Question 1
Which of the following best describes a “geographic pattern” in lung imaging?
- A. Uniformly distributed abnormalities throughout the lung fields
- B. Sharply demarcated areas of differing attenuation resembling a map
- C. Diffuse ground-glass opacities without clear borders
- D. Nodules randomly distributed across all lung zones
Answer: B. Sharply demarcated areas of differing attenuation resembling a map
Explanation: Geographic patterns are characterized by sharply demarcated areas of abnormal attenuation or density, often reflecting regional variations in pathology.
?Geographic patterns refer to sharply defined areas of lung involvement, often resembling a map-like distribution.?
Reference: Radiopaedia ? Geographic Patterns.
Question 2
Which imaging finding is most commonly associated with mosaic attenuation in geographic patterns?
- A. Reticular opacities
- B. Consolidation
- C. Perfusion defects from vascular diseases
- D. Nodular opacities
Answer: C. Perfusion defects from vascular diseases
Explanation: Mosaic attenuation typically reflects regional perfusion or ventilation abnormalities and is a hallmark of vascular or small airways diseases.
?Mosaic attenuation on HRCT is often caused by regional variations in perfusion or ventilation.?
Reference: Radiopaedia ? Mosaic Attenuation.
Question 3
Which disease commonly presents with geographic patterns of patchy consolidation on imaging?
- A. Sarcoidosis
- B. Organizing Pneumonia
- C. Lymphangioleiomyomatosis (LAM)
- D. Pulmonary Langerhans Cell Histiocytosis (PLCH)
Answer: B. Organizing Pneumonia
Explanation: Organizing pneumonia often presents as patchy areas of consolidation with sharp demarcation, forming a geographic pattern.
?Patchy, sharply defined consolidation is a typical feature of organizing pneumonia.?
Reference: Radiographics ? Organizing Pneumonia.
Question 4
In which condition would you most likely find geographic changes with mosaic attenuation?
- A. Pulmonary embolism
- B. Idiopathic pulmonary fibrosis (IPF)
- C. Asbestosis
- D. Hypersensitivity pneumonitis (HP)
Answer: D. Hypersensitivity pneumonitis (HP)
Explanation: Mosaic attenuation due to air trapping and regional perfusion variations is commonly seen in hypersensitivity pneumonitis.
?Hypersensitivity pneumonitis frequently demonstrates mosaic attenuation with geographic patterns due to air trapping.?
Reference: Fleischner Society ? Hypersensitivity Pneumonitis Guidelines.
Question 5
Which of the following features is NOT associated with geographic patterns in lung imaging?
- A. Sharp demarcation of affected areas
- B. Map-like distribution of lung abnormalities
- C. Diffuse homogenous opacity throughout the lungs
- D. Patchy areas of consolidation or ground-glass opacities
Answer: C. Diffuse homogenous opacity throughout the lungs
Explanation: Geographic patterns involve patchy, sharply demarcated abnormalities rather than diffuse, homogenous changes.
?Geographic patterns are characterized by sharp contrasts between affected and unaffected regions, unlike diffuse homogenous changes.?
Reference: Radiopaedia ? Geographic Patterns.