Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology Indian Medical PG Practice Questions and MCQs

Question 181: What condition is characterized by an apple core appearance on barium enema?

A. Carcinoma of the colon (Correct Answer)
B. Tuberculous caecum
C. Crohn's disease
D. Ulcerative colitis

Explanation: **Explanation:** The **"Apple Core" appearance** (also known as the napkin-ring sign) is the classic radiologic hallmark of **annular constricting Carcinoma of the Colon**, most commonly seen in the sigmoid colon. This appearance is caused by a circumferential, short-segment narrowing of the bowel lumen with overhanging edges (shouldering). The "core" represents the narrowed lumen due to the infiltrating tumor, while the "shoulders" represent the abrupt transition from normal tissue to the mass. **Analysis of Options:** * **A. Carcinoma of the Colon (Correct):** The irregular, eccentric narrowing and mucosal destruction are characteristic of malignancy. * **B. Tuberculous Caecum:** Typically presents with a **"Conical Caecum"** or the **"Stierlin Sign"** (rapid emptying of the inflamed segment). It involves the ileocecal junction rather than a short-segment annular constriction. * **C. Crohn’s Disease:** Characterized by the **"String Sign of Kantor"** (long, thin segment of barium due to spasm/fibrosis) and "Skip Lesions." * **D. Ulcerative Colitis:** Chronic cases show a loss of haustrations, leading to a **"Lead Pipe"** or "Garden Hose" appearance. **NEET-PG High-Yield Pearls:** * **Most common site for Apple Core sign:** Sigmoid colon. * **Differential Diagnosis:** While usually malignant, focal diverticulitis or chronic ischemia can sometimes mimic this appearance (though they typically have longer segments and smoother transitions). * **Clinical Correlation:** Patients often present with altered bowel habits, occult blood in stools, or intestinal obstruction.

Question 182: What is the investigation of choice for choledocolithiasis?

A. CT (Correct Answer)
B. USG
C. PET scan
D. HIDA scan

Explanation: **Explanation:** The investigation of choice for **choledocholithiasis** (stones in the common bile duct) is **CT (specifically Multidetector CT or CT Cholangiography)**. While Ultrasound is often the first-line screening tool, CT has higher sensitivity and specificity for detecting CBD stones, especially those located in the distal portion which may be obscured by bowel gas on ultrasound. **Why the other options are incorrect:** * **USG (Ultrasound):** This is the **initial/screening investigation** for biliary pathologies. It is excellent for detecting gallbladder stones (cholelithiasis) and CBD dilation, but it has low sensitivity (approx. 20-50%) for directly visualizing stones within the CBD itself. * **PET Scan:** This is a functional imaging modality used primarily for oncology (detecting metastases) and inflammatory processes; it has no role in the mechanical diagnosis of gallstones. * **HIDA Scan:** This is a nuclear medicine study used to assess gallbladder function and cystic duct patency. It is the **gold standard for diagnosing Acute Cholecystitis**, but it cannot visualize stones. **High-Yield Clinical Pearls for NEET-PG:** 1. **Initial Investigation:** USG Abdomen. 2. **Investigation of Choice (Non-invasive):** MRCP (Magnetic Resonance Cholangiopancreatography) is often considered the "Gold Standard" non-invasive test, but among the provided options, CT is the most definitive diagnostic tool. 3. **Gold Standard (Invasive/Therapeutic):** ERCP (Endoscopic Retrograde Cholangiopancreatography). It allows for both diagnosis and stone extraction. 4. **IOC for Acute Cholecystitis:** HIDA Scan. 5. **IOC for Cholelithiasis (Gallbladder stones):** USG.

Question 183: The double bubble sign is typically seen in which of the following conditions?

