VIQ - GIT

Question 1

@# 12. At endoscopic ultrasound scan for staging of an oesophageal carcinoma, the tumour is seen extending into the hypoechoic fourth layer of the oesophagus but not beyond this. What is the T staging of the tumour?

A. Tis

B. T1

C. T2

D. T3

E. T4

Answer 1

C. T2

Endoscopic ultrasound is the most accurate method for local staging of oesophageal cancer.

At endoscopic ultrasound, the oesophageal wall appears as five distinct alternating hyperechoic and hypoechoic bands that correspond to the histological layers of the oesophagus.

The innermost hyperechoic layer represents the interface between the lumen and the mucosa.

The hypoechoic second layer is a hypoechoic band that represents the muscularis mucosa.

The third layer is a hyperechoic band that represents the submucosa.

The fourth layer is a hypoechoic band that represents the muscularispropria.

The fifth outermost layer is a hyperechoic band that represents the oesophageal adventitia.

The fifth layer in the stomach, duodenum and rectum represents the serosa.

For oesophageal cancer, T1 tumours invade the lamina propria or submucosa.

T2tumours invade the muscularis propria,

T3 tumours invade the adventitia

and T4tumours invade adjacent tissue.

Tis represents carcinoma in situ.

Question 2

@#e 6. The following statements concerning oesophageal carcinoma are correct: (T/F)

(a) 90% of cases are squamous cell carcinomas.

(b) Most commonly located in the upper third of the oesophagous.

(c) Plummer-Vinson syndrome is a recognised predisposing factor.

(d) It is associated with ulcerative colitis.

(e) Commonest appearance on double contrast barium swallow is of a large ulcer within a bulging mass.

Answer 2

Answers:

(a) Correct
(b) Not correct
(c) Correct
(d) Not correct
(e) Not correct

Explanation:

Oesophageal carcinoma most commonly located in the middle and lower third of the oesophagus. Only 20 occur in the upper one third. Polypoidal or fungating form is the commonest type. Predisposing factors for oesophageal carcinoma include Barrett’s esophagus, alcohol abuse, smoking, coeliac disease & Achalasia.

Question 3

@# 8. A 69-year-old man undergoes staging of gastric carcinoma diagnosed at upper gastrointestinal endoscopy. CT of the abdomen demonstrates focal gastric wall thickening with extension into the perigastric fat, but no invasion of adjacent structures. Five local lymph nodes measuring 10–12 mm in short axis diameter are identified. There is no distant metastatic disease. What is the TNM staging of the tumour?

A. T2 N0 M0

B. T2 N1 M0

C. T2 N2 M0

D. T3 N1 M0

E. T3 N2 M0

Answer 3

D. T3 N1 M0

T3 tumours penetrate the subserosa but do not invade adjacent structures. On CT, this may be appreciated as blurring of the tumour margin or wide reticular strands radiating from the tumour edge.

Nodal staging depends on the number of regional nodes visible, with nodes larger than 8cm being regarded as pathological.

The presence of 1–6 regional nodes results in a stage of N1, with 7–15 nodes and >15 nodes representing nodal stages of N2 and N3 respectively.

Non-regional nodes such as para-aortic and retropancreatic nodes are considered M1 disease.

Question 4

@# 14.A patient with a metastasis from a GIST tumour undergoes a contrast-enhanced CT study before and after chemotherapy. On the initial study, the lesion measures 5 cm in diameter and has a density of 100 HU. At follow up, the lesion measures 6 cm and has a density of 80 HU. How should you classify the response to chemotherapy?

(a) Complete response

(b) Partial response

(c) Mixed response

(d) Stable disease

(e) Progressive disease

Answer 4

(b) Partial response

metastatic GIST tumours are treated with monoclonal antibody agents. These typically reduce the blood supply and metabolism of the tumours with little change in tumour size and as such, the RECIST criteria are of little value.

The Choi criteria differ from RECIST in that to obtain a PR, one needs a 10% reduction in size or a 15% reduction in density. Progressive disease requires 1 tumour growth a 15% reduction in lesion density, a lesion or a or growing nodule of enhancing tumour within an existing lesion. There is no mixed response category.

