Question 1
What is the defining characteristic of ground-glass opacity (GGO) on CT imaging?
- A. Homogeneous high-density areas obscuring bronchial and vascular structures
- B. Hazy increased attenuation with visible underlying bronchovascular structures
- C. Reticular patterns with traction bronchiectasis
- D. Nodular opacities with cavitation
Answer: B. Hazy increased attenuation with visible underlying bronchovascular structures
Explanation: GGO is defined by increased attenuation on CT where bronchial and vascular structures remain visible, differentiating it from consolidation.
?GGOs are hazy areas of increased attenuation through which normal bronchial and vascular structures can be identified.?
Reference: Radiopaedia ? Ground-Glass Opacity.
Question 2
Which of the following conditions is most associated with the head cheese sign in lung imaging?
- A. Hypersensitivity pneumonitis
- B. Idiopathic pulmonary fibrosis
- C. Pulmonary embolism
- D. Congestive heart failure (CHF)
Answer: A. Hypersensitivity pneumonitis
Explanation: The head cheese sign, a combination of GGO, normal lung, and consolidation, is characteristic of hypersensitivity pneumonitis and reflects heterogeneous involvement.
?The head cheese sign is a hallmark finding in hypersensitivity pneumonitis, combining areas of GGO, normal lung, and consolidation.?
Reference: Radiographics ? Hypersensitivity Pneumonitis.
Question 3
How does normal expiration on CT affect lung appearance, and how does it compare to GGO?
- A. Both show increased attenuation but GGO persists independent of expiration
- B. Expiration increases vascular markings, while GGO shows sharp borders
- C. GGO and expiration both show sharp nodular opacities
- D. Expiration resolves GGO completely
Answer: A. Both show increased attenuation but GGO persists independent of expiration
Explanation: In normal expiration, lungs appear denser due to reduced air volume, but GGOs remain persistent and indicate pathology.
?GGO persists on imaging despite normal expiration, differentiating it from normal expiratory changes in lung density.?
Reference: Radiology Key ? Ground-Glass Opacities.
Question 4
Which of the following infectious conditions commonly presents with GGO on CT?
- A. Pneumocystis jirovecii pneumonia (PJP)
- B. Pulmonary tuberculosis (TB)
- C. Lung abscess
- D. Bronchiectasis
Answer: A. Pneumocystis jirovecii pneumonia (PJP)
Explanation: PJP often presents with diffuse or patchy GGO on CT, especially in immunocompromised patients.
?Diffuse ground-glass opacities are a hallmark finding in Pneumocystis jirovecii pneumonia.?
Reference: PubMed ? Pneumocystis Pneumonia Imaging.
Question 5
Which pulmonary condition is characterized by basal and peripheral GGO with subpleural sparing on CT?
- A. Cryptogenic organizing pneumonia (COP)
- B. Nonspecific interstitial pneumonia (NSIP)
- C. Acute respiratory distress syndrome (ARDS)
- D. Adenocarcinoma in situ (AIS)
Answer: B. Nonspecific interstitial pneumonia (NSIP)
Explanation: NSIP commonly shows basal and peripheral GGO, with subpleural sparing differentiating it from other interstitial lung diseases.
?Basal-predominant GGOs with subpleural sparing are characteristic of nonspecific interstitial pneumonia.?
Reference: Radiopaedia ? NSIP.
Question 6
What pattern is frequently associated with GGO in conditions like ARDS or PJP?
- A. Reticular opacities
- B. Nodular changes
- C. Crazy paving pattern
- D. Centrilobular nodules
Answer: C. Crazy paving pattern
Explanation: The crazy paving pattern combines GGO with superimposed interlobular septal thickening and is seen in conditions like ARDS and PJP.
?Crazy paving, characterized by septal thickening over ground-glass opacities, is a hallmark in ARDS and PJP.?
Reference: Radiographics ? Crazy Paving Pattern.
Question 7
Which of the following drugs is associated with GGO due to drug-induced lung injury?
- A. Amiodarone
- B. Aspirin
- C. Azithromycin
- D. Prednisone
Answer: A. Amiodarone
Explanation: Amiodarone-induced lung injury commonly presents with GGO, reflecting alveolar or interstitial damage.
?Amiodarone toxicity typically presents with diffuse or patchy GGOs on HRCT.?
Reference: Radiopaedia ? Amiodarone Lung Toxicity.
Question 8
Which radiological finding distinguishes GGO from consolidation on CT?
- A. Presence of air bronchograms
- B. Visibility of underlying bronchial and vascular structures
- C. Sharply demarcated margins
- D. Diffuse high attenuation without texture changes
Answer: B. Visibility of underlying bronchial and vascular structures
Explanation: GGO preserves the visibility of bronchial and vascular structures, unlike consolidation, which obscures them completely.
?Ground-glass opacity is defined by hazy attenuation with preserved lung architecture.?
Reference: Fleischner Society ? Imaging Guidelines.
Question 9
Which of the following diseases can show the head cheese sign on CT?
- A. Sarcoidosis
- B. Hypersensitivity pneumonitis (HP)
- C. Pulmonary embolism (PE)
- D. Congestive heart failure (CHF)
Answer: B. Hypersensitivity pneumonitis (HP)
Explanation: The head cheese sign combines GGO, normal lung, and areas of consolidation, seen in hypersensitivity pneumonitis.
?The head cheese sign reflects heterogeneous involvement with GGO, normal lung, and consolidation, often seen in hypersensitivity pneumonitis.?
Reference: Radiopaedia ? Head Cheese Sign.
Question 10
What is the most likely underlying cause of peripheral GGOs seen in viral pneumonia?
- A. Septal thickening due to CHF
- B. Alveolar filling with inflammatory cells
- C. Fibrosis due to chronic lung disease
- D. Airway obstruction due to mucus plugging
Answer: B. Alveolar filling with inflammatory cells
Explanation: Peripheral GGOs in viral pneumonia result from partial alveolar filling due to inflammation and edema.
?Peripheral ground-glass opacities are typical of viral pneumonias and reflect inflammatory cell infiltration.?
Reference: Radiology Key ? Viral Pneumonia.