Tigroid pattern on MRI is seen in -
Epidural hematoma on CT scan shows which of the following?
Investigation of choice for soft tissue sarcoma is -
On CT chest, the 'halo sign' is particularly associated with which condition in immunocompromised patients?
In a patient with a tender and rigid abdomen, what is the expected finding on X-ray?
Which of the following statements about lipoma is radiologically true?
Which of the following X-ray findings is associated with Chilaiditi syndrome?
Which of the following is NOT a typical ultrasonographic finding in autosomal recessive polycystic kidney disease (ARPKD)?
Cobra head appearance on excretory urography is suggestive of?
Investigation of choice to evaluate intracranial hemorrhage of less than 48 hours is -
NEET-PG 2015 - Radiology NEET-PG Practice Questions and MCQs
Question 11: Tigroid pattern on MRI is seen in -
- A. Wilson's disease
- B. Metachromatic leukodystrophy (Correct Answer)
- C. Parkinsonism
- D. GB syndrome
Explanation: ***Metachromatic leukodystrophy*** - The **tigroid pattern** on MRI, characterized by **perivascular sparing** within demyelinated white matter, is highly characteristic of metachromatic leukodystrophy. - This pattern results from the accumulation of **sulfatides** in oligodendrocytes and macrophages, leading to central demyelination with spared U-fibers and white matter adjacent to vessels. *Wilson's disease* - Wilson's disease involves **copper accumulation** and typically presents with abnormalities in the **basal ganglia**, thalami, and brainstem. - While it causes neurodegeneration, it does not produce a characteristic tigroid demyelination pattern. *Parkinsonism* - Parkinsonism refers to a group of neurological disorders characterized by motor symptoms like **bradykinesia, rigidity, tremor, and postural instability**. - MRI findings in Parkinsonism often show **nigral degeneration** but do not typically involve a tigroid pattern of leukodystrophy. *GB syndrome* - **Guillain-Barré syndrome (GBS)** is an acute autoimmune peripheral neuropathy affecting the **peripheral nerves and nerve roots**. - It does not involve central nervous system demyelination or display a tigroid pattern on brain MRI.
Question 12: Epidural hematoma on CT scan shows which of the following?
- A. Biconvex hyperdense lesion (Correct Answer)
- B. Crescent-shaped hyperdense lesion
- C. Biconcave hypodense lesion
- D. Ring-enhancing hypodense lesion
Explanation: ***Biconvex hyperdense lesion*** - An epidural hematoma is characterized by a **biconvex** (lens-shaped) collection of blood between the dura mater and the skull. - Since it is an acute hemorrhage, the blood appears **hyperdense** (bright white) on a CT scan. *Crescent-shaped hyperdense lesion* - A **crescent shape** is characteristic of an **acute subdural hematoma**, not an epidural hematoma. - While acute subdural hematomas are also hyperdense, their crescent shape (following the contour of the brain) distinguishes them from the biconvex epidural hematomas. - Epidural hematomas are limited by suture lines and appear lens-shaped, while subdural hematomas can cross suture lines. *Biconcave hypodense lesion* - A **biconcave** shape is not a standard description in neuroradiology and does not represent epidural hematoma. - **Hypodense** would indicate an older lesion or other pathology, not acute hemorrhage. *Ring-enhancing hypodense lesion* - **Ring-enhancing lesions** are typically associated with abscesses, glioblastoma, or metastatic tumors, not an acute hematoma. - A **hypodense** (darker) center with enhancement would indicate an abscess or necrotic tumor, not a fresh extravasation of blood.
Question 13: Investigation of choice for soft tissue sarcoma is -
- A. CT
- B. MRI (Correct Answer)
- C. Ultrasound
- D. X-ray
Explanation: ***MRI*** - **Magnetic Resonance Imaging (MRI)** is the investigation of choice for soft tissue sarcomas due to its superior **soft tissue contrast resolution**, allowing for detailed assessment of tumor size, location, and extent within muscle, fat, and neurovascular structures. - MRI is crucial for **surgical planning**, helping to define tumor margins and evaluate involvement of adjacent critical structures. *CT* - While CT scans can identify masses, they have **limited soft tissue contrast resolution** compared to MRI, making it less effective for precise delineation of soft tissue sarcomas. - CT is often used for **staging to detect metastatic disease**, particularly in the lungs, rather than for primary tumor characterization. *Ultrasound* - **Ultrasound** is a good initial screening tool for soft tissue masses due to its accessibility and lack of radiation, but it is **operator-dependent** and has limitations in assessing deep or large lesions. - It can help differentiate cystic from solid lesions and guide biopsies but **lacks the comprehensive detail** of MRI for definitive diagnosis and staging. *X-ray* - **X-rays** are primarily used to visualize **bone abnormalities** and are generally not effective for evaluating soft tissue masses unless there is associated calcification or bone erosion. - They provide **minimal information** regarding the internal structure or extent of a soft tissue sarcoma.
