Abdominal and Pelvic Radiology Practice Questions

Q: Colonic diverticulosis is best diagnosed by which imaging modality?

Barium enema. **Explanation:** **Colonic diverticulosis** refers to the presence of multiple outpouchings (diverticula) of the colonic mucosa and submucosa through the muscular layers. **Why Barium Enema is the Correct Answer:** Historically and for the specific diagnosis of "diverticulosis" (the presence of sacs without inflammation), **Barium Enema** is considered the gold standard and most sensitive imaging modality. It provides excellent mucosal detail, allowing for the visualization of the characteristic "saw-tooth" appearance of the colon and the filling of the diverticular sacs with contrast, which appear as flask-shaped outpouchings. **Analysis of Incorrect Options:** * **Colonoscopy (A):** While it can visualize diverticula, it is primarily used to rule out malignancy. It is less sensitive than barium studies for quantifying the extent of diverticulosis and carries a risk of perforation if acute inflammation is present. * **Nuclear Scan (B):** Technetium-99m labeled RBC scans are used to localize the site of **active diverticular bleeding**, not for the primary diagnosis of diverticulosis. * **CT Scan (D):** CT is the **investigation of choice for Acute Diverticulitis** (to look for wall thickening, fat stranding, or abscesses). However, for simple, non-inflamed diverticulosis, it is less sensitive than a barium enema in detecting small mucosal outpouchings. **NEET-PG High-Yield Pearls:** * **Most common site:** Sigmoid colon (due to high intraluminal pressure). * **Investigation of choice for Diverticulosis:** Barium Enema. * **Investigation of choice for Acute Diverticulitis:** Contrast-Enhanced CT (CECT). * **Contraindication:** Barium enema and Colonoscopy are **contraindicated** in the acute phase of diverticulitis due to the high risk of perforation.

Q: In case of suspected perforation, which radiological view is best?

Erect. **Explanation:** The primary radiological sign of a hollow viscus perforation is **pneumoperitoneum** (free intraperitoneal air). The **Erect Chest X-ray** (or Erect Abdomen) is the gold standard initial screening view because air, being lighter than fluid and solid organs, rises to the highest point in the peritoneal cavity. In the upright position, this air collects under the diaphragm, appearing as a thin, radiolucent crescent (the "crescent sign"). As little as 1–2 ml of free air can be detected on a well-taken erect film. **Analysis of Options:** * **A. Erect (Correct):** Gravity allows air to rise and contrast against the undersurface of the diaphragm and the density of the liver/spleen. * **B. Supine:** In this position, air collects anteriorly and spreads out. It is difficult to visualize unless there is a large volume, where it may show the **Rigler sign** (gas on both sides of the bowel wall) or the **Football sign**. * **C. Lateral Decubitus:** This is the alternative if the patient is too ill to stand. The patient lies on their **left side** (Left Lateral Decubitus) so that air rises and collects between the liver and the right abdominal wall. While sensitive, it is secondary to the erect view. **Clinical Pearls for NEET-PG:** * **Most sensitive view:** The **Left Lateral Decubitus** is technically more sensitive than the erect view for very small amounts of air, but the **Erect Chest X-ray** remains the "best" and most common initial investigation. * **Gold Standard Investigation:** While X-ray is the initial step, **NCCT (Non-Contrast CT) Abdomen** is the most sensitive overall imaging modality for detecting pneumoperitoneum. * **Positioning Tip:** For maximum sensitivity, the patient should remain in the erect or decubitus position for **10–20 minutes** before the film is taken to allow air to migrate.

Q: The given image shows findings most consistent with which of the following conditions?