Question 5

@#e 32.Where do gastrointestinal stromal tumours (GIST) most commonly arise?

(a) Esophagus

(b) Stomach

(c) Small intestine

(d) Colon

(e) Appendix

Answer 5

(b) Stomach

Approximately 60% arise in the stomach, 30% in the small bowel, 7% in the ano-rectal region and the remainder in the oesophagus and colon .

Question 6

@# The CT of a 50-year-old man with abdominal pain shows a stellate enhancing mesenteric mass with a radiology pattern of linear densities emanating from the mass. Adjacent small bowel loops show tethering and thickening. Which is the most likely diagnosis?

A. Primary mesenteric mesothelioma

B. Desmoid tumour

C. Non-Hodgkin’s Lymphoma (NHL)

D. Metastatic carcinoid tumour

E. Abdominal TB

Answer 6

D. Metastatic carcinoid tumour

The stellate pattern is characteristic for carcinoid tumor.

Question 7

@# 5. A 60-year-old woman presents with weight loss and diarrhoea. CT of the abdomen demonstrates multiple, enlarged, low-attenuation mesenteric lymph nodes containing fat–fluid levels and splenic atrophy. What is the most likely diagnosis?

A. tuberculosis

B. coeliac disease

C. Whipple’s disease

D. lymphoma

E. metastatic squamous cell carcinoma

Answer 7

B. coeliac disease

Cavitating mesenteric lymph node syndrome is a rare complication of coeliac disease, in which multiple enlarged lymph nodes are seen in the jejunoileal mesentery.

The nodes have central low attenuation and may contain fat or fluid, or fat–fluid levels.

Splenic atrophy is usually seen,

and jejunal or duodenal biopsy confirms villous atrophy of the small bowel mucosa.

Low-attenuation lymphadenopathy may also be seen in tuberculosis, Whipple’s disease, lymphoma & necrotic mets,

but fat–fluid levels have been reported only in coeliac disease.

Question 8

@# Enteropathy-associated T-cell lymphoma is most commonly associated with which of the following conditions?

(a) Coeliac disease

(b) Crohn’s disease

(c) Lymphangiectasia

(d) Whipple’s disease

(e) Peutz-Jegher’ssyndrorme

Answer 8

(a) Coeliac disease

This is invariably seen in the underlying bowel in patients this condition, although it may not have been diagnosed prior to the lymphoma. The other conditions do not predispose to lymphomas.

Question 9

@# (Ped) 48) A 17-year-old girl presents with abdominal pain and rectal bleeding. She undergoes colonoscopy, which demonstrates multiple polypoid lesions in the colon. Which feature would favour a diagnosis of juvenile polyposis rather than familial adenomatous polyposis?

a. a total of 10 polyps in the colon

b. a histological diagnosis of tubulovillous polyps

c. involvement of the rectum

d. mucocutaneous pigmentation

e. a first-degree relative with multiple colonic polyps

Answer 9

a. a total of 10 polyps in the colon

In familial adenomatous polyposis (FAP), multiple (usually around 1000) tubular or tubulovillous adenomatous polyps are seen in the GI tract, predominantly in the colon.

Patients usually become symptomatic in the third to fourth decades and present with abdominal pain, weight loss and diarrhoea.

Juvenile polyposis (JP) is the commonest cause of colonic polyps in children, and usually presents with rectal bleeding. The polyps are hamartomatous and may occur throughout the GI tract. They are less numerous than in FAP, and the condition may be diagnosed with five or more polyps.

Both conditions are autosomal dominant, with 80% penetrance in FAP and variable penetrance in JP.

The rectosigmoid is involved in 80% of cases of JP, whereas the rectum is always involved in FAP. In both conditions, patients are at increased risk of associated adenocarcinoma, seen in 15% of patients by 35 years of age in JP, but in 100% of patients by 20 years after diagnosis in FAP.

Mucocutaneous pigmentation is a feature of Peutz–Jeghers syndrome.

