Contrast and Radiological Procedures — MCQs
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Gastro-oesophageal reflux is best detected by?
A barium swallow is performed in a 44-year-old female who has had difficulty swallowing for months. Radiographically, there is marked dilation of the esophagus with beaking in the distal portion where marked luminal narrowing exists. A biopsy of the lower esophagus shows prominent submucosal fibrosis without much inflammation. What is the most likely cause?
For which part of the gastrointestinal tract is a barium follow-through examination primarily used?
Scrambled egg appearance is seen in which of the following conditions?
In which one of the following conditions is sialography contraindicated?
Which of the following acts as a hardener?
Which of the following conditions is characterized by a 'bird beak' appearance of the esophagus on barium swallow?
All of the following appear hypo-intense on MRI except?
Calcified lesions are better visualized on which imaging modality?
In which position should a renal scan be performed?
Contrast and Radiological Procedures Indian Medical PG Practice Questions and MCQs
Question 31: Gastro-oesophageal reflux is best detected by?
- A. Endoscopy (Correct Answer)
- B. USG
- C. Barium study
- D. Isotope scan
Explanation: **Explanation:** **1. Why Endoscopy is the Correct Answer:** Upper Gastrointestinal (GI) Endoscopy is the gold standard for evaluating Gastro-oesophageal Reflux Disease (GERD). Its primary value lies in its ability to directly visualize the esophageal mucosa to detect complications such as **reflux esophagitis, Barrett’s esophagus, and strictures**. It also allows for biopsies to rule out malignancy or eosinophilic esophagitis. While 24-hour pH monitoring is the gold standard for diagnosing the *acid reflux event* itself, endoscopy is the definitive clinical tool for assessing the *impact* of the disease and guiding management. **2. Analysis of Incorrect Options:** * **B. USG:** Ultrasound has no significant role in diagnosing GERD in adults due to the interference of air in the GI tract, though it is sometimes used in pediatric populations to observe the gastro-oesophageal junction. * **C. Barium Study:** While a Barium swallow can detect structural issues like hiatal hernias or severe strictures, it has very **low sensitivity** for detecting mucosal changes caused by reflux. It cannot diagnose esophagitis reliably. * **D. Isotope Scan (Gastro-oesophageal Scintigraphy):** This involves swallowing Technetium-99m sulfur colloid. While it can quantify reflux and detect pulmonary aspiration, it is rarely used in routine clinical practice due to low sensitivity compared to pH monitoring and endoscopy. **3. NEET-PG High-Yield Pearls:** * **Investigation of Choice (IOC) for GERD diagnosis:** 24-hour ambulatory pH monitoring (specifically the DeMeester score). * **Best initial investigation for GERD with "Alarm Symptoms"** (dysphagia, weight loss, anemia): Endoscopy. * **Barrett’s Esophagus:** Metaplasia of stratified squamous epithelium to columnar epithelium (with goblet cells). It is a precursor to Adenocarcinoma. * **Gold Standard for Achalasia Cardia:** Manometry (showing "bird-beak" appearance on Barium swallow).
Question 32: A barium swallow is performed in a 44-year-old female who has had difficulty swallowing for months. Radiographically, there is marked dilation of the esophagus with beaking in the distal portion where marked luminal narrowing exists. A biopsy of the lower esophagus shows prominent submucosal fibrosis without much inflammation. What is the most likely cause?