A. Diaphragmatic hernia (Correct Answer)
B. Lad's band
C. Annular pancreas
D. Pancreatic pseudocyst

Explanation: **Explanation:** The **Double Bubble Sign** is a classic radiological finding on an abdominal X-ray representing a dilated stomach and a dilated proximal duodenum. This occurs due to a complete or high-grade obstruction at the level of the second part of the duodenum. **Why Diaphragmatic Hernia is correct:** In the context of this specific question, **Congenital Diaphragmatic Hernia (CDH)**, particularly the Bochdalek type, can lead to a double bubble appearance if the stomach and duodenum are herniated into the thorax or if there is associated malrotation/volvulus causing duodenal obstruction. While Duodenal Atresia is the most common cause overall, CDH is a recognized cause of high intestinal obstruction in neonates. **Analysis of Incorrect Options:** * **Lad’s Band:** These are fibrous stalks associated with intestinal malrotation. While they can compress the duodenum and cause a "double bubble" or "triple bubble" sign, they usually cause partial obstruction. In many exam patterns, if Duodenal Atresia or CDH is present, they are considered more "classic" representations of the sign. * **Annular Pancreas:** This is a congenital anomaly where pancreatic tissue encircles the duodenum. While it *can* cause a double bubble sign, it is a less common cause compared to atresia or major structural defects like CDH in neonatal presentations. * **Pancreatic Pseudocyst:** This is an acquired collection of fluid following pancreatitis. It typically causes displacement of the stomach or widening of the duodenal C-loop, but not the classic "double bubble" of neonatal obstruction. **Clinical Pearls for NEET-PG:** * **Most Common Cause:** Duodenal Atresia (strongly associated with **Down Syndrome/Trisomy 21**). * **Differential Diagnosis:** Duodenal atresia, duodenal web, annular pancreas, malrotation with midgut volvulus, and diaphragmatic hernia. * **Triple Bubble Sign:** Associated with **Jejunal Atresia**. * **Gasless Abdomen:** Often seen in esophageal atresia without a tracheoesophageal fistula.

Question 184: Which of the following signs is seen in Crohn's disease?

A. String sign of Kantor (Correct Answer)
B. Strout's sign
C. Pincer sign
D. Inverted 3 sign

Explanation: **Explanation:** **String Sign of Kantor (Correct Answer):** This is a classic radiological sign seen on a Barium meal follow-through (BMFT) in patients with **Crohn’s disease**. It represents severe narrowing of the terminal ileum due to transmural inflammation, persistent spasm, and eventually, cicatricial fibrosis. The lumen becomes so constricted that it resembles a thin "string" of barium. It is most commonly associated with the stenotic phase of Crohn’s. **Analysis of Incorrect Options:** * **Strout’s Sign:** This refers to the thickening and straightening of the mucosal folds of the small bowel, often seen in **Malabsorption syndromes** (like Celiac disease) or Giardiasis. * **Pincer Sign (Claw Sign):** This is the characteristic appearance of **Intussusception** on a Barium enema. It occurs when the contrast outlines the leading edge of the intussusceptum (the prolapsed segment). * **Inverted 3 Sign (Frostberg’s Sign):** This is seen on a barium study of the duodenum in cases of **Carcinoma of the Head of the Pancreas** or chronic pancreatitis. The "3" shape is formed by the pressure of the enlarged pancreas on the medial wall of the duodenum. **High-Yield Clinical Pearls for NEET-PG:** * **Crohn’s Disease:** Other key signs include **Cobblestoning** (longitudinal/transverse ulcers), **Proud Flesh** (polypoid regeneration), and **Skip Lesions**. * **Ulcerative Colitis:** Look for the **Lead Pipe appearance** (loss of haustrations) and **Thumbprinting** (due to mucosal edema). * **Comb Sign:** On CT, this refers to prominent vasa recta in the mesentery, indicating active Crohn’s disease.

Question 185: The 'keyhole sign' is a radiological finding typically associated with which of the following conditions?

