is diffuse involvement of both lungs by submillimetre micronodulations. Uptake on bone scintigraphy is intense. The majority of patients are asymptomatic, although shortness of breath on exertion, cyanosis and digital clubbing may be present. Lungs may appear more dense than the heart shadow on a chest radiograph, and radiographic features are disproportionate to the degree of symptoms.

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81. A. Adenocarcinoma of the small bowel Crohn’s disease is a risk factor for the development of small bowel tumours, including lymphoma and small bowel adenocarcinoma. Lymphoma, however, is usually associated with lymphadenopathy and rarely involves the duodenum, being more common in the ileum or stomach. It is also more commonly extraluminal. In contrast, adenocarcinoma is most commonly intraluminal. Hamartomatous polyps arc benign polyps usually associated with Peutz-Jeghers syndrome, which is also a risk factor for small bowel adenocarcinoma. Gastrointestinal stromal tumours are usually extramural exophytic masses. Pancreatic carcinoma is not usually associated with Crohn’s disease but could cause a bulky tumour mass in this region, although it should arise from the pancreas and invade the duodenum.

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82. E. Papilloma Papillomas are benign lesions (hyperplastic epithelium on a stalk) usually found in an ectatic subareolar major duct. They are the most common cause of blood or serous discharge. Papillomatosis refers to multiple peripheral papillomas that are located in the duct lumen just proximal to the lobule; it carries an increased risk of malignancy. Ductal ectasia is a benign entity that represents accumulation of cellular debris in enlarged subareolar ducts. Presentation is usually with non-bloody discharge and/or pain. It is the second most common cause of blood or serous discharge. Plasma cell mastitis refers to an inflammatory component associated with extensive secretory calcification.

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83. C. Sjögren’s syndrome Most high grade mucoepidermoid carcinomas, undifferentiated carcinomas, adenocarcinomas and squamous cell carcinomas of the major salivary glands have low to intermediate signal intensity on long repetition time images. Some malignancies, however, exhibit elevated signal intensity on T2-weighted images. Most commonly, this is seen in low-grade mucoepidermoid carcinomas, in some adenoid cystic carcinoma, and rarely in adenocarcinomas. Among benign masses that are not hyperintense on long repetition time images, Warthin’s tumour, the second most common benign mass in the adult parotid gland, is often of intermediate, low or mixed signal intensity on T2-weighted images. The chronic sialadenitis, such as Sjögren disease, Mikulicz disease (also known as Sjögren Type 1 or sicca syndrome without a connective tissue disorder) and radiation sialadenitis may also appear hypointense on T2 weighted images. In most series, these exceptions account for the 25% error rate that occurs if one relies solely on signal intensity on T2-weighted images to predict histologic diagnosis.

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84. A. Cartilage injury Conventional radiographs demonstrate physeal widening, irregularity and fragmentation. MR imaging can be used to further characterise the injury by demonstrating oedema in the adjacent bone on T2-weighted or STIR MR images and focal extensions of unmineralised cartilage into the metaphysis, which appear as ‘tongues’ of high signal intensity on T2-weighted, STIR and gradient-recalled echo (GRE) images and as intermediate signal intensity on T1-weighted images. Continued overuse leads to further physeal widening, irregularity and occasionally bone bridging.

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85. D. Pars flaccida (attic) cholesteatomas are located at the lower one-third portion of the tympanic membrane. Cholesteatomas can be classified as either congenital or acquired, though the origins are indistinguishable with histology and imaging. Only the location of the lesion, the clinical history of the patient, and the otologic status of the tympanic membrane (TM) give some idea how to differentiate these two types of cholesteatomas. Congenital cholesteatomas develop from embryonic epithelial rests and can be located anywhere in the temporal bone: in the middle ear, in the mastoid, in the petrous apex in the squama of the temporal bone, within the TM or in the external auditary canal (EAC). Furthermore, the same histologic entity can arise in other areas of the skull, in the extracranial soft tissues or in an intracranial extra-axial location, where it is referred to as epidermoid cyst. Middle ear congenital cholesteatomas represent approximately 2% of all middle ear cholesteatomas. Primary acquired cholesteatomas (80% of all middle ear cholesteatomas) develop behind an apparently intact TM, usually in the region of the pars flaccida. Secondary acquired cholesteatomas (18% of all middle ear cholesteatomas) grow into the middle ear through a perforated TM, usually through the pars tensa and sometimes the pars flaccida. Pars flaccida (attic) cholesteatomas are located at the upper one third portion of the TM. Pars tensa (sinus) cholesteatomas develop most often through a defect of the lower two-thirds portion of the TM.