Ischemic colitis. ***Ischemic colitis*** - The image demonstrates classic **"thumbprinting"** sign on plain X-ray, characterized by **mucosal edema** and **submucosal hemorrhage** creating rounded protrusions into the colonic lumen. - **Ischemic colitis** typically affects the **splenic flexure** and **sigmoid colon** in elderly patients, showing **wall thickening** and loss of haustral markings. *Ileal atresia* - Presents with **multiple dilated small bowel loops** on X-ray, typically in **newborns** with **bilious vomiting**. - Shows **absence of gas** in the distal bowel beyond the point of atresia, not the thumbprinting pattern seen here. *Meconium ileus* - Radiologically shows **soap bubble appearance** in the **right lower quadrant** due to **inspissated meconium** mixed with air. - Associated with **cystic fibrosis** in neonates, presenting with **small bowel obstruction** without the colonic changes observed. *Crohn's disease* - Demonstrates **"string sign"** on imaging due to **strictures** and **skip lesions** affecting the **terminal ileum** predominantly. - Shows **cobblestone appearance** with **deep ulcerations** and **fistula formation**, distinct from the acute thumbprinting pattern.

Q: What is the most appropriate investigation for the diagnosis of common bile duct stones?

ERCP (Endoscopic Retrograde Cholangiopancreatography). **Explanation:** The diagnosis and management of Common Bile Duct (CBD) stones (choledocholithiasis) require high sensitivity and, ideally, therapeutic capability. **Why ERCP is the Correct Answer:** Endoscopic Retrograde Cholangiopancreatography (ERCP) is traditionally considered the **Gold Standard** for the diagnosis of CBD stones. Its primary advantage is that it is both **diagnostic and therapeutic**. Once stones are identified via fluoroscopy with contrast injection, they can be immediately removed via sphincterotomy and stone extraction (using balloons or baskets). While MRCP is now the preferred non-invasive diagnostic tool, ERCP remains the definitive "investigation of choice" in clinical scenarios where intervention is anticipated. **Analysis of Incorrect Options:** * **Ultrasonography (USG):** This is the **initial/screening investigation** for biliary disease. While excellent for detecting gallstones (cholelithiasis) and CBD dilation, it has low sensitivity (approx. 20-50%) for directly visualizing stones in the distal CBD due to interference from overlying bowel gas. * **Oral Cholecystography:** This historical method involves oral contrast to visualize the gallbladder. It is obsolete and cannot reliably visualize the CBD or detect choledocholithiasis. * **Intravenous Cholangiography:** This involves IV contrast excreted into the bile. It has been replaced by safer, more accurate modalities like MRCP and ERCP due to high toxicity and poor opacification in jaundiced patients. **High-Yield Clinical Pearls for NEET-PG:** * **Best Initial Investigation:** USG Abdomen. * **Best Non-Invasive Investigation (Gold Standard for Diagnosis):** MRCP (Magnetic Resonance Cholangiopancreatography). * **Gold Standard (Diagnostic + Therapeutic):** ERCP. * **IOC for Gallstones (Cholelithiasis):** USG. * **Most sensitive per-operative method:** Intraoperative Ultrasound or Cholangiography.

Q: The String sign is seen in which of the following conditions?

All of the above. The **"String Sign"** is a classic radiological finding characterized by a thin, thread-like appearance of a contrast-filled lumen, indicating severe narrowing or stenosis. ### **Explanation of Options:** * **Crohn’s Disease (Kantor’s String Sign):** This is the most classic association. It occurs due to severe narrowing of the terminal ileum caused by transmural inflammation, edema, and subsequent fibrosis/cicatrization. On a Barium meal follow-through, the lumen appears as a thin string. * **TB of the Ileocaecal Region:** Similar to Crohn’s, intestinal tuberculosis causes circumferential thickening and fibrotic strictures of the ileum and ileocaecal valve. This leads to a narrowed lumen, producing a string-like appearance on contrast studies. * **Idiopathic Hypertrophic Pyloric Stenosis (IHPS):** In infants, hypertrophy of the pyloric muscle causes extreme narrowing of the pyloric canal. On a Barium swallow, the elongated, constricted canal appears as a "string" connecting the stomach to the duodenum. ### **High-Yield Clinical Pearls for NEET-PG:** 1. **Kantor’s String Sign:** Specifically refers to Crohn’s disease. 2. **Stierlin’s Sign:** Seen in Ileocaecal TB (rapid emptying of the inflamed segment). 3. **String Sign of Chiari:** Seen in **Budd-Chiari Syndrome** (narrowing of the IVC). 4. **Carotid String Sign:** Seen in **Carotid Artery Dissection** or severe stenosis. 5. **IHPS Ultrasound Signs:** Look for "Target sign" or "Donut sign" (transverse) and "Cervix sign" (longitudinal). Since all three conditions involve a pathologically narrowed lumen that can manifest as a thin line of contrast, **"All of the above"** is the correct answer.

