Questions
- Which of the following best describes a ground-glass nodule (GGN)?
- A) A nodule with solid opacity obscuring bronchial structures and vessels.
- B) A focal, hazy lung opacity with visible underlying structures.
- C) A diffuse, bilateral hazy lung opacity.
- D) A sharply circumscribed nodule with no ground-glass appearance.
Answer: B) A focal, hazy lung opacity with visible underlying structures.
Comment (Correct Answer): GGNs are characterized by hazy opacities that do not obscure the underlying bronchial structures or pulmonary vessels.
“Ground-glass nodules are defined as focal, hazy opacities on CT imaging with visible underlying structures.” (Radiopaedia)Incorrect Answers:
- A) A nodule with solid opacity obscuring bronchial structures and vessels.
“This describes a solid nodule, not a GGN.” (Radiopaedia) - C) A diffuse, bilateral hazy lung opacity.
“Diffuse hazy opacities are typical of ground-glass opacities (GGO), not nodules.” (AJR) - D) A sharply circumscribed nodule with no ground-glass appearance.
“This describes a purely solid nodule, not a GGN.” (Radiology Key)
- What is the most common cause of a persistent ground-glass nodule (GGN)?
- A) Transient inflammation.
- B) Adenocarcinoma or atypical adenomatous hyperplasia (AAH).
- C) Fungal infection.
- D) Organizing pneumonia.
Answer: B) Adenocarcinoma or atypical adenomatous hyperplasia (AAH).
Comment (Correct Answer): Persistent GGNs are commonly associated with pre-malignant or malignant processes such as adenocarcinoma or AAH.
“Persistent GGNs are strongly associated with early-stage adenocarcinoma and atypical adenomatous hyperplasia.” (Radiopaedia)Incorrect Answers:
- A) Transient inflammation.
“Transient inflammation is a common cause of transient GGNs but not persistent lesions.” (Radiology Key) - C) Fungal infection.
“Fungal infections can cause GGNs but are less likely to persist without resolution.” (AJR) - D) Organizing pneumonia.
“Organizing pneumonia may present with GGOs but is typically diffuse rather than nodular.” (Radiopaedia)
- Which of the following imaging modalities is least reliable for evaluating GGNs?
- A) PET-CT.
- B) High-resolution CT (HRCT).
- C) Chest X-ray.
- D) MRI.
Answer: C) Chest X-ray.
Comment (Correct Answer): Chest X-ray lacks the resolution to reliably detect or characterize GGNs, which are better visualized on HRCT.
“Chest X-rays are insensitive for detecting ground-glass nodules due to their subtle attenuation.” (Radiopaedia)Incorrect Answers:
- A) PET-CT.
“While PET-CT may show low metabolic activity for pure GGNs, it can still help in assessing solid components.” (Radiology Key) - B) High-resolution CT (HRCT).
“HRCT is the gold standard for detecting and characterizing GGNs.” (AJR) - D) MRI.
“MRI is less commonly used but can provide adjunctive information in select cases.” (Radiopaedia)
- True or False: Persistent GGNs with new solid components should prompt consideration of PET-CT or biopsy.
- A) True.
- B) False.
Answer: A) True.
Comment (Correct Answer): The development of new solid components in a GGN is concerning for invasive adenocarcinoma and warrants further investigation, including PET-CT or biopsy.
“New solid components within a GGN suggest malignant transformation and should prompt PET-CT or biopsy.” (Radiopaedia)
- What is the Fleischner Society’s recommendation for follow-up of a pure GGN >6 mm in size?
- A) No follow-up is needed.
- B) CT at 6-12 months, then every 2 years for up to 5 years if stable.
- C) CT at 3 months to confirm persistence.
- D) Immediate biopsy.
Answer: B) CT at 6-12 months, then every 2 years for up to 5 years if stable.
Comment (Correct Answer): The Fleischner guidelines recommend follow-up CT scans for pure GGNs >6 mm to monitor for growth or development of solid components.
“Pure GGNs >6 mm should be followed with CT at 6-12 months and every 2 years for up to 5 years if stable.” (Fleischner Society)Incorrect Answers:
- A) No follow-up is needed.
“No follow-up is only recommended for GGNs ≤6 mm.” (Radiopaedia) - C) CT at 3 months to confirm persistence.
“This recommendation applies to part-solid GGNs, not pure GGNs.” (Radiology Key) - D) Immediate biopsy.
“Biopsy is reserved for nodules with concerning features or significant growth.” (AJR)
- True or False: Ground-glass nodules (GGNs) require longer follow-up compared to solid nodules if stable.
- A) True.
- B) False.
Answer: A) True.
Comment (Correct Answer): GGNs grow more slowly than solid nodules, so even stable GGNs after 2 years of follow-up may require additional monitoring to detect potential late malignant transformation.
“Unlike solid nodules, GGNs are slow-growing and may require prolonged follow-up even if stable for 2 years.” (Fleischner Society)