TEST PAPER 7 Flashcards
1
Q
1.A middle-aged patient who sustained RTC 6 months ago presents with progressive visual lossand exophthalmos on the right. MRI demonstrated a dilated superior ophthalmic vein withflow voids in the cavernous sinus. What is the likely diagnosis?
A. Buphthalmos
B. Carotid-cavernous fistula
C. Orbital pseudotumour
D. Arteriovenous malformation
E. Dural fistula
A
1.B. Carotid-cavernous fistula
Carotid-cavernous fistula (also described as caroticocavernous fistula) is an abnormalcommunication between the internal carotid artery (ICA) and the veins of the cavernous sinus.
It is mostly due to trauma with laceration of the ICA within the cavernous sinus usually due to a skull base fracture or penetrating trauma. Ultrasound and MRI usually show arterial flow in the cavernous sinus and superior ophthalmic vein.
2
Q
2.A preterm neonate on the intensive care unit develops gross abdominal distension andbleeding per rectum. A supine abdominal radiograph is performed demonstrating multipleloops of dilated bowel loops.
Given the likely diagnosis, all of the following would be expected findings on the supine radiograph, except:
A. Mottled gas shadows within the bowel wall
B. Branching gas pattern overlying the liver shadow
C. Foci of calcification projected over the renal angles
D. Generalised lucency overlying the liver shadow
E. Rounded area of lucency within the central abdomen
A
2.C. Foci of calcification projected over the renal angles
The main observations to be made on the plain abdominal radiograph relate primarily to thepresence, amount and distribution of gas, which includes intraluminal gas, intramural gas, portal venous gas and free intraperitoneal gas. From observations of the intraluminal gas, it may sometimes be possible to make inferences regarding the presence of bowel wall thickening, free fluid and focal fluid collections.
Dilatation with loss of the mosaic pattern and the development of rounded or elongated loops is more suggestive that an abnormality is present. On plain abdominal radiographs, intramural gas may be diffuse or localised and appears as linear or rounded radiolucencies. Extensive intramural gas can result in a mosaic pattern or bubbly appearance. Portal venous gas appears as branching, linear, radiolucent vessels that may extend from the region of the main portal vein towards the periphery of both hepatic lobes.
On the supine view, large amounts of gas may give rise to the ‘football’ sign, where the gas outlines the whole of the peritoneal cavity, the undersurface of the diaphragm and the falciform ligament (the lacing of the football). In this view, even smaller amounts of free gas may be detected when both sides of the bowel wall are outlined (Rigler’s sign).
3
Q
3.Which of the following is a recognised cause of a ‘bone within bone’ appearance?
A. Renal osteodystrophy
B. Paget’s disease
C. Hyperparathyroidism
D. Melorheostosis
E. Osteopathia striata
A
3.B. Paget’s disease
A ‘bone within bone’ appearance describes the radiographic appearance whereby a bone appearsto have another bone within it, which results from endosteal new bone formation. Recognised causes include Paget’s disease, sickle cell disease, thalassemia, Gaucher’s disease, acromegaly, hypervitaminosis D, scurvy and rickets, among many others. It can also be a normal finding in infants, particularly in the thoracolumbar spine.
4
Q
4.A 25-year-old woman with recurrent urinary tract infections and post-void dribbling attendsthe urology clinic. The urologist suspects a urethral diverticulum. What is the mostappropriate first-line test?
A. Micturating cystourethrogram
B. Urodynamics
C. Transvaginal ultrasound
D. Double balloon catheter positive pressure urethrography
F. Pre- and post void magnetic resonance imaging of urethra
A
4.E. Pre- and post-void magnetic resonance imaging of urethra
Female urethral diverticula are thought to be caused by obstruction of Skene’s glands. Rarely,carcinoma (usually adenocarcinoma) or calculi can form within them. The gold standard imaging investigation is double-balloon catheter positive pressure urethrography; however, this is invasive and uses ionising radiation. The best first-line test is a pre- and post void magnetic resonance imaging (MRI) of the urethra, as this avoids ionising radiation and does not involve invasive placement of catheters, and the patient can empty her bladder in private between scans. Positive pressure urethrography is reserved for cases where MRI is equivocal. The remaining options are inappropriate: transvaginal ultrasound may show a lesion but will not clearly demonstrate its relationship to the urethra; micturating cystourethrogram would have a high likelihood of a false negative, requires catheterisation, uses ionising radiation and requires the patient to void in the presence of the radiologist; urodynamics are a functional examination.
5
Q
5.A 40-year-old male and intravenous drug user, is on your barium list. The history on the cardsays ‘c/o dysphagia. Exclude pouch!’. During the barium swallow, you notice no oesophagealpouch but there are at least three giant 3- to 4 cm flat ulcers noted within the oesophagus near the gastro-oesophageal junction. The intervening oesophagus appears normal. Which of the following is the most likely diagnosis?
A. Cytomegalovirus oesophagitis
B. Caustic oesophagitis
C. Candida oesophagitis
D. Behcet’s disease
E. Crohn’s disease
A
- A. Cytomegalovirus oesophagitis
Cytomegalovirus oesophagitis almost always occurs exclusively in human immunodeficiency virus (HIV)-positive patients. Barium swallow or endoscopy appearances are of giant ovoid flat ulcers >2 cm near the gastro-oesophageal junction or less commonly, smaller superficial ulcers. Giant ulcers can also be seen in HIV at the time of seroconversion. Caustic ingestion would usually have a different clinical history and tends to produce stricture of the oesophagus. Candida tends to involve the upper oesophagus, has linear plaques and is associated with abnormal motility. Behcet’s disease (a rare immune-mediated systemic vasculitis) produces aphthous ulcers. Crohn’s disease rarely affects the oesophagus and also would produce aphthous ulcers.
6
Q
- A 16-year-old girl with a history of recurrent bronchitis undergoes chest X ray. The lungs are clear but there is tracheal deviation to the left, with a focal indentation of the right wall of the trachea. Underlying vascular anomaly is suspected, and the patient undergoes a magnetic resonance imaging scan for further evaluation. All of the following will explain the above Chest X-ray appearance, except:
A. Double aortic arch
B. Right aortic arch with aberrant left subclavian artery and patent ductus arteriosus
C. Aberrant left pulmonary artery
D. heft aortic arch with aberrant right subclavian artery and patent ductus arteriosus
E. Common origin of innominate and left common carotid artery
A
- C. Aberrant left pulmonary artery
Double aortic arch variants and right aortic arch with aberrant left subclavian artery and patent ductus arteriosus are the two most common types of vascular rings which encircle the mediastinal airways. Both these conditions cause leftward deviation of the trachea and indentation of the right tracheal wall visible on the chest X-ray together with a large posterior oesophageal impression visible on oesophagogram. Left aortic arch with aberrant right subclavian artery is the most common vascular anomaly of the aortic arch, but only in the extremely rare association with patent ductus arteriosus will it cause similar appearances.
A less common vascular anomaly, which may cause a similar appearance of the trachea but does not cause any oesophageal indentation, is a common origin of innominate and left common carotid artery. Aberrant left pulmonary artery’ causes posterior tracheal indentation and anterior oesophageal impression.
7
Q
- A 50 year-old man was recently diagnosed with a thyroid cancer following an ultrasound guided FNA of a thyroid lesion. Regarding malignant thyroid nodules, which of die following statements is true?
A. Punctate calcification is a feature of papillary carcinoma.
B. Anaplastic carcinoma is associated with MEN syndrome.
C. Echogenic foci seen in medullary carcinoma are due to calcitonin deposits.
D. Characteristic lymphadenopathy in medullary carcinoma is hypoechoic to muscle.
E. Follicular carcinoma can he differentiated from follicular adenoma on US.
A
- A. Punctate calcification is a feature of papillary carcinoma.
Thyroid calcifications may occur in both benign and malignant diseases. Thyroid calcifications can be classified as microcalcification, coarse calcification or peripheral calcification. Microcalcifications are found in 29%-59% of all primary thyroid carcinomas, most commonly in papillary thyroid carcinoma. Their occurrence has been described in follicular and anaplastic
thyroid carcinomas as well as in benign conditions such as follicular adenoma and Hashimoto’s thyroiditis.