A. Polycystic kidney disease
B. Renal agenesis
C. Ureteropelvic junction obstruction
D. Bladder outlet obstruction (Correct Answer)

Explanation: ### Explanation The **'Keyhole Sign'** is a classic sonographic finding seen in male fetuses, representing a dilated posterior urethra and a thick-walled, distended urinary bladder. **1. Why the Correct Answer is Right:** The sign is most commonly associated with **Posterior Urethral Valves (PUV)**, the most frequent cause of **Bladder Outlet Obstruction** in male infants. The "keyhole" appearance is formed by the combination of: * The **round, distended bladder** (the head of the keyhole). * The **dilated posterior urethra** proximal to the obstruction (the neck of the keyhole). This finding is often accompanied by bilateral hydroureteronephrosis and oligohydramnios. **2. Why the Incorrect Options are Wrong:** * **Polycystic Kidney Disease:** Characterized by bilateral enlarged, echogenic kidneys with multiple cysts (Autosomal Dominant) or microcysts (Autosomal Recessive). It does not involve urethral dilation. * **Renal Agenesis:** This is the congenital absence of one or both kidneys. In bilateral cases, the bladder is typically absent or non-visualized due to a lack of urine production. * **Ureteropelvic Junction (UPJ) Obstruction:** This is the most common cause of neonatal hydronephrosis. However, the obstruction is at the level of the kidney; therefore, the ureters and bladder remain normal in caliber. **3. Clinical Pearls for NEET-PG:** * **PUV** is the most common cause of bladder outlet obstruction in male newborns. * **Gold Standard Investigation:** Voiding Cystourethrogram (VCUG) is the definitive test to diagnose PUV postnatally. * **Associated Finding:** Look for "thickening of the bladder wall" (>2mm) on ultrasound. * **Differential:** Prune Belly Syndrome can also present with a dilated bladder, but it lacks the mechanical obstruction seen in PUV.

Question 186: A sentinel loop is seen on an X-ray. What is the most likely diagnosis?

A. Meckel's diverticulum
B. Acute cholecystitis
C. Acute mesenteric adenitis
D. Acute pancreatitis (Correct Answer)

Explanation: ### **Explanation** **1. Why Acute Pancreatitis is the Correct Answer:** A **sentinel loop** refers to a localized segment of paralyzed, dilated small bowel (paralytic ileus) occurring adjacent to an inflamed organ. In the context of **acute pancreatitis**, the intense inflammatory process in the retroperitoneum spreads to the nearby jejunal loops. This irritation causes local aperistalsis and subsequent gas accumulation. On an abdominal X-ray, this typically appears as a single or double dilated loop of small bowel in the **left upper quadrant** or epigastrium. **2. Analysis of Incorrect Options:** * **Meckel's Diverticulum:** Usually asymptomatic or presents with painless lower GI bleeding or intestinal obstruction (intussusception/volvulus). It does not typically cause a localized sentinel loop on X-ray. * **Acute Cholecystitis:** While inflammation of the gallbladder can occasionally cause a sentinel loop in the **right upper quadrant**, it is far less common than in pancreatitis. The classic X-ray finding for cholecystitis (if any) is gallstones or rarely "emphysematous cholecystitis" (gas in the gallbladder wall). * **Acute Mesenteric Adenitis:** This mimics appendicitis and involves inflammation of mesenteric lymph nodes. It does not typically result in localized ileus or the sentinel loop sign. **3. Clinical Pearls & High-Yield Facts for NEET-PG:** * **Colon Cut-off Sign:** Another classic X-ray sign of acute pancreatitis; it refers to abrupt collapse of the colon at the splenic flexure due to inflammation spreading along the phrenicocolic ligament. * **Gold Standard Imaging:** While X-ray shows these supportive signs, **Contrast-Enhanced CT (CECT)** is the investigation of choice for diagnosing complications and assessing the severity (Balthazar score) of acute pancreatitis. * **Sentinel Loop Locations:** * LUQ: Pancreatitis * RUQ: Cholecystitis * RLQ: Appendicitis