Question 10

@#e QUESTION 5
A 19-year-old female student presents with acute abdominal pain, elevated CRP and a low-grade temperature. On clinical examination, there is tenderness to light palpation in the right iliac fossa and the patient is febrile. A graded compression ultrasound examination is performed. Which one of the following statements is true?

A A transverse appendiceal diameter of 5 mm is diagnostic of acute appendicitis.

B The finding of a pelvic fluid collection makes a diagnosis of acute appendicitis unlikely.

C The presence of hyperechoic fat in the right iliac fossa makes a diagnosis of acute appendicitis unlikely.

D The sensitivity of graded compression ultrasound in suspected acute appendicitis is 75—90%.

E The specificity of graded compression ultrasound in suspected acute appendicitis is 35—50%.

Answer 10

D The sensitivity of graded compression ultrasound in suspected acute appendicitis is 75—90%.

Graded compression ultrasound of the appendix can avoid unnecessary surgery and ionising radiation particularly relevant for children and women of childbearing age. The finding of a non-compressible appendix with transverse diameter of 6 mm or greater is highly suggestive of acute appendicitis (specificity 86-100%). Other ultrasound findings include hyperechoic fat in the right iliac fossa, peri-appendiceal fluid or a pelvic fluid collection (appendiceal abscess)

Question 11

@#e QUESTION 6
A 42-year-old man presents to the Emergency Department with a 7-day history of severe bloody diarrhoea and abdominal pain. He has previously been fit and well with no significant medical history. On examination, the patient is dehydrated with generalized abdominal tenderness but no clinical evidence of peritonism. An abdominal radiograph is performed. Which radiographic finding would be most suggestive of a toxic megacolon?

A Caecum measuring 4.5 cm in diameter

B Multiple mucosal islands in a dilated transverse colon

C Pseudodiverticulae in the descending colon

D Thickened haustrae throughout the entire colon

E ‘Thumbprinting’ of the transverse and descending colon

Answer 11

B Multiple mucosal islands in a dilated transverse colon

The presence of severe ulceration leading to mucosal islands is a major sign of toxic megacolon (the other key finding is colonic dilatation > 5 cm).

Question 12

@#e QUESTION 24
A 23-year-old woman complains of episodes of diarrhoea and rectal bleeding. Her father died of colorectal cancer aged 39. A double contrast barium enema is performed and demonstrates more than one hundred small polyps, measuring up to 5 mm in size, throughout the colon. An upper GI endoscopy demonstrates multiple polypoid lesions in the stomach and duodenum. What is the most likely diagnosis?

A Carcinoid syndrome

B Familial adenomatous polyposis

C Hereditary non-polyposis colorectal cancer

D Juvenile polyposis

E Peutz-Jeghers syndrome

Answer 12

B Familial adenomatous polyposis

Autosomal dominant condition with multiple colonic adenomas and 100%risk of colorectal carcinoma 20 years after diagnosis. Associated with hamartomas in stomach, gastric & duod adenomas & periampullary carcinoma.

Question 13

@#e QUESTION 66
A 79-year-old woman trips and falls whilst stepping off a bus. She suffers a fractured right neck of femur and undergoes a hemiarthroplasty the following day. Her early recovery is complicated by bronchopneumonia which resolves after 5 days of broad-spectrum antibiotics. On her tenth day in hospital she develops abdominal pain and diarrhoea and pseudomembranous colitis is suspected clinically. Which one of the following statements is true regarding pseudomembranous colitis?

A A normal abdominal CT effectively excludes pseudomembranous colitis.

B Ascites is present in up to 40% of patients.

C CT carries a low positive predictive value for pseudomembranous colitis.

D Extensive pericolonic stranding is a typical feature on CT.

E The rectum is not involved in 40—50% of patients.

Answer 13

B Ascites is present in up to 40% of patients.

Ascites can occur with other colitides, but is often seen in pseudomembranous colitis. CT typically demonstrates mucosal enhancement and marked colonic wall thickening but only mild pericolonic stranding, in patients with pseudomembranous colitis. These findings have a high positive predictive value but a normal CT does not exclude pseudomembranous colitis. Rectal sparing occurs in around 10% of patients.

