Abdominal and Pelvic Radiology Practice Questions

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: 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.

Q: The "Rim Sign" on contrast studies of the kidney is characteristically seen in which of the following conditions?

Chronic Hydronephrosis. **Explanation:** The **"Rim Sign"** (also known as the Crescent Sign) is a classic radiological finding in **Chronic Hydronephrosis** seen during the nephrogram phase of an Intravenous Urography (IVU) or Contrast-Enhanced CT (CECT). **1. Why Chronic Hydronephrosis is correct:** In long-standing, severe hydronephrosis, the renal parenchyma becomes markedly thinned and compressed due to the high pressure of the dilated collecting system. When contrast is administered, the remaining functional collecting ducts in the compressed parenchyma are oriented parallel to the surface of the dilated calyces. This results in a thin, opacified "rim" or "crescent" of contrast surrounding the radiolucent, fluid-filled dilated calyces. **2. Why other options are incorrect:** * **Renal Cortical Necrosis:** Characterized by the **"Reverse Rim Sign"** (or Cortical Rim Sign), where the medulla and a thin rim of subcapsular cortex enhance, but the necrotic cortex remains non-enhancing. * **Renal Papillary Necrosis:** Associated with findings like the **"Egg-in-a-cup"** appearance, "Lobster claw" sign, or "Ring sign" (due to sloughed papilla), but not the Rim Sign. * **Renal Cell Carcinoma (RCC):** Typically presents as a heterogeneously enhancing mass with areas of necrosis. It does not produce a circumferential rim of compressed parenchyma. **High-Yield Clinical Pearls for NEET-PG:** * **Rim Sign:** Chronic Hydronephrosis. * **Reverse Rim Sign:** Renal Cortical Necrosis (also seen in Renal Artery Occlusion). * **Maiden Waist Deformity:** Retroperitoneal Fibrosis (medial deviation of ureters). * **Drooping Lily Sign:** Duplex collecting system (obstructed upper pole). * **Phantom Calyx:** Renal Tuberculosis or RCC.

Q: What is the incidence of adrenal incidentaloma on CT scan?

<5%. **Explanation:** An **adrenal incidentaloma** is defined as an asymptomatic adrenal mass (≥1 cm) discovered during an imaging study performed for reasons other than suspected adrenal disease. **1. Why Option A is correct:** In the general population, the incidence of adrenal incidentalomas on CT scans is approximately **4% to 5%**. While the prevalence increases significantly with age (less than 1% in patients under 30 years to nearly 7-10% in those over 70 years), the overall average remains below the 5% threshold. Most of these lesions (approx. 80%) are non-functional benign adenomas. **2. Why other options are incorrect:** * **Option B (5-10%):** This range is too high for the general population, though it may be seen in specific elderly cohorts. * **Options C & D (10-20% and >25%):** These figures are inaccurate for incidental findings. Such high percentages are typically only seen in autopsy series of very elderly patients or patients with known primary malignancies (where the adrenal is a common site for metastasis). **Clinical Pearls for NEET-PG:** * **Initial Workup:** Every incidentaloma must be evaluated for **hormonal activity** (Pheochromocytoma, Cushing’s, and Primary Aldosteronism) and **malignancy**. * **Imaging Characteristics:** A benign adenoma typically has **low attenuation ( 40% or absolute washout of >60% on delayed contrast CT suggests a benign adenoma. * **Size Threshold:** Masses **>4 cm** have a higher risk of malignancy and are often considered for surgical resection (Adrenalectomy).

Q: What is the investigation of choice for recurrent GIST?

PET CT. **Explanation:** **Gastrointestinal Stromal Tumors (GIST)** are mesenchymal tumors arising from the Interstitial Cells of Cajal. The management and follow-up of GIST have been revolutionized by Tyrosine Kinase Inhibitors (TKIs) like Imatinib. **1. Why PET-CT is the Correct Answer:** While Contrast-Enhanced CT (CECT) is the standard for initial staging and routine follow-up, **PET-CT (using 18F-FDG)** is the investigation of choice for **recurrent GIST** and for assessing **early treatment response**. * **Functional Assessment:** GISTs are highly glucose-avid. PET-CT can detect metabolic changes within 2–4 weeks of starting therapy, long before structural changes (size reduction) appear on a regular CT. * **Recurrence:** It is superior in differentiating postoperative changes/fibrosis from active tumor recurrence and identifying small peritoneal implants. **2. Why Other Options are Incorrect:** * **MIBG (Metaiodobenzylguanidine):** This is a radiopharmaceutical used for neuroendocrine tumors like Pheochromocytoma and Neuroblastoma. It has no role in GIST. * **MRI:** While useful for rectal GISTs or liver-specific metastasis (using gadoxetic acid), it is not the primary choice for generalized recurrence monitoring compared to PET-CT. * **CECT:** This is the "gold standard" for initial diagnosis and monitoring size (using RECIST criteria). However, in the specific context of **recurrent** disease or evaluating TKI resistance, PET-CT is more sensitive. **Clinical Pearls for NEET-PG:** * **Most common site:** Stomach (60%), followed by the small intestine. * **Marker:** **CD117 (c-KIT)** is the most specific immunohistochemical marker. * **Choi Criteria:** These are specific CT criteria used to evaluate GIST response (measuring tumor density/Hounsfield units rather than just size). * **Mutation:** Most commonly involves the **KIT gene**.