Q: What is the investigation of choice for acute cholecystitis?

USG. **Explanation:** **1. Why USG is the Correct Answer:** Ultrasonography (USG) is the **initial investigation of choice** and the gold standard screening tool for acute cholecystitis. It is highly sensitive (approx. 90-95%) and specific. Its advantages include being non-invasive, radiation-free, cost-effective, and widely available. * **Key USG findings:** Gallbladder wall thickening (>3 mm), pericholecystic fluid, presence of gallstones (usually impacted in the neck), and the **Ultrasonographic Murphy’s sign** (maximal tenderness over the gallbladder when compressed by the USG probe), which has a high predictive value. **2. Why Other Options are Incorrect:** * **B. HIDA Scan (Radionuclide Scan):** This is the **most sensitive/accurate** investigation (Gold Standard for diagnosis). However, it is not the "investigation of choice" because it is time-consuming, expensive, and involves radiation. It is reserved for cases where USG is inconclusive. * **C. CT Scan:** While CT is excellent for identifying complications like perforation, gangrene, or emphysematous cholecystitis, it is less sensitive than USG for detecting gallstones and is not used as a first-line tool. * **D. X-ray:** Only 10-15% of gallstones (pigment stones) are radio-opaque. X-rays are generally unhelpful for diagnosing acute cholecystitis. **3. High-Yield Clinical Pearls for NEET-PG:** * **IOC for Gallstones/Cholecystitis:** USG. * **Most Accurate Test for Acute Cholecystitis:** HIDA Scan (Positive result = Non-visualization of the gallbladder due to cystic duct obstruction). * **IOC for Choledocholithiasis (CBD stones):** MRCP (Non-invasive) or ERCP (Gold standard/Therapeutic). * **Emphysematous Cholecystitis:** Characterized by air in the GB wall; more common in diabetics; CT is the most sensitive for this subtype.

Q: What is the earliest pathological change seen on X-ray in ulcerative colitis?

Mucosal granularity. **Explanation:** In **Ulcerative Colitis (UC)**, the disease process is characterized by continuous, superficial inflammation starting from the rectum and extending proximally. **Why Mucosal Granularity is correct:** The earliest radiological sign of UC on a double-contrast barium enema is **mucosal granularity**. This occurs due to edema and hyperemia of the mucosa, which creates a fine, "sandpaper-like" appearance. As the disease progresses, these granules may enlarge, leading to stippling or a "picket-fence" appearance. **Analysis of Incorrect Options:** * **Loss of haustration (Option A):** This is a feature of **chronic** or long-standing UC. The colon becomes a rigid, shortened, and featureless tube, commonly referred to as the **"Lead-pipe colon."** * **Aphthous ulcerations (Option B):** These are small, shallow ulcers surrounded by a halo of edema. They are the hallmark early sign of **Crohn’s Disease**, not UC. * **Skip lesions (Option D):** These refer to areas of diseased bowel separated by normal segments. This is a classic feature of **Crohn’s Disease**. UC is characterized by continuous involvement without skip areas. **High-Yield Clinical Pearls for NEET-PG:** * **Collar-button ulcers:** Deep, undermined ulcers seen in UC when the disease penetrates the submucosa. * **Pseudopolyps:** Islands of regenerating mucosa surrounded by areas of ulceration; seen in chronic UC. * **Toxic Megacolon:** A life-threatening complication of UC where the transverse colon dilates >6 cm. * **Backwash Ileitis:** Involvement of the terminal ileum in UC (seen in ~10% of pancolitis cases).

Q: Light bulb appearance in MRI scan is/are seen in which of the following conditions?

