Abdominal and Pelvic Radiology Practice Questions

Q: The initial imaging investigation for suspected intestinal obstruction is?

X-ray abdomen. ***Correct: X-ray abdomen*** - An **X-ray of the abdomen** is usually the **initial imaging investigation** due to its widespread availability, low cost, and ability to quickly identify signs of obstruction like **dilated bowel loops** and **air-fluid levels**. - While not as sensitive or specific as a CT scan, it serves as a crucial **first-line diagnostic tool** to determine the presence of an obstruction and guide further workup. *Incorrect: Ultrasound* - Ultrasound can be useful, especially in specific scenarios like suspected **intussusception** in children or **pyloric stenosis**. - However, its diagnostic accuracy for general intestinal obstruction in adults is often limited by **bowel gas** and operator dependence, making it less ideal as the initial test compared to X-ray. *Incorrect: CT scan* - A **CT scan with intravenous and oral contrast** is considered the **gold standard** for diagnosing intestinal obstruction, precisely localizing the obstruction, and identifying its cause. - It is typically performed **after an initial X-ray** has confirmed suspicion or as a primary investigation if an X-ray is inconclusive or complex pathology is suspected from the outset. *Incorrect: Barium study* - **Barium studies** (e.g., small bowel follow-through) involve administering contrast orally or rectally to visualize the bowel lumen. - While historically used, they are generally **avoided in suspected acute obstruction** due to the risk of barium impaction proximal to the obstruction or peritonitis if a perforation is present.

Q: A 70-year-old male presents with a pulsatile abdominal mass. Which diagnostic study is most appropriate to confirm the presence of an abdominal aortic aneurysm?

Abdominal ultrasound. ***Abdominal ultrasound*** - An abdominal ultrasound is the **initial and most appropriate diagnostic study** due to its non-invasive nature, accessibility, and high accuracy in visualizing the **aorta's diameter** and presence of a pulsatile mass. - It can effectively **measure the size of the aneurysm**, detect its presence, and monitor its progression over time. *CT angiography* - While **CT angiography** provides detailed anatomical information, it involves **ionizing radiation** and **contrast dye**, making it a less preferred initial diagnostic tool compared to ultrasound for screening or initial confirmation. - It is typically reserved for **surgical planning** or in cases where ultrasound findings are inconclusive, or more detailed vascular mapping is required. *MRI* - **MRI** is an excellent imaging modality for soft tissue and vascular structures but is generally **more expensive and time-consuming** than ultrasound, and less readily available, making it less suitable as a first-line diagnostic test for AAA. - Its use is often limited to patients who cannot undergo CT due to **renal insufficiency** or **contrast allergy**. *Plain X-ray* - A **plain X-ray** of the abdomen is **not sensitive** or specific enough to accurately diagnose or rule out an abdominal aortic aneurysm. - It may incidentally show **aortic calcification**, but it cannot reliably measure the aortic diameter or confirm an aneurysm.

Q: Which imaging technique is essential for evaluating a suspected perforation of the gastrointestinal tract?

CT scan with IV contrast. ***CT scan with IV contrast*** - A **CT scan with intravenous (IV) contrast** is the most sensitive and specific imaging modality for detecting **gastrointestinal (GI) perforation**. - It can visualize **free air**, fluid collections, and the site of perforation, providing crucial information for surgical planning. *Abdominal ultrasound* - While useful for detecting **free fluid** or abscesses, **abdominal ultrasound** is less sensitive for identifying **free air** in the abdomen, which is a hallmark of perforation. - Its diagnostic accuracy depends heavily on the operator's skill and patient body habitus. *X-ray using oral contrast* - An **X-ray using oral contrast** (e.g., gastrografin) can demonstrate a leak if the contrast extravasates, but it is less sensitive for small perforations and can be time-consuming. - Oral contrast is contraindicated if there's a risk of aspiration in an unstable patient, or if there is a known large perforation where the contrast could enter the peritoneal cavity and cause peritonitis. *MRI of the abdomen* - **MRI of the abdomen** is generally not the first-line imaging technique for acute GI perforation due to its longer acquisition times and higher cost. - Although it can detect **free fluid** and inflammation, it is not as readily available or as rapid as a CT scan, which is critical in an emergency setting.

Q: A patient with fever, back pain, and difficulty walking is diagnosed with a psoas abscess. Which imaging modality is the most effective for confirming the diagnosis?

