Here is a set of multiple-choice questions (MCQs) based on the TCV definition of Pulmonary Embolism (PE), integrating insights from reputable sources.
Question 1:
What is the most common cause of a pulmonary embolism (PE)?
A. Amniotic fluid embolism
B. Air embolism
C. Fat embolism
D. Deep vein thrombosis (DVT)
Correct Answer: D. Deep vein thrombosis (DVT)
Reference: The majority of PEs originate from thrombi in the deep veins of the lower extremities. (Radiopaedia)
Question 2:
Which of the following is an abnormal finding indicating significant right heart strain in pulmonary embolism?
A. Reflux of contrast into the inferior vena cava (IVC)
B. Reflux of contrast into hepatic veins
C. Bowing of the interventricular septum toward the right ventricle
D. Azygos vein size less than 7 mm
Correct Answer: B. Reflux of contrast into hepatic veins
Reference: Reflux into the hepatic veins is abnormal and indicates elevated right-sided pressures. (Fleischner Society Glossary)
Question 3:
Which of the following imaging findings is most characteristic of acute pulmonary embolism?
A. Eccentric filling defects with vessel wall thickening
B. Central filling defects with vessel enlargement
C. Calcified thrombi in pulmonary arteries
D. Wedge-shaped subpleural opacity
Correct Answer: B. Central filling defects with vessel enlargement
Reference: Acute emboli typically present as central filling defects, often with vessel dilation, on CT pulmonary angiography. (Radiopaedia)
Question 4:
What does the “feeding vessel” sign in pulmonary embolism indicate?
A. Thrombus occlusion in the main pulmonary artery
B. A vessel leading to a lesion, suggesting embolism or vascular abnormality
C. Recanalization of a chronic embolus
D. Peribronchial thickening from inflammatory processes
Correct Answer: B. A vessel leading to a lesion, suggesting embolism or vascular abnormality
Reference: The feeding vessel sign is seen as a prominent vessel leading to an affected lung region, indicating embolism.
Question 5:
What is the role of dual-energy CT in the evaluation of pulmonary embolism?
A. Identifying perfusion defects with iodine maps
B. Measuring right ventricular wall thickness
C. Detecting chronic thromboembolic pulmonary hypertension (CTEPH)
D. Visualizing small peripheral emboli directly
Correct Answer: A. Identifying perfusion defects with iodine maps
Reference: Dual-energy CT with iodine maps identifies areas of reduced perfusion, complementing standard CTPA findings. (Fleischner Society Glossary)
Question 6:
Which of the following features helps distinguish chronic pulmonary embolism from acute pulmonary embolism?
A. Vessel enlargement and sharply demarcated filling defects
B. Calcification of thrombi and web-like structures in pulmonary arteries
C. Reflux of contrast into hepatic veins
D. Ground-glass opacity on CT
Correct Answer: B. Calcification of thrombi and web-like structures in pulmonary arteries
Reference: Chronic PE is characterized by fibrotic or calcified thrombi and web-like intravascular structures. (Radiopaedia)
Question 7:
What are the primary sources of oxygenation in the lungs, relevant to pulmonary infarction?
A. Pulmonary veins and arteries
B. Alveoli, pulmonary arteries, and bronchial arteries
C. Pulmonary capillaries and venules
D. Systemic arteries and lymphatic vessels
Correct Answer: B. Alveoli, pulmonary arteries, and bronchial arteries
Reference: The lung?s dual blood supply reduces the risk of infarction unless collateral flow is compromised. (Radiopaedia)
Question 8:
What imaging feature on CT pulmonary angiography (CTPA) suggests right heart strain?
A. RV/LV ratio >1
B. Thickening of pulmonary artery walls
C. Ground-glass opacity in peripheral lung zones
D. Pleural effusion without vascular findings
Correct Answer: A. RV/LV ratio >1
Reference: Right ventricular dilation with an RV/LV ratio >1 is a classic sign of right heart strain in PE. (Fleischner Society Glossary)
Question 9:
What is the clinical significance of occlusive vs. non-occlusive emboli?
A. Non-occlusive emboli do not require treatment.
B. Occlusive emboli are more likely to cause severe perfusion defects and hemodynamic instability.
C. Non-occlusive emboli are more likely to result in infarction.
D. Occlusive emboli always lead to pulmonary infarction.
Correct Answer: B. Occlusive emboli are more likely to cause severe perfusion defects and hemodynamic instability.
Reference: Occlusive thrombi completely block the vessel lumen, causing more severe consequences. (RadiologyKey)
Question 10:
Which of the following is a hallmark finding on chest X-ray (CXR) in pulmonary embolism?
A. Normal appearance
B. Hampton hump (wedge-shaped opacity)
C. Bilateral pleural effusions
D. Central mediastinal widening
Correct Answer: B. Hampton hump (wedge-shaped opacity)
Reference: The Hampton hump is a classic but uncommon finding, representing infarction in PE. (Radiopaedia)
Question 11:
Which imaging modality is preferred for diagnosing pulmonary embolism in a pregnant patient with a normal chest X-ray?