Question 187: Flower vase appearance on IVP is seen in:

A. Horseshoe kidney (Correct Answer)
B. Polycystic kidney
C. Pyonephrosis
D. Congenital megaureter

Explanation: **Explanation:** **1. Why Horseshoe Kidney is Correct:** Horseshoe kidney is the most common renal fusion anomaly, where the lower poles are typically joined by a midline parenchymal or fibrous isthmus. Because the isthmus lies anterior to the aorta and inferior to the origin of the Inferior Mesenteric Artery (IMA), the kidneys are prevented from ascending and rotating normally. On an Intravenous Pyelogram (IVP), the lower poles are oriented medially, and the ureters are displaced laterally as they pass over the isthmus. This specific configuration—lower poles pointing inward and ureters bowing outward—creates the characteristic **"Flower Vase"** or **"Handshake" appearance.** **2. Why Other Options are Incorrect:** * **Polycystic Kidney Disease:** Typically shows bilateral enlarged kidneys with a **"Spider Leg" appearance** due to the elongation and stretching of the calyces by multiple cysts. * **Pyonephrosis:** Characterized by an obstructed, infected collecting system. Radiologically, it shows poor or absent excretion on IVP and internal echoes/debris on ultrasound, but not a specific vase-like shape. * **Congenital Megaureter:** Presents as a dilated ureter (usually distal) due to a functional or anatomical obstruction at the vesicoureteric junction. It does not alter the axis of the renal poles. **3. High-Yield Clinical Pearls for NEET-PG:** * **Level of Isthmus:** Usually at **L3-L5** (trapped by the Inferior Mesenteric Artery). * **Associated Complications:** Increased risk of nephrolithiasis (due to stasis), PUJ obstruction, and **Wilms tumor** (in children) or Renal Cell Carcinoma. * **Trauma:** Horseshoe kidneys are more susceptible to blunt abdominal trauma as the isthmus is compressed against the vertebral column. * **Other IVP Signs:** Look for **"Reverse Pyelogram"** or vertical/medial orientation of the long axis of the kidneys.

Question 188: Which of the following is NOT a feature of Ulcerative Colitis?

A. Fine mucosal granularity
B. Pseudopolyps
C. String sign of Kantor (Correct Answer)
D. Lead pipe appearance

Explanation: ### Explanation The correct answer is **C. String sign of Kantor**, which is a classic radiological feature of **Crohn’s Disease**, not Ulcerative Colitis (UC). #### Why String Sign of Kantor is the Correct Answer: The "String sign of Kantor" refers to the terminal ileum becoming severely narrowed due to transmural inflammation, edema, and spasm. On a barium study, this appears as a thin, string-like opacification. Since UC is a mucosal disease that primarily affects the colon and involves the terminal ileum only via "backwash ileitis" (which results in a dilated, patulous ileum), the string sign is characteristic of Crohn’s. #### Analysis of Incorrect Options: * **A. Fine mucosal granularity:** This is the **earliest** radiological sign of UC. It represents mucosal edema and hyperemia, giving the bowel wall a "sandpaper" appearance on double-contrast barium enema. * **B. Pseudopolyps:** These are islands of normal or regenerating mucosa surrounded by areas of extensive ulceration. They are a hallmark of chronic UC. * **C. Lead pipe appearance:** This occurs in the chronic stage of UC. Due to repeated cycles of inflammation and healing, the colon loses its haustrations, shortens, and becomes rigid, resembling a lead pipe. #### NEET-PG High-Yield Pearls: * **Distribution:** UC is continuous and starts from the rectum (rectum is always involved). Crohn’s has "skip lesions" and is transmural. * **Thumbprinting:** Seen in acute phases of UC or ischemic colitis due to severe mucosal edema. * **Collar Button Ulcers:** Deep, undermining ulcers seen in UC when the ulceration penetrates the lamina propria. * **Stovepipe Colon:** Another name for the "Lead pipe" appearance. * **Cobblestone Appearance:** Characteristic of Crohn’s Disease (due to longitudinal and transverse ulcers).