- A. Portal hypertension
- B. Iron deficiency
- C. Barrett esophagus
- D. CREST syndrome (Correct Answer)
Explanation: ### Explanation **Correct Answer: D. CREST syndrome** The clinical and radiological presentation describes **Achalasia-like features** (marked dilation with distal "beaking"). In the context of **CREST syndrome** (a limited form of Systemic Sclerosis), esophageal involvement is common. The underlying pathophysiology is the replacement of the distal two-thirds of the esophageal smooth muscle with **submucosal fibrosis**. This leads to aperistalsis and a failure of the Lower Esophageal Sphincter (LES) to relax properly, mimicking primary achalasia on a barium swallow (the "Bird-beak" appearance). The biopsy finding of "prominent submucosal fibrosis without inflammation" is a classic histological hallmark of scleroderma/CREST. **Why other options are incorrect:** * **A. Portal hypertension:** This leads to esophageal varices, which appear as "worm-like" filling defects (cobblestone appearance) on barium swallow, not distal beaking or massive dilation. * **B. Iron deficiency:** Associated with **Plummer-Vinson Syndrome**, which presents with upper esophageal **webs** (post-cricoid region), not distal narrowing or submucosal fibrosis. * **C. Barrett esophagus:** This is a premalignant metaplastic change due to chronic GERD. While it can lead to strictures, it does not typically cause the massive "mega-esophagus" dilation seen here and is characterized by specialized columnar epithelium, not isolated submucosal fibrosis. **High-Yield Pearls for NEET-PG:** * **CREST components:** **C**alcinosis, **R**aynaud’s, **E**sophageal dysmotility, **S**clerodactyly, **T**elangiectasia. * **Barium Swallow Sign:** "Bird-beak" or "Rat-tail" appearance is seen in both Achalasia Cardia and Scleroderma. * **Key Distinction:** In primary Achalasia, LES pressure is **high**; in Scleroderma/CREST, LES pressure is typically **low/absent** (leading to severe reflux), though the structural fibrosis eventually causes the "beaked" obstructive appearance. * **Antibody:** Anti-Centromere antibody is highly specific for CREST syndrome.
Question 33: For which part of the gastrointestinal tract is a barium follow-through examination primarily used?
- A. Esophagus
- B. Stomach and duodenum
- C. Small intestine (Correct Answer)
- D. Colon and rectum
Explanation: **Explanation:** The **Barium Follow-Through (BFT)** is a fluoroscopic study specifically designed to evaluate the **small intestine** (jejunum and ileum). In this procedure, the patient drinks a barium suspension, and serial radiographs are taken at timed intervals (usually every 15–30 minutes) as the contrast propels through the small bowel until it reaches the ileocaecal junction. It is the gold standard conventional radiological investigation for diagnosing conditions like Crohn’s disease, malabsorption syndromes, and small bowel strictures. **Analysis of Options:** * **A. Esophagus:** Evaluated via a **Barium Swallow**, which focuses on the anatomy and motility of the esophagus. * **B. Stomach and Duodenum:** Evaluated via a **Barium Meal**. This study ends at the duodenojejunal (DJ) flexure. * **D. Colon and Rectum:** Evaluated via a **Barium Enema**, where contrast is administered retrograde through the anal canal to visualize the large bowel. **High-Yield Clinical Pearls for NEET-PG:** * **Enteroclysis (Small Bowel Enema):** Considered superior to BFT for mucosal detail. It involves intubating the duodenum (using a Bilbao-Dotter tube) and injecting contrast directly to achieve better distension. * **Contrast Choice:** Barium is contraindicated if **perforation** is suspected; in such cases, water-soluble contrast like **Gastrografin** (Diatrizoate) is used. * **Appearance:** The jejunum is characterized by a "feathery" appearance due to *valvulae conniventes*, while the ileum appears smoother. * **Moulage Sign:** A classic BFT finding in Celiac disease where the mucosal folds are lost, appearing like "melted wax."
Question 34: Scrambled egg appearance is seen in which of the following conditions?
- A. Carcinoma of the pancreas (Correct Answer)
- B. Carcinoma of the esophagus
- C. Carcinoma of the urinary bladder
- D. Carcinoma of the prostate
Explanation: **Explanation:** The **"Scrambled Egg Appearance"** is a classic radiological sign seen on a **Barium Meal** or hypotonic duodenography in cases of **Carcinoma of the Head of the Pancreas**. **Why it occurs:** When a tumor arises in the head of the pancreas, it can invade or compress the medial wall of the descending (second) part of the duodenum. This leads to irregular mucosal destruction, ulceration, and nodular filling defects. On a barium study, these distorted mucosal folds and intraluminal filling defects create a chaotic, mottled appearance resembling scrambled eggs. **Analysis of Options:** * **Option A (Correct):** Carcinoma of the pancreas causes this specific duodenal mucosal distortion. Another related sign is the **"Reverse 3 Sign" (Frostberg’s Sign)**, caused by the tumor fixing the ampulla while expanding the duodenal loops above and below. * **Option B (Incorrect):** Carcinoma of the esophagus typically presents with a **"Rat-tail"** or **"Bird-beak"** appearance (if mimicking achalasia) or irregular "Apple-core" narrowing. * **Option C (Incorrect):** Carcinoma of the urinary bladder is visualized on IVP or Cystogram as an irregular, fixed **filling defect**, but not a scrambled egg pattern. * **Option D (Incorrect):** Carcinoma of the prostate may show an irregular indentation on the base of the bladder (J-shaped ureters/Fish-hooking is seen in BPH), but not this sign. **High-Yield Clinical Pearls for NEET-PG:** * **Frostberg’s Sign (Reverse 3 Sign):** Also seen in Pancreatic Head Carcinoma. * **Double Bubble Sign:** Seen in Duodenal Atresia. * **Rose-thorn Ulcers:** Seen in Crohn’s Disease. * **Pad Sign:** Extrinsic compression of the duodenal loop by a pancreatic mass or pseudocyst.