Question 14

@#e QUESTION 77
A 48-year-old man has a strong family history of colorectal cancer. He is found to have a mild microcytic anaemia and a stool sample for faecal occult blood testing is positive. A CT colonography is performed and, on 3D images, a 1-cm focal polypoid mass is seen in the wall of the sigmoid colon. The reporting radiologist is unsure whether this lesion is significant and reviews the 2D supine and prone axial images. Which additional feature would be most consistent with a polyp?

A The lesion contains a locule of gas at its base.

B The lesion has a mean density of -150 HU.

C The lesion is of homogeneous attenuation.

D The lesion lies on the dependent surface of the bowel on prone and supine images.

E There are diverticulae seen in the sigmoid colon.

Answer 14

C The lesion is of homogeneous attenuation.

A polyp will usually demonstrate uniform soft tissue density, similar to the surrounding bowel wall.

Question 15

@#e 11. Regarding diverticular disease:

(a) Colonic diverticulosis affects 70-80% by 80 years of age.

(b) Rectosigmoid colon is most commonly affected.

(c) 10-25% of individuals with colonic diverticular disease develop diverticulitis.

(d) Fistula formation occurs in 40-50% of cases complicating acute diverticulitis.

(e) Moderate diverticulitis is present when the bowel wall is thickened >3mm.

Answer 15

Answers:

(a) Correct
(b) Correct
(c) Correct
(d) Not correct
(e) Correct

Explanation:

Fistula formation is seen in 15% of the cases of complicated acute diverticulitis.

Question 16

@#e A 37-year-old in an presents to his GP with increasing right upper quadrant pain. On examination, he is afebrile with right upper quadrant tenderness and fullness. An abdominal ultrasound is performed and demonstrates a5-cm diameter cystic lesion in the right lobe of liver. The mass contains multiple septations with a large cyst centrally and multiple small cystic spaces peripherally. Echogenic debris is seen within the cystic lesion and alters in position when the patient lies on his side. From the clinical and sonographic details, what is the most likely diagnosis?

A Amoebic abscess

B Hydatid cyst

C Pyogenic liver abscess

D Simple liver cyst

E Solitary metastasis

Answer 16

B Hydatid cyst

A multiloculated cystic mass with daughter cysts and echogenic debris (‘hydatid sand’) is characteristic of a hydatid liver cyst.

Question 17

@#e A 22-year-old woman presents to her GP with a 4-month history of increasing right upper quadrant pain. An abdominal ultrasound is performed and demonstrates a 6-cm solid lesion of increased reflectivity in segment 6 of the liver. A contrast-enhanced CT of the liver is performed and demonstrates that the lesion enhances moderately and has a lobulated margin. Which additional finding would make a diagnosis of fibrolamellar carcinoma more likely than that of focal nodular hyperplasia (FNH)?

A A hyperechoic central scar

B A preexisting history of chronic liver disease

C Delayed enhancement of a central scar

D Punctuate calcification in the lesion

E The patient is talking the combined oral contraceptive pill

Answer 17

D Punctuate calcification in the lesion

There is considerable overlap in the imaging appearances of these two conditions, but punctate calcification occurs in over half of patients with fibrolamellar carcinoma and is extremely unusual in FNH.

Question 18

@# 30 A patient a pyrexia of unknown origin is referred for a radio-labelled white cell scan with Tc-99m HMPAO. At which time points should imaging of the abdomen be performed?

(a) 1 and 3 hours

(b) 1, 3 and 6 hours

(c) 1 and 6 hours

(d) 1, 3 and 24 hours

(e) 1, 6 and 24 hours

Answer 18

(a) 1 and 3 hours

99mTC-HAMPAO begins to break down by 4 hours as it is not as stable as 111In; thereafter, breakdown products may be seen within the bile as and intestines.

Question 19

@# 31 A patient is referred for the investigation of right upper quadrant pain. US has equivocal findings and a HIDA examination is requested. At 35 minutes, there is little uptake within the liver, but renal excretion is noted. What is the most likely cause for these findings?

