Abdominal and Pelvic Radiology Practice Questions

Q: A unilateral small smooth kidney is seen in which of the following conditions?

Renal artery stenosis. **Explanation:** The correct answer is **Renal artery stenosis (RAS)**. The size and contour of the kidney are determined by the adequacy of blood supply and the integrity of the renal parenchyma. **1. Why Renal Artery Stenosis is correct:** In RAS, the chronic reduction in renal blood flow leads to **ischemic atrophy**. Because the global blood supply is reduced, the kidney shrinks uniformly. This results in a **small, smooth-surfaced kidney**. It is typically unilateral if only one artery is affected (e.g., due to atherosclerosis or fibromuscular dysplasia). **2. Analysis of Incorrect Options:** * **Reflux Nephropathy:** This typically causes **unilateral small kidneys with irregular outlines**. The hallmark is polar scarring (usually at the poles) and associated calyceal clubbing, making the surface "bumpy" rather than smooth. * **Lobar Infarction:** An infarct leads to localized tissue death and subsequent scarring. This results in a **focal contour defect** or a "depressed scar" on the kidney surface, not a global smooth reduction in size. * **Chronic Glomerulonephritis:** While this causes small smooth kidneys, it is a systemic metabolic/immunological process that almost always affects both kidneys. Therefore, it presents as **bilateral** small smooth kidneys. **Clinical Pearls for NEET-PG:** * **Unilateral Small Smooth Kidney:** Renal artery stenosis, Congenital hypoplasia. * **Unilateral Small Irregular Kidney:** Chronic pyelonephritis, Reflux nephropathy, Renal infarction. * **Bilateral Small Smooth Kidneys:** Chronic glomerulonephritis, Hypertensive nephrosclerosis, Bilateral RAS. * **Goldblatt Kidney:** A classic experimental model of hypertension caused by unilateral renal artery constriction.

Q: Which imaging modality is best for detecting focal liver lesions?

MRI. **Explanation:** **MRI (Magnetic Resonance Imaging)** is the gold standard for detecting and characterizing focal liver lesions. Its superiority lies in its **high soft-tissue contrast resolution** and the ability to use **Hepatobiliary-specific contrast agents** (e.g., Gadoxetate disodium/Primovist). These agents are taken up by functional hepatocytes, allowing for the differentiation between lesions containing hepatocytes (like FNH) and those that do not (like metastases or HCC), significantly increasing sensitivity and specificity. **Why other options are incorrect:** * **CT (Computed Tomography):** While excellent for staging and rapid assessment, CT has lower soft-tissue contrast than MRI. It relies heavily on vascularity patterns (Triple-phase CT) but may miss small or isodense lesions that MRI can easily detect. * **USG (Ultrasonography):** This is the **initial screening modality** of choice due to its cost-effectiveness and lack of radiation. However, it is operator-dependent and has limited sensitivity for very small lesions or lesions in cirrhotic livers. * **PET Scan:** Primarily used for detecting metabolic activity (metastases or recurrence). It is not the primary modality for initial detection or anatomical characterization of primary liver lesions. **High-Yield Clinical Pearls for NEET-PG:** * **Best Initial Investigation:** USG. * **Best Modality for Characterization:** MRI. * **IOC for Hemangioma:** MRI (shows peripheral globular enhancement with "filling in"). * **IOC for HCC:** Triple-phase CT or Dynamic MRI (shows arterial enhancement with venous "washout"). * **Steatosis:** MRI (In-phase and Out-of-phase imaging) is the most sensitive for quantifying hepatic fat.

Q: Which is not a usual feature of Ulcerative colitis on barium enema?

Colovesical fistula. **Explanation:** The correct answer is **Colovesical fistula**. Ulcerative Colitis (UC) is a mucosal disease characterized by continuous inflammation limited to the mucosa and submucosa. Because it does not involve transmural inflammation, the formation of fistulae (such as colovesical or perianal fistulae) is extremely rare. Fistula formation is a hallmark of **Crohn’s Disease**, which involves transmural inflammation. **Analysis of Options:** * **Fine mucosal granularity (A):** This is the earliest radiological sign of UC on a double-contrast barium enema. It represents edema and hyperemia of the mucosa. * **Pseudopolyps (B):** These are islands of regenerating or normal mucosa surrounded by areas of extensive mucosal ulceration and depletion. They are a common feature of chronic UC. * **Lead pipe colon (C):** This refers to a featureless, narrowed, and shortened colon. It occurs in chronic stages due to the loss of haustral markings, longitudinal shortening, and muscular hypertrophy. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign on Barium Enema:** Fine mucosal granularity. * **Collar-button ulcers:** Deep ulcers formed when the inflammatory process undermines the mucosa (also seen in UC). * **Backwash Ileitis:** Involvement of the terminal ileum in UC (occurs in ~10% of cases of pancolitis); unlike Crohn's, the ileocecal valve is usually patent/incompetent. * **Toxic Megacolon:** A life-threatening complication of UC where the transverse colon diameter exceeds **6 cm** on plain X-ray.