At US imaging, microcalcifications appear as punctate hyperechoic foci without acoustic shadowing. Coarse calcifications may coexist with microcalcifications in papillary cancers, and they are the most common type of calcification in medullary thyroid carcinomas. Inspissated colloid calcifications in benign thyroid lesions may mimic microcalcifications in thyroid malignancies, but the former can be distinguished from malignant calcifications by the observation of ring-down or reverberation artefact. Peripheral calcification is one of the patterns most commonly seen in a multinodular thyroid but may also be seen in malignancy.
US features that should arouse suspicion about lymph node metastases include a rounded bulging shape, increased size, replaced fatty hilum, irregular margins, heterogeneous echotexture, calcifications, cystic area and vascularity throughout the lymph node instead of normal central hilar vessels at Doppler imaging.
8
Q
- A 6-year-old boy presents with a 1-month history of progressive left-sided proptosis. An orbital MRI reveals a large, lobulated, retro-orbital mass without any intracranial or globe invasion. The mass is isointense to muscle on Tl and hyperintense on T2 with uniform enhancement post-contrast. The patient is afebrile, and inflammatory markers are not significantly raised. What is the most likely diagnosis?
A. Dermoid cyst
B. Orbital cellulitis with abscess formation
C. Lymphangioma
D. Capillary’ haemangioma
E. Rhabdomyosarcoma
A
- E. Rhabdomyosarcoma
Rhabdomyosarcoma is the most common mesenchymal tumour in children. Rhabdomyosarcoma is an aggressive, rapidly growing tumour and most often manifests with rapidly progressive proptosis or globe displacement. Orbital cellulitis is differential, but patients are afebrile and inflammatory markers are normal. On CT images, orbital rhabdomyosarcoma generally appears as an extraconal, irregular ovoid, well-circumscribed, homogeneous mass that is isoattenuated relative to muscle. Calcification is usually seen only in association with bone destruction. At MRI, they are isointense to muscle or brain with T1-weighted sequences and variably hyperintense to muscle and brain with T2-weighted pulse sequences. They enhance uniformly with contrast.
Dermoid cyst is the most common orbital mass in children. Imaging features that suggest a dermoid include a cystic appearance, internal fat attenuation or signal intensity (T1 hyperintensity) and internal calcification, all of which are uncommon in rhabdomyosarcoma.
On images, vascular malformations are often cystic and multiloculated with ill-defined borders. They frequently contain fluid-fluid levels because of haemorrhage into the cysts, whereas fluid fluid levels are quite uncommon in rhabdomyosarcoma. Peripheral enhancement can be seen around cystic area, which is uncommon in rhabdomyosarcomas.
9
Q
- A 30-year-old woman was involved in a severe road traffic accident and sustained direct high-energy trauma to her pelvis. Among other injuries, she was found to have a fracture on her left sacroiliac joint and left ischiopubic ramus. What type of fracture has she sustained?
A. Open book
B. Straddle
C. Bucket handle
D. Duverney
E. Malgaigne
A
- E. Malgaigne
Pelvic fractures can be divided into stable and unstable fractures. The Malgaigne, open book, straddle and bucket-handle fractures are all unstable, as the pelvic ring is interrupted in two places. The Malgaigne fracture is described in this case. The open book fracture implies fracture/ diastasis of both ischiopubic rami and sacroiliac joints, the straddle fracture involves both obturator rings and the bucket-handle fracture refers to an SI joint fracture with a contralateral ischiopubic ramus fracture. Patients with unstable fractures are at significant risk of pelvic organ injury and haemorrhage. Duverney fracture is an isolated fracture of the iliac wing and is a stable fracture.
10
Q
- A patient undergoes a routine abdominal ultrasound for generalised abdominal pain.
Unfortunately, the spleen cannot be detected. Which of the following is the least likely cause for this?
A. Myelofibrosis
B. Sickle cell anaemia
C. Polysplenia syndrome
D. Traumatic fragmentation of the spleen
E. Wandering spleen
A
- A. Myelofibrosis
Myelofibrosis causes splenomegaly and therefore make splenic detection easier. All of the other options provided are potential causes of a non-visualised spleen. Polysplenia syndrome (also known as bilateral left-sidedness) is, as the name suggests, actually associated with multiple spleens, but these are usually in the wrong place (in addition to a vast array of other intra-abdominal anomalies). A wandering spleen relates to the condition where the spleen is attached to an abnormally long and mobile pedicle, which means that the spleen can be found in places other than in the left upper quadrant
11
Q
- A 6-year-old boy presents with adrenal insufficiency and developmental delay. Magnetic resonance imaging demonstrates diffuse T2 hyperintensity in the deep white matter, most predominant in the posterior parieto-occipital region and splenium of the corpus callosum. Which of the following is the most likely cause for this finding?
A. Metachromatic leukodystrophy
B. Acute disseminated encephalomyelitis
C. X-linked adrenoleukodystrophy
D. Alexander disease
F. Canavan disease
A
- C. X-linked adrenoleukodystrophy
Dysmyelinating diseases, or leukodystrophies, encompass a wide spectrum of inherited neurodegenerative disorders affecting the integrity of myelin in the brain and peripheral nerves. Most of these disorders fall into one of three categories lysosomal storage diseases, peroxisomal disorders and diseases caused by mitochondrial dysfunction - and each leukodystrophy has distinctive clinical, biochemical, pathological and radiological features. X-linked adrenoleukodystrophy is an inherited white matter disorder caused by gene mutation (ALD gene) resulting in abnormal formation of myelin. The childhood cerebral form (CCALD) is the mast common and affects males aged between 4 and 10 years. Hyperpigmentation can occur as a result of adrenal insufficiency. The diagnostic clue is symmetric, peritrigonal white matter abnormality involving the splenium. Alexander disease characteristically involves the frontal white matter preferentially, and Canavan disease causes diffuse white matter abnormality.
12
Q
- A 26-year-old woman who had an intrauterine contraceptive device (IUCD) coil inserted 6 years ago presents to her general practitioner complaining of right iliac fossa pain, constipation, night sweats and fevers. The practitioner refers her for a transvaginal ultrasound, which shows a right-sided convoluted cobra-shaped structure containing fluid echogenicity and some polypoidal outgrowths from the wall. Adjacent to this is
a cystic left adnexal mass containing internal echoes. Which of the following is the likely diagnosis?
A. Actinomycosis
B. Appendix abscess
C. Diverticulitis with pericolic abscess
D. Migrated IUCD causing hydroureter
E. Salpingitis secondary to tuberculosis
A
- A. Actinomycosis
Pelvic actinomycosis is a rare chronic bacterial infection but is commonly seen in the setting of a long-standing IUCD. It can also be associated with recent surgery. It often causes abdominal pain, low grade fever and an abdominal or pelvic mass/abscess, which can mimic a malignant mass as it can get quite large if left untreated. The earlier it is diagnosed and treated, the less likely the patient will require surgery. The cobra-shaped structure is an infected dilated tube. Endometriosis can give cysts containing low-level echoes but fever would be unusual with pain. Appendix and diverticulitis can cause irritation of the adjacent tube but the clue is the long-standing IUCD.
13
Q
- A 75-year-old man had a history of dyspnoea associated with haemoptysis and weight loss. Computed tomography (CT) showed a 1.5 cm spiculated mass in the anterior segment of the right upper lobe, 5 cm deep to the pleural surface on a background of widespread emphysematous change. The case was referred for discussion at multidisciplinary team meeting to consider safety of undergoing a CT-guided lung biopsy. In this patient’s case, which of the following statements concerning CT-guided lung biopsy is correct?
A. The patient carries a 10%-15% risk of developing pneumothorax.
B. As the lesion is not contiguous with the pleural surface, there is a lower risk of pneumothorax.
C. The patient carries an increased risk of developing pulmonary haemorrhage post-procedure.
D. If a pneumothorax were to develop as a complication, he is less likely to require subsequent intercostal drain insertion.
E. The procedure is relatively contraindicated because pulmonary function tests revealed a forced expiratory volume in 1 second (FEV1) of 45% predicted
A
- C. This patient carries an increased risk of developing pulmonary haemorrhage
post-procedure.