Answer 62

86. B. Round and hypoechoic node US criteria for benign versus malignant nodes:

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87. C. Ankylosing spondylitis Ventilation in the lungs is better in the upper zones than in the lower zones. By contrast, perfusion is better in the lower zones than in the upper zones. Accordingly, there is a tendency for occupational dust exposure to cause interstitial fibrosis with a predominantly upper zone distribution (although asbestosis is a notable exception, with a lower zone distribution). Ankylosing spondylitis also has an upper zone distribution. Lower zone fibrosis tends to arise as a result of haematogenous factors. Hence, drug-induced fibrosis (e.g. that caused by methotrexate) and collagen vascular diseases (such as systemic lupus erythematosus, rheumatoid arthritis and scleroderma) show' lower zone predominance. Idiopathic pulmonary fibrosis is the most common cause of lower zone interstitial fibrosis.

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88. D. Malignant GIST (gastrointestinal stromal tumour) Gastrointestinal stromal tumours are the most common mesenchymal tumours of the gastrointestinal tract. They are usually found around the stomach and are often exophytic in nature. Commonly, they are found incidentally and can become very large before causing symptoms. These are difficult to distinguish from leiomyomas, leiomyosarcomas, schwannomas and neurofibromas radiologically and are characterised on immunohistochemistry by their expression of the KIT gene. It is important to appropriately identify GISTs as these can be treated successfully with tyrosine kinase inhibitors (Glivec®). Gastrointestinal stromal tumours can metastasise to the liver and peritoneum but lymphadenopathy is very uncommon. Once these tumours are over 5 cm malignancy becomes more likely. Lymphoma would usually be associated with lymphadenopathy. A gastric adenocarcinoma of this size would also be likely to have associated lymphadenopathy. Gastric lipoma should not enhance and be of low attenuation. Ectopic pancreas is usually endoluminal with an ill-defined border and is more often found in the antrum of the stomach and duodenum.

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89. B. The absence of the lateral epicondyle ossification centre is often a normal finding in a 12-year old. The ossification centres occur in order of appearance according to the commonly recited mnemonic CRITOE - capitellum, radial, internal (medial epicondyle), trochlear, olecranon and external (lateral epicondyle). Although the associated age groups are commonly stated as 1, 3, 5, 7, 9 and 11 years of age, respectively, there is actually some variability, particularly as the final ossification centres appear. As such, the lateral epicondyle ossification centre may not appear until age 13. Medial epicondyle avulsion injuries are far more common than lateral epicondyle avulsion injuries. The common extensor tendon inserts onto the lateral epicondyle and the common flexor tendons insert onto the medial epicondyle.

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90. D. Gymnast’s wrist results in negative ulnar variance In Little Leaguer’s shoulder, excessive overhead throwing leads to widening and irregularity of the proximal humeral physis on radiographs and MR images. In gymnast’s wrist, repetitive weight-bearing on the wrist can lead to physeal stress changes of the distal portion of the radius and, occasionally, the ulna. Abnormal distal radial growth produces positive ulnar variance. At a later stage, this could be associated with injury to the TFC complex. The valgus stress of the cocking and acceleration phases of pitching results in a traction injury to the medial epicondyle that is known as Little Leaguer's elbow. MR imaging is more sensitive than conventional radiography for detecting physeal changes.