Question 14: On CT chest, the 'halo sign' is particularly associated with which condition in immunocompromised patients?
- A. Pulmonary hydatid cyst
- B. Round pneumonia
- C. Bronchiectasis
- D. Invasive pulmonary aspergillosis (Correct Answer)
Explanation: ***Invasive pulmonary aspergillosis*** - The **halo sign** on CT chest, characterized by a ground-glass opacity surrounding a nodule, is a classic radiographic finding in **invasive pulmonary aspergillosis**, especially in immunocompromised patients. - This sign represents hemorrhage around the fungal nodule and indicates active tissue invasion by *Aspergillus* species. *Pulmonary hydatid cyst* - Hydatid cysts are typically well-defined, thin-walled cystic lesions, often displaying the **water lily sign** if complicated by rupture, which is different from the halo sign. - These cysts are caused by the larval stage of *Echinococcus granulosus* and are not associated with a peripheral ground-glass opacity. *Round pneumonia* - Round pneumonia is a localized, **spherical consolidation** often seen in children, which does not typically exhibit the perilesional ground-glass opacity characteristic of the halo sign. - It usually represents bacterial infection and resolves with antibiotics, unlike the invasive fungal disease suggested by the halo sign. *Bronchiectasis* - Bronchiectasis is characterized by **irreversible dilation of the bronchi**, often appearing as "tram-track" opacities or "signet ring" signs on CT. - It is a chronic condition related to airway damage and mucus retention, and not associated with acute nodular lesions or the halo sign.
Question 15: In a patient with a tender and rigid abdomen, what is the expected finding on X-ray?
- A. Blood under the diaphragm
- B. Air under the diaphragm (Correct Answer)
- C. Hazy lung fields
- D. Prominent vascular markings
Explanation: ***Air under the diaphragm*** - The presence of **free air** (pneumoperitoneum) beneath the diaphragm on an upright abdominal X-ray is a classic sign of **visceral perforation**. - A **tender and rigid abdomen** (peritoneal signs) indicates irritation of the peritoneum, most commonly due to a ruptured hollow viscus. *Blood under the diaphragm* - While blood can accumulate under the diaphragm (e.g., from **trauma** or a ruptured ectopic pregnancy), it typically manifests as a **hemoperitoneum** on imaging. - Blood is **fluid** and would appear as a fluid collection, not free air, on X-ray. *Hazy lung fields* - **Hazy lung fields** suggest conditions like **pulmonary edema**, pneumonia, or acute respiratory distress syndrome (ARDS). - These findings are primarily associated with pulmonary pathology and are not directly indicative of an acute abdominal emergency like perforation. *Prominent vascular markings* - **Prominent vascular markings** often indicate increased blood flow to the lungs or **pulmonary hypertension**. - This finding is unrelated to acute abdominal pain or peritoneal irritation.
Question 16: Which of the following statements about lipoma is radiologically true?
- A. Low attenuation on CT scan (Correct Answer)
- B. Hyperechoic on ultrasound
- C. Hyperintense on fat-suppressed sequences
- D. Hyper-intense on T2-weighted MRI
Explanation: ***Low attenuation on CT scan*** - Lipomas, being composed of **fat**, appear as areas of **low attenuation** (typically -50 to -150 Hounsfield Units) on computed tomography (CT) scans. - This low attenuation is a **key diagnostic characteristic** that helps differentiate lipomas from other soft tissue masses. *Hyperechoic on ultrasound* - Lipomas typically appear **isoechoic to hypoechoic** on ultrasound, not consistently hyperechoic. - They may have a thin echogenic capsule, but the internal contents are usually similar to or less echogenic than adjacent subcutaneous fat. *Hyperintense on fat-suppressed sequences* - This is **incorrect** - lipomas show **signal dropout** (become dark/hypointense) on fat-suppressed sequences (STIR, fat-sat T1/T2). - Signal suppression on fat-saturated sequences is actually a **diagnostic feature** confirming the fatty nature of the lesion. - Note: Lipomas ARE hyperintense on standard T1-weighted imaging due to fat content. *Hyper-intense on T2-weighted MRI* - Lipomas typically show **intermediate to slightly hyperintense signal** on T2-weighted MRI, but not markedly hyperintense like fluid. - They are less bright than fluid-filled structures or highly vascular lesions on T2-weighted sequences.
Question 17: Which of the following X-ray findings is associated with Chilaiditi syndrome?