Studies have identified lesion depth as being the most important risk factor for pulmonary haemorrhage, with an increased risk in lesions deeper than 2 cm. The incidence of pneumothorax is reported to be between 22% and 45%, of which 3.3-15% will require a chest drain. The risk of developing pneumothorax increases significantly if the lesion is not contiguous with the pleural surface. Studies have shown that the presence of chronic obstructive airway disease increases the necessity of chest drain insertion, although this does not necessarily hold for risk of pneumothorax. Although there are no definite absolute contraindications to CT guided lung biopsy, there are, however, several relative contraindications. Patients should not undergo the procedure without adequate prebiopsy assessment or if they plan to fly within 6 weeks of the procedure. The risk is increased by abnormalities of lung function, respiratory failure (including mechanical ventilation), arterial and venous pulmonary hypertension and coagulation abnormalities. The balance of benefit against risk for the procedure should be assessed at a multidisciplinary meeting. Previous contralateral pneumonectomy precludes needle biopsy; however, if the lesion abuts the pleural surface and can be accessed with no needle traversing lung tissue, then the risk of pneumothorax is very low and may not, therefore, be considered as a contraindication. Patients should not undergo needle biopsy without further multidisciplinary team assessment if pulmonary function tests demonstrate an FEV1 of <35%.
14
Q
- A 58-year-old man, who underwent coronary artery bypass grafting 8 years ago, presents to the cardiology clinic with symptoms of progressive shortness of breath on exertion, associated with increase in abdominal girth and peripheral oedema. Clinical examination elicits raised jugular venous pressure, with bibasal fine inspiratory crackles, shifting dullness and bilateral ankle pitting oedema. Elective ECG-gated spin-echo cardiac MRI demonstrates limited ability of the right ventricle to distend during filling (diastole), assuming a tubular shape, with limited change in cavity size during the end-systolic phase. Pericardial thickening of 6 mm and calcification is evident, with a moderate pericardial effusion and dilated superior vena cava and azygos vein. Which of the following is the most likely diagnosis?
A. Cardiac tamponade
B. Restrictive cardiomyopathy
C. Constrictive pericarditis
D. Dressier syndrome
E. Hypertrophic cardiomyopathy
A
- C. Constrictive pericarditis
Constrictive pericarditis is a recognised complication of cardiac surgery, with recent evidence showing an incidence of 0.2%. The most common cause, however, would be idiopathic, thought to result from an occult viral pericarditis, with tuberculosis being the most common cause worldwide. Clinical symptoms attributed to both left- and right-sided heart failure are usually present.
The hallmarks of pericardial constriction are pericardial thickening, pericardial calcification and abnormal diastolic ventricular function. Other findings associated with raised right-sided pressure such as dilatation of the superior vena cava and azygos vein help support the diagnosis. Constrictive pericarditis can be distinguished from restrictive cardiomyopathy on the basis of pericardial thickness measuring more than 4 mm in the presence of characteristic haemodynamic findings.
Dressier syndrome typically occurs 3 weeks to several months, not years, after cardiac surgery.
15
Q
- An 8-month-old boy presents with a right upper quadrant mass. Blood results reveal a raised alpha fetoprotein (AFP). Ultrasound of the abdomen demonstrates a large 7-cm, hypervascular, heterogeneous hyperechoic mass in the liver with a few cystic regions.
There is no vascular invasion. No renal or suprarenal lesions are present. Which of the following differential diagnoses is most likely?
A. Hepatoblastoma
B. Infantile haemangioendothelioma
C. Hepatic haemangioma
D. Mesenchymal hamartoma of the liver
E. Fibrolamcllar hepatocellular carcinoma
A
- A. Hepatoblastoma
Hepatoblastoma is the most common primary hepatic tumour in children. Hepatoblastoma has been associated with several syndromes, including Beckwith-Wiedemann syndrome,
Gardner syndrome, familial adenomatous polyposis, type 1A glycogen storage disease and trisomy 18.
Hepatoblastomas are most often hyperechoic relative to adjacent liver on US. A spoke-wheel appearance with areas of alternating echogenicity may be seen at antenatal imaging. CT shows a sharply circumscribed mass that is slightly hypoattenuating relative to the adjacent liver on unenhanced and contrast-enhanced images. Epithelial hepatoblastomas demonstrate a more homogeneous appearance, while mixed tumours are more heterogeneous in attenuation. Speckled or amorphous calcification is seen in more than 50% of lesions. The tumour enhances slightly, but less than adjacent liver.
At MR imaging, epithelial hepatoblastomas are homogeneously slightly hypointense on T1-weighted images and hyperintense on T2-weighted images relative to adjacent liver parenchyma. Mixed tumours demonstrate more heterogeneous signal intensity characteristics. Fibrotic septa are hypointense on both Tl- and T2-weighted images and enhance after intravenous administration of gadolinium contrast material.
Infantile haemangioendothelioma (IHE) is a vascular tumour and enhances much more than adjacent liver, while hepatoblastoma typically enhances much less than adjacent liver. Occasionally, the peripheral rim enhancement on arterial phase images seen in hepatoblastoma may suggest IHE, but IHE is distinguished by intense nodular or corrugated peripheral enhancement with centripetal fill-in on delayed phase images. Mesenchymal hamartoma of the liver (MHL) is a benign tumour that manifests in the same age group as hepatoblastoma. It can usually be distinguished from hepatoblastoma by normal serum AFP levels in MHL, predominantly cystic appearance and age at diagnosis >5 years (cf. hepatoblastoma generally diagnosed <5 years).
16
Q
- What is the purpose of the heel-toe manoeuvre in ultrasound examination of the shoulder?
A. To decrease the beam angle incidence
B. To minimise anisotropy
C. To increase the field of view
D. To minimise posterior reverberation artefact
E. To minimise beam width artefact
A
- B. To minimise anisotropy
The purpose of the heel-toe manoeuvre in ultrasound is the same in all situations regardless of the site being imaged. It is to reduce anisotropy artefacts that result when the probe is not perpendicular to the structure being imaged. Similarly, reducing beam angle incidence would increase such artefacts. Reducing probe compression reduces posterior reverberation artefact. Placing the structure of interest within the central region of the probe and placing the focal zone at the region of interest reduce beam width artefact.
17
Q
- A 23-year-old woman presents with left iliac fossa pain. The uterus and both ovaries are within normal limits. There is an anechoic left adnexal cyst adjacent to the uterus that appears separate from the ovary. You note that the patient has had a previous ultrasound for left adnexal pain, and that a left adnexal cyst with similar dimensions was noted then. Which of the following is the most likely diagnosis?
A. Theca lutein cyst
B. Paraovarian cyst
C. Endometrioma
D. Adenomyosis
E. Dermoid cyst
A
- B. Paraovarian cyst
Paraovarian cysts arc responsible for about 10% of adnexal masses. They do not usually change in size. They are susceptible to torsion or bleeding which can cause pain but are usually asymptomatic. They are congenital, occurring from embryonic Wolffian or mesonephric duct remnants within the broad ligament, and are separate from the ovary. Theca lutein cysts are usually bilateral.
Endometriomas usually contain low-level echoes and there is often more than one deposit; they are also less likely to remain static over time. Adenomyosis is a uterine abnormality that involves abnormal glandular tissue within the myometrium and causes thickening of the myometrium.
An ovarian dermoid would usually be hyperechoic or contain mixed elements, giving it a heterogeneous appearance.
17
Q
- A patient undergoes pancreatic transplantation. Which of the following statements is least likely?
A. The transplanted pancreatic duct is normally dilated.
B. Indistinct pancreatic margins on ultrasound may indicate graft rejection.
C. Most patients have a simultaneous renal transplant
D. The donor pancreas is normally grafted onto the external iliac vessels.
E. Most patients achieve insulin independence
A
- A. The transplanted pancreatic duct is normally dilated.
Pancreatic transplant is a potentially curative treatment option predominantly for Type 1 diabetes. The pancreas is normally grafted onto the external iliac vessels. In most cases, the procedure is combined with a simultaneous renal transplant. Exocrine pancreatic secretions can be redirected either into the bladder (easier with simultaneous renal transplant) or bowel. There are advantages and disadvantages of both approaches; redirection to the bladder enables close monitoring of secretions but can lead to acidosis. Radiological input is usually required in postoperative monitoring. Ultrasound scanning can reveal peripancreatic collections/pseudocysts, vessel thrombosis and other signs of acute rejection (indistinct pancreatic margins, acoustic inhomogeneity of the pancreas and dilatation of the pancreatic duct).
18
Q
- A 30-year-old woman presents with bilateral foot drop 2 days post-partum. What finding on MRI would explain this?