CT scan. ***CT scan*** - **CT scan** is the **most effective** imaging modality for diagnosing a psoas abscess due to its superior ability to visualize deep soft tissue structures and precisely delineate the abscess. - It clearly shows the **inflammation**, fluid collection, and extension of the abscess, guiding potential drainage. *Ultrasound* - While useful for superficial collections, **ultrasound** has limited penetration and is often obscured by bowel gas, making it less effective for deep structures like the psoas muscle. - It may be used as a **bedside tool** for initial assessment or guided aspiration if the abscess is readily accessible. *X-ray* - **X-rays** have very limited utility in diagnosing psoas abscesses as they primarily visualize bony structures and cannot effectively delineate soft tissue collections. - They might show indirect signs like **loss of the psoas shadow**, but this is non-specific and insensitive. *MRI* - **MRI** provides excellent soft tissue contrast and is highly sensitive for detecting abscesses, but it is typically reserved for cases where CT is inconclusive or when there is a need to rule out spinal involvement. - It is **more expensive** and less readily available than CT, making it a secondary option for initial diagnosis.

Q: What does the 'football sign' on an abdominal X-ray indicate?

Pneumoperitoneum. ***Pneumoperitoneum*** - The **"football sign"** is observed on a supine abdominal X-ray and is characterized by the visualization of the entire anterior abdominal wall due to a large amount of **free air** in the peritoneal cavity. - This sign indicates **pneumoperitoneum**, which is often a critical finding suggesting **viscus perforation**. *Ascites* - **Ascites** refers to the accumulation of fluid in the peritoneal cavity, which would typically cause a generalized hazy appearance and sometimes **flank bulging** on X-ray. - It would not result in the distinct outlining of the abdominal wall by air as seen in the **football sign**. *Bowel obstruction* - **Bowel obstruction** is characterized by dilated loops of bowel, often with **air-fluid levels** on erect views, but does not present with free intraperitoneal air. - While it can sometimes lead to perforation and subsequent pneumoperitoneum, the football sign itself directly indicates the presence of **free air**, not the obstruction itself. *Renal stone* - A **renal stone** (nephrolithiasis) would appear as a **radio-opaque density** in the region of the kidney or ureter on an abdominal X-ray. - This finding is unrelated to the distribution of air within the abdominal cavity or the **football sign**.

Q: Identify the radiological sign of Ischemic colitis from the image provided.

Thumbprinting sign of Ischemic colitis. ***Thumbprinting sign of Ischemic colitis*** - The image displays prominent **indentations (thumbprinting)** along the bowel wall, especially in the descending colon (indicated by arrows). These indentations are caused by **edema** and **hemorrhage** in the submucosal layer due to ischemia. - This characteristic appearance on a barium enema or CT scan is a classic radiological sign highly suggestive of **ischemic colitis**. *Diverticulitis* - Diverticulitis typically presents with **saccular outpouchings** (diverticula) that become inflamed, potentially showing wall thickening or **pericolonic fat stranding**. - This image does not show typical diverticula or signs of severe inflammation associated with diverticulitis, but rather diffuse mucosal changes. *Appendicitis* - Appendicitis is characterized by inflammation of the **vermiform appendix**, typically seen as a **dilated**, non-compressible appendix with surrounding fat stranding in the right lower quadrant. - The radiological findings in the image are of the colon, not the appendix, and are inconsistent with acute appendicitis. *None of the options* - The image presents a clear and characteristic radiological sign that points to a specific diagnosis, making this option incorrect. - The presence of **thumbprinting** is a well-established indicator for ischemic colitis.

Q: Chain of lakes appearance is seen in?

Chronic pancreatitis. ***Chronic pancreatitis*** - The **"chain of lakes" appearance** refers to the characteristic imaging finding of **multiple dilated pancreatic ducts** with intervening strictures, indicative of chronic inflammation and fibrosis. - This morphology is a hallmark of advanced chronic pancreatitis on **ERCP or MRCP**, reflecting irreversible damage to the pancreatic ductal system. *Gallstone ileus* - Characterized by **mechanical obstruction of the small intestine** by a gallstone that has entered the bowel lumen through a cholecystoenteric fistula. - Imaging shows signs of small bowel obstruction, pneumobilia, and ectopic gallstone, not pancreatic ductal abnormalities. *Sub-acute intestinal obstruction* - Refers to partial or intermittent bowel obstruction with features like abdominal pain, distension, vomiting, and altered bowel habits. - Imaging findings relate to dilated bowel loops proximal to the obstruction, not pancreatic duct changes. *Acute pancreatitis* - While acute pancreatitis can involve ductal inflammation and occasionally transient dilation, it does not present with the **permanent "chain of lakes" morphology** seen in chronic disease. - Acute pancreatitis shows peripancreatic inflammation, fluid collections, or necrosis rather than chronic ductal strictures and dilatations.

Q: Which condition is associated with the "Drooping lily sign"?