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91. B. Two-chamber view in mid-diastole In cardiac CT imaging, standard views include the four-chamber (both atria and ventricles), three-chamber (left ventricle and atrium and aortic root), two-chamber (left atrium and ventricle) and short axis projection views. Five-chamber views (both atria and ventricles and aortic root) can also be used. These views are usually formulated using maximal intensity projection technique on source images, with two-chamber, three-chamber and four-chamber view's obtained by rotating the imaging plane along the left ventricle’s long axis. Combinations A through E will all demonstrate the mitral valve, but the two-chamber view taken in mid-diastolic is the optimal view and timing for the assessment of the mitral valve.

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92. E. Haemochromatosis The patient is likely to have undetected haemochromatosis; the dense liver will be caused by iron deposition and this would give a low signal on T2-weighted (especially T2*) magnetic resonance images. Deposition in the pancreas and gonads can cause diabetes, erectile dysfunction and hypogonadism, respectively. Haemochromatosis is often termed bronze diabetes, as there is hyperpigmentation in the skin because of the deposition of iron. It is known to cause osteoarthritic changes at many joints because of iron deposition, and the most characteristic place for this to occur is the metacarpo-phalangeal joints, especially the second and third, where there may also be hook-like osteophytes. Amyloidosis causes a decrease in the liver density. Wilson disease can give a dense liver and is associated with arthropathy, although this is usually of the large joints and spine; it does not cause diabetes and more often causes neuropsychiatric complaints. Haemophilia would tend to present as an arthropathy first involving multiple joints and at a younger age. The dense liver may be caused by repeated blood transfusions but is less likely to be associated with diabetes in this case. Gaucher disease (the most common glycogen storage disease) tends to present earlier in life, although late cases are not unheard of. They tend to present with splenomegaly, lytic bone lesions and haematological upset.

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93. C. Radionuclide imaging using an analogue of guanethidine such as metaiodobenzylguanidine (MIBG) An MIBG scan will help evaluate an extra-adrenal paraganglioma. Radionuclide imaging using an analogue of guanethidine such as MIBG is concentrated in sympatho-adrenal tissue and is thus used to image adrenal medullary disorders.

Answer 70

94. C. Prostate cancer metastases Metastases to bone are 15 100 times more common than primary skeletal neoplasms and are found at sites of dominant haematopoietic marrows because of its rich haematopoietic marrow. In adults, this includes the calvarium, spine, flat bones and proximal humeral and femoral metaphyses. Focal sclerotic lesions are hypointense on T1 and T2-weighted sequences. The most common metastases in adult men are due to prostate carcinoma. Renal metastases are usually lytic. Haemangiomas are hyperintense on both T1 and T2-weighted sequences

Answer 71

95. B. Premaxillary and retro-antral fat are rarely involved. The combination of necrotising granulomatous lesions of the upper and lower respiratory tracts, generalised necrotising vasculitis of arteries and veins and glomerulonephritis is called Granulomatosis and polyangitis (previously called Wegener’s granulomatosis). The disease may affect the eyes, skin, joints, muscles and cardiac system as well as the paranasal sinuses, lungs and kidneys. Advanced Wegener’s granulomatosis may lead to destructive lesions of the hard palate, sinonasal-oral fistulas or complete nasal septal destruction. The premaxillary soft tissues, retro-antral fat, pterygopalatine fossa, infratemporal fossa and orbits are commonly involved. Sarcoidosis may have a similar appearance. When a destructive mass in the nasal septum extends into the orbits, Wegener’s granulomatosis should be considered in the differential diagnosis. Intracranial involvement may also result, usually in the anterior cranial fossa, owing to the spread of the disease through the cribriform plate. As the disease becomes chronic, the walls of the residual paranasal sinuses (particularly the maxillary sinuses) become markedly thickened while the sinus volume is gradually reduced, and the nasal septum may completely disappear.