A. Posterior disc protrusion at L3/L4
B. Bilateral common peroneal nerve entrapment
C. Bilateral sciatic nerve compression
D. Paracentral disc protrusion at L3/L4
E. Spinal canal stenosis at L3/L4
A
- B. Bilateral common peroneal nerve entrapment
Common peroneal neuropathy (CPN) is the most common mononeuropathy in the lower extremity. In most cases, CPN neuropathy occurs in the knee region, whereas neuropathy of the superficial peroneal nerve (SPN) and deep peroneal nerve (DPN) occurs more distally in the leg, ankle or foot.
The CPN is particularly prone to entrapment because it is fixed in position at the greater sciatic foramen (peroneal division) and around the fibular head. There are two common compression sites of the CPN. The nerve may be compressed as it crosses the fibular neck, owing to its superficial location, or as it travels under the origin of the peroneus longus muscle. Injury to the nerve at these locations may be the result of extrinsic compression, stretch injury or direct trauma.
Extrinsic compression of the CPN can be the result of external compression by various agents such as short-leg cast, crush injury, surgery, tumour, osteochondroma, synovial cyst, intraneural
and extraneural ganglia, varicosities, aberrant muscle, prolonged immobilisation (Saturday night palsy), prolonged squatting (strawberry pickers’ palsy) and extended lithotomy position due to childbirth or obstetric surgery will typically produce bilateral CPN entrapment. Diabetic patients are at an increased risk for entrapment of the CPN within the fibrous tunnel underneath the peroneus longus muscle.
Patients with CPN often present with frequent tripping related to a foot drop. Pain may be present at the site of compression. Sensory disturbances include paraesthesia and anaesthesia along the lateral lower leg and dorsal foot. On physical examination, patients demonstrate foot drop, weak foot extension (anterior tibial muscle), weak foot eversion (peroneus longus and brevis muscles) and loss of sensation in the lower lateral two-thirds of the leg and the dorsum of the foot.
19
Q
- On an antenatal ultrasound, a foetus is found to have an intracranial anomaly. At birth, the cranial ultrasound reveals a large cystic mass in the posterior fossa communicating with the fourth ventricle with hypoplasia of the cerebellar vermis.
What other associated abnormality would you not expect to be associated with the underlying condition?
A. Subependymal calcification
B. Corpus callosum agenesis
C. Grey matter heterotopia
D. Schizencephaly
E. Occipital encephalocoele
A
- A. Subependymal calcification
Dandy-Walker malformation is the most common posterior fossa malformation. The key neuroimaging features are hypoplasia (or, rarely, agenesis) of the cerebellar vermis (whose inferior portion is typically affected, possibly in combination with its superior portion), which is elevated and upwardly rotated; and dilatation of the cystic-appearing fourth ventricle, which consequently may fill the entire posterior fossa.
Additional malformations, including dysgenesis or agenesis of the corpus callosum, occipital encephalocele, polymicrogyria and grey matter heterotopia, may be present in 30% 50%. Hydrocephalus is associated in about 90% of patients.
Subependymal calcification is a feature of tuberous sclerosis.
20
Q
- A 13-year-old boy presents with symptoms and radiographic evidence of a slipped capital femoral epiphysis (SCFE). It is noted on his radiographs that the physes are generally wide with flaring of the metaphyses. Which of the following is the most likely diagnosis?
A. Rickets
B. Hypophosphatasia
C. Blounts disease
D. Achondroplasia
E. Renal osteodystrophy
A
- A. Rickets
Rickets is the paediatric equivalent of osteomalacia. It affects the metaphysis of hones as these are the most metabolically active sites. Common sites of involvement include proximal humerus, proximal tibia and proximal and distal femur. Appearances include widened and irregularly shaped physeal lucencies and metaphyseal flaring. There may be long bone deformation with lower limb bowing. Patients with rickets are at increased risk of Salter-Harris I fractures of the epiphyses that most commonly occur at the proximal femur (SCFE).
While Blount’s disease is often associated with bow legged-ness in infants and children, it is an abnormality at the knee with an increase in the tibial metaphyseal angle. There arc a few cases in the literature of SCFE in association with Blount’s disease.
While hypophosphatasia may give similar findings to rickets, its incidence 1:10 0000 is several orders of magnitude less than rickets (1:100-1:1000).
21
Q
- A 76 year-old woman is having a pelvic magnetic resonance imaging (MRI) scan to assess for a possible hernia. She is noted to have a 6 cm very low intensity lesion within the right ovary on both Tl and T2. Some fluid is also noted within the pelvis. Which of the following is the most likely diagnosis?
A. Ovarian mucinous cystadenoma
B. Krukenberg tumour
C. Ovarian fibroma
D. Dermoid cyst
E. Clear cell carcinoma of the ovary
A
- C. Ovarian fibroma
Ovarian fibromas typically arise in postmenopausal women and are usually asymptomatic. Rarely, they can cause pressure-type symptoms if they get large enough, or tort causing pain.
Ovarian fibromas are classically known to cause Meigs syndrome, which is the combination of ascites, pleural effusion and a benign ovarian tumour. The ascites and pleural effusion often resolve after tumour removal. They are also more common in Gorlin (basal cell naevus) syndrome, where they tend to occur at a younger age and are more likely to be bilateral. Owing to their highly fibrous component, they have a similar intensity to uterine fibroids, being low on IT and T2-weighted sequences. On ultrasound, they are often hypoechoic with attenuation of the ultrasound beam as it passes through the lesion. About 1% can undergo malignant transformation to a fibrosarcoma.
Krukenberg tumours result from ovarian metastases, classically from the stomach; however, colon, breast, lung, gynaecological tumours, sarcomas and melanoma can also spread to the ovary.
These tumours would less likely be so low intensity on Tl and T2-weighted images and there may be a history of cancer. Ovarian mucinous cystadenomas tend to contain a jelly-like fluid, so are usually cystic on imaging, but can contain solid components. A dermoid cyst usually contains mixed elements including fat and would not usually cause ascites. Clear cell carcinoma is an aggressive ovarian lesion associated with endometriosis and a poor prognosis; these often have cystic and solid components.
22
Q
- You are reviewing the X-rays of a 44-year-old male patient who has complained of mild breathlessness and a cough but otherwise well. Several chest radiographs performed over an 18 month period demonstrate diffuse ground glass shadowing with several scattered confluent areas of air-space consolidation. The lung changes do not appear
to have any zonal predilection, and no mediastinal, hilar or cardiac abnormality is evident. HRCT also showed fairly extensive smooth interlobular septal thickening.
The intervening lung appears normal, and there is sharp demarcation between the abnormal and normal lung parenchyma. Which of the following is most likely given the radiological findings described?
A. Pulmonary vasculitis
B. Pulmonary oedema
C. Primary tuberculosis
D. Alveolar proteinosis
E. Extrinsic allergic alveolitis
A
- D. Alveolar proteinosis
Alveolar proteinosis is a rare disorder that is characterised by the abnormal accumulation of proteinaceous material in alveoli, secondary to altered surfactant homeostasis. It affects young to middle-aged adults and is more common in men. There is a strong association with cigarette smoking. Clinical features are variable, with symptoms usually being of gradual onset. Chest radiography typically demonstrates bilateral air-space opacity with either an ill-defined nodular or ground glass pattern. An important discriminator from pulmonary oedema is the presence of perihilar lung changes in the absence of cardiomegaly, pulmonary venous hypertension and pleural effusions. Similarly, while sarcoidosis can mimic many lung conditions, the absence of lymphadenopathy is an important feature to note in alveolar proteinosis. The classic computed tomography finding is known as crazy paving - the description given to the combination of patchy ground-glass opacities with smooth interlobular septal thickening in a geographical distribution.
23
Q
- An otherwise healthy 44-year-old patient presents acutely unwell with new-onset epigastric pain and is found to have a significantly raised amylase level. Which of the following clinical scenarios is least likely?
A. Alcoholic patient, recent 48-h binge
B. Previous bouts of right upper quadrant abdominal pain
C. Recent flu like symptoms
D. Computed tomography report describing a 6 cm pseudocyst
E. Fulminant haemolytic-uraemic syndrome
A
- D. Computed tomography report describing a 6 cm pseudocyst
The clinical scenario presented is that of new-onset acute pancreatitis. Pseudocysts are encapsulated collections of pancreatic fluid found in a peripancreatic position. Classically, these take 4 weeks to develop. The other options provided are all potential causes of acute pancreatitis. Alcoholism and cholelithiasis are the most common causes. Recent viral infection (e.g., mumps, hepatitis, glandular fever), trauma, structural anomalies (pancreas divisum), some drugs (e.g., steroids, azathioprine, diuretics) and multisystem conditions (shock, haemolytic-uraemic syndrome, systemic lupus erythematosus) are all recognised causes of pancreatitis. In a large number of patients, no definite cause is ever identified (idiopathic).