Q: All of the following are signs of Hydatid Cyst except?

Mercedes Benz sign. **Explanation:** The **Mercedes Benz sign** is the correct answer because it is a characteristic radiological feature of **cholelithiasis (gallstones)**, not hydatid disease. It represents the presence of triradiate, nitrogen-filled gas fissures within a gallstone, seen on a plain X-ray or CT scan. **Analysis of Hydatid Cyst Signs (Echinococcus granulosus):** * **Camalote sign (Water Lily sign):** This occurs when the endocyst ruptures, causing the germinal membrane to detach and float on the surface of the remaining cyst fluid. It is a classic sign seen on imaging (USG/CT/MRI). * **Floating membrane sign:** This is essentially the same mechanism as the Camalote sign, where detached membranes are seen undulating within the cyst cavity. * **Cartwheel (Ca wheel) appearance:** This occurs when multiple daughter cysts are arranged peripherally within the mother cyst, separated by internal septations (hydatid sand and matrix). This is characteristic of a **Type II hydatid cyst** (Gharbi classification). **High-Yield Clinical Pearls for NEET-PG:** * **Gharbi Classification:** Used to stage hydatid cysts (Type I: Pure fluid; Type II: Split wall/Membranes; Type III: Daughter cysts; Type IV: Solid/Heterogeneous; Type V: Calcified wall). * **Eggshell Calcification:** A common finding in the wall of a chronic hydatid cyst (Type V). * **Treatment:** The **PAIR** technique (Puncture, Aspiration, Injection of scolicidal agent, Re-aspiration) is a minimally invasive treatment option. * **Serology:** ELISA for Echinococcus IgG is the most common screening test.

Q: What is the characteristic appearance of a "Ca-wheel" on ultrasound?

Hydatid cyst. **Explanation:** The **"Cartwheel appearance"** (also known as the "spoke-wheel" or "honeycomb" appearance) is a classic radiological sign of a **Hydatid cyst** (caused by *Echinococcus granulosus*) on ultrasonography. This appearance occurs during the **WHO Stage CE2** (Active stage). It is produced by the presence of multiple **daughter cysts** separated by internal septations (representing the collapsed germinal membranes) within a larger mother cyst. **Why the other options are incorrect:** * **Intussusception:** Characteristically shows a **"Target sign"** or **"Donut sign"** on transverse sections and a **"Pseudokidney sign"** on longitudinal sections due to the telescoping of bowel loops. * **Hydatidiform mole:** Displays a characteristic **"Snowstorm appearance"** on ultrasound, caused by multiple hydropic villi appearing as tiny echogenic foci with interspersed cystic spaces. **High-Yield Clinical Pearls for NEET-PG:** 1. **Gharbi Classification:** Used for staging Hydatid cysts on USG. * **Type I:** Pure fluid collection (Anechoic). * **Type II:** Fluid collection with a split wall (**Water-lily sign** - detached endocyst). * **Type III:** Daughter cysts with septations (**Cartwheel/Honeycomb appearance**). * **Type IV:** Heterogeneous mass (Solid pattern). * **Type V:** Calcified wall (Inactive/Dead cyst). 2. **Treatment of Choice:** PAIR (Puncture, Aspiration, Injection, Re-aspiration) or surgical excision, usually covered with Albendazole. 3. **Serology:** ELISA is the most sensitive screening test for Hydatid disease.

Q: A 43-year-old woman presents with right upper quadrant abdominal pain and vomiting. She has had three children. The white blood cell count is 14.3x10^9/L and liver function tests are normal. What is the test of choice to establish the diagnosis in this patient?