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96. D. Absence of drop metastases on MRI spine imaging The description would fit with a medulloblastoma. Drop metastases arc commonly found at presentation, and complete imaging of the neuraxis is strongly recommended at diagnosis. Cerebrospinal fluid (CSF) seeding, with the resultant formation of spinal intradural ‘drop metastases’, is a well-known mode of dissemination for many intracranial neoplasms. This manner of tumour spread is most commonly observed in medulloblastoma. Ependymomas, anaplastic gliomas, germinomas, choroid plexus tumours and pineal parenchymal tumours (pineoblastomas and pineocytomas) are other intracranial tumours that frequently deposit metastases in the spinal canal. Intradural metastases may also occur as a result of haematogenous spread from extracranial neoplasms, most commonly lung and breast adenocarcinoma and from haematological malignancies.

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97. B. Grade 2 The most common location for injury to the premature brain is the periventricular white matter, with ischaemic parenchyma manifesting as periventricular leukomalacia (PVL). Initial sonograms show hyperechogenic globular change in the periventricular regions, and MR images depict areas of T1 hyperintensity within larger areas of T2 hyperintensity. Subsequent cavitation and periventricular cyst formation, features that are required for a definitive diagnosis of PVL, develop 2-6 weeks after injury and are easily seen on sonograms as localised anechoic or hypoechoic lesions. The progressive change ventricular dilatation occurs, described as end-stage PVL Subsequent reperfusion to the ischaemic tissues in the setting of weakened capillaries and increased venous pressure result in germinal matrix haemorrhage, ranging in severity from subependymal haemorrhage (Grade 1) to intraventricular haemorrhage without (Grade 2) and with (Grade 3) ventricular dilatation, to parenchymal extension and coexisting periventricular venous infarction (Grade 4).

Answer 74

98. B. Presence of microcalcification These are general recommendations for adult patients who have a thyroid nodule on US images, regardless of how the nodule was initially detected. The recommendations may not apply to all patients, including those who have historical, physical or any other features suggesting they arc at increased risk for cancer or who have a history of thyroid cancer. Part I The following are general recommendations for nodules 1.0 cm or greater in largest diameter. Solitary nodule: Strongly consider FNA for (1) a nodule 1.0 cm or more in largest diameter if microcalcifications are present and (2) a nodule 1.5 cm or more in largest diameter if any of the following apply: (a) nodule is solid or almost entirely solid or (b) there are coarse calcifications within the nodule. Consider FNA for (1) a nodule 2.0 cm or more in largest diameter if any of the following apply: (a) the nodule is mixed solid and cystic or (b) the nodule is almost entirely cystic with a solid mural component; or (2) the nodule has shown substantial growth since prior US examination. FNA is likely unnecessary if the nodule is almost entirely cystic, in the absence of the above-listed features. Multiple nodules: Consider FNA of one or more nodules, with selection prioritised on the basis of the previously stated criteria in the order listed above. FNA is likely unnecessary in diffusely enlarged glands with multiple nodules of similar US appearance without intervening normal parenchyma. Note that these recommendations are not absolute or inflexible. In certain circumstances, the physician's clinical judgment may lead him or her to determine that FNA need not be performed for nodules that meet the recommendations above. In others, FNA may be appropriate for nodules that do not meet the criteria listed above. Part II The recommendation for non-diagnostic aspirates from initial FNA is as follows: Consider a second FNA of nodules meeting the criteria for FNA of solitary nodules, as outlined above. Part III The presence of abnormal lymph nodes overrides the US features criteria and should prompt biopsy of the lymph node and/or (if necessary) of an ipsilateral thyroid nodule.

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99. A. Transection of the proximal thoracic duct Disruption of the thoracic duct results in a chylothorax. The thoracic duct measures 45 cm and commences at the level of T12, ascending on the right side of the aorta, crossing the midline at the level of T5 and ascending in the left hemithorax to drain into the confluence of the left subclavian and internal jugular veins. Accordingly, disruption of the proximal thoracic duct results in a right-sided pleural effusion, and disruption of the distal thoracic duct causes a left-sided pleural effusion. Dissecting aneurysm of the thoracic aorta and traumatic rupture of the aorta both result in left-sided effusions, as does spontaneous oesophageal rupture (Boerhaave syndrome) and gastric carcinoma. Pancreatitis can give rise to bilateral or unilateral pleural effusions, with more than two-thirds of pancreatitis-related effusions occurring on the left.

