NEET-PG 2013 - Radiology Practice Questions

Q: For pericardial calcifications, which is the best investigation?

CT scan. ***Correct: CT scan*** - **CT scans** are highly sensitive and specific for detecting **pericardial calcifications** due to their excellent spatial resolution and ability to measure calcium density (Hounsfield units). - They provide detailed anatomical information about the **pericardium** and can accurately map the extent, location, and thickness of calcified areas. - **CT is the gold standard** for detecting and quantifying pericardial calcification, particularly in constrictive pericarditis. *Incorrect: Ultrasound* - While ultrasound (echocardiography) can visualize the pericardium and may detect calcifications, its ability to definitively identify and characterize **calcifications** is limited compared to CT. - **Acoustic shadowing** from calcifications can obscure underlying structures, making a precise assessment challenging. - Useful for detecting pericardial effusion and thickening, but not optimal for calcification assessment. *Incorrect: MRI* - **MRI excels** in visualizing soft tissues, pericardial inflammation, and fluid collections, but it is **poor at detecting calcium**. - Calcifications typically appear as signal voids (black) on MRI, making it difficult to differentiate them from other structures, air, or motion artifacts. - MRI is valuable for assessing pericardial inflammation and constriction but not the preferred method for calcification. *Incorrect: Transesophageal echocardiography* - TEE offers high-resolution images of cardiac structures and is primarily used for assessing valve function, intracardiac masses, endocarditis, and aortic pathology. - Its utility in detecting and characterizing **pericardial calcifications** is limited compared to CT, especially for diffuse or subtle calcifications. - The pericardium is not optimally visualized with TEE compared to transthoracic echocardiography.

Q: Barium swallow is used for -

Esophagus. ***Esophagus*** - A **barium swallow** specifically visualizes the **esophagus**, pharynx, and sometimes the early stomach. - It's used to identify abnormalities like **dysphagia**, strictures, **achalasia**, or tumors by coating the mucosal lining. *Colon* - The colon is typically examined using a **barium enema**, where barium sulfate is administered rectally. - This procedure is effective for visualizing the large intestine for conditions like **polyps**, diverticula, or inflammatory bowel disease. *Duodenum* - While a barium swallow may transiently show the **duodenum**, its primary target is the esophagus and stomach. - More detailed imaging of the duodenum often requires an **upper GI series (UGI)**, which is a broader study of the upper digestive tract. *Jejunum* - The jejunum is part of the small intestine and is best visualized through a **small bowel follow-through (SBFT)** procedure. - This involves ingesting barium and taking serial X-rays as it progresses through the small bowel, to detect conditions like **Crohn's disease** or obstructions.

Q: "String of beads" appearance on horizontal abdominal view X-ray is suggestive of:

Small bowel obstruction. ***Small bowel obstruction*** - A "string of beads" appearance on a horizontal abdominal view X-ray refers to small gas bubbles trapped between the valvulae conniventes in a dilated small bowel loop. - This finding is highly suggestive of **complete small bowel obstruction**, particularly when accompanied by multiple air-fluid levels and dilated bowel loops. *Intussusception* - While it causes obstruction, intussusception usually appears as a **target sign** (doughnut sign) on ultrasound or a **meniscus sign** on barium enema, not a string of beads on plain X-ray. - Plain X-rays may show signs of **bowel obstruction**, but the string of beads is not characteristic. *Sigmoid volvulus* - Sigmoid volvulus is characterized by a **dilated loop of colon** forming an inverted U-shape, often described as a **coffee bean sign** or **omega sign**, on plain X-ray. - This involves the large bowel, and the "string of beads" specifically relates to gas in the small bowel. *Large bowel obstruction* - Large bowel obstruction typically presents with a **dilated colon** proximal to the obstruction and a collapsed distal colon, often with absent or minimal gas in the rectum and sigmoid. - While air-fluid levels can be present, the "string of beads" is a specific sign of gas within dilated small bowel loops, distinguishing it from most large bowel obstructions.

Q: What condition is indicated by the double bubble sign on an abdominal X-ray?

Duodenal atresia. ***Duodenal atresia*** - The **double bubble sign** on an abdominal X-ray is pathognomonic for **duodenal atresia**, characterized by two air-filled bubbles: one in the stomach and one in the proximal duodenum, separated by the pylorus. - This congenital anomaly results from a complete obstruction of the duodenum, preventing the passage of air and fluid past this point. *Duodenal stenosis* - While also an obstruction of the duodenum, **duodenal stenosis** is an incomplete obstruction, meaning some gas will pass beyond the duodenum. - This would result in gas being present in the distal bowel, which is not seen with a classic "double bubble" where the bowel distal to the duodenum is gasless. *Volvulus* - **Volvulus** involves the twisting of a loop of intestine, leading to obstruction and potentially ischemia. - While it can cause obstruction, it typically presents with a "corkscrew" appearance on an upper GI series or signs of diffuse bowel distension, not the isolated double bubble. *All of the options* - The double bubble sign is highly specific to **duodenal atresia** due to the complete obstruction it signifies. - Other conditions like duodenal stenosis and volvulus cause different radiological patterns, making this option incorrect.