Ultrasound. **Explanation:** The clinical presentation of right upper quadrant (RUQ) pain, vomiting, and leukocytosis in a middle-aged woman (fitting the "4F" profile: Female, Forty, Fertile, Fat) is highly suggestive of **Acute Cholecystitis** or symptomatic cholelithiasis. **Why Ultrasound is the Correct Answer:** Ultrasound (USG) is the **initial investigation of choice** for suspected gallbladder disease. It has high sensitivity (>90%) and specificity for detecting gallstones and signs of inflammation. Key sonographic findings of acute cholecystitis include gallbladder wall thickening (>3 mm), pericholecystic fluid, and the **Sonographic Murphy’s sign** (maximal tenderness over the gallbladder when compressed by the probe), which has a high positive predictive value. **Analysis of Incorrect Options:** * **A. CT Scan:** While useful for detecting complications (like perforation or gangrene) or alternative diagnoses, it is less sensitive than USG for detecting gallstones and involves ionizing radiation. * **C. HIDA Scan (Hepatobiliary Iminodiacetic Acid):** This is the **most sensitive (Gold Standard)** test for diagnosing acute cholecystitis (showing non-visualization of the gallbladder). However, it is not the *initial* test of choice because it is time-consuming, expensive, and involves nuclear medicine. * **D. MRI/MRCP:** These are excellent for visualizing the biliary tree (choledocholithiasis) but are not first-line due to cost and lack of immediate availability. **NEET-PG High-Yield Pearls:** * **Initial test for RUQ pain:** Ultrasound. * **Most sensitive/Gold Standard for Acute Cholecystitis:** HIDA Scan. * **Best test for Choledocholithiasis (CBD stones):** MRCP (Non-invasive) or ERCP (Invasive/Therapeutic). * **WES Triad on USG:** Wall-Echo-Shadow (indicates a gallbladder packed with stones).

Q: Cobra head deformity in the lower end of ureter is seen in which of the following conditions?

Ureterocele. **Explanation:** The **Cobra Head sign** (also known as the Adder head sign) is a classic radiological finding seen on an Intravenous Pyelogram (IVP) or Contrast CT, diagnostic of an **orthotopic ureterocele**. 1. **Why Ureterocele is correct:** A ureterocele is a congenital cystic dilatation of the distal-most intramural portion of the ureter. On a contrast study, the dilated ureter is filled with contrast (the "head"), which is surrounded by a thin, radiolucent halo representing the wall of the ureterocele and the bladder mucosa. This appearance mimics the hood of a cobra. 2. **Why other options are wrong:** * **Vesical diverticula:** These appear as contrast-filled outpouchings from the bladder wall (Hutch diverticulum), not as a filling defect within the bladder. * **Carcinoma of the urinary bladder:** This typically presents as an irregular, fixed filling defect. If it involves the ureteric orifice, it may cause hydroureter, but not the smooth, cystic "cobra head" appearance. * **Urethral stricture:** This is a narrowing of the urethra, best visualized on a Retrograde Urethrogram (RGU), and does not affect the distal ureteric morphology. **High-Yield Clinical Pearls for NEET-PG:** * **Simple (Orthotopic) Ureterocele:** Located at the normal vesicoureteric junction; usually seen in adults and produces the Cobra Head sign. * **Ectopic Ureterocele:** Located at the bladder neck or urethra; more common in children and often associated with a **duplicated collecting system** (Weigert-Meyer Law). * **Negative Cobra Head Sign:** If the radiolucent halo is thick or irregular, suspect a "pseudoureterocele," which can be caused by a stone impacted at the UVJ or a bladder tumor infiltrating the ureteric orifice.

Q: Radio-lucent renal stones are typically composed of which substance?

Uric acid. ### Explanation The radiopacity of a renal stone on a plain X-ray (KUB) depends on its effective atomic number. Stones containing elements with high atomic numbers, like Calcium, appear **radio-opaque** (white), while those composed of organic compounds without heavy metals appear **radiolucent** (black/invisible). **1. Why Uric Acid is Correct:** Uric acid stones are composed of carbon, nitrogen, oxygen, and hydrogen. These elements have low atomic numbers, making the stones **radiolucent** on conventional radiography. However, they are easily visualized as "hyperdense" on a Non-Contrast CT (NCCT) scan, which is the gold standard for diagnosis. **2. Analysis of Incorrect Options:** * **Calcium Phosphate (Option B):** These are the most radio-opaque stones due to the high atomic number of Calcium. * **Cysteine (Option A):** These stones contain sulfur atoms. While they are less opaque than calcium stones, they are described as **"ground-glass"** or **faintly radio-opaque**, not radiolucent. * **All of the above (Option D):** Incorrect, as the degree of opacity varies significantly between chemical compositions. **3. Clinical Pearls for NEET-PG:** * **Mnemonic for Radiolucent Stones (PU):** **P**urine (Uric acid) and **U**ndissolved medications (like Indinavir). * **Gold Standard Investigation:** NCCT KUB (detects all stones except Indinavir stones). * **Struvite Stones (Triple Phosphate):** Associated with Proteus infections; they are radio-opaque and often form **Staghorn calculi**. * **Management Tip:** Uric acid stones are unique because they can often be dissolved via **urinary alkalinization** (maintaining pH > 6.5).