Question 35: In which one of the following conditions is sialography contraindicated?
- A. Ductal calculus
- B. Chronic parotitis
- C. Acute parotitis (Correct Answer)
- D. Recurrent sialadenitis
Explanation: **Explanation:** **Sialography** is a radiographic procedure involving the injection of a radio-opaque contrast medium into the salivary ducts (usually the Parotid or Submandibular glands) to visualize the ductal system. **Why Acute Parotitis is the Correct Answer:** The primary contraindication for sialography is **acute infection (Acute Parotitis)**. Performing the procedure during an acute phase is avoided for two main reasons: 1. **Spread of Infection:** The retrograde pressure used to inject the contrast can push bacteria and inflammatory debris deeper into the glandular parenchyma, potentially leading to abscess formation or systemic spread. 2. **Severe Pain:** The procedure involves cannulation and ductal distension, which is excruciatingly painful for a patient with an acutely inflamed gland. **Analysis of Incorrect Options:** * **A. Ductal Calculus:** Sialography is often used to identify radiolucent stones or to visualize the degree of ductal dilatation (sialodochitis) proximal to a calculus. * **B. Chronic Parotitis:** This is a classic indication. Sialography helps assess the extent of damage, showing characteristic "sialectasis" (punctate, globular, or cavitary patterns). * **C. Recurrent Sialadenitis:** Sialography is indicated during the quiescent (non-acute) phase to identify underlying structural causes like strictures or sialoliths that predispose the patient to recurrence. **High-Yield Clinical Pearls for NEET-PG:** * **Indications:** Sialolithiasis (radiolucent stones), strictures, fistulae, and autoimmune conditions like Sjögren’s syndrome. * **Sjögren’s Syndrome Appearance:** Classically described as a **"Branchless Fruit Tree"** or "Snowstorm" appearance due to punctate sialectasis. * **Contrast Media:** Oil-based (Lipiodol) was used historically, but water-soluble (e.g., Sinografin) is preferred today as it is more easily eliminated. * **Other Contraindications:** Known allergy to iodine or contrast media.
Question 36: Which of the following acts as a hardener?
- A. Sodium sulfite
- B. Ammonium sulfite
- C. Aluminium salts (Correct Answer)
- D. None of the above
Explanation: In conventional radiography, the processing of X-ray film involves several chemical stages. The **Fixer solution** is responsible for removing unexposed silver halide crystals and permanently hardening the film emulsion. ### **Explanation of the Correct Answer** **C. Aluminium salts:** These are the primary **hardening agents** used in the fixer solution (specifically Potassium Alum or Aluminium Chloride). Their role is to shrink and harden the gelatin emulsion of the film. This prevents physical damage (scratches) to the film during handling and ensures the film does not over-swell or retain excess water, allowing for rapid drying. ### **Analysis of Incorrect Options** * **A. Sodium sulfite:** This acts as a **preservative** in both the developer and fixer solutions. It prevents the oxidation of the fixing agent (sodium thiosulfate) and helps maintain chemical stability. * **B. Ammonium sulfite:** Similar to sodium sulfite, this is used as a preservative. Note that *Ammonium thiosulfate* is the actual "clearing agent" (fixing agent) used in rapid fixers, but the *sulfite* component remains a preservative. ### **High-Yield Clinical Pearls for NEET-PG** * **The Developer:** Its main ingredient is **Hydroquinone** (builds contrast/black tones) and **Phenidone/Metol** (brings out gray tones). * **The Fixer:** The most common fixing agent is **Ammonium thiosulfate** ("Hypo"). * **Acidifier:** Acetic acid is added to the fixer to neutralize the alkaline developer carried over on the film. * **Sequencing:** The standard manual processing sequence is: **Developer → Rinsing (Stop bath) → Fixer → Washing → Drying.** * **Hardener in Developer:** Glutaraldehyde is sometimes used as a hardener in the developer stage of automatic processors to prevent the film from sticking to rollers.