(a) Poor liver function

(b) Acute cholecystitis

(c) Poor renal function

(d) Sphincter Of Oddi dysfunction

(e) Chronic cholecystitis

Answer 19

(a) Poor liver function

Liver uptake should be seen within 10 minutes. Thereafter, there is filling of the gallbladder and subsequent excretion to the bowel. Cholecystitis impairs uptake to the GB.

Question 20

@#e A 64-year-old woman presents to her GP with increasing discomfort in her upper abdomen and anorexia. There is a past medical history of gallstones. The GP requests an abdominal ultrasound and this demonstrates a 6 x 4 cm mixed echogenicity lesion in the gallbladder fossa, with the gallbladder not separately visualised. On CT, the gallbladder fossa mass demonstrates central low attenuation with peripheral enhancement and mild intrahepatic biliary dilatation. Low attenuation lymph nodes are present at the porta hepatis(measuring up to 1.5 cm short axis). Which diagnosis is most likely?

A Adenomyomatosis

B Gallbladder carcinoma

C Hepatocellular carcinoma

D Porcelain gallbladder

E Xanthogranulomatous cholecystitis

Answer 20

B Gallbladder carcinoma

A gallbladder fossa mass with little/no visible normal gallbladder and hilarbiliary obstruction is highly suggestive of gallbladder carcinoma.

Question 21

@# Which is the most likely source of a metastatic deposit to the pancreas?

A. Bronchogenic carcinoma

B. Breast cancer

C. Renal Cell Carcinoma (RCC)

D. Soft tissue sarcoma

E. Colon carcinoma

Answer 21

C. Renal Cell Carcinoma (RCC)

The most likely primary tumor leading to a metastatic deposit to the pancreas is renal cell carcinoma. These metastases are usually solitary and heterogeneously enhancing masses with increased attenuation relative to the pancreas.

Question 22

@# 3. A 64-year-old woman presents to the dermatologist with erythematous maculopapular lesions on her legs, buttocks and face, and is diagnosed with necrolytic migratory erythema. Which initial imaging investigation is most appropriate?

A. no imaging

B. mammography

C. CT of the brain

D. chest radiograph

E. CT of the abdomen

Answer 22

E. CT of the abdomen

Necrolytic migratory erythema is a rare dermatological condition with a strong association with glucagonoma, an islet-cell tumour of the pancreas derived from alpha cells. Over 70% of patients with glucagonoma demonstrate the condition, and they may also complain of weight loss, diarrhoea and diabetes. The association is considered strong enough to warrant thorough investigation for pancreatic malignancy. Glucagonomas typically occur in the pancreatic body or tail, and are large (2.5– 25 cm) Hypervascular tumours with solid and necrotic components. They have a high rate of malignant transformation, and around 50% of patients have liver metastases at the time of diagnosis

Question 23

@# A patient with a 4-month history of severe upper abdominal pain undergoes an endoscopic US. This reports a combination of echogenic and echo-poor foci throughout the pancreas, an irregular contour of the pancreatic duct and thickening of the duct wall with some side duct dilatation. What is the most likely diagnosis?

(a) Autoimmune pancreatitis

(b) Pancreatic adenocarcinoma

(c) Intraductal papillary mucinous tumour

(d) von Hippel Linda u syndrome

(e) Chronic pancreatitis

Answer 23

(e) Chronic pancreatitis

These are the typical findings of chronic pancreatitis at endoscopic ultrasound.

Question 24

@# Which of the following is associated with an increased risk of developing pancreatic adenocarcinoma?

(a) Hereditary pancreatitis

(b) High alcohol consumption

(c) High coffee consumption

(d) Low fiber diet

(e) Type-I diabetes mellitus

Answer 24

(a) Hereditary pancreatitis

There is a 70-foId increase in pancreatic adenocarcinoma in this condition. Dietary factors play no role, but cigarette smoking is associated. Diabetes mellitus may be a presenting feature, but is not associated with an increased risk Of malignancy.

