(L1) Which of the following best describes a pulmonary nodule?
A) A focal opacity measuring over 3 cm in diameter.
B) A rounded or irregular opacity measuring up to 3 cm in diameter.
C) A focal opacity involving the pleura.
D) A cavitating lesion measuring more than 3 cm in diameter. Answer: B) A rounded or irregular opacity measuring up to 3 cm in diameter. Comment: Pulmonary nodules are defined as focal opacities in the lung parenchyma measuring up to 3 cm. Larger lesions are classified as masses. “A pulmonary nodule is a focal, rounded, or irregular opacity up to 3 cm in size.” (Radiopaedia) Incorrect Answers:
A) A focal opacity measuring over 3 cm in diameter. “Lesions over 3 cm are classified as masses.” (Fleischner Guidelines)
C) A focal opacity involving the pleura. “Pleural-based lesions are not classified as pulmonary nodules.” (Radiology Key)
D) A cavitating lesion measuring more than 3 cm in diameter. “Cavitating lesions over 3 cm are classified as masses.” (Radiographics)
(L1) Which type of nodule is most likely associated with lymphatic spread? (More than one answer may be correct)
A) Centrilobular nodules.
B) Randomly distributed nodules.
C) Nodules in the interlobular septum.
D) Cavitating nodules. Answer: A) Centrilobular nodules, C) Nodules in the interlobular septum. Comment: Both centrilobular nodules and nodules in the interlobular septum can be associated with lymphatic spread. Centrilobular nodules are located along the small airways, which are often accompanied by lymphatic vessels. Nodules in the interlobular septum are more directly associated with lymphatic involvement, as seen in lymphangitic carcinomatosis or sarcoidosis. “Centrilobular nodules and interlobular septal nodules are both associated with lymphatic spread, reflecting their proximity to lymphatic pathways.” (Radiopaedia) Incorrect Answers:
B) Randomly distributed nodules. “Random nodules suggest hematogenous dissemination.” (Radiopaedia)
D) Cavitating nodules. “Cavitating nodules are usually associated with necrotizing infections or malignancies, not lymphatic spread.” (Radiology Key)
(L1) Which nodules calcify?
A) Granuloma.
B) Hamartoma.
C) Rheumatoid nodule.
D) Pulmonary infarct. Answer: A) Granuloma, B) Hamartoma. Comment: Granulomas and hamartomas are both commonly associated with calcifications. Granulomas, representing the majority of benign pulmonary nodules (80-90%), calcify in about 10-15% of cases due to healed infections like tuberculosis or histoplasmosis. Hamartomas, while less common (8% of benign nodules), demonstrate calcifications more frequently (15-30%) often in a characteristic “popcorn” pattern. “Granulomas and hamartomas are the most common calcifying benign nodules, with hamartomas showing a higher frequency of calcifications.” (Radiopaedia) Incorrect Answers:
C) Rheumatoid nodule. “Rheumatoid nodules are rare and typically not associated with calcifications.” (AJR)
D) Pulmonary infarct. “Pulmonary infarcts are not commonly associated with calcifications in benign contexts.” (Radiology Key)
(L1) True or False: Ground-glass nodules (GGNs) typically grow faster than solid nodules.
A) True.
B) False. Answer: B) False. Comment: GGNs grow more slowly than solid nodules, often necessitating longer follow-up intervals to monitor for malignancy. “GGNs grow more slowly than solid nodules and require prolonged follow-up.” (Fleischner Society Guidelines)
(L1) Which imaging modality is the most sensitive for detecting pulmonary nodules?
A) Chest X-ray.
B) Low-dose CT.
C) PET-CT.
D) MRI. Answer: B) Low-dose CT. Comment: Low-dose CT is the most sensitive imaging modality for detecting pulmonary nodules, especially small ones. “CT, particularly low-dose CT, is highly sensitive for nodule detection.” (Radiopaedia) Incorrect Answers:
A) Chest X-ray. “Chest X-rays often miss small nodules, especially those less than 5 mm.” (AJR)
C) PET-CT. “PET-CT is used for metabolic assessment rather than initial detection.” (Radiology Key)
D) MRI. “MRI is not routinely used for detecting pulmonary nodules.” (Radiopaedia)
(L2) According to the Fleischner Society guidelines, how should a solitary solid lung nodule measuring 7 mm in a low-risk patient be managed?
