Abdominal and Pelvic Radiology Practice Questions

Q: Central stellate scar is typically associated with which of the following conditions?

Focal nodular hyperplasia (FNH). ***Focal nodular hyperplasia (FNH)*** - FNH is a benign liver lesion characterized by a central fibrous scar with radiating septa, giving it the characteristic appearance of a **central stellate scar** on imaging. - This scar contains **malformed blood vessels** and bile ductules, which are key diagnostic features. - On dynamic imaging, FNH typically shows **spoke-wheel arterial enhancement** pattern and the central scar shows **delayed enhancement** on MRI. *Hepatic adenoma* - Hepatic adenomas are typically composed of sheets of **hepatocytes** with absent portal triads and are usually **homogeneous** on imaging without a central scar. - They are associated with **oral contraceptive use** and have a risk of hemorrhage and malignant transformation. *Chronic liver disease* - Chronic liver disease, such as **cirrhosis**, is characterized by widespread **fibrosis** and **nodule formation** throughout the liver, but it does not typically present with a solitary lesion with a central stellate scar. - The scarring in cirrhosis is diffuse and leads to architectural distortion, rather than a focal central scar. *Hepatocellular carcinoma* - Hepatocellular carcinoma (HCC) typically presents as a **vascular mass** that may or may not be solitary, usually arising in the context of chronic liver disease or cirrhosis. - Although the **fibrolamellar variant of HCC** (seen in younger patients without cirrhosis) can show a central scar, this is less common and the scar typically shows **hypointensity on T2-weighted imaging**, unlike FNH where the scar is **hyperintense on T2**. - Typical HCC does not show a distinct central stellate scar as a characteristic feature.

Q: Which of the following is NOT a characteristic X-ray finding of small intestinal malabsorption syndrome?

Increased transit time. ***Increased transit time*** - Small intestinal malabsorption typically leads to **decreased intestinal transit time** or **accelerated transit**, as unabsorbed contents rush through the bowel. - An increased transit time is more commonly associated with conditions causing **obstruction** or **delayed gastric emptying**, not primary malabsorption. *Mucosal atrophy* - **Mucosal atrophy**, or flattening of the villi, is a classic finding in many malabsorption syndromes, such as **celiac disease**, as it reduces the absorptive surface area. - This change can be visualized indirectly through X-ray studies by assessing the mucosal fold pattern. *Dilatation of bowel* - In malabsorption, particularly chronic cases, the accumulation of unabsorbed fluid and gas can lead to **distension** and **dilatation of bowel loops**. - This is often seen in conditions like **tropical sprue** or severe giardiasis. *Flocculation of barium* - **Flocculation and segmentation of barium** are historical X-ray findings in malabsorption, where barium mixes with excess fluid and mucus, appearing clumped and discontinuous. - This indicates altered mucosal surface tension and the presence of abnormal intraluminal contents hindering uniform barium distribution.

Q: Which of the following types of urinary stones is not radio-opaque?

Uric acid stones. ***Uric acid stones*** - **Uric acid stones** are composed of purine metabolites and are **non-radio-opaque**, meaning they do not show up on standard x-rays. - Their presence often necessitates diagnostic tools like **ultrasound** or **CT scans** for detection due to their radiolucent nature. *Calcium stones* - **Calcium oxalate** and **calcium phosphate stones** are the most common type of urinary stones and are typically **radio-opaque**. - They are readily visible on plain abdominal radiographs (KUB x-rays) due to their high calcium content. *Struvite stones* - Also known as **infection stones**, struvite stones are composed of **magnesium ammonium phosphate** and are highly **radio-opaque**. - They often form in the presence of **bacterial infections** that produce urease, visible on X-rays. *Cystine stones* - **Cystine stones** result from an inherited metabolic disorder (cystinuria) and contain sulfur, making them **moderately radio-opaque**. - While not as dense as calcium stones, they are generally still detectable on plain radiographs.

Q: A 'string of pearls' appearance is seen in -

Small Bowel Obstruction. ***Small Bowel Obstruction*** - The "string of pearls" sign on an **abdominal X-ray** is a classic radiographic finding in **small bowel obstruction**. - It results from small pockets of **air trapped** between the plicae circulares of a dilated, fluid-filled small bowel, appearing as a linear array of small lucencies. *Toxic Megacolon* - Characterized by **colonic dilation** (typically transverse colon >6 cm) with signs of systemic toxicity. - X-ray findings usually show a **markedly dilated colon** with **loss of haustra**, not a string of pearls. *Ischaemic Colitis* - Radiographic features often include **thumbprinting** (due to submucosal edema/hemorrhage) and **segmental bowel thickening**. - It does not typically present with the "string of pearls" sign, which is specific to small bowel obstruction. *Ulcerative Colitis* - Common X-ray findings include **loss of haustral markings** (leading to a "lead pipe" appearance in chronic cases) and **mucosal edema**. - It is a disease of the large intestine and does not cause the "string of pearls" sign, which is characteristic of dilated small bowel loops.