Question 37: Which of the following conditions is characterized by a 'bird beak' appearance of the esophagus on barium swallow?
- A. Achalasia cardia (Correct Answer)
- B. Cancer esophagus
- C. Schatzki ring
- D. Diffuse esophageal spasm (DES)
Explanation: **Explanation:** **Achalasia Cardia (Correct Answer):** Achalasia is a primary esophageal motility disorder characterized by the failure of the Lower Esophageal Sphincter (LES) to relax and the absence of peristalsis in the distal esophagus. On a Barium Swallow, the proximal esophagus becomes dilated (mega-esophagus) due to food stasis, while the persistently contracted LES creates a smooth, tapered narrowing at the gastroesophageal junction. This classic radiological sign is known as the **'Bird Beak'** or **'Rat Tail'** appearance. **Analysis of Incorrect Options:** * **Cancer Esophagus:** Typically presents with an **'Irregular Apple Core'** appearance or a 'Shouldering' effect due to eccentric luminal narrowing and mucosal destruction by the malignancy. * **Schatzki Ring:** Characterized by a smooth, thin, symmetrical mucosal ring (B-ring) at the squamocolumnar junction, appearing as a **'Steakhouse Syndrome'** narrowing rather than a beak. * **Diffuse Esophageal Spasm (DES):** Presents with uncoordinated, high-amplitude contractions, giving the esophagus a **'Corkscrew'** or **'Rosary Bead'** appearance. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Esophageal Manometry (shows incomplete LES relaxation and aperistalsis). * **Heller’s Myotomy:** The definitive surgical treatment. * **Chagas Disease:** A common secondary cause of achalasia (caused by *Trypanosoma cruzi*). * **Sigmoid Esophagus:** The term used for the advanced, tortuous stage of Achalasia Cardia.
Question 38: All of the following appear hypo-intense on MRI except?
- A. Air in lung
- B. Ligaments
- C. Adipose tissue (Correct Answer)
- D. CSF
Explanation: **Explanation:** In MRI, the signal intensity (brightness) of a tissue depends on its proton density and relaxation times (T1 and T2). **Adipose tissue (Fat)** is unique because it has a very short T1 relaxation time, causing it to appear **hyper-intense (bright)** on T1-weighted images. On T2-weighted images, fat also remains relatively bright. Therefore, it is the only option among the choices that does not appear hypo-intense. **Analysis of Options:** * **Air in lung:** Air has a very low proton density. Since MRI relies on the excitation of hydrogen protons, areas with minimal water or fat (like the lungs or sinuses) produce little to no signal and appear **hypo-intense (black)**. * **Ligaments:** Dense connective tissues like ligaments, tendons, and cortical bone have very low mobile water content and extremely short T2 relaxation times. This results in a lack of signal, making them appear **hypo-intense** on all standard sequences. * **CSF (Cerebrospinal Fluid):** CSF is a simple fluid. While it is hyper-intense on T2-weighted images, it is characteristically **hypo-intense (dark)** on T1-weighted images. In the context of general MRI appearances, "hypo-intense" is a standard descriptor for CSF on T1 sequences. **High-Yield Clinical Pearls for NEET-PG:** * **T1 vs. T2:** Remember **"WW"**—**W**ater is **W**hite on T2. Conversely, Water (CSF) is Dark on T1. * **Fat Suppression:** Techniques like STIR (Short Tau Inversion Recovery) are used to null the signal from fat to better visualize pathology. * **Flow Void:** Rapidly flowing blood in arteries often appears hypo-intense (black) due to the "flow void" phenomenon.