24
Q
- A 73-year-old woman with weight loss, previous history of endometriosis and a CA-125 of 983 μg/mL, attends for an magnetic resonance imaging (MRI) scan of the pelvis after a cystic mass with nodules was noted in the left adnexa on ultrasound. There is a 6 cm predominately unilocular cystic mass in the left adnexa, which is bright on T1W & T1W fat-saturated images with enhancing solid mural nodules along its wall. It remains high signal on fat-saturated imaging. Which of the following is the most likely diagnosis?
A. Dysgerminoma
B. Brenner tumour of the ovary
C. Endometrioma
D. Ovarian dermoid
E. Clear cell carcinoma of the ovary
A
- E. Clear cell carcinoma of the ovary
Clear cell carcinoma and endometrioid carcinomas are commonly found in patients with previous endometriosis. Clear cell carcinoma is an aggressive carcinoma. It is frequently cystic with enhancing mural nodules. The cystic and solid components are high signal on both Tl- and T2-weighted images. Brenner tumour of the ovary is low signal on Tl- and T2-weighted imaging. Endometrioma may have a bright Tl signal but should not have enhancing mural nodules or be associated with weight loss. Dysgerminoma is a solid germ cell tumour of the ovary, typically solid with a fibrous capsule and fibrous septa. Ovarian dermoid should contain fat and would not be associated with weight loss.
25
Q
- A 32-year old lady presents with acute sudden onset headache to the A&E department. CT shows haemorrhage within the fourth ventricle. Which vessel is most likely to be involved?
A. Anterior cerebral communicating artery
B. Anterior cerebral artery
C. Posterior cerebral artery
D. Posterior cerebral communicating artery
E. Posterior inferior cerebellar artery
A
- E. Posterior inferior cerebellar artery
With posterior inferior cerebellar artery (PICA) aneurysms, the rate of intraventricular haemorrhage is high due to reflux of blood. If there is an isolated intraventricular haemorrhage, a peripheral PICA aneurysm. King in or near the fourth ventricle, may be suspected.
26
Q
- A 4-year-old child undergoes a CXR for suspicion of chest infection. The request mentions that the child has a congenital cardiac anomaly, which is, as yet, untreated. No further information regarding the type of anomaly is provided. The only abnormalities you can detect on the CXR include mild generalised cardiomegaly and increased pulmonary arterial flow. You note from the A&E department notes that the child is not cyanosed. What is the most likely diagnosis?
A. Ebstein anomaly
B. Ventricular septal defect
C. Tetralogy of Fallot
D. Atrial septal defect
E. Truncus arteriosus
A
- B. Ventricular septal defect
Congenital cardiac anomalies can be categorised according to whether or not the child is cyanosed. Thereafter, assessment of both heart size and pulmonary arterial flow allows considerable shortening of the differential diagnosis:
In the case provided, the only conditions not associated with cyanosis are ventricular septal defect (VSD) and atrial septal defect (ASD). VSD is the most common congenital heart anomaly.
27
Q
- An elderly patient presents to the orthopaedic clinic with progressive hip pain. He has a history of a hip replacement performed 5 years ago. A radionuclide bone scan is ordered and demonstrates increased uptake around the proximal aspect of the prosthesis. This finding is sensitive and specific for which of the following conditions?
A. Prosthetic fracture
B. Mechanical loosening
C. Periprosthetic fracture
D. Particle disease
E. None of the above
A
- E. None of the above
A cemented component in a total hip joint replacement (THR) will demonstrate increased uptake on a radionuclide bone scan for up to 1-2 years. Following this time, increased uptake is good evidence to support mechanical loosening or infection with a 50%-100% sensitivity. It is, however, not specific and therefore correlation with the patients clinical presentation and plain radiography is required. Aspiration under fluoroscopic guidance may be required to diagnose or exclude infection. An arthrogram can be performed at the same time, which may allow a confident diagnosis of mechanical loosening to be made; however, a negative arthrogram does not exclude this.
Cementless THR components may have persistently increased radionuclide uptake. This is secondary to bone ingrowth into die prosthesis and needs to be differentiated from pathology.
28
Q
- A 68-year-old male patient presents with painless jaundice. Abdominal ultrasound reveals both intrahepatic and extrahepatic biliary dilatation. The gallbladder is thin walled and there are no gallstones. No other significant abnormality is detected, but the report mentions that ‘… the pancreas was not visualized due to overlying bowel gas What is the most likely underlying diagnosis?
A. Pancreas divisum
B. Pancreatic acinar cell carcinoma
C. Pancreatic adenocarcinoma
D. Pancreatic islet cell tumour
E. Pancreatic pseudocyst
A
- C. Pancreatic adenocarcinoma
Painless jaundice commonly occurs secondary to tumours in the head of pancreas. The most common pancreatic tumour, by far, is adenocarcinoma. All the other tumours described are rare by comparison. Pancreas divisum is an anatomical variant relating to pancreatic duct morphology where rather than having a single pancreatic duct, the patient has two (embryologically, there is a failure of fusion); it has an association with idiopathic, recurrent pancreatitis but not with bile duct obstruction. Pancreatic pseudocyst is an encapsulated collection of pancreatic fluid found either within the pancreas or in a peripancreatic position. It most commonly occurs secondary to acute pancreatitis.
29
Q
- A 55-year-old man presents with a several-week history of worsening stridor. He has had several chest infections over recent months, with repeated courses of antibiotics providing little relief of symptoms. Mediastinal lymph adenopathy is evident on chest radiograph, with a few intrapulmonary nodules in the periphery of both lungs. Computed tomography confirms the presence of multiple nodules, most numerous in the subpleural region of the right lower lobe. Also of note is a mucosal polypoid lesion in the upper trachea and a further endobronchial lesion just distal to the carina in the right main bronchus. Which condition encompasses these clinical and radiographic findings?
A. Amyloidosis
B. Alveolar proteinosis
C. Pulmonary vasculitis
D. Histoplasmosis
E. Hydatid disease
A
- A. Amyloidosis
Amyloidosis is a rare condition, which can affect one specific organ, or present as a systemic illness. The disease is characterised by the deposition of proteinaceous material either in a focal, tumour like lesion or an infiltrative fashion. Within the chest, cardiac involvement is the most commonly seen, with patients presenting with variable symptoms ranging from arrhythmias to cardiac failure. Pulmonary involvement is typically in the setting of multiple previous chest infections. Computed tomography often demonstrates ‘tree-in-bud’ opacity, usually in a peripheral location, at sites of previous pneumonia. Within the tracheo bronchial tree, mass-like lesions arc seen arising from the internal wall, often significantly compromising the airway lumen.
While the other conditions listed could result in scattered intrapulmonary nodules, the additional endobronchial abnormality makes amyloidosis more likely.
30
Q
- A neonate is noted to be markedly cyanosed, worsening when she cries. A CXR performed on day 1 is normal. Which of the following types of congenital cardiac anomaly is most likely?
A. Patent ductus arteriosus
B. Ebstein anomaly
C. Coarctation of the aorta
D. Tricuspid atresia
E. Tetralogy of Fallot
A
- D. Tricuspid atresia
Congenital cardiac anomalies can be categorised according to whether or not the child is cyanosed. Thereafter, assessment of both heart size and pulmonary arterial flow allows considerable shortening of the differential diagnosis:
In the case provided, the child is cyanosed; this excludes patent ductus arteriosus and coarctation as the cause. Ebstein anomaly classically produces a grossly enlarged heart. While tetralogy of Fallot is the most common congenital cardiac anomaly to cause cyanosis, it has characteristic CXR features; upturned cardiac apex and deficient main pulmonary artery creates a ‘boot-shaped’ heart. In addition, there is usually decreased pulmonary vascularity associated with Fallot’s tetralogy.
Tricuspid atresia is the third most common congenital cardiac cause of cyanosis after tetralogy of Fallot and transposition of the great vessels.
31
Q
- Pick’s disease affects which of the following?