A. CT Pulmonary Angiography (CTPA)
B. Doppler ultrasound of the lower extremities
C. V/Q scan
D. MRI
Correct Answer: C. V/Q scan
Reference: According to the Fleischner Society and Radiopaedia, V/Q scans are favored in pregnancy when the chest X-ray is normal because they deliver lower radiation doses to maternal breast tissue compared to CTPA.
Question 12:
What is the approximate fetal radiation dose from a V/Q scan in pregnancy?
A. <0.1 mSv
B. 0.1?0.3 mSv
C. 1.0 mSv
D. >4 mSv
Correct Answer: B. 0.1?0.3 mSv
Reference: Radiology literature, including Radiopaedia, estimates the fetal dose from V/Q scans in pregnancy at approximately 0.1?0.3 mSv, slightly higher than CTPA but within safe limits.
Question 13:
Which of the following findings on a V/Q scan is most specific for pulmonary embolism?
A. Matched defects
B. Mismatched defects
C. Diffuse ground-glass opacity
D. Bilateral pleural effusion
Correct Answer: B. Mismatched defects
Reference: The Fleischner Society Glossary describes mismatched defects (normal ventilation with perfusion defects) as the hallmark feature of pulmonary embolism on a V/Q scan.
Question 14:
Which imaging finding is consistent with fat embolism?
A. Central filling defects in the pulmonary arteries
B. Cavitation in peripheral nodules
C. Diffuse ground-glass opacities and interlobular septal thickening
D. Wedge-shaped pleural-based opacity
Correct Answer: C. Diffuse ground-glass opacities and interlobular septal thickening
Reference: Fat embolism syndrome affects small vessels, producing diffuse ground-glass opacities and interlobular septal thickening, as highlighted in Radiopaedia?s articles on non-thrombotic pulmonary embolism.
Question 15:
Why is V/Q scan preferred over CTPA for pulmonary embolism in pregnancy?
A. Lower fetal radiation dose
B. Avoids iodinated contrast and reduces maternal breast radiation
C. Higher sensitivity and specificity
D. Faster and requires no preparation
Correct Answer: B. Avoids iodinated contrast and reduces maternal breast radiation
Reference: V/Q scan is preferred in pregnancy due to its lower radiation dose to breast tissue and avoidance of iodinated contrast, as noted in RadiologyKey and Radiopaedia.
Question 16:
What distinguishes a paradoxical embolus in pulmonary embolism?
A. Thrombus bypasses the pulmonary circulation through a right-to-left shunt
B. It involves fat emboli from long bone fractures
C. It originates from septic foci in the body
D. It occurs in the absence of predisposing factors
Correct Answer: A. Thrombus bypasses the pulmonary circulation through a right-to-left shunt
Reference: A paradoxical embolus occurs when elevated right-sided pressures allow a venous thrombus to bypass the lungs via a patent foramen ovale or atrial septal defect, as explained by the Fleischner Society Glossary.
Question 17:
Which is true about septic emboli in pulmonary embolism?
A. They commonly involve the central pulmonary arteries.
B. They do not cause cavitation.
C. They may cavitate and present with peripheral nodules.
D. They appear as diffuse ground-glass opacities on CT.
Correct Answer: C. They may cavitate and present with peripheral nodules.
Reference: Radiopaedia notes that septic emboli often cavitate, particularly in the peripheral lung regions, and may lead to abscess formation.
Question 18:
What is the recommended imaging sequence for diagnosing pulmonary embolism in a pregnant patient with a contraindication to iodinated contrast?
A. CTPA followed by Doppler ultrasound
B. V/Q scan followed by MRI
C. Doppler ultrasound followed by V/Q scan
D. Echocardiography followed by V/Q scan
Correct Answer: C. Doppler ultrasound followed by V/Q scan
Reference: The Fleischner Society and Radiopaedia recommend Doppler ultrasound first to detect DVT. If positive, anticoagulation therapy can be initiated, followed by V/Q scan if further confirmation is needed.
Question 19:
What is the primary benefit of dual-energy CT with iodine maps in evaluating pulmonary embolism?
A. Reduces radiation exposure
B. Detects small subsegmental emboli
C. Identifies regional perfusion defects
D. Avoids contrast administration
Correct Answer: C. Identifies regional perfusion defects
Reference: According to RadiologyKey, dual-energy CT with iodine maps highlights areas of perfusion deficit, aiding in the evaluation of PE when standard CTPA findings are equivocal.
Question 20:
Which finding on CTPA is most indicative of acute right heart strain due to pulmonary embolism?