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100. A. In-phase and out-of-phase T1-weighted images The hyperechoic area seen on ultrasound anteriorly within Segment 4 is most commonly caused by focal fatty infiltration and is a common finding at ultrasound and is more common in heavy drinkers, hyperlipidaemia and in obese patients. It is also commonly seen at the portal bifurcation. Although all of the above sequences will be important in accurately defining the lesion, the most useful sequence when this is likely to be focal fatty infiltration will be the in-phase and out-of-phase T1-weighted images. Focal fat should lose signal between the in-phase T1-weighted images and the out-of-phase T1-weighted images.

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101. C. MIBG, an analogue of guanethidine, is used to image adrenal cortical disorders. All the statements are correct except option C. MIBG, an analogue of guanethidine, is used to image adrenal medullary disorders. 18F FDG has been reported to be able to differentiate between benign adenomas and metastases.

Answer 78

102. E. The AC ligament and CC ligament are ruptured with detachment of the deltoid muscle. The Rockwood classification is used to classify ACJ injuries. Lifting of the clavicle above the superior border of the acromion implies a severe strain injury with typical complete derangement of the internal attachments and stabilising structures (Grade III injury). Grade IV VI injuries also imply the same degree of soft-tissue injuries, but there is accompanying complete dislocation with the clavicle displacing into various positions. Grade I injuries have an intact CC with AC ligament strain. Grade II injuries (elevation of the clavicle but not above the superior border of the acromion) have a ruptured AC ligament and joint capsule, with strain of the CC ligament.

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103. D. Mounier-Kuhn disease Tracheobronchomegaly, known as Mounier- Kuhn disease, is a rare condition, usually affecting men in the fourth and fifth decade of life. It is characterised by marked dilatation of the trachea and bronchi. Patients typically present with recurrent respiratory infections and bronchitis. It is caused by atrophy and dysplasia of the tracheal wall and the tracheal diameter is usually more than 3 cm. Tracheopathia osteoplastica is a rare benign disease affecting the trachea and characterised by multiple submucosal osteocartilaginous growths within the anterior and lateral walls. This condition, as the others listed above (relapsing polychondritis, tracheal Wegeners granulomatosis, tracheal sarcoidosis), cause significant narrowing of the tracheal diameter with wall thickening and symptoms of stridor, wheeze, cough and dyspnoea

Answer 80

104. D. Carcinoid syndrome Carcinoid syndrome is a collection of symptoms that are caused by a small proportion of carcinoid tumours. This nearly always occurs following metastasis to the liver, although it can happen if a carcinoid tumour occurs outside the gut and its excreted chemicals (adrenocorticotropic hormone, histamine, serotonin, etc.) bypass liver metabolism. These chemicals cause recurrent diarrhoea, bronchospasm, flushing and right-sided heart failure. A spiculated mesenteric mass with calcification and a desmoplastic effect on the adjacent bowel in a patient with these symptoms is characteristic of carcinoid syndrome. These tumours are often hyperintense on T2-weighted magnetic resonance imaging as they are very’ vascular. They also produce hypervascular metastases. If there is carcinoid syndrome, the carcinoid tumour is usually located in small bowel. Malignant melanomas are often bright on T1 and do not usually give a desmoplastic mesenteric reaction or give flushing. Cholangiocarcinomas produce hypervascular liver metastases but mesenteric deposits are unusual and the biliary tree appeared normal in this case. Retractile mesenteritis would not cause liver lesions. Mesenteric abscesses from cholecystitis would be rare and only the rim should enhance with gadolinium. This condition would also not be expected to produce a desmoplastic reaction.

