NEET-PG 2013 - Radiology Practice Questions

Q: What is the most common feature of sarcoidosis on chest X-ray?

Bilateral hilar lymphadenopathy. ***Bilateral hilar lymphadenopathy*** - **Bilateral hilar lymphadenopathy** is the hallmark radiological feature of sarcoidosis, seen in over 75% of cases. - This finding, often symmetrical, represents the accumulation of **non-caseating granulomas** in the lymph nodes. - Classic presentation in **Stage I and Stage II** sarcoidosis. *Pleural effusion* - **Pleural effusions** are uncommon in sarcoidosis, occurring in less than 5% of cases. - When present, they are usually small and unilateral, and their presence should prompt consideration of alternative diagnoses. *Cavitation* - **Cavitation** is a rare manifestation of sarcoidosis and is more characteristic of infectious processes like **tuberculosis** or certain fungal infections. - If seen, it usually suggests severe parenchymal involvement or superimposed infection. *Reticular opacities* - While **reticular opacities** (interstitial changes) can be seen in later stages of sarcoidosis, representing **pulmonary fibrosis**, they are not the *most common* initial finding. - These opacities indicate chronic disease progression (Stage III/IV) rather than the initial presentation.

Q: Radiological sign in case of Perthes disease?

Flattening of femoral head. ***Flattening of femoral head*** - **Flattening** and **fragmentation** of the femoral head are characteristic radiological findings in **early-stage** Perthes disease. - This flattening is a direct consequence of the **avascular necrosis** and subsequent **remodeling** of the femoral epiphysis. *Fragmentation of femoral head epiphysis* - While **fragmentation** is a key feature of Perthes disease, it's typically observed **after** the initial flattening and sclerosis in the avascular stage. - It represents the process of **resorption** and **revascularization** as the bone attempts to heal. *Lateral femoral head displacement* - **Lateral displacement** of the femoral head is a more common finding in conditions like **slipped capital femoral epiphysis (SCFE)**, where the epiphysis slips from the metaphysis. - In Perthes disease, the primary issue is the **necrosis and collapse** of the femoral head itself, rather than displacement from the neck. *Limited hip abduction* - **Limited hip abduction** is a clinical sign, not a radiological sign, and it is a common symptom in Perthes disease due to pain, inflammation, and deformity of the femoral head. - Radiological signs are visual abnormalities observed on imaging studies like X-rays.

Q: Which of the following conditions is the MOST COMMON cause of rib notching?

Coarctation of aorta. ***Coarctation of aorta*** - **Coarctation of the aorta** is the classic and **most common cause** of rib notching. - The notching is caused by the enlargement and tortuosity of the **intercostal arteries** as they provide collateral circulation to bypass the narrowed aorta. *Chronic superior venacava obstruction* - Chronic superior vena cava (SVC) obstruction may lead to the development of collateral circulation through the azygos and hemiazygos veins, but it does **not typically cause rib notching**. - Rib notching is specifically related to collateral flow bypassing an aortic obstruction, not a venous obstruction. *Atrial septal defect* - An **atrial septal defect (ASD)** is a communication between the atria that can lead to right heart volume overload and pulmonary hypertension. - While it's a congenital heart defect, an ASD does **not cause rib notching** as it does not involve an obstruction of systemic arterial flow requiring collateral circulation via the intercostal arteries. *Congenital interruption of aorta* - While **congenital interruption of the aorta** also involves an aortic obstruction, it is a **much rarer condition** than coarctation of the aorta. - Due to its rarity, it is not considered the most common cause of rib notching, even though it would theoretically lead to similar collateral vessel formation.

Q: Frequency of ultrasound waves in USG -

>2 MHz. ***>2 MHz*** - Medical diagnostic ultrasound typically uses frequencies in the **range of 2-15 MHz**, with some applications extending from 1-20 MHz. - Frequencies **above 2 MHz** are considered the standard for diagnostic ultrasonography, providing adequate **spatial resolution** and tissue penetration for imaging internal structures. - **Frequency selection** depends on the application: - **2-5 MHz**: Deep structures (abdominal, obstetric imaging) - better penetration - **5-10 MHz**: Vascular studies, cardiac imaging - **7-15 MHz**: Superficial structures (thyroid, breast, musculoskeletal) - better resolution - Higher frequencies provide better resolution but less penetration; the choice represents a trade-off based on clinical needs. *2000 Hz* - This frequency (2 kHz) falls within the **audible range** for humans (20 Hz to 20 kHz). - Such low frequencies would not provide the necessary **spatial resolution** for diagnostic imaging and lack the characteristics needed for medical ultrasound. *5000 Hz* - At 5 kHz, this is still within the **audible frequency range**. - These frequencies are far too low for medical ultrasound imaging, which requires **megahertz frequencies** to generate diagnostically useful images with adequate detail. * 20 kHz), are generally **below the diagnostic range** for most clinical applications. - Although lower frequencies offer better tissue penetration, frequencies below 2 MHz provide **insufficient spatial resolution** for standard diagnostic medical imaging.

Q: Gyromagnetic property of proton is seen in -

MRI. ***MRI*** - Magnetic Resonance Imaging (MRI) relies on the **gyromagnetic properties of protons**, primarily hydrogen nuclei in water and fat. - These protons align with a strong magnetic field and, when pulsed with radiofrequency waves, emit detectable signals that form the image. *CT* - Computed Tomography (CT) utilizes **X-rays** and their differential absorption by various tissues to create cross-sectional images. - It does not involve the gyromagnetic properties of protons. *PET scan* - Positron Emission Tomography (PET) scans detect **gamma rays** emitted from radiotracers, typically radionuclides like Fluorine-18, that accumulate in metabolically active tissues. - This imaging modality is based on radioactive decay, not proton spin. *USG* - Ultrasonography (USG) generates images by sending **high-frequency sound waves** into the body and detecting the echoes that bounce back from various tissues. - It relies on acoustic properties and tissue interfaces, not magnetic properties of protons.

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.

Question 1

What is the most common feature of sarcoidosis on chest X-ray?

Accepted Answer

Bilateral hilar lymphadenopathy

Answer

Cavitation

Answer

Pleural effusion

Answer

Reticular opacities

Question 2

Radiological sign in case of Perthes disease?

Accepted Answer

Flattening of femoral head

Answer

Fragmentation of femoral head epiphysis

Answer

Lateral femoral head displacement

Answer

Limited hip abduction

Question 3

Which of the following conditions is the MOST COMMON cause of rib notching?

Accepted Answer

Coarctation of aorta

Answer

Atrial septal defect

Answer

Chronic superior venacava obstruction

Answer

Congenital interruption of aorta

Question 4

What is an X-ray artifact?

Accepted Answer

An unwanted image distortion that doesn't represent actual anatomy

Answer

A radiographic finding that indicates disease pathology

Answer

A normal anatomical structure visible on X-ray

Answer

An image distortion produced when the patient moves during the X-ray procedure

Question 5

Frequency of ultrasound waves in USG -

Accepted Answer

>2 MHz

Answer

2000 Hz

Answer

5000 Hz

Answer

< 2 MHz

Question 6

Gyromagnetic property of proton is seen in -

Accepted Answer

MRI

Answer

CT

Answer

PET scan

Answer

USG

Question 7

For pericardial calcifications, which is the best investigation?

Accepted Answer

CT scan

Answer

Ultrasound

Answer

MRI

Answer

Transesophageal echocardiography

Question 8

Barium swallow is used for -

Accepted Answer

Esophagus

Answer

Colon

Answer

Duodenum

Answer

Jejunum

Question 9

"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 10

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

NEET-PG 2013 — Radiology