A. Fronto-parietal lobe
B. Temporo-parietal
C. Temporo-frontal
D. Parieto-occipital
E. Frontal
A
- C. Temporo-frontal
Pick’s disease is a neurodegenerative disease, and one of the tauopathies (group of neurodegenerative diseases characterised by abnormal metabolism of tau proteins leading to intracellular accumulation and formation of neurofibrillary tangles, similar to Alzheimer’s disease) characterised by the accumulation of the Pick bodies. It is sometimes used synonymously with fonto-temporal lobar degeneration (FTLD), although strictly it is incorrect since all causes of FTLD isn’t pathologically Pick’s disease.
The primary imaging abnormality is that of cortical atrophy of the frontal and temporal lobes. These changes can be markedly asymmetric and affect one region much more than another. Volume of the head of the caudate nucleus may also be reduced. Differentials include Alzheimer’s disease and corticobasal degeneration where parietal lobe involvement is more pronounced.
32
Q
- A 36-year-old woman is being investigated for possible renal stones with CT KUB.
An incidental “polka-dot” appearance to the T12 vertebral body is noted on the axial CT images. MRI at the same level shows characteristic high signal in the vertebral body on Tl and T2W images. All of the following statements regarding this entity are true, except
A. They may extend to involve the posterior element.
B. They are commonly multiple.
C. Compressive lesions are common in the lumbar spine.
D. Low T1W lesions are more likely to be active.
E. Most are asymptomatic.
A
- C. Compressive lesions are common in the lumbar spine
Vertebral haemangiomas are a hamartomatous lesion. Spinal haemangiomas arc common and frequently multiple. The prevalence of haemangiomas seems to increase with age and is greatest after middle age, with a slight female predilection. Most haemangiomas are seen in the thoracic and lumbar spine. They are usually confined to the vertebral body, although they may occasionally extend into the posterior elements. Most spinal haemangiomas are asymptomatic. Occasionally, vertebral haemangiomas may increase in size and compress the spinal cord and nerve roots. Compressive vertebral haemangiomas can occur in patients of any age, with a peak prevalence in young adults and preferentially occur in the thoracic spine.
CT shows the pattern as multiple dots (polka-dot appearance). At scintigraphy, the appearance of osseous haemangiomas ranges from photopenia to a moderate increase in radiotracer uptake. The presence of high signal intensity on T1- and T2-weighted MR images is related to the amount of adipocytes or vessels and interstitial oedema, respectively.
Fatty vertebral haemangiomas (high on T1-weighted MR) may represent inactive forms of this lesion, whereas low signal intensity at T1-weighted MR imaging may indicate a more active lesion with the potential to compress the spinal cord.
33
Q
- An alcoholic patient is referred for an ultrasound from the A&E department of your hospital. The request states that the patient has deranged liver function tests and raises the possibility of underlying liver cirrhosis. Which of the following findings would not help you to confirm this diagnosis?
A. Caudate lobe hypertrophy
B. Increased echogenicity of the liver parenchyma
C. Coarse echotexture to the liver
I). Decreased resistive index in hepatic artery
E. Hepatofugal flow within the portal vein
A
- D. Decreased resistive index in hepatic artery
There are many features of liver cirrhosis identifiable with ultrasound. Most commonly, these include an echo bright, irregular, shrunken liver (late stage) with a coarse echotexture and hypertrophy of the caudate lobe (earlier in the disease the entire liver can hypertrophy). Isoechoic regenerative nodules may be apparent. If measured, there should be an increase in the resistive index (RI) of the hepatic artery. Reversal of portal venous flow (hepatofugal), portalisation of the hepatic veins, ascites and splenomegaly are extrahepatic signs that are commonly identified. Hepatocellular carcinoma is a major complication of cirrhosis that should always be borne in mind when examining these patients.
34
Q
- A 53-year-old man is assessed by the receiving surgeon, having presented with severe chest pain, vomiting and sepsis. Mediastinal emphysema is evident on chest radiograph and computed tomography confirms oesophageal perforation. Which of the following statements is incorrect with regard to this condition?
A. Plain chest radiography is normal in approximately 10% of cases.
B. Iatrogenic injury is the most common single cause of oesophageal perforation.
C. Upper oesophageal perforations typically result in right-sided pleural collection.
I). In blunt chest trauma, the perforation usually occurs in the lower third of the oesophagus.
E. Water-soluble contrast agents should be used for fluoroscopic assessment.
A
- D. In blunt chest trauma, the perforation usually occurs in the lower third of the
oesophagus.
Oesophageal perforation is a surgical emergency that carries a high mortality. Oesophageal instrumentation, biopsy, balloon dilatation and attempted intubation (iatrogenic) are the most common causes of rupture and typically result in lower oesophageal injury’. Spontaneous rupture, also known as Boerhaave syndrome, arises when intraluminal pressure is elevated during sudden and severe vomiting episodes. While oesophageal rupture in blunt chest trauma is rare, this typically results in upper oesophageal injury and resultant right-sided hydrothorax.
Chest radiography signs include mediastinal and neck emphysema, mediastinal widening and hydrothorax. Barium can be used in the assessment of patients with possible oesophageal perforation, but only after water-soluble contrast swallow has not shown an abnormality.
35
Q
- A normally well 8-year-old child presents to the A&E department short of breath and pyrexial complaining of joint pain. Chest X-ray shows an enlarged heart with upper lobe venous blood diversion and small bilateral pleural effusions. No focal collapse/consolidation is evident, but there are patchy interstitial infiltrates in a perihilar distribution. Further questioning reveals that the child recently had a sore throat. What is the most likely underlying diagnosis?
A. Toxic synovitis
B. Juvenile rheumatoid arthritis
C. Reiter’s disease
D. Rheumatic fever
E. Septicaemia
A
- D. Rheumatic fever
The imaging features described are those of acute congestive heart failure. In the context of joint pain following a recent sore throat and with no previous cardiac history, rheumatic fever should be considered.
Rheumatic fever commonly causes a pancarditis with valve insufficiency that can lead to acute congestive heart failure in severe cases. This follows a streptococcal pharyngitis. Chronically, rheumatic heart disease can cause valve stenosis with varying degrees of regurgitation, arrhythmias and ventricular dysfunction. Rheumatic fever as a child is the most common cause of valvular heart disease in adults in the western world. The mitral valve is the most commonly affected. Currently, the disease rarely affects children in the West, but the condition remains common in the developing world.
36
Q
- All the following cause basal ganglia calcification except?
A. Pseudohypoparathyroidism
B. Lead poisoning
C. Ageing
D. Hypothyroidism
E. Wilson’s disease
A
- E. Wilson’s disease Basal ganglia calcification:
Common causes: Hypoparathyroidism, pseudohypoparathyroidism, idiopathic, normal variant, physiologic with ageing.
Uncommon causes: AIDS encephalopathy, atherosclerosis, birth anoxia, hypoxia, carbonic anhydrase II deficiency, carbon monoxide intoxication, Fahr disease (ferrocalcinosis), familial idiopathic symmetrical basal ganglia calcification and microcephaly, Hallervorden-Spatz disease, haemorrhage, hyperparathyroidism, hypothyroidism, cretinism, Kearns Sayre syndrome, lead encephalopathy, lipoid proteinosis, MELAS syndrome, methotrexate therapy for childhood leukaemia, oculodento-osseous dysplasia, parasitic disease (e.g., toxoplasmosis, cysticercosis), parkinsonism, phenylketonuria variants, pseudopseudohypoparathyroidism, radiation therapy, Down’s syndrome, tuberous sclerosis, viral encephalitis.
37
Q
- An 82-year-old woman presents with postmenopausal bleeding. Transvaginal ultrasound shows a thickened endometrium and a left adnexal lobulated multicystic lesion, which has some solid elements. Some of the cysts contain fluid-fluid levels and have thick septa. Which of the following is the most likely diagnosis?
A. Endometriosis
B. Granulosa cell tumour
C. Endometrial hyperplasia and haemorrhagic corpus luteal cyst
D. Serous cystadenocarcinoma
E. Fibrothecoma
A
- B. Granulosa cell tumour
Many ovarian tumours produce oestrogen, the most common being granulosa cell tumour. This results in postmenopausal bleeding, irregular bleeding in premenopausal women and precocious puberty in prepubertal girls. Breast tenderness is another sign, particularly in postmenopausal women. The fluid levels are caused by haemorrhage into the tumour cysts. Endometriosis tends to improve in postmenopausal women as there is no longer oestrogen being produced; it should not cause a thickened endometrium. Endometrial hyperplasia and haemorrhagic corpus luteal cyst are related to ovulation, so do not occur in postmenopausal women. Serous cystadenocarcinomas may produce adnexal masses but do not produce oestrogen, so do not cause endometrial thickening. Fibrothecomas can produce oestrogen and cause endometrial thickening but tend to be solid hypoechoic lesions.