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105. E. Uraemic cystic disease About 40% of patients with end-stage renal disease develop renal cysts. The incidence increases with time on dialysis so that incidence of uraemic cystic disease is 90% in patients 5 years on dialysis. Associated complications include haemorrhage within the cysts and rarely malignancy. Cysts regress after successful transplantation.

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106. D. Cervical spine CT. In high-risk patients or patients with limited physical examination, given the relative insensitivity of plain films, CT should be performed. In a rheumatoid patient there is an increased risk of cervical injury. Repeat views would not be of benefit Age and mechanism of injury would indicate CT cervical spine according to NICE guidelines.

Answer 83

107. B. Stress fracture of the femoral neck involves the superior surface. The most common cause of stress fractures is a chronic and repeated workload. Children with extremity malalignment or abnormal weight-bearing also are at increased risk. Typical locations of stress fractures in children include the tibia, fibula, femur and tarsal and metatarsal bones. MR imaging is currently the best diagnostic modality for stress fractures. Stress fractures of the femur tend to occur after skeletal maturity and resemble adult injuries, affecting the inferior surface of the neck, the shaft and the distal metaphysis. This injury is most common in endurance athletes, such as runners, triathletes or soccer players but also occurs in association with abnormal weight-bearing, such as with a coxa vara deformity. The most common site for stress fractures in the adolescent athlete is the tibia. Tibial stress fractures occur with activities requiring sudden stops or changes in direction, such as football, soccer and tennis. Stress also can result in shin splints, which are probably an early stress response secondary to periosteal traction. In cases of stress fractures, MR imaging shows diffuse and irregular bone marrow oedema, whereas in shin splints, the area of high signal intensity often is more linear and is limited to the medial aspect of the tibia. Spondylolysis is a stress injury of the pars interarticularis that is due to repetitive extension and torsion of the trunk. Usually occurring in the lower segments of the lumbar spine, stress injuries of the pars interarticularis have been observed in young female gymnasts, college football players and wrestlers.

Answer 84

108. B. Destruction of underlying bone is normally seen at presentation on plain radiography. If joint inflammation is limited to a single joint, infection must first be carefully excluded. The cause of septic arthritis is usually related to haematogenous seeding owing to staphylococcal or streptococcal microorganisms. The radiographic features of a septic joint encompass those of any inflammatory arthritis namely, periarticular osteopenia, uniform joint space narrowing, soft-tissue swelling and bone erosions. Not all findings may be present simultaneously, and, acutely, bone erosions may not be evident. Furthermore, the joint space may be initially widened owing to the effusion. Joint space widening may also be seen with more indolent and atypical infections, such as those related to tuberculosis and fungal agents. The Phemister triad describes these findings classically seen in tuberculous arthritis: juxta- articular osteopenia, peripheral bone erosions and gradual narrowing of the joint space. The presence of anterior capsular distension was noted as convexity of the anterior recess and compared to contralateral normal side in equivocal cases.

Answer 85

109. A. Malignant melanoma About 90% of all tracheal tumours are malignant and of those metastases are the most common group. Malignant melanoma, renal cell tumour, breast carcinoma and colonic adenocarcinoma are the most common sources of haematogenous metastatic spread to the tracheal mucosa. The lesions are usually multiple, polypoid, well defined and without tracheal wall thickening or extratracheal extension, as commonly seen in primary tracheal tumours. Cancers of the thyroid, oesophagus, larynx and lung may invade the tracheal wall by direct extension from the primary source, and this type of spread is the most common in secondary tracheal malignancies. The symptoms of tracheal malignancies are non-specific and include haemoptysis, dyspnoea, chest pain, cough and wheeze.

Answer 86

110. A. Hashimoto thyroiditis Hashimoto thyroiditis, also known as chronic autoimmune lymphocytic thyroiditis, is a disease with a typical clinical presentation of painless diffuse enlargement of the thyroid gland accompanied by hypothyroidism and thyroid autoantibodies. The sonographic appearance of Hashimoto thyroiditis is well recognised. The gland is often diffusely enlarged, and the parenchyma is coarsened, hypoechoic and often hypervascular. A micronodular pattern on ultrasound is highly diagnostic of Hashimoto thyroiditis with a positive predictive value of 95%. Discrete nodules may, however, also occur within diffusely altered parenchyma or within sonographically normal parenchyma. The nodular form of Hashimoto thyroiditis has not received nearly as much analysis as the diffuse form, and the reported findings have been variable.