Duplicated collecting system. ***Duplicated collecting system*** - The "drooping lily sign" is a classic radiographic finding in congenital **duplicated collecting systems** where the lower pole ureter and corresponding renal pelvis are displaced inferiorly and laterally due to an obstructed, dilated, and ectopic upper pole ureter and dilated calyces. - This displacement gives the lower pole calyces the appearance of a **"drooping lily"** on an intravenous pyelogram (IVP) or other imaging studies. *Hydronephrosis* **Hydronephrosis** refers to the swelling of a kidney due to a build-up of urine, typically due to obstruction. - While a duplicated system can cause hydronephrosis in the obstructed upper pole, **hydronephrosis itself doesn't directly present with a "drooping lily sign"** but rather features like dilated renal pelvis and calyces. *Chronic pyelonephritis* - **Chronic pyelonephritis** is an inflammatory condition of the kidney and renal pelvis, often due to recurrent infections. - Imaging typically shows **scarring, cortical thinning, and blunting of calyces**, distinct from the "drooping lily" appearance. *Renal cell carcinoma* - **Renal cell carcinoma (RCC)** is a malignant tumor of the kidney. - Imaging features usually include a **renal mass**, often with calcifications, necrosis, or vascular invasion, which is unrelated to the "drooping lily sign."

Q: Which of the following is a valid imaging criterion for unresectable carcinoma of the pancreas?

Encasement of the superior mesenteric artery. ***Encasement of the superior mesenteric artery*** - **Encasement** (defined as >180-degree circumferential contact) of the **superior mesenteric artery (SMA)** is a definitive **local imaging criterion** for unresectable pancreatic cancer per NCCN guidelines. - This represents the classic teaching point for imaging-based assessment of resectability based on tumor-vessel relationships. - SMA encasement precludes safe surgical resection with negative margins. *Invasion of the duodenal wall* - Duodenal wall invasion is typically managed during **pancreaticoduodenectomy (Whipple procedure)** with en-bloc resection of the duodenum. - Isolated duodenal invasion does not render the tumor unresectable and is expected in most pancreatic head tumors. *Metastatic spread to vertebrae* - While **distant metastases** (including vertebral metastases) absolutely indicate unresectability, they represent **systemic spread** rather than a local imaging criterion for assessing primary tumor resectability. - In clinical practice, the assessment of resectability based on imaging primarily focuses on **local tumor-vessel relationships** (SMA, celiac axis, portal vein, SMV). - Metastatic disease is typically categorized separately under staging rather than resectability criteria based on locoregional anatomy. *Irregular increase in density of omental fat* - Increased omental fat density may suggest **peritoneal carcinomatosis** but is non-specific and not a definitive criterion. - Requires tissue confirmation and is not a standard imaging criterion for determining unresectability.

Question 1

The initial imaging investigation for suspected intestinal obstruction is?

Accepted Answer

X-ray abdomen

Answer

Ultrasound

Answer

CT scan

Answer

Barium study

Question 2

A 70-year-old male presents with a pulsatile abdominal mass. Which diagnostic study is most appropriate to confirm the presence of an abdominal aortic aneurysm?

Accepted Answer

Abdominal ultrasound

Answer

MRI

Answer

Plain X-ray

Answer

CT angiography

Question 3

Which imaging technique is essential for evaluating a suspected perforation of the gastrointestinal tract?

Accepted Answer

CT scan with IV contrast

Answer

Abdominal ultrasound

Answer

X-ray using oral contrast

Answer

MRI of the abdomen

Question 4

A patient with fever, back pain, and difficulty walking is diagnosed with a psoas abscess. Which imaging modality is the most effective for confirming the diagnosis?

Accepted Answer

CT scan

Answer

Ultrasound

Answer

X-ray

Answer

MRI

Question 5

A 60-year-old male with a history of smoking presents with severe abdominal pain and a pulsatile abdominal mass. What is the most appropriate next step in managing this patient?

Accepted Answer

CT angiography

Answer

Immediate surgery

Answer

Ultrasound of the abdomen

Answer

Observation

Question 6

What does the 'football sign' on an abdominal X-ray indicate?

Accepted Answer

Pneumoperitoneum

Answer

Ascites

Answer

Bowel obstruction

Answer

Renal stone

Question 7

Identify the radiological sign of Ischemic colitis from the image provided.

Accepted Answer

Thumbprinting sign of Ischemic colitis

Answer

Diverticulitis

Answer

Appendicitis

Answer

None of the options

Question 8

Chain of lakes appearance is seen in?

Accepted Answer

Chronic pancreatitis

Answer

Gallstone ileus

Answer

Sub-acute intestinal obstruction

Answer

Acute pancreatitis

Question 9

Which condition is associated with the "Drooping lily sign"?

Accepted Answer

Duplicated collecting system

Answer

Hydronephrosis

Answer

Chronic pyelonephritis

Answer

Renal cell carcinoma

Question 10

Which of the following is a valid imaging criterion for unresectable carcinoma of the pancreas?

Accepted Answer

Encasement of the superior mesenteric artery

Answer

Invasion of the duodenal wall

Answer

Metastatic spread to vertebrae

Answer

Irregular increase in density of omental fat

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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