Q: Thumb print sign in a plain X-ray is seen in:

Ischemic colitis. ***Ischemic colitis*** - The **thumbprint sign** on a plain X-ray or CT scan is characteristic of ischemic colitis, resulting from submucosal edema and hemorrhage. - This appearance is due to the thickened, edematous **haustral folds** projecting into the colonic lumen. *Ulcerative colitis* - While it affects the colon, classic imaging findings for ulcerative colitis include **loss of haustral folds** (lead pipe sign) and pseudopolyps, not the thumbprint sign. - **Toxic megacolon** is a severe complication, identifiable by colonic dilation and wall thickening, distinct from thumbprint sign. *Pseudomembranous colitis* - This condition is caused by *Clostridioides difficile* infection and typically manifests with **thickened, nodular colonic walls** or inflammatory pseudomembranes on imaging. - It does not typically present with the classic "thumbprint" appearance indicative of ischemic changes. *Appendicitis* - Appendicitis is an inflammation of the appendix, diagnosed usually by findings like a **dilated appendix** with surrounding fat stranding on imaging. - The imaging findings are localized to the right lower quadrant and do not involve diffuse colonic changes like the "thumbprint sign."

Q: String sign of Kantor is a radiological feature of:

Crohn's disease. ***Crohn's disease*** - The **string sign of Kantor** is a classic radiological finding in **Crohn's disease**, particularly with involvement of the terminal ileum. - It represents severe luminal narrowing due to **inflammation, fibrosis, and spasm**, appearing as a thin, continuous stripe of barium. *Ulcerative colitis* - This condition primarily affects the **colon** and rectum, causing diffuse inflammation and ulceration. - Radiological features include **loss of haustra**, pseudopolyps, and continuous involvement, not typically a "string sign." *Ileocaecal tuberculosis* - While it can cause **strictures and inflammation** in the ileocecal region, the "string sign of Kantor" is more specifically associated with Crohn's. - **Tuberculosis** often presents with skip lesions but also involves other features like calcified lymph nodes. *Ischemic colitis* - This condition results from **reduced blood flow to the colon**, typically causing "thumbprinting" due to submucosal edema and segmental involvement. - It does not usually present with the long, thin, continuous luminal narrowing characteristic of the **string sign**.

Q: The most sensitive imaging modality to detect early renal tuberculosis is:

Magnetic resonance imaging. ***Magnetic resonance imaging*** - **MRI** is the most sensitive imaging modality for detecting **early renal tuberculosis** due to its superior soft tissue contrast resolution. - It can identify subtle **parenchymal inflammatory changes**, early granulomas, and edema before calcification or cavitation occurs. - MRI is particularly useful for detecting **early renal cortical involvement** and small lesions that may be missed by other modalities. - Provides excellent anatomical detail without ionizing radiation. *Computed tomography* - **CT** is excellent for detecting **established renal tuberculosis** with calcifications, cavitations, and collecting system abnormalities. - However, calcifications and cavitations represent **intermediate to late findings**, not early disease. - CT is less sensitive than MRI for detecting subtle parenchymal inflammatory changes in early stages. - More useful once the disease has progressed to structural changes. *Ultrasound* - **Ultrasound** is useful for screening and follow-up but has significant limitations for early disease detection. - May miss small lesions, subtle parenchymal changes, and early calcifications. - Operator-dependent and limited by **acoustic windows** and patient body habitus. *Intravenous urography* - **IVU** primarily detects changes in the **collecting system** such as strictures, calyceal clubbing, and ureteral abnormalities. - These represent **late manifestations** of renal tuberculosis, not early disease. - Has largely been replaced by cross-sectional imaging (CT/MRI) for evaluating renal pathology. - Less sensitive for parenchymal involvement compared to CT or MRI.

Q: What percentage of gallstones are radiopaque?

10%. ***10%*** - Approximately **10% of gallstones** contain enough calcium to be visible on a plain X-ray and are considered **radiopaque** (some sources cite up to 15%). - The majority of gallstones are primarily composed of cholesterol, which is **radiolucent** and not visible on plain radiographs. - **Pigment stones** (calcium bilirubinate) are more likely to be radiopaque than cholesterol stones. *20%* - This percentage is too high; the actual proportion of radiopaque gallstones is significantly lower. - Most gallstones are **cholesterol-based** (about 80%) and therefore not visible on standard X-rays. *30%* - This percentage greatly overestimates the number of radiopaque gallstones. - The lack of significant calcium content in most gallstones makes them **undetectable by plain X-ray imaging**. *40%* - This percentage is incorrect and far exceeds the actual proportion of radiopaque gallstones. - **Ultrasound or CT scan** are the preferred imaging modalities for detecting gallstones, not plain X-ray.