Question 39: Calcified lesions are better visualized on which imaging modality?
- A. Ultrasound (USG)
- B. X-ray
- C. Computed Tomography (CT) (Correct Answer)
- D. Magnetic Resonance Imaging (MRI)
Explanation: **Explanation:** **Computed Tomography (CT)** is the gold standard for detecting and characterizing calcified lesions. This is because CT has superior **spatial resolution** and **high contrast sensitivity** for high-density materials. Calcium has a high atomic number, causing significant attenuation of X-ray beams, which results in high Hounsfield Units (HU) (typically >100 HU). This makes even tiny specks of calcium (microcalcifications) appear bright white and easily distinguishable from surrounding soft tissues. **Analysis of Options:** * **X-ray:** While X-rays can detect gross calcifications (like a large staghorn calculus), they lack the sensitivity of CT. Overlapping structures and lower contrast resolution make small or faint calcifications difficult to visualize. * **Ultrasound (USG):** Calcifications appear as hyperechoic (bright) foci with **posterior acoustic shadowing**. While useful for gallstones or kidney stones, USG is operator-dependent and cannot visualize calcifications deep within the lungs or brain due to poor penetration through bone/air. * **MRI:** This is generally **insensitive** to calcium. Calcifications typically appear as "signal voids" (dark/black) on most sequences (T1/T2), making them difficult to differentiate from flowing blood or air. **High-Yield Clinical Pearls for NEET-PG:** * **CT** is the investigation of choice for **acute head injury** to rule out hemorrhage and for detecting **intracranial calcifications** (e.g., Neurocysticercosis, TORCH infections). * **Mammography** (a specialized X-ray) is the gold standard for detecting **microcalcifications** in breast cancer screening. * **Susceptibility Weighted Imaging (SWI)** is the specific MRI sequence that can detect calcium (appearing "bloomed" or dark), though CT remains superior for confirmation.
Question 40: In which position should a renal scan be performed?
- A. Supine
- B. Prone (Correct Answer)
- C. Sitting
- D. Left lateral
Explanation: **Explanation:** The correct answer is **Prone (Option B)**. This is primarily due to the anatomical location of the kidneys. **1. Why Prone is Correct:** The kidneys are **retroperitoneal organs** located closer to the posterior abdominal wall than the anterior wall. In nuclear medicine renal scans (using tracers like DTPA, MAG3, or DMSA), a gamma camera is used to detect radiation. To minimize **attenuation** (absorption of gamma rays by overlying tissues), the detector should be as close to the kidneys as possible. Placing the patient in a **prone position** (or using a posterior detector in a supine patient) ensures the shortest distance between the kidneys and the camera, resulting in better image resolution and more accurate quantification of renal function. **2. Why Other Options are Incorrect:** * **Supine (A):** In this position, the anterior abdominal contents (bowel, fat, liver) lie between the kidneys and the camera, causing significant photon attenuation and poor image quality. *Exception:* Supine is used for transplanted kidneys (located in the iliac fossa) or horseshoe kidneys. * **Sitting (C) & Left Lateral (D):** These positions are unstable for the duration of a dynamic scan and do not provide the optimal posterior proximity required for standard native kidney imaging. **3. High-Yield Clinical Pearls for NEET-PG:** * **Transplanted Kidney:** Always scanned in the **Supine** position because the graft is placed anteriorly in the iliac fossa. * **Horseshoe Kidney:** Best imaged **Anteriorly (Supine)** because the isthmus crosses anterior to the spine. * **Radiopharmaceuticals:** * **DTPA:** Used for GFR estimation. * **MAG3:** Best for ERPF (Effective Renal Plasma Flow), especially in neonates or renal failure. * **DMSA:** The "Gold Standard" for cortical scarring and ectopic kidneys.
Practice by Chapter
Iodinated Contrast Media
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MRI Contrast Agents
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Ultrasound Contrast Agents
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Adverse Reactions to Contrast Media
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Management of Contrast Reactions
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Contrast-Induced Nephropathy
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Barium Studies
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Intravenous Urography
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Angiography Techniques
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Lymphangiography
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Contrast Administration Protocols
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Pretesting and Premedication
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