A) No follow-up required.
B) CT at 3 months.
C) CT at 6-12 months, then at 18-24 months if stable.
D) Immediate biopsy. Answer: C) CT at 6-12 months, then at 18-24 months if stable. Comment: The Fleischner guidelines recommend follow-up for solitary solid nodules between 6-8 mm with CT at 6-12 months, and an additional scan at 18-24 months if stable, even for low-risk patients. This ensures monitoring for potential growth or malignancy. “Nodules >6 mm in low-risk patients require serial CT follow-up.” (Fleischner Society Guidelines) Incorrect Answers:
A) No follow-up required. “Nodules >6 mm require follow-up to assess stability or growth.” (Radiopaedia)
B) CT at 3 months. “CT at 3 months is typically reserved for part-solid nodules to confirm persistence.” (Radiology Key)
D) Immediate biopsy. “Biopsy is indicated for nodules with concerning features or significant growth.” (AJR)
(L2) Which of the following features are suggestive of a malignant nodule? (Select all that apply)
A) Irregular or spiculated margins.
B) Doubling time between 20-400 days.
C) Presence of fat within the nodule.
D) Central calcification. Answer: A) Irregular or spiculated margins, B) Doubling time between 20-400 days. Comment: Irregular or spiculated margins and a doubling time between 20-400 days are both suggestive of malignancy. Spiculated margins indicate invasive growth, and rapid doubling time within this range strongly correlates with malignancy. “Irregular or spiculated margins and rapid growth are classic features of malignant nodules.” (Radiopaedia) Incorrect Answers:
C) Presence of fat within the nodule. “Fat within a nodule is characteristic of benign hamartomas.” (Radiology Key)
D) Central calcification. “Central calcification is commonly associated with benign granulomas.” (AJR)
(L2) Which nodule distribution pattern most suggests hematogenous spread?
A) Random.
B) Centrilobular.
C) Interlobular septal.
D) Subpleural. Answer: A) Random. Comment: Randomly distributed nodules are typically associated with hematogenous dissemination, as seen in metastatic disease or miliary tuberculosis. “Hematogenous spread often results in a random distribution of nodules.” (Radiopaedia) Incorrect Answers:
B) Centrilobular. “Centrilobular nodules are more indicative of airway diseases.” (AJR)
C) Interlobular septal. “Interlobular septal nodules are associated with lymphatic involvement.” (Radiology Key)
D) Subpleural. “Subpleural nodules are often seen in inflammatory or pleural-based conditions.” (Radiopaedia)
(L2) True or False: All ground-glass nodules (GGNs) require biopsy.
A) True.
B) False. Answer: B) False. Comment: Not all GGNs require biopsy. Persistent GGNs >6 mm with new solid components are more concerning and warrant further investigation. “Biopsy is typically reserved for GGNs with concerning features or growth.” (Fleischner Society Guidelines)
(L2) What characteristic features are associated with a hamartoma? (Select all that apply)
A) Spiculated margins.
B) Popcorn calcifications.
C) Ground-glass opacity.
D) Central necrosis. Answer: B) Popcorn calcifications. Comment: Hamartomas often display “popcorn” calcifications, a distinguishing feature among benign nodules. “Popcorn calcifications are characteristic of hamartomas.” (Radiopaedia) Incorrect Answers:
A) Spiculated margins. “Spiculated margins are more indicative of malignant nodules.” (AJR)
C) Ground-glass opacity. “Ground-glass opacities are often seen in adenocarcinoma or inflammatory conditions.” (Radiology Key)
D) Central necrosis. “Central necrosis is more commonly associated with malignant or infectious processes.” (Radiopaedia)
