A chest X-ray shows bilateral lung infiltrates. What is the next best investigation?
Hose pipe appearance of intestine is a feature of
What is the primary use of the Balthazar scoring system?
Which condition is characterized by a specific radiological appearance resembling a sunburst pattern?
Retrocardiac lucency with air fluid level is seen in
Gyromagnetic property of proton is seen in -
What is an X-ray artifact?
Frequency of ultrasound waves in USG -
Radiological sign in case of Perthes disease?
What is the standard radiation dose to point A in the cervix for brachytherapy in the treatment of cervical cancer?
NEET-PG 2013 - Radiology NEET-PG Practice Questions and MCQs
Question 11: A chest X-ray shows bilateral lung infiltrates. What is the next best investigation?
- A. Sputum examination
- B. CT (Correct Answer)
- C. Bronchoscopy
- D. Echocardiography
Explanation: ***CT*** - A **CT scan (preferably HRCT)** provides a more detailed view of the lung parenchyma, allowing for better characterization of the infiltrates (e.g., location, pattern, presence of nodules, ground-glass opacities, or consolidation). - This detailed imagery is crucial for narrowing down the differential diagnosis and guiding further diagnostic or therapeutic interventions. - **CT is the best next investigation** for characterizing bilateral lung infiltrates seen on chest X-ray. *Sputum examination* - While important for identifying infectious causes, **sputum examination** is often only productive in certain types of pneumonia or infections and might not directly clarify the morphology or distribution of the infiltrates as a CT scan would. - It might be a subsequent step once the nature of the infiltrate is better understood through imaging. *Bronchoscopy* - **Bronchoscopy** is an invasive procedure generally reserved for cases where less invasive methods have failed to yield a diagnosis or when specific findings from imaging (like a CT scan) suggest the need for direct visualization, lavage, or biopsy. - It's not typically the immediate next step after identifying bilateral infiltrates on a chest X-ray. *Echocardiography* - **Echocardiography** is useful for evaluating cardiac causes of bilateral infiltrates (such as pulmonary edema from heart failure). - However, it does not directly visualize or characterize the lung parenchymal infiltrates themselves, making CT more valuable as the next investigation.
Question 12: Hose pipe appearance of intestine is a feature of
- A. Malabsorption syndrome
- B. Ulcerative colitis (Correct Answer)
- C. Crohn's disease
- D. Hirschsprung disease
Explanation: ***Crohns disease*** - The **hose pipe appearance** of the intestine on imaging is due to **transmural inflammation** and **strictures**, characteristic of Crohn's disease [1]. - This feature indicates a **narrowed lumen** due to fibrosis, often affecting the small intestine or colon [1]. *Malabsorption syndrome* - This condition is primarily associated with **nutrient absorption issues**, not structural changes in the intestine. - It typically presents with **diarrhea**, **weight loss**, and **malnutrition**, lacking the characteristic imaging findings. *Ulcerative colitis* - Usually presents with **continuous lesions** confined to the colonic mucosa, leading to ulcers and inflammation but not a **hose pipe appearance**. - Symptoms include **bloody diarrhea** and **abdominal pain**, distinctly different from Crohn's disease. *Hirsprung disease* - A congenital condition causing **intestinal obstruction** due to the absence of ganglion cells, leading to **dilated proximal bowel** rather than a hose pipe appearance. - Typically presents in infants with **severe constipation** and **abdominal distension**, unrelated to imaging features seen in Crohn's disease. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 366-367.
Question 13: What is the primary use of the Balthazar scoring system?
- A. Acute Pancreatitis (Correct Answer)
- B. Acute Appendicitis
- C. Acute Cholecystitis
- D. Cholangitis
Explanation: ***Acute Pancreatitis*** - The Balthazar score (also known as the **CT Severity Index** for pancreatitis) is primarily used to assess the severity of **acute pancreatitis** based on findings from a **CT scan**. - It evaluates pancreatic inflammation and necrosis, correlating with patient prognosis and the risk of complications. *Acute Appendicitis* - Acute appendicitis is typically diagnosed clinically, often with the help of the **Alvarado score** or imaging like ultrasound/CT, but not the Balthazar score. - The Balthazar score's focus on pancreatic changes is irrelevant to appendiceal inflammation. *Acute Cholecystitis* - Diagnosis of acute cholecystitis is based on clinical signs, lab tests, and imaging (ultrasound showing **gallbladder wall thickening**, pericholecystic fluid, or stones). - The Balthazar scoring system does not apply to the assessment of gallbladder inflammation. *Cholangitis* - Cholangitis is an infection of the bile ducts, diagnosed using the **Tokyo Guidelines**, which consider systemic inflammation, cholestasis, and imaging of biliary obstruction. - The Balthazar score is specific to pancreatic inflammation and does not provide information relevant to cholangitis.
Question 14: Which condition is characterized by a specific radiological appearance resembling a sunburst pattern?
- A. Chondrosarcoma
- B. Fibrosarcoma
- C. Osteosarcoma (Correct Answer)
- D. Ewing's sarcoma
Explanation: ***Osteosarcoma*** - **Osteosarcoma** is known for its classic radiological findings, including the **sunburst (rising sun)** or **spiculated periosteal reaction**, where new bone forms perpendicular to the cortex. - Another characteristic finding is **Codman's triangle**, which is a triangular elevation of the periosteum visible on X-ray. *Chondrosarcoma* - **Chondrosarcomas** are typically characterized by a **"rings and arcs"** pattern of calcification within the cartilaginous matrix on imaging studies. - They tend to appear as lobular masses with endosteal scalloping and soft tissue components rather than the sunburst pattern. *Ewing's sarcoma* - **Ewing's sarcoma** classically presents with an **"onion skin" (lamellated)** periosteal reaction due to layers of parallel new bone formation. - It often appears as an ill-defined lytic lesion with cortical destruction, differing from the sunburst appearance. *Fibrosarcoma* - **Fibrosarcomas** are typically **lytic lesions** with aggressive cortical destruction and soft tissue involvement. - They generally do not produce characteristic periosteal reactions like the sunburst or onion skin appearance, often presenting as non-specific destructive lesions.