Q: What is the best way to diagnose gallbladder stones?

USG. ***USG*** - **Ultrasound (USG)** is the preferred and most **sensitive imaging modality** for detecting gallbladder stones due to its non-invasive nature and high diagnostic accuracy. - It can effectively visualize stones as **echogenic foci** with **posterior acoustic shadowing** within the gallbladder lumen. *Oral cholecystography* - This method involves ingesting a contrast agent, which is then absorbed and excreted by the liver into the bile, outlining the gallbladder. - It has largely been replaced by ultrasound due to its **lower sensitivity** for small stones, **patient inconvenience**, and potential for **adverse reactions** to the contrast. *Percutaneous transhepatic cholangiography* - **PTC** is an **invasive procedure** where a needle is inserted through the skin and liver into the bile ducts to inject contrast. - It is typically reserved for cases where **other imaging modalities are inconclusive** or for **therapeutic interventions** in patients with biliary obstruction, not routine stone detection. *Intravenous cholangiogram* - This involves intravenous administration of a contrast agent that is concentrated in the bile and allows visualization of the bile ducts and gallbladder. - It has also been **largely replaced by USG and ERCP** due to the risk of **allergic reactions** to contrast, **poor visualization** in cases of liver dysfunction, and lower sensitivity than ultrasound.

Q: The X-ray appearance of a CBD stone on cholangiography is:

Meniscus sign. ***Meniscus sign*** - A **meniscus sign** on cholangiography is characteristic of a **filling defect** caused by a gallstone within the **common bile duct (CBD)**. - The contrast agent outlines the stone, creating a crescent-shaped or **meniscus-like appearance** around it. *Non-central occlusion* - This term usually refers to an incomplete or **partial blockage** that doesn't necessarily have the distinct outline of a stone. - While a stone can cause occlusion, "meniscus sign" specifically describes the **radiographic appearance** of the stone itself. *Abrupt cut-off* - An **abrupt cut-off** suggests a sudden and complete obstruction, often seen with **malignant strictures** or **impacted stones** without clear outlining. - It does not specifically describe the characteristic rimming of contrast around a stone that defines a meniscus sign. *Benign tapering* - **Benign tapering** typically indicates a gradual, smooth narrowing of the duct, often associated with **inflammatory strictures** or **fibrotic changes**. - This appearance is different from the distinct filling defect caused by a stone.

Question 1

Central stellate scar is typically associated with which of the following conditions?

Accepted Answer

Focal nodular hyperplasia (FNH)

Answer

Hepatic adenoma

Answer

Chronic liver disease

Answer

Hepatocellular carcinoma

Question 2

Which of the following is NOT a characteristic X-ray finding of small intestinal malabsorption syndrome?

Accepted Answer

Increased transit time

Answer

Dilatation of bowel

Answer

Flocculation of barium

Answer

Mucosal atrophy

Question 3

Which of the following types of urinary stones is not radio-opaque?

Accepted Answer

Uric acid stones

Answer

Calcium stones

Answer

Struvite stones

Answer

Cystine stones

Question 4

A 'string of pearls' appearance is seen in -

Accepted Answer

Small Bowel Obstruction

Answer

Toxic Megacolon

Answer

Ischaemic Colitis

Answer

Ulcerative Colitis

Question 5

Thumb print sign in a plain X-ray is seen in:

Accepted Answer

Ischemic colitis

Answer

Ulcerative colitis

Answer

Pseudomembranous colitis

Answer

Appendicitis

Question 6

String sign of Kantor is a radiological feature of:

Accepted Answer

Crohn's disease

Answer

Ulcerative colitis

Answer

Ileocaecal tuberculosis

Answer

Ischemic colitis

Question 7

The most sensitive imaging modality to detect early renal tuberculosis is:

Accepted Answer

Magnetic resonance imaging

Answer

Intravenous urography

Answer

Ultrasound

Answer

Computed tomography

Question 8

What percentage of gallstones are radiopaque?

Accepted Answer

10%

Answer

20%

Answer

30%

Answer

40%

Question 9

What is the best way to diagnose gallbladder stones?

Accepted Answer

USG

Answer

Oral cholecystography

Answer

Percutaneous transhepatic cholangiography

Answer

Intravenous cholangiogram

Question 10

The X-ray appearance of a CBD stone on cholangiography is:

Accepted Answer

Meniscus sign

Answer

Non-central occlusion

Answer

Abrupt cut-off

Answer

Benign tapering

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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