Question 25

@#e QUESTION 41
A 68-year-old man presents to his GP with weight loss and jaundice. Liver function tests demonstrate obstructive jaundice and an abdominal ultrasound shows mild intrahepatic biliary dilatation with a common bile duct measuring 12 mm in diameter. In the pancreatic head, a 3-cm hypoechoic mass is present. An ERCP is performed with insertion of a plastic stent and brushings confirm a pancreatic ductal adenocarcinoma. A triple-phase (precontrast, arterial and portal venous) multidetector CT of the pancreas is performed. Which finding would indicate a non resectable pancreatic tumour?

A Enhancing pancreatic parenchyma between the tumour and superior mesenteric vein

B The pancreatic duct dilated to 6 mm

C The presence of a 5-mm coeliac axis lymph node

D The tumour has invaded the duodenum

E The tumour in contact with 75% of the superior mesenteric artery

Answer 25

E The tumour in contact with 75% of the superior mesenteric artery

If the tumour is in contact with more than half of the vessel circumference, it is very unlikely to be resectable.

Question 26

@#e QUESTION 90
A 41-year-old man has a 3-month history of weight loss and recurrent central abdominal pain. The pain is intermittent and radiates from the epigastrium through to his back. His past medical history includes excessive alcohol consumption and two previous admissions to hospital for acute pancreatitis. A contrast-enhanced CT of the abdomen is performed with precontrast, arterial and portal venous phase images of the upper abdomen. Which CT finding would be more suggestive of chronic pancreatitis than ductal pancreatic adenocarcinoma?

A Common bile duct dilatation

B Focal enlargement of the pancreatic head

C Intraductal pancreatic calcification

D Peripancreatic fat stranding and ascites

E Reduced enhancement of body of pancreas

Answer 26

C Intraductal pancreatic calcification

Intraductal calcification may be focal or diffuse and is not seen in all patients with chronic pancreatitis. When it is present, however, it is a highly reliable sign of chronic pancreatitis.

Question 27

@# A 47-year-old patient is referred for abdominal US. In the spleen, several rounded, thin-walled hypoechoic lesions are seen in a subcapsular position. CT shows the lesions have a density of 20 HU and there is no enhancement with intravenous contrast medium. What is the most likely diagnosis?

(a) Infarction

(b) hemangioma

(c) Lymphangioma

(d) Hamartoma

(e) abscess

Answer 27

(C) Lymphangioma. Corrected

These are the typical imaging features of these asymptomatic lesions. Infarcts are usually wedge-shaped, whilst the remaining lesions usually show some enhancement.

Question 28

@# 18 A patient is referred for a CT of the chest, abdomen and pelvis, the clinical details read “Riedel’s thyroiditis. Hyper- IgG4 disease”. Are any other organs involved? Which of the following conditions are not associated?

(a) Cryptogenic organising pneumonia

(b) Benign pleural mesothelioma

(c) Systemic sclerosis

(d) Autoimmune pancreatitis

(e) Retroperitoneal fibrosis

Answer 28

(c) Systemic sclerosis

Hyper lgG4 is a chronic inflammatory condition that may involve a number of organs. It is characterized histologically by a lymphoplasmacytic inflammation with lgG4-positive cells and. exuberant fibrosis, which leaves dense fibrosis on resolution. It may respond to corticosteroids or other immunosuppressant therapy. Sclerosing sialadenitis, retro-orbital pseudotumour, and panniculitis.

Question 29

@# (GU) 40 With regards to the anatomy of the retroperitoneum, which of the following statements is true?

(a) The right perirenal space communicates with the bare area of the liver

(b) The left perirenal space communicates with the scrotum

(c) The adrenal gland is in the anterior pararenal space

(d) The psoas muscle is in the posterior pararenal space

(e) The posterior pararenal space contains the ascending and descending colon

Answer 29

(a) The right perirenal space communicates with the bare area of the liver

The psoas lies posterior to the posterior pararenal space.

The adrenal gland is in the perirenal space.

The ascending and descending colon are in the anterior pararenal space.