Q: Which of the following is the most specific and sensitive screening test for renovascular hypertension?

CT angiography. **Explanation:** **Renovascular Hypertension (RVH)** is primarily caused by Renal Artery Stenosis (RAS), leading to activation of the Renin-Angiotensin-Aldosterone System (RAAS). **Why CT Angiography (CTA) is correct:** CTA is currently considered the **most sensitive (95-98%) and specific (90-94%)** non-invasive screening tool for detecting renal artery stenosis. It provides high-resolution anatomical detail, allowing for the visualization of the main renal arteries as well as accessory arteries. It is particularly superior in identifying stenosis caused by atherosclerosis or fibromuscular dysplasia (FMD). **Analysis of Incorrect Options:** * **A. HRCT:** High-Resolution CT is used primarily for lung parenchyma imaging (e.g., interstitial lung disease) and has no role in vascular imaging or renovascular hypertension. * **C. Captopril Radionuclide Scan:** While historically popular, its sensitivity is lower than CTA, especially in patients with impaired renal function or bilateral disease. It is a functional test rather than an anatomical one. * **D. MRI (MRA):** Magnetic Resonance Angiography is highly accurate but generally slightly less sensitive than CTA for distal or accessory renal arteries. It is also more expensive and contraindicated in patients with metallic implants or severe renal failure (due to Nephrogenic Systemic Fibrosis risk). **NEET-PG High-Yield Pearls:** * **Gold Standard (Definitive Test):** Digital Subtraction Angiography (DSA). It is both diagnostic and therapeutic (allows for stenting). * **Best Initial Screening (Non-invasive):** Duplex Doppler Ultrasound (though operator-dependent). * **Most Sensitive/Specific Screening:** CT Angiography. * **Commonest cause of RAS:** Atherosclerosis (older males) followed by Fibromuscular Dysplasia (young females; "string of beads" appearance).

Question 1

A unilateral small smooth kidney is seen in which of the following conditions?

Accepted Answer

Renal artery stenosis

Answer

Reflux nephropathy

Answer

Lobar infarction

Answer

Chronic glomerulonephritis

Question 2

A plain radiograph of the abdomen demonstrates gas within the bowel wall (pneumatosis). Which of the following would MOST likely be associated with this finding?

Accepted Answer

Gas in the portal vein

Answer

Air in the biliary tract

Answer

Blood in the biliary tract

Answer

Gas in the hepatic veins

Question 3

Which imaging modality is best for detecting focal liver lesions?

Accepted Answer

MRI

Answer

CT

Answer

USG

Answer

PET scan

Question 4

Which is not a usual feature of Ulcerative colitis on barium enema?

Accepted Answer

Colovesical fistula

Answer

Fine mucosal granularity

Answer

Pseudopolyps

Answer

Lead pipe colon

Question 5

All of the following are signs of Hydatid Cyst except?

Accepted Answer

Mercedes Benz sign

Answer

Camalote sign

Answer

Floating membrane sign

Answer

Ca wheel appearance

Question 6

What is the characteristic appearance of a "Ca-wheel" on ultrasound?

Accepted Answer

Hydatid cyst

Answer

Intussusception

Answer

Hydatidiform mole

Answer

All of the above

Question 7

A 43-year-old woman presents with right upper quadrant abdominal pain and vomiting. She has had three children. The white blood cell count is 14.3x10^9/L and liver function tests are normal. What is the test of choice to establish the diagnosis in this patient?

Accepted Answer

Ultrasound

Answer

Computerized axial tomography scan

Answer

Hydroxy iminodiacetic acid scan

Answer

Magnetic resonance imaging scan

Question 8

Cobra head deformity in the lower end of ureter is seen in which of the following conditions?

Accepted Answer

Ureterocele

Answer

Vesical diverticula

Answer

Carcinoma of the urinary bladder

Answer

Urethral stricture

Question 9

Radio-lucent renal stones are typically composed of which substance?

Accepted Answer

Uric acid

Answer

Cysteine

Answer

Calcium phosphate

Answer

All of the above

Question 10

Which of the following is the most specific and sensitive screening test for renovascular hypertension?

Accepted Answer

CT angiography

Answer

HRCT

Answer

Captopril enhanced radionuclide scan

Answer

MRI

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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