A. Calcifications in pulmonary arteries
B. Bowing or straightening of the interventricular septum toward the left ventricle
C. Enlargement of the azygos vein without reflux
D. Normal RV/LV ratio
Correct Answer: B. Bowing or straightening of the interventricular septum toward the left ventricle
Reference: Fleischner Society guidelines describe septal bowing or straightening as a classic indicator of acute right heart strain secondary to increased pulmonary pressures.
Question 11:
What is the initial imaging modality preferred for diagnosing pulmonary embolism in a pregnant patient?
A. CT Pulmonary Angiography (CTPA)
B. Doppler ultrasound of the lower extremities
C. V/Q scan
D. MRI
Correct Answer: B. Doppler ultrasound of the lower extremities
Reference: Doppler ultrasound is the first test for suspected PE in pregnancy as it avoids radiation. If positive for DVT, anticoagulation can start without further imaging. (Radiopaedia)
Question 12:
What is the approximate fetal radiation dose from a V/Q scan in pregnancy?
A. <0.1 mSv
B. 0.1?0.3 mSv
C. 1.0 mSv
D. >4 mSv
Correct Answer: B. 0.1?0.3 mSv
Reference: The fetal radiation dose for a V/Q scan is slightly higher than CTPA but remains within safe limits. (Radiopaedia)
Question 13:
Which of the following findings on a V/Q scan is most specific for pulmonary embolism?
A. Matched defects
B. Mismatched defects
C. Diffuse ground-glass opacity
D. Bilateral pleural effusion
Correct Answer: B. Mismatched defects
Reference: Mismatched defects (normal ventilation with perfusion defects) are highly indicative of pulmonary embolism. (Fleischner Society Glossary)
Question 14:
Which imaging finding is consistent with fat embolism?
A. Central filling defects in the pulmonary arteries
B. Cavitation in peripheral nodules
C. Diffuse ground-glass opacities and interlobular septal thickening
D. Wedge-shaped pleural-based opacity
Correct Answer: C. Diffuse ground-glass opacities and interlobular septal thickening
Reference: Fat embolism affects small vessels and presents as diffuse ground-glass opacities on CT. (Radiopaedia)
Question 15:
Why is V/Q scan preferred over CTPA for pulmonary embolism in pregnancy?
A. Lower fetal radiation dose
B. Avoids iodinated contrast and reduces maternal breast radiation
C. Higher sensitivity and specificity
D. Faster and requires no preparation
Correct Answer: B. Avoids iodinated contrast and reduces maternal breast radiation
Reference: V/Q scan minimizes breast radiation exposure and avoids iodinated contrast, which may affect the fetal thyroid. (Radiopaedia)
Question 16:
What distinguishes a paradoxical embolus in pulmonary embolism?
A. Thrombus bypasses the pulmonary circulation through a right-to-left shunt
B. It involves fat emboli from long bone fractures
C. It originates from septic foci in the body
D. It occurs in the absence of predisposing factors
Correct Answer: A. Thrombus bypasses the pulmonary circulation through a right-to-left shunt
Reference: Paradoxical emboli bypass the pulmonary circulation via a patent foramen ovale or atrial septal defect. (Fleischner Society Glossary)
Question 17:
Which is true about septic emboli in pulmonary embolism?
A. They commonly involve the central pulmonary arteries.
B. They do not cause cavitation.
C. They may cavitate and present with peripheral nodules.
D. They appear as diffuse ground-glass opacities on CT.
Correct Answer: C. They may cavitate and present with peripheral nodules.
Reference: Septic emboli often cavitate and are associated with abscess formation. (Radiopaedia)
Question 18:
What is the recommended imaging sequence for diagnosing pulmonary embolism in a pregnant patient with a contraindication to iodinated contrast?
A. CTPA followed by Doppler ultrasound
B. V/Q scan followed by MRI
C. Doppler ultrasound followed by V/Q scan
D. Echocardiography followed by V/Q scan
Correct Answer: C. Doppler ultrasound followed by V/Q scan
Reference: Doppler ultrasound is a safe first-line test. If positive, anticoagulation can start, with a V/Q scan as a secondary test if needed. (Fleischner Society Glossary)
Question 19:
What is the primary benefit of dual-energy CT with iodine maps in evaluating pulmonary embolism?
A. Reduces radiation exposure
B. Detects small subsegmental emboli
C. Identifies regional perfusion defects
D. Avoids contrast administration
Correct Answer: C. Identifies regional perfusion defects
Reference: Dual-energy CT provides iodine maps for regional perfusion evaluation, supplementing standard CTPA. (RadiologyKey)
Question 20:
Which finding on CTPA is most indicative of acute right heart strain due to pulmonary embolism?
A. Calcifications in pulmonary arteries
B. Bowing or straightening of the interventricular septum toward the left ventricle
C. Enlargement of the azygos vein without reflux
D. Normal RV/LV ratio
Correct Answer: B. Bowing or straightening of the interventricular septum toward the left ventricle
Reference: Bowing of the interventricular septum is a key sign of acute right heart strain. (Fleischner Society Glossary)