Question 15: Retrocardiac lucency with air fluid level is seen in
- A. Distal esophageal obstruction
- B. Diaphragmatic eventration
- C. Hiatus hernia (Correct Answer)
- D. None of the options
Explanation: ***Hiatus hernia*** - A **hiatus hernia** occurs when part of the stomach protrudes into the chest through the **esophageal hiatus** of the diaphragm. - This can lead to a **retrocardiac lucency** (gas-filled stomach) with an **air-fluid level** visible on chest X-rays due to gastric contents. - The herniated gastric fundus appears as a characteristic gas bubble behind the heart, particularly well-seen on lateral chest radiographs. *Distal esophageal obstruction* - While distal esophageal obstruction can cause esophageal dilation and sometimes an **air-fluid level** within the esophagus, it generally presents as a tubular structure *behind* the heart rather than a distinct retrocardiac lucency representing a portion of the stomach. - The appearance would be more suggestive of a dilated esophagus filled with contents, not a herniated stomach. *Diaphragmatic eventration* - **Diaphragmatic eventration** is an abnormal elevation of a portion of the diaphragm, often due to congenital weakness or phrenic nerve paralysis. - It does not typically cause a **retrocardiac lucency** with an **air-fluid level**, as it involves the diaphragm itself rather than the herniation of an abdominal organ. - It may show elevation of the hemidiaphragm but without the characteristic gas-filled viscus appearance. *None of the options* - Hiatus hernia is a well-established radiological diagnosis for retrocardiac lucency with an **air-fluid level**, making this option clearly incorrect.
Question 16: Gyromagnetic property of proton is seen in -
- A. MRI (Correct Answer)
- B. CT
- C. PET scan
- D. USG
Explanation: ***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.
Question 17: What is an X-ray artifact?
- A. A radiographic finding that indicates disease pathology
- B. A normal anatomical structure visible on X-ray
- C. An image distortion produced when the patient moves during the X-ray procedure
- D. An unwanted image distortion that doesn't represent actual anatomy (Correct Answer)
Explanation: ***An unwanted image distortion that doesn't represent actual anatomy*** - An **X-ray artifact** is any feature or distortion on a radiographic image that is not present in the actual object being imaged. - These can arise from various sources such as patient movement, equipment malfunction, or improper technique, leading to **misinterpretation** of the image. - Artifacts are unwanted findings that can obscure true pathology or mimic disease. *A normal anatomical structure visible on X-ray* - This describes a **true anatomical finding**, which is the intended purpose of an X-ray. - Normal anatomical structures are expected and assist in diagnosis, unlike artifacts which obscure or mimic pathology. *An image distortion produced when the patient moves during the X-ray procedure* - While **patient motion** is a common cause of X-ray artifacts, this describes just one specific type (motion artifact), not a comprehensive definition of what an artifact is. - Other sources like metallic objects, scatter radiation, or detector issues can also cause artifacts. *A radiographic finding that indicates disease pathology* - This describes **true pathology** or disease findings, which is what radiologists aim to identify. - Artifacts are the opposite - they are false findings that do not represent actual anatomy or pathology.
Question 18: Frequency of ultrasound waves in USG -
- A. 2000 Hz
- B. 5000 Hz
- C. < 2 MHz
- D. >2 MHz (Correct Answer)
Explanation: ***>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. *< 2 MHz* - Frequencies below 2 MHz, while technically ultrasound (>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.
Question 19: Radiological sign in case of Perthes disease?
- A. Flattening of femoral head (Correct Answer)
- B. Fragmentation of femoral head epiphysis
- C. Lateral femoral head displacement
- D. Limited hip abduction
Explanation: ***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.
Question 20: What is the standard radiation dose to point A in the cervix for brachytherapy in the treatment of cervical cancer?
- A. 8000 rad (Correct Answer)
- B. 6000 rad
- C. 10000 rad
- D. 4000 rad
Explanation: ***8000 rad*** - The standard **total cumulative radiation dose** to **Point A** in the cervix for the treatment of cervical cancer is approximately **8000 rad (80 Gy)**. - This represents the **combined dose** from external beam radiation therapy (EBRT, typically 45-50 Gy) plus intracavitary brachytherapy (typically 30-40 Gy to Point A). - Point A is a classical reference point defined as **2 cm superior to the external cervical os and 2 cm lateral to the uterine canal**, representing the location where the uterine artery crosses the ureter. - This total dose aims to provide adequate tumor control while minimizing toxicity to surrounding organs like the bladder and rectum. *6000 rad* - A total dose of **6000 rad** is insufficient for definitive local control of cervical cancer. - This dose is below the therapeutic threshold and would result in significantly higher rates of local recurrence and treatment failure. - Adequate doses are essential for curative intent in cervical cancer management. *10000 rad* - A dose of **10000 rad** to Point A would be excessively high and significantly increase the risk of severe acute and late toxicities to surrounding tissues. - Such a high dose could lead to serious complications including **rectovaginal or vesicovaginal fistulas, proctitis, cystitis, bowel strictures, and tissue necrosis**. - The therapeutic window would be exceeded, causing more harm than benefit. *4000 rad* - A dose of **4000 rad** would be substantially lower than the standard therapeutic dose for cervical cancer. - This suboptimal dose would likely result in **inadequate tumor control and increased risk of local recurrence**. - It is far below the dose required for curative treatment of cervical cancer.