Q: Investigation with least radiation dose in the diagnosis of Meckel's diverticulum is -

Technetium -99m scanning. ***Technetium-99m scanning*** - **Technetium-99m pertechnetate scan** (Meckel's scan) is the **gold standard investigation** for diagnosing Meckel's diverticulum with ectopic gastric mucosa - Among the investigations that can actually **diagnose Meckel's diverticulum**, it has the **lowest radiation dose** (approximately 1-2 mSv) - The radioisotope is specifically taken up by ectopic gastric mucosa, providing both diagnostic utility and relatively low radiation exposure - **Sensitivity: 85-95%** for detecting ectopic gastric mucosa in Meckel's diverticulum - The radiation dose is comparable to a few months of natural background radiation and significantly lower than CT or contrast studies *MRI* - While **MRI uses no ionizing radiation**, it is **not a standard or practical investigation** for diagnosing Meckel's diverticulum - MRI cannot identify ectopic gastric mucosa specifically - It is rarely used in clinical practice for this indication - The question asks about investigation "in the diagnosis" of Meckel's diverticulum, implying a test that is actually used diagnostically *CT* - **Computed Tomography (CT)** delivers a **high radiation dose** (typically 5-10 mSv or more) - While it can identify structural abnormalities, it is not specific for Meckel's diverticulum - Not the first-line investigation for this condition *Contrast radiography* - **Contrast studies** (barium studies) use **moderate ionizing radiation** (3-5 mSv) - Limited utility in diagnosing Meckel's diverticulum as it primarily assesses luminal patency - Cannot identify ectopic gastric mucosa - Lower sensitivity compared to Tc-99m scanning

Q: Which condition is characterized by a 'moth-eaten' appearance of the bones?

Multiple myeloma. ***Multiple myeloma*** [1][2] - Characterized by **punched-out lytic lesions** in bones, often described as **moth-eaten** appearance on imaging [1]. - Associated with **elevated serum proteins** and **Bence Jones proteins** in urine, confirming the diagnosis [2]. *Eosinophilic granuloma* - Usually presents with **solitary bone lesions** and is linked to **Langerhans cell histiocytosis** rather than the moth-eaten pattern. - Does not typically cause generalized **lytic bone lesions** seen in cases of multiple myeloma. *Chondromyxoid fibroma* - Generally appears as a **well-defined cortical lesion** and is not associated with a moth-eaten appearance. - It predominantly affects the **metaphysis** of long bones and shows a characteristic **cartilaginous matrix**. *Osteoid osteoma* - Presents with a **nidus** of osteoid formation, leading to localized bone pain, and does not exhibit a moth-eaten consistency. - Tends to cause **cortical bone thickening** rather than the diffuse lytic lesions associated with multiple myeloma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 608. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 616-617.

Q: Which type of arthritis is characterized by the absence of a periosteal reaction?

Neuropathic arthritis. ***Neuropathic arthritis*** - **Neuropathic arthritis** (**Charcot joint**) is characterized by progressive joint destruction due to loss of proprioception and pain sensation, leading to severe bone and joint damage without a typical **periosteal reaction**. - The absence of normal protective reflexes results in repetitive microtrauma, often leading to bone resorption and fragmentation rather than new bone formation (periosteal reaction). *Psoriatic arthritis* - **Psoriatic arthritis** often presents with distinctive **periosteal reactions**, particularly at entheses and along the shafts of small bones (e.g., "pencil-in-cup" deformities and fluffy periostitis) [1]. - These periosteal changes are a hallmark of the inflammatory process affecting bone and connective tissues in psoriatic arthritis. *Rheumatoid arthritis* - **Rheumatoid arthritis** primarily involves the synovium, leading to erosions rather than prominent periosteal reactions in early stages [1]. - While periostitis can occur in chronic, destructive rheumatoid arthritis, it is not a primary or characteristic finding compared to other inflammatory arthritides. *Reactive arthritis* - **Reactive arthritis** frequently causes **periosteal reactions**, particularly at entheses (where tendons and ligaments attach to bone) and along the shafts of long bones, often described as "fluffy" periostitis [1]. - These new bone formations are a key radiological feature distinguishing it from other types of inflammatory arthritis.

Q: Which condition is associated with the pencil in cup deformity?

Psoriatic arthritis. ***Psoriatic arthritis*** - The **pencil-in-cup deformity** is a classic radiographic finding in advanced psoriatic arthritis, occurring due to **periarticular bone erosion** and phalangeal telescoping. - This specific deformity is characterized by the proximal phalanx eroding and fitting into the expanded distal phalanx, resembling a "pencil in a cup." *Rheumatoid arthritis* - While rheumatoid arthritis causes significant joint destruction, it typically presents with **periarticular erosions** and **joint space narrowing**, but not the characteristic pencil-in-cup morphology. - Common deformities include **swan-neck** and **boutonnière** deformities, and ulnar deviation. *Ankylosing spondylitis* - This condition primarily affects the **axial skeleton**, leading to spinal fusion and **sacroiliitis**. - Peripheral joint involvement is less common and typically does not result in the pencil-in-cup deformity; instead, it can cause **syndesmophytes**. *Avascular necrosis* - **Avascular necrosis** (AVN) involves the death of bone tissue due to lack of blood supply, primarily affecting the femoral head or other major joints. - Radiographic findings include **subchondral collapse**, crescent sign, and eventual joint destruction, but not the specific deformities seen in inflammatory arthritis like pencil-in-cup.