Answer 87

111. D. Atrophic gastritis Atrophic gastritis has a high association with B12 deficiency. It occurs in the older population and is often caused by autoimmune disease. However, it can also be caused by Helicobacter pylori, leading to chronic inflammation of the gastric mucosa and eventually fibrosis. Atrophic gastritis particularly affects the chief and parietal cells, resulting in achlorhydria and B12 deficiency, and causes the classic featureless stomach. It is associated with an increased risk of gastric carcinoma. Infectious gastritis, Menetrier disease and eosinophilic gastritis are often associated with thickened folds. Linitis plastica would have a history of weight loss and iron deficiency anaemia as opposed to B12 deficiency.

Answer 88

112. C. Transvaginal ultrasound This patient has a suspected ectopic pregnancy, which is a potentially fatal gynaecological emergency. Transvaginal ultrasound (TVUS) can detect intrauterine pregnancy 1 week sooner than transabdominal ultrasound (TAUS). If no intrauterine pregnancy (IUP) is seen on TAUS, you should therefore confirm that there is no IUP by TVUS where possible. The free fluid in this case is the result of a ruptured bleeding tube secondary to an ectopic pregnancy; the fluid may be echogenic because of blood content. TVUS is preferable to CT, as the patient may have a viable early pregnancy. In hospitals where TVUS is not available, emergency laparoscopy may be considered. However, MRI is not a safe environment for a potentially unstable patient.

Answer 89

113. C. Periarticular osteoporosis Degenerative arthritis and osteoarthritis are interchangeable terms that can be used to describe the clinical and radiographic joint changes associated with ageing. Early changes include damage to the articular cartilage with progressive damage to and loss of the ground substance that eventually leads to the subchondral bone being exposed Clinically, patients present with joint pain worsened with use and the joint may be found on examination to be enlarged, deformed, tender with crepitus and possibly display joint effusion. The five radiographic hallmarks are asymmetrical joint space narrowing, subchondral sclerosis, subchondral cysts, osteophytes and lack of osteoporosis. Periarticular osteoporosis is much more characteristic of rheumatoid arthritis.

Answer 90

114. C. There is associated dilatation of the superior ophthalmic vein. Graves’ disease of the orbit is also known as thyroid ophthalmopathy or endocrine exophthalmos. It is produced by long-acting thyroid stimulating hormone, probably due to cross reactivity against antigens shared by thyroid and orbital tissue. Signs and symptoms usually develop within 1 year of hyperparathyroidism, it is the most common cause of unilateral/bilateral proptosis in adults. It commonly involves the inferior rectus first (mnemonic I’M SLOW). The superior ophthalmic vein is dilated due to compromised orbital venous drainage at the orbital apex. There is increased density of the orbital fat late in the disease.

Answer 91

115. C. Squamous cell carcinoma of the urethra Primary urethral carcinoma is rare. About 50%-75% occur in the bulbar urethra and nearly 90% are squamous type, particularly if there has been a stricture in the past. Urethral carcinoma is often advanced at diagnosis, explaining the weight loss. Primary transitional cell carcinomas (TCC) are closer to the bladder neck, although secondary TCCs can occur anywhere in the urethra when seeded from the bladder in patients with a bladder TCC history, when they are often multiple (these are the most commonly encountered male urethral tumours). Adenocarcinomas are extremely rare and tend to occur at the prostatic utricle or glands of Littre. Haematogenous metastases to the urethra are exceedingly rare but are most likely to be from melanoma. Prostatic carcinoma would be more likely to involve the prostatic urethra. Benign strictures can appear a little irregular, but weight loss would not be expected.