38
Q
- A 33-year-old woman with progressive increase in back pain and perineal pain was sent for further evaluation to the spinal surgeons. Axial and coronal reformatted O’ image showed a well-defined lytic lesion of the right upper part of the sacrum with extension through the right sacroiliac joint and absence of a sclerotic rim. All the following arc features of this lesion except?
A. Most commonly affected bone is sacrum.
B. Extension into intervertebral disc helps to differentiate GCT from ABC.
C. Septa show intense enhancement post-contrast injection.
I). Doughnut sign on scintigraphy usually suggests an alternate diagnosis.
E. Fluid-fluid level is not specific for this lesion
A
- C. Septa show intense enhancement post-contrast injection.
Giant cell tumour of the spine occurs in the 2nd-4th decades of life, more frequently in females. Sacrum is affected in 90% of such cases. It is usually located in the upper sacrum and sacral wing. Extension to the iliac wing through the sacroiliac joint is possible. Lumbar, thoracic and cervical spine may be affected. It usually predominates in the vertebral body, with frequent involvement of the posterior arch. Extraosseous involvement of the soft tissues is common. Intervertebral disk invasion and extension into an adjacent vertebra are possible.
In radiography, they appear as lytic lesion with cortical expansion. CT demonstrates lack of a sclerotic rim. Bone scintigraphy shows increased radiotracer uptake. The tumour usually has low-to- intermediate signal intensity on T1-weighted MR images. Areas of high signal intensity suggest haemorrhage. More specifically, they have low to intermediate signal intensity on T2-weighted images, caused by haemosiderin and high collagen content. Enhancement reflects its vascular supply. Cystic areas, haemorrhage, fluid-fluid levels and a peripheral low-signal-intensity pseudocapsule may also be seen.
ABC occurs between 5 and 20 years but can manifest at any age. There may be a slight female predilection. Thoracic spine is most commonly affected. Spinal involvement is typically in the posterior elements, although extension into the vertebral body is common. Spinal ABC may extend into the adjacent vertebrae or intervertebral disk, ribs and the paravertebral soft tissue. CT and MR imaging typically show a well-defined lesion with internal septation. Fluid-fluid level is better seen on MRI. The predominant bone scintigraphic pattern is moderate to intense radiotracer accumulation at the periphery with little activity at its centre (‘doughnut sign’). Post-contrast images show intense enhancement of the septa. Solid components suggest secondary ABC.
39
Q
- A 38-year-old woman is undergoing investigations for infertility. She is otherwise asymptomatic. On hysterosalpingography, there is a large filling defect within the uterine fundus with a linear defect that extends into the filling defect. She subsequently has an MRI scan, which demonstrates a myometrial mass with indistinct margins, which abuts the junctional zone and has lower signal on T2 when compared with the adjacent myometrium. There are a few focal high T2 signal intensity areas within, some which
appear more linear. It demonstrates less enhancement than its adjacent myometrium.
Which of the following is the most likely diagnosis?
A. Leiomyosarcoma
B. Leiomyoma
C. Endometrial carcinoma
D. Adenomyosis
E. Hydatidiform mole
A
- D. Adenomyosis
Adenomyosis can be focal or diffuse, the latter being the more common. The aetiology is unclear, but prominent endometrial glands extend into the myometrium with adjacent smooth muscle hyperplasia. Leiomyoma tends to be sharply demarcated as opposed to ill defined and tends to have low-intensity Tl and T2 signals, although multiple signal characteristics arc seen. It would be unusual for leiomyomas to have linear bands extending from the endometrium; this is more commonly seen in adenomyosis. Leiomyoma and leiomyosarcomas cannot be differentiated accurately on imaging; secondary features of lymphadenopathy or metastasis can help raise the suspicion of leiomyosarcoma. Endometrial carcinoma usually presents in an older age group and tends to present with symptoms of irregular bleeding, which is why it is often diagnosed at an early stage. There would likely be endometrial thickening also. Hydatidiform moles would usually be identified clinically, particularly in a patient being investigated for infertility, as she would have raised beta-human chorionic gonadotrophin levels.
40
Q
- Before being referred for a CT colonography, a patient asks to speak with a radiologist to clear up a few points regarding colon cancer; Of the following statements, which is most correct?
A. Smaller polyps are more likely to be malignant than larger ones.
B. Most colonic polyps are malignant.
C. Gardener syndrome carries an increased risk of cancer but Peutz-Jeghers syndrome does not.
D. Most colon cancers start as an adenomatous polyp.
E. Inflammatory bowel disease carries no increased risk of cancer.
A
- D. Most colon cancers start as an adenomatous polyp.
The vast majority of colon cancers begin as an adenomatous polyp (>90%), although the vast majority of polyps are benign (>90%). With increasing size comes an increased risk of malignant change. In addition, of the three recognised pathological subtypes (tubular, tubulovillous and villous), villous adenomas carry the greatest risk of malignant transformation. There are a large number of other risk factors for developing colon cancer but among them are the hereditary’ polyposis syndromes (Peutz-Jeghers syndrome is less commonly’ related as the polyps are more likely in the small bowel) and the inflammatory bowel diseases ‘Crohn’s disease and ulcerative colitis’.
41
Q
- A 75-year old man presents with abdominal pain after eating and mesenteric angina is suspected. You decide to perform a celiac axis angiogram using a mechanical contrast pump. What is an appropriate volume and flow rate of contrast to use?
A. 32 mL @ 8 mL/s
B. 20 mL @ 20 mL/s
C. 40 mL @ 20 mL/s
D. 30 mL @ 20 mL/s
E. 20 mL @ 6 mL/s
A
- A. 32 mL @ 8 mL/s
The aim is to closely replicate the natural blood flow in the vessel. A hand-injected test run is essential before a pump run to highlight the anatomy and confirm that the catheter tip is not in a subintimal position. An 8/32 injection delivers 8 mL of contrast per second to a total of 32 mL and lasts 4 s. The patients are usually asked to keep as still as possible and hold their breath to minimise artefact caused by motion.
42
Q
- A 62-year old postmenopausal woman has a magnetic resonance imaging (MRI) scan to look for a hernia. In the right ovary is a 1 cm sharply demarcated low T1 and T2 signal solid mass with adjacent calcification. There is also a multilocular cystic lesion within the same ovary, containing multiple thin-walled septa. Which of the following is the most likely cause of the well-demarcated low-signal lesion?
A. Ovarian fibroma
B. Ovarian Brenner tumour
C. Ovarian dermoid cyst
D. Endometrioma
E. Corpus luteal cyst
A
- B. Ovarian Brenner tumour
Brenner tumours are uncommon tumours that are almost always benign. These tumours have a large fibrous component and therefore have a similar appearance to an ovarian fibroma (low signal on Tl- and T2-weighted imaging) on both ultrasound and MRI. Brenner tumours are commonly found with an adjacent epithelial tumour of the same ovary (usually mucinous cystadenoma); hence, in this case, the diagnosis of Brenner tumour is more likely than ovarian fibroma. An ovarian dermoid would usually contain fat but would also be in the differential diagnosis. However, the patient is postmenopausal and so endometrioma and corpus luteal cyst are unlikely.
43
Q
- Which of the following is specific for osteomalacia?
A. Brown tumour
B. Looser zones
C. Cloaca
D. Cyclops lesion
E. Wimberger’s sign
A
- B. Looser zones
Looser zones are a highly specific radiographic feature of osteomalacia. They are sometimes referred to as pseudofractures and are focal linear areas of undermineralised osteoid at sites of mechanical loading. They are often seen bilaterally as linear lucencies that run perpendicular to the bone cortex and do not involve the whole bone width. Common locations include the medial cortex of the femoral necks, the inferior scapula and the ribs.
These need to be differentiated from bisphosphonate fractures, which start at the lateral cortex of the proximal femur, are often bilateral and are termed as atypical fractures in patients on bisphosphonate therapy.