Q: Enhancement in CT contrast is due to -

Iodine. ***Iodine*** - **Iodine-based contrast agents** are commonly used in CT scans to enhance the visualization of blood vessels, organs, and certain lesions due to their **high atomic number** and ability to absorb X-rays. - The degree of enhancement observed on a CT image is directly proportional to the concentration of **iodine** in the tissue or blood. *Gadolinium* - **Gadolinium-based contrast agents** are predominantly used in **Magnetic Resonance Imaging (MRI)**, not CT scans. - Gadolinium works by altering the **magnetic properties** of water molecules in tissues, thereby improving MRI signal intensity. *Mercury* - **Mercury** is a highly toxic heavy metal and is **not used as a contrast agent** in any imaging modality due to its severe health risks. - While historically used in some medical applications, it has been replaced by safer alternatives. *Silver* - **Silver** is not used as a contrast agent in medical imaging; it has no suitable properties for enhancing images in CT or other common modalities. - It is known for its **antimicrobial properties** and is sometimes used in wound dressings.

Q: Normal prevertebral soft tissue thickness in adults at C3 level is

7 mm. ***7 mm*** * The normal prevertebral soft tissue thickness in adults at the **C3 level** is approximately **7 mm** (upper limit 5-7 mm) on a lateral cervical spine radiograph. * The **C1-C4 levels** have relatively thin prevertebral soft tissue as they lie above the hypopharynx and esophagus. * Exceeding this measurement can indicate **prevertebral hematoma, edema, abscess**, or other pathologies such as retropharyngeal abscess or cervical spine fracture with soft tissue swelling. *Incorrect: 15 mm* * A measurement of 15 mm at the **C3 level** would be considered **abnormal** and indicates prevertebral soft tissue swelling. * This value exceeds the normal limit by more than double and warrants further investigation. *Incorrect: 22 mm* * A measurement of 22 mm at the **C3 level** is significantly **abnormal** and highly suggestive of serious pathology such as retropharyngeal hematoma, abscess, or cervical spine injury. * Note that 22 mm may be within normal limits at the **C6-C7 level** where the esophagus widens the prevertebral space. *Incorrect: 30 mm* * 30 mm is severely abnormal at the **C3 level**. * While prevertebral soft tissue thickness can be greater at lower cervical levels (C5-C7) due to the esophagus, even at those levels 30 mm would suggest pathology. * Such measurements indicate significant conditions like large hematoma, abscess, or tumor.

Question 1

For pericardial calcifications, which is the best investigation?

Accepted Answer

CT scan

Answer

Ultrasound

Answer

MRI

Answer

Transesophageal echocardiography

Question 2

Barium swallow is used for -

Accepted Answer

Esophagus

Answer

Colon

Answer

Duodenum

Answer

Jejunum

Question 3

"String of beads" appearance on horizontal abdominal view X-ray is suggestive of:

Accepted Answer

Small bowel obstruction

Answer

Intussusception

Answer

Sigmoid volvulus

Answer

Large bowel obstruction

Question 4

What condition is indicated by the double bubble sign on an abdominal X-ray?

Accepted Answer

Duodenal atresia

Answer

Duodenal stenosis

Answer

Volvulus

Answer

All of the options

Question 5

Investigation with least radiation dose in the diagnosis of Meckel's diverticulum is -

Accepted Answer

Technetium -99m scanning

Answer

MRI

Answer

CT

Answer

Contrast radiography

Question 6

Which condition is characterized by a 'moth-eaten' appearance of the bones?

Accepted Answer

Multiple myeloma

Answer

Osteoid osteoma

Answer

Eosinophilic granuloma

Answer

Chondromyxoid fibroma

Question 7

Which type of arthritis is characterized by the absence of a periosteal reaction?

Accepted Answer

Neuropathic arthritis

Answer

Psoriatic arthritis

Answer

Rheumatoid arthritis

Answer

Reactive arthritis

Question 8

Which condition is associated with the pencil in cup deformity?

Accepted Answer

Psoriatic arthritis

Answer

Rheumatoid arthritis

Answer

Ankylosing spondylitis

Answer

Avascular necrosis

Question 9

Enhancement in CT contrast is due to -

Accepted Answer

Iodine

Answer

Gadolinium

Answer

Mercury

Answer

Silver

Question 10

Normal prevertebral soft tissue thickness in adults at C3 level is

Accepted Answer

7 mm

Answer

15 mm

Answer

22 mm

Answer

30 mm

NEET-PG 2013 — Radiology