- A. Pseudopneumoperitoneum (Correct Answer)
- B. Pseudopneumothorax
- C. Pneumothorax
- D. Hydropneumothorax
Explanation: ***Pseudopneumoperitoneum*** - Chilaiditi syndrome is characterized by the **interposition of a loop of colon (usually transverse colon) or, less commonly, small intestine** between the liver and the right hemidiaphragm. - This anatomical variation can mimic **free air under the diaphragm** on an X-ray, leading to the misdiagnosis of pneumoperitoneum. *Pseudopneumothorax* - This term describes the appearance of **air in the pleural space** that is not actually present, which is not associated with Chilaiditi syndrome. - While Chilaiditi syndrome involves misinterpretation of air, it specifically relates to the **abdominal cavity**, not the thoracic cavity. *Pneumothorax* - A **true pneumothorax** is the presence of air in the pleural cavity causing partial or complete lung collapse, which is a significant medical emergency. - It is distinct from Chilaiditi syndrome, which involves **abdominal content displacement** mimicking abdominal free air. *Hydropneumothorax* - This condition involves the presence of both **fluid and air in the pleural cavity**. - It is a pathology of the thoracic cavity and has **no direct association** with the abdominal interposition of bowel loops seen in Chilaiditi syndrome.
Question 18: Which of the following is NOT a typical ultrasonographic finding in autosomal recessive polycystic kidney disease (ARPKD)?
- A. Increased echogenicity
- B. Cysts larger than 2 cm (Correct Answer)
- C. Enlarged kidneys
- D. Corticomedullary differentiation is lost
Explanation: **Cysts larger than 2 cm** - **ARPKD** is characterized by numerous tiny cysts (typically 1-2 mm, rarely up to 1 cm) that are microscopically dilated collecting ducts, leading to diffuse renal enlargement. - Cysts larger than 2 cm are much more typical of **autosomal dominant polycystic kidney disease (ADPKD)**, which involves macroscopic cysts of various sizes. *Enlarged kidneys* - The proliferation of dilated collecting ducts and associated interstitial fibrosis in **ARPKD** leads to significantly enlarged kidneys, which is a hallmark ultrasound finding. - This enlargement is often bilateral and can be detected prenatally or in neonates. *Increased echogenicity* - The presence of numerous tiny cysts and dense fibrous tissue throughout the renal parenchyma in **ARPKD** causes increased diffuse echogenicity on ultrasound. - This is a common and important diagnostic feature, often described as "bright" or "hyperechoic" kidneys. *Corticomedullary differentiation is lost* - In **ARPKD**, the normal distinct differentiation between the renal cortex and medulla is obliterated due to the widespread involvement of the collecting ducts and the diffuse nature of the disease. - This loss of corticomedullary differentiation is a typical finding on ultrasound for severe renal parenchymal disease, including ARPKD.
Question 19: Cobra head appearance on excretory urography is suggestive of?
- A. Horseshoe kidney
- B. Duplication of renal pelvis
- C. Simple cyst of kidney
- D. Ureterocele (Correct Answer)
Explanation: ***Ureterocele*** - A **cobra head appearance** on excretory urography is a classic sign of a **ureterocele**, which is a cystic dilation of the distal ureter that protrudes into the bladder. - This appearance is due to the dilated ureter appearing like an oval or round filling defect within the bladder lumen, surrounded by a thin radiolucent halo created by the ureteral wall and urine. *Horseshoe kidney* - A horseshoe kidney is characterized by the fusion of the lower poles of the kidneys, causing a **"U" shape** across the midline, often identified by the isthmus. - It does not present with a cobra head appearance but rather a typical anatomical variation of renal position and fusion. *Duplication of renal pelvis* - Duplication of the renal pelvis involves two separate collecting systems draining one kidney, which can be seen as two distinct pelvicalyceal systems. - This condition does not create a cobra head appearance; instead, it shows an abnormal number of collecting systems within a single kidney. *Simple cyst of kidney* - A simple renal cyst typically appears as a **well-defined, anechoic (on ultrasound) or hypodense (on CT) mass** within the kidney parenchyma. - It does not involve the ureter or bladder and thus does not produce a cobra head appearance on urograms.
Question 20: Investigation of choice to evaluate intracranial hemorrhage of less than 48 hours is -
- A. CT scan (Correct Answer)
- B. MRI
- C. PET
- D. SPECT
Explanation: ***CT scan*** - **Non-contrast CT** is the most sensitive and rapid imaging modality for detecting acute intracranial hemorrhage, appearing as a **hyperdense** (bright) area within the brain parenchyma or subarachnoid space. - It is readily available in emergency settings and is crucial for immediate diagnosis to guide management, especially within the first **48 hours**. *MRI* - While MRI can detect hemorrhage, its sensitivity for **acute hemorrhage** (especially within the first few hours) is less than CT, and it is more time-consuming. - MRI is superior for detecting older hemorrhage or subtle lesions, but it is not the **first-line investigation** for acute bleeding. *PET* - **Positron Emission Tomography** (PET) scans are primarily used to assess metabolic activity and blood flow in the brain, often for conditions like cancer, epilepsy, or dementia. - It does not directly visualize fresh blood and therefore is not used for the diagnosis of **acute intracranial hemorrhage**. *SPECT* - **Single-Photon Emission Computed Tomography** (SPECT) is used to evaluate cerebral blood flow and neuronal activity, similar to PET but with different tracers and resolution. - It is not indicated for the rapid assessment of **acute intracranial hemorrhage** as it does not directly image blood.