Q: Which of the following are ultrasound signs of fetal death?

Hegar's sign. To master NEET-PG Radiology and Obstetrics, it is crucial to differentiate between clinical signs of early pregnancy and radiological signs of fetal demise. ### **Explanation of the Correct Answer** **Hegar’s Sign (Option D)** is the correct answer because it is **not** an ultrasound sign of fetal death. Instead, it is a **clinical sign of early pregnancy** (usually detectable between 6–12 weeks). It refers to the softening of the uterine isthmus felt during a bimanual examination. Since the question asks for ultrasound signs of fetal death, Hegar’s sign is the "odd one out." ### **Analysis of Incorrect Options (Ultrasound Signs of Fetal Death)** * **Heartbeat Absent (Option B):** This is the most definitive and immediate ultrasound sign of fetal death. The absence of cardiac activity on M-mode or Doppler confirms the diagnosis. * **Spalding Sign (Option C):** A classic radiological sign referring to the **overlapping of fetal skull bones** caused by the liquefaction of the brain and loss of intra-cranial pressure following death. It typically appears 4–7 days after demise. * **Halo Sign / Deuel’s Sign (Option A):** This refers to the secondary scalp edema that creates a "halo" appearance around the fetal head on ultrasound, indicating fetal maceration. ### **High-Yield Clinical Pearls for NEET-PG** * **Robert’s Sign:** The presence of gas in the fetal heart or great vessels (earliest radiological sign, seen within 12 hours of death). * **Spalding’s Sign vs. Robert’s Sign:** Spalding’s involves the skull (delayed); Robert’s involves gas (early). * **Confirmatory Test:** Transvaginal Ultrasound (TVS) is superior to Transabdominal Ultrasound (TAS) for detecting early embryonic cardiac activity. * **Hegar’s Sign vs. Goodell’s Sign:** Hegar’s is isthmus softening; Goodell’s is cervical softening. Both are signs of pregnancy, not death.

Q: A 'cut off' sign on a plain X-ray of the abdomen is indicative of which of the following conditions?

Acute pancreatitis. **Explanation:** The **'Colon Cut-off Sign'** is a classic radiologic finding in **Acute Pancreatitis**. It refers to the abrupt termination of gas within the transverse colon at the level of the splenic flexure. **Mechanism:** In acute pancreatitis, inflammatory exudate and enzymes track along the **phrenicocolic ligament** to the splenic flexure. This causes localized inflammation and functional spasm of the adjacent colon. Consequently, the proximal colon (ascending and transverse) becomes dilated with air, while the descending colon remains collapsed, creating the "cut-off" appearance. **Analysis of Options:** * **A. Mesenteric Ischemia:** Typically presents with "thumbprinting" (due to mucosal edema) or pneumatosis intestinalis (air in the bowel wall) in late stages, rather than a localized cut-off sign. * **B. Intussusception:** Characterized by a "target sign" or "pseudokidney sign" on ultrasound. On X-ray, it may show a soft tissue mass or signs of distal bowel obstruction, but not the colon cut-off sign. * **D. Acute Cholangitis:** This is a clinical diagnosis (Charcot’s Triad). Imaging usually focuses on biliary tree dilatation via USG or MRCP; plain X-rays are generally non-specific. **High-Yield Clinical Pearls for NEET-PG:** * **Sentinel Loop:** Another X-ray sign of acute pancreatitis, representing a localized paralytic ileus of a jejunal loop near the inflamed pancreas. * **Ground Glass Appearance:** May be seen on X-ray if there is significant ascites (pancreatic ascites). * **Gold Standard Imaging:** Contrast-Enhanced CT (CECT) is the investigation of choice to assess the severity and complications (necrosis) of pancreatitis, usually performed 48–72 hours after symptom onset.

Question 1

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 2

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 3

What is the investigation of choice for acute cholecystitis?

Accepted Answer

USG

Answer

HIDA-Scan

Answer

CT-Scan

Answer

X-ray

Question 4

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

Question 5

The "Rim Sign" on contrast studies of the kidney is characteristically seen in which of the following conditions?

Accepted Answer

Chronic Hydronephrosis

Answer

Renal Cortical Necrosis

Answer

Renal Papillary Necrosis

Answer

Renal Cell Carcinoma (RCC)

Question 6

What is the X-ray appearance of a common bile duct stone on cholangiography?

Accepted Answer

Meniscus appearance

Answer

Sudden cut off

Answer

Smooth tapering

Answer

Eccentric occlusion

Question 7

What is the incidence of adrenal incidentaloma on CT scan?

Accepted Answer

<5%

Answer

5-10%

Answer

10-20%

Answer

>25%

Question 8

What is the investigation of choice for recurrent GIST?

Accepted Answer

PET CT

Answer

MIBG

Answer

MRI

Answer

CECT

Question 9

Which of the following are ultrasound signs of fetal death?

Accepted Answer

Hegar's sign

Answer

Halo sign of the head

Answer

Heart beat absent

Answer

Spalding sign

Question 10

A 'cut off' sign on a plain X-ray of the abdomen is indicative of which of the following conditions?

Accepted Answer

Acute pancreatitis

Answer

Mesenteric ischemia

Answer

Intussusception

Answer

Acute cholangitis

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

On this page

Practice by Chapter

Want unlimited practice?