Pheochromocytoma. **Explanation:** The **"Light Bulb Appearance"** is a classic radiological sign seen on **T2-weighted MRI** images. It refers to a lesion that exhibits intense, bright hyperintensity (shining like a light bulb) compared to the surrounding liver or muscle tissue. **1. Why Pheochromocytoma is correct:** Pheochromocytomas are catecholamine-secreting tumors of the adrenal medulla. Due to their high cellularity, vascularity, and presence of cystic or necrotic components, they have a very high water content. On T2-weighted MRI sequences, this results in a characteristic **marked hyperintensity**. While not present in 100% of cases, it is a highly specific diagnostic clue for this "10% tumor." **2. Why the other options are incorrect:** * **Adrenal Adenoma:** These are the most common adrenal masses. They typically contain intracellular lipid (fat). Therefore, they are best identified by **signal dropout on "Out-of-Phase" Chemical Shift MRI**, not by T2 hyperintensity. * **Adrenal Cortical Tumor (Carcinoma):** These are usually large, heterogeneous, and aggressive. While they may have some T2 signal, they do not typically show the uniform, intense "light bulb" brightness seen in pheochromocytoma. * **Adrenal Calcification:** Calcifications appear as areas of **signal void (black)** on all MRI sequences (T1 and T2) and do not exhibit hyperintensity. **3. High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s for Pheochromocytoma:** 10% bilateral, 10% malignant, 10% pediatric, 10% extra-adrenal (Paraganglioma). * **Nuclear Medicine:** The investigation of choice for localization is **123I-MIBG scan**. * **Biochemical Test:** Best initial screening test is plasma free metanephrines or 24-hour urinary metanephrines. * **Other "Light Bulb" signs:** Also classically described for **Hepatic Hemangiomas** on T2-weighted MRI.

Question 1

Colonic diverticulosis is best diagnosed by which imaging modality?

Accepted Answer

Barium enema

Answer

Colonoscopy

Answer

Nuclear scan

Answer

CT scan

Question 2

In case of suspected perforation, which radiological view is best?

Accepted Answer

Erect

Answer

Supine

Answer

Lateral decubitus

Answer

None

Question 3

The given image shows findings most consistent with which of the following conditions?

Accepted Answer

Ischemic colitis

Answer

Ileal atresia

Answer

Meconium ileus

Answer

Crohn's disease

Question 4

What is the most appropriate investigation for the diagnosis of common bile duct stones?

Accepted Answer

ERCP (Endoscopic Retrograde Cholangiopancreatography)

Answer

Ultrasonography

Answer

Oral Cholecystography

Answer

Intravenous Cholangiography

Question 5

Extraluminal abdominal calcification in a newborn may be seen in which of the following conditions?

Accepted Answer

Meconium peritonitis

Answer

Meconium aspiration

Answer

Hirschsprung's disease

Answer

Meconium plug syndrome

Question 6

The String sign is seen in which of the following conditions?

Accepted Answer

All of the above

Answer

Crohn's disease

Answer

TB of the ileocaecal region

Answer

Idiopathic hypertrophic pyloric stenosis

Question 7

For purely diagnostic purposes, what is the preferred mode of visualizing the biliary tree?

Accepted Answer

Magnetic Resonance Cholangiopancreaticogram (MRCP)

Answer

Endoscopic Retrograde Cholangiopancreatogram (ERCP)

Answer

Percutaneous Transhepatic Cholangiogram (PTC)

Answer

CT angiogram

Question 8

What is the investigation of choice for acute cholecystitis?

Accepted Answer

USG

Answer

HIDA-Scan

Answer

CT-Scan

Answer

X-ray

Question 9

What is the earliest pathological change seen on X-ray in ulcerative colitis?

Accepted Answer

Mucosal granularity

Answer

Loss of haustration

Answer

Aphthous ulcerations

Answer

Skip lesions

Question 10

Light bulb appearance in MRI scan is/are seen in which of the following conditions?

Accepted Answer

Pheochromocytoma

Answer

Adrenal adenoma

Answer

Adrenal cortical tumor

Answer

Adrenal calcification

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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