Question 189: What is the best diagnostic modality for pelvi-ureteric junction obstruction presenting as hydronephrosis?

A. Ultrasound
B. Excretory urogram
C. Nuclear imaging (Correct Answer)
D. Retrograde pyelography

Explanation: **Explanation:** The gold standard for diagnosing and assessing the functional significance of **Pelvi-Ureteric Junction Obstruction (PUJO)** is **Nuclear Imaging**, specifically **Diuretic Renography (DTPA or MAG3 scan)**. 1. **Why Nuclear Imaging is Correct:** While anatomical imaging can show dilatation, it cannot reliably differentiate between a "dilated but non-obstructed" system and a "true mechanical obstruction." Nuclear medicine provides a **functional assessment**. By administering a diuretic (Furosemide), clinicians can observe the "washout" rate of the radiotracer. A **T½ (half-life of drainage) > 20 minutes** is diagnostic of true mechanical obstruction. MAG3 is generally preferred over DTPA in patients with impaired renal function. 2. **Why other options are incorrect:** * **Ultrasound:** This is the **initial screening modality** of choice. It identifies hydronephrosis but cannot confirm if the cause is an active obstruction or a functional delay. * **Excretory Urogram (IVP):** Historically used to show the "Pelvic Box" deformity, it is now largely obsolete due to radiation and the inability to quantify the degree of obstruction or differential renal function. * **Retrograde Pyelography (RGP):** This is an invasive procedure used to delineate anatomy before surgery or if the site of obstruction is unclear; it is not the primary diagnostic tool. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of neonatal hydronephrosis:** PUJO. * **Best initial test:** Ultrasound. * **Best confirmatory/functional test:** Diuretic Renography (MAG3/DTPA). * **Dietl’s Crisis:** Episodic loin pain after fluid intake (alcohol/caffeine) associated with PUJO. * **Crossing Vessel:** An aberrant lower pole renal artery is a common extrinsic cause of PUJO.

Question 190: Which ultrasonographic finding is characteristic of a hydatidiform mole?

A. Snowstorm pattern (Correct Answer)
B. Snow-driven pattern
C. Cotton wool appearance
D. Polka dot sign

Explanation: **Explanation:** **Hydatidiform mole** (a type of Gestational Trophoblastic Disease) is characterized by the proliferation of trophoblastic tissue and hydropic degeneration of chorionic villi. On ultrasonography, these multiple small, hydropic vesicles (cysts) create a classic **"Snowstorm pattern."** This appearance is due to the presence of numerous echogenic areas interspersed with small sonolucent (cystic) spaces, representing the swollen villi and intrauterine hemorrhage, without a viable fetus in a complete mole. **Analysis of Incorrect Options:** * **B. Snow-driven pattern:** This is a distractor term not used in standard radiological nomenclature for molar pregnancy. * **C. Cotton wool appearance:** This is a classic radiological description for **Paget’s disease of the bone** (specifically the skull), representing thickened calvarium with disorganized sclerotic and lytic patches. * **D. Polka dot sign:** This is the characteristic CT/MRI appearance of a **Vertebral Hemangioma**, caused by thickened vertical trabeculae seen in cross-section. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Ultrasonography is the primary modality for diagnosis. * **Biochemical Marker:** Markedly elevated **serum β-hCG** levels (often >100,000 mIU/mL) are characteristic. * **Theca Lutein Cysts:** Large, multiloculated ovarian cysts are frequently seen bilaterally due to high hCG stimulation. * **Management:** The treatment of choice is **Suction and Evacuation**. * **The "Bunch of Grapes" appearance:** This refers to the macroscopic/gross pathological appearance of the vesicles.

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