Brown tumours are lucent lesions seen in hyperparathyroidism. Cloacas are seen in established osteomyelitis. Wimberger’s sign refers to localised bilateral metaphyseal destruction of the medial proximal tibias. It is a pathognomonic sign for congenital syphilis. Wimberger’s ring sign (sometimes also called just Wimberger’s sign to create confusion) is a radiographic sign seen in scurvy, showing thin pencil-like sclerosis along the epiphyseal margins. The cyclops lesion is an intra-articular mass of fibrotic tissue that may be seen post-anterior cruciate ligament (ACL) graft repair.
44
Q
- AP radiograph of the leg of a 3-year-old girl shows periosteal reaction in the mid-fibula. Exuberant periosteal reaction was worrisome for malignancy, and MRI was performed. Coronal STIR images showed a low signal intensity fracture line surrounded by extensive soft tissue and bone marrow oedema. No mass was depicted. Other sites commonly affected in toddlers fracture include all the following, except:
A. Tibia
B. Humerus
C. Talus
D. Calcaneum
E. Cuboid
A
- B. Humerus
Stress fractures of the lower extremities associated with the onset of ambulation are called toddler’s fractures. These fractures typically occur in children between 9 months and 3 years of age, manifest with a refusal to bear weight and arc not preceded by a recognised acute traumatic event.
A similar injury can result from subtle torsional forces, such as those occurring in a toddler who stumbles and falls on a positioned foot.
‘The typical toddler’s fracture is a non-displaced oblique fracture of the distal portion of the tibia. Although other locations are less common, weight-bearing can also account for toddler’s fractures of the fibula, posterior aspect of the calcaneus, the base of the cuboid and the talus
45
Q
- A 63-year old man presents with progressive vertical gaze abnormality and cognitive symptoms. MRI of the brain demonstrates volume loss of the mid brain, which was described by the reporting radiologist as Hummingbird sign. What is the diagnosis?
A. Multisystem atrophy
B. Progressive supranuclear palsy
C. Parkinson’s disease
D. Shy-Drager syndrome
E. Amyotrophic lateral sclerosis
A
- B. Progressive supranuclear palsy
Conventional MRI is usually not helpful in the diagnosis of early Parkinson’s disease because it most often yields normal findings. In advanced disease, abnormalities of the substantia nigra, including volume loss, decreased T2 signal reflecting iron deposition and blurring of the margins, can be seen. However, the primary role of MRI is to exclude structural abnormalities that potentially mimic Parkinson’s disease (e.g., NPH - normal pressure hydrocephalous, intracranial mass and bilateral subdural haematomas).
FDG PET images are most often normal and show preserved metabolism in the putamen and globus pallidus. This is a defining feature of Parkinson’s disease and allows differentiation from both PSP (progressive supranuclear palsy) and MSA (multisystem atrophy, Shy-Drager syndrome), which commonly demonstrate reduced basal ganglia FDG activity.
In patients with MSA-Parkinson’s type, abnormalities are confined to the putamen and include atrophy, symmetric hypointensity on T2 and T2*-weighted images and ‘slitlike’ marginal T2 hyperintensity. Putaminal atrophy appears to help discriminate MSA from Parkinson’s disease, whereas T2 hypointensity is a non specific sign that can be seen in PSP, Wilson’s disease, neurodegeneration with brain iron accumulation and other acquired conditions.
Patients with PSP exhibit atrophy of the midbrain and tegmentum, manifesting as third ventricular dilatation, reduced midbrain AP diameter or flattening of the superior midbrain. Reduced midbrain AP diameter at the level of the superior colliculi on axial images gives rise to the Mickey Mouse sign. Midbrain atrophy with relative preservation of pons produces the hummingbird sign or penguin sign. Additional findings include superior cerebellar peduncle atrophy and increased FLAIR signal, both of which have reasonably high sensitivity and specificity in distinguishing PSP from Parkinson’s disease and MSA.
46
Q
- A patient is diagnosed with Helicobacter pylori infection. Which of the following findings would you not expect?
A. Gastric ulcer
B. Duodenal ulcer
C. Linitis plastica
D. Polypoid gastritis
E. Thickened gastric folds
A
- C. Linitis plastica
Helicobacter pylori infects the gastric mucosa. In most cases, it is asymptomatic but can be associated with epigastric pain and dyspepsia. Imaging can demonstrate the sequelae of gastritis (thickened folds, polypoidal changes and enlarged areae gastricae), but most commonly patients have either a gastric or duodenal ulcer (or both!). Helicobacter pylori is the most common cause of both gastric and duodenal ulcer diseases.
Linitis plastica (also known as leather bottle stomach) is a form of gastric stenosis that leads to narrowing of the stomach and which occurs secondarily to a number of conditions but is most frequently seen secondary to malignancy.
47
Q
- You performed a catheter angiogram and angioplasty for right popliteal stenosis on a patient in the vascular ward and are there to review him the following day. The nurse asks you to prescribe him some analgesia because, overnight, his limb has become painful and pale with loss of power and intolerable tingling. Which of the following is your next step?
A. Review the puncture site (you find no significant haematoma) and prescribe analgesics
B. Arrange for the patient to be taken back to the suite for further angiography
C. You immediately page the vascular surgeon on call
D. Organise urgent CTPA to exclude pulmonary embolism
E. You start the patient on low molecular weight heparin and organise US leg veins
A
- C. You immediately page the vascular surgeon on call
You have just heard the dreaded symptoms and signs of compartment syndrome. The patient needs urgent surgical fasciotomy to prevent muscle necrosis. Any salvage treatment can be planned after that.
Muscle oedema will raise the intracompartmental pressure in the calf fascial compartments. If it is not released promptly, it will lead to muscle necrosis. The patient must have suffered an embolus during the angioplasty procedure. This is a medical emergency and needs urgent treatment.
The team can consider revascularisation options after this is done.
50
Q
- Which of the following combination of MRI signal is characteristic for cerebral abscess?
A
- C. High Low
The typical appearance of a brain abscess at conventional MRI is that of a ring enhancing lesion, with high signal intensity on T2-weighted images and low or intermediate signal intensity on T1-weighted images. A mature abscess has a low signal-intensity capsule on T2 weighted images.
However, the presence of a ring-enhancing lesion in the brain is not diagnostic of abscess and must be distinguished from a necrotic neoplasm and other cystic lesions. Data from recent studies suggest that DWI is more sensitive than conventional MRI in distinguishing brain abscesses and cystic tumours. Pus in brain abscesses is strongly hyperintense on trace DWI and has a reduced ADC. On the contrary, most necrotic or cystic brain tumours have intermediate signal intensity on DWI and elevated ADC values
116
Q
- Which of the following is incorrect?
A
- D. Choroid plexus papilloma Poorly circumscribed and poorly enhancing tumours Predominant imaging patterns of astrocytoma are mass with a enhancing or non-enhancing cyst
and an intensely enhancing mural nodule, necrotic mass with a central non-enhancing zone or predominantly solid mass. They are associated with NFL Craniopharyngiomas are relatively benign neoplasms arising in the sellar/suprasellar region, often presenting with endocrine abnormalities. Paediatric craniopharyngiomas typically appear multicystic the solid portions enhancing heterogeneously with characteristic calcifications in paediatric craniopharyngiomas may not be discernible without SWI. Occasionally, they are predominantly solid, typically without calcification.
PNETs arise from primitive (undifferentiated) brain cells. They are typically heterogeneous and are usually iso- to hyperdense on CT, with calcifications in 70%. On MRI, they may appear iso- to hyperintense to grey matter on FLAIR and T2-weighted images. The solid component usually has avid heterogeneous enhancement with minimal oedema. Necrosis and haemorrhage are common and are seen as restriction on DWI.
On MR images, choroid plexus papillomas appear as isointense to hypointense intraventricular masses compared with normal brain parenchyma. Flow voids, consistent with flowing blood, are common. CT show intense enhancement. Hydrocephalus is very common.
Gangliogliomas develop in the temporal lobe and are commonly associated with refractory seizures, partial complex type. Calcification is seen in 30%. Peripherally located gangliogliomas may cause scalloped pressure erosion of the calvaria. At MRI, a well-defined cystic mass with a solid mural nodule is typically seen; however, a solid mass with non specific low to intermediate signal intensity on T1-weighted images and high signal on T2-weighted images is also not uncommon. Enhancement is variable, ranging from non-enhancing to ring like to intense homogeneity. There is usually little associated mass effect or oedema.