Answer 92

116. C. Tracheomalacia Weakening of the tracheal walls associated with posterior tracheal wall collapse during expiration is a recognised complication post-intubation and tracheal tube placement, when the cuff pressures exceed 25 cmH20. This condition is often underdiagnosed as it can present with non-specific symptoms such as shortness of breath, wheeze, stridor and recurrent chest infections. Dynamic CT scan during inspirational and expirational phases is the modality of choice for its diagnosis, and it is considered positive when the AP diameter of the trachea decreases more than 50% during expiration. Tracheomalacia may also be a complication of chronic obstructive pulmonary disease (COPD), relapsing polychondritis and recurrent infections. Tracheal diverticulum and saber-sheath trachea (decreased coronal diameter of trachea) are conditions associated with COPD, and carrot-shaped trachea refers to a narrowing of the tracheal diameter in the caudal direction as a result of an aberrant left pulmonary artery.

Answer 93

117. C. Small bowel lymphoma Small bowel lymphoma is a soft pliable tumour and therefore can often be quite large in size without causing a bowel obstruction. Characteristically, it destroys Auerbach’s plexus, leading to aneurysmal dilatation of the small bowel; however, this is a rare finding. It often fistulates, mimicking Crohn’s disease, but there would be more likely to be skip lesions with Crohn’s disease. Tuberculosis can have similar appearance, but these patients will often be from an endemic area or have HIV; fever and night sweats will also be more prominent, although these symptoms can also occur in lymphoma.

Answer 94

118. B. Liposarcoma Liposarcoma is a malignant tumour of mesenchymal origin; it is the second most common soft-tissue sarcoma in adults after malignant fibrous histiocytoma (now' called pleomorphic undifferentiated sarcoma or PUS). It usually presents in the fifth to sixth decade. On CT, it is seen as a non-specific soft-tissue mass, as the fat content is usually not radiologically detectable. On MRI, because of the high content of myxoid cells (the most common type of liposarcoma), it is low signal on T1-weighted sequences and high signal on T2-weighted sequences. A lipoma would not be expected to enhance post-contrast. A large lymph node would be unlikely to reach the sizes described and additionally may be hyperintense to muscle on T1-weighted sequences. A soft-tissue fibroma would have a small hypointense nodule on all sequences. Lipoblastoma usually affects children less than 3 years of age.

Answer 95

119. D. The beta angle can help to determine the dysplasia subtype. The Graf method for ultrasound classification system for developmental dysplasia of the hip (DDH) in infants combines both the alpha and beta angles. The alpha angle is formed by the acetabular roof to the vertical cortex of the ilium. The normal value is greater than or equal to 60 degrees. Less than 60 degrees suggests acetabular dysplasia. The beta angle is defined as the angle formed between the vertical cortex of the ilium and the triangular labral fibrocartilage (echogenic triangle). There is a great deal of variability in the beta angle and is not universally used. The beta angle is necessary to determine the subtype of hip dysplasia. Acetabular angle is a radiographic assessment for dysplasia. It is formed by a horizontal line connecting both triradiate cartilages (Hilgenreiner line) and a second line which extends along the acetabular roofs.

Answer 96

120. C. Pott’s puffy tumour Pott’s puffy tumour is defined as a subperiosteal abscess of the frontal bone with frontal osteomyelitis. Frontal sinus infection can spread directly through the thin bone wall of this sinus or through the network of small veins that drain its mucosa. Today, this is a rare complication, given the widespread use of antibiotics. Trauma and frontal sinusitis arc the most common causes of this condition. The bacteria causing Pott’s puffy tumour usually reflect the type of bacterial species responsible for community-acquired chronic sinusitis. The most common causal organisms are streptococci, staphylococci and anaerobic bacteria. Cultures frequently reveal polymicrobial involvement. The infection may spread as a thrombophlebitis from the frontal sinus through the diploic veins, involving the intracranial space with consequent epidural or subdural empyema, meningitis, brain abscess and venous sinus thrombosis.

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