Question 30

@#e 38. A 60-year-old presents with left groin pain. Ultrasound shows a 2 cm hypoechoic lesion bulging medial to the epigastric vessels on Valsalva manoeuvre and absent on rest. What is the most likely diagnosis?

(a) Direct inguinal hernia

(b) Indirect inguinal hernia

(c) Obturator hernia

(d) Spigelian hernia

(e) Femoral hernia

Answer 30

38. (a) Direct inguinal hernia

A direct inguinal hernia is seen medial to the inferior epigastric vessels whereas an indirect hernia is seen lateral to them.

Question 31

@# 6. A 45-year-old man is admitted after a road traffic accident in which he sustained abdominal injuries. After fluid resuscitation he undergoes CT of the abdomen and pelvis with intravenous contrast. This demonstrates a serpiginous area of attenuation value 130 HU at the splenic hilum with surrounding lower-attenuation material. What is this most likely to represent?

A. active arterial extravasation

B. acute clotted blood

C. acute unclotted blood

D. splenic arterial calcification

E. ascites

Answer 31

A. active arterial extravasation

In the evaluation of haemoperitoneum by CT, attenuation values can help differentiate ascites, unclotted blood, active bleeding and haematoma.

Blood usually has a higher measured attenuation than other body fluids, but its appearance depends on the age, extent and location of hemorrhage.

Unclotted blood has an attenuation value of 30–45 HU, but this may be lower in patients with a lower serum haematocrit and if the hemorrhage is more than 48 hours old.

Clotted blood has an attenuation value of 45–70 HU, and identification of the area of highest-attenuation haematoma (sentinel clot) on CT indicates the site of bleeding.

Active arterial extravasation is seen as an area of higher attenuation resembling that in the aorta, ranging from 85 HU to 370 HU.

It may be surrounded by lower-attenuation haematoma. This finding indicates the need for urgent embolization or surgical treatment.

Question 32

@# 8. A patient undergoes 111In-labelled white blood cell scintigraphy for investigation of suspected occult sepsis. Which of these would be regarded as abnormal on imaging at 4 hours?

A. uptake in the large bowel

B. splenic uptake greater than that of the liver

C. uptake in the bone marrow

D. diffuse uptake in the lungs

E. uptake in the thymus in children

Answer 32

A. uptake in the large bowel

Radiolabelled white cell imaging is used for detection of infection and inflammation. Images reflect the distribution of white blood cells within the body, and also localize areas of infection or inflammation.

Imaging is usually performed at 18–24 hours, by which time blood pool activity is normally no longer present, and the most intense uptake is seen in the spleen, followed by the liver and then the bone marrow.

Imaging is also usually performed at 2–6 hours for investigation of suspected inflammatory bowel disease, as sloughed inflamed cells may move distally and provide misleading information as to the affected site if only imaged at 24 hours.

Physiological diffuse lung uptake may be seen in the first 4 hours due to cellular activation from in vitro cell manipulation, but normally decreases after this.

Thymus activity may be seen normally in children.

Bowel and genitourinary activity are not normally seen, and gastrointestinal activity is always abnormal. In general,

focal activity outside the normal white cell distribution, which is greater than that of the spleen, suggests the presence of an abscess.

Activity equal to that of the liver indicates a significant inflammatory focus.

Activity less than that of the bone marrow suggests a low-level inflammatory response.

Question 33

@# 13. What is the most common side effect associated with administration of superparamagnetic iron oxide particles as a contrast agent during MRI?

A. urticarial skin rash

B. back pain

C. nephrotoxicity

D. nausea

E. headache

Answer 33

B. back pain

‘The most common complication of administration of superparamagnetic iron oxide particles is acute severe back pain, which is seen in approximately 4% of patients. This isthought to be a side effect of particulate agents in general, and lasts for the duration of the infusion and slightly beyond. The risk is higher in patients with liver dysfunction, and when the infusion is administered more rapidly than over the recommended 30 minutes. Slowing of the infusion rate or termination of the infusion with recommencement after resolution of the back pain is usually sufficient to alleviate the symptoms