Level 1 Questions (Basic Knowledge)

L1 Question 1: What is the size range of a Solitary Pulmonary Nodule (SPN)?

a) <3 mm
b) 3 mm to 30 mm
c) >30 mm
d) Any size
e) None of the above

Answer: b) 3 mm to 30 mm

Comment (Correct Answer):
SPNs are defined as discrete, round, or oval lesions measuring between 3 mm and 30 mm in size. This specific size range is crucial for distinguishing SPNs from micronodules (<3 mm) and masses (>30 mm).
“Nodules are defined as rounded or irregular opacities, well or poorly defined, measuring up to 3 cm in diameter. Lesions greater than 3 cm are masses.” (Fleischner Society Guidelines)

Incorrect Answers:

• a) <3 mm:
  “Lesions smaller than 3 mm are classified as micronodules and are not considered SPNs.” (Radiopaedia)
• c) >30 mm:
  “Lesions larger than 30 mm are classified as masses rather than nodules.” (Radiographics)
• d) Any size:
  “SPNs have a specific size range of 3 mm to 30 mm, making this option incorrect.” (Fleischner Society Guidelines)
• e) None of the above:
  “Option b correctly describes the size range of SPNs.” (Radiopaedia)

L1 Question 2: Which of the following is NOT a common characteristic of an SPN?

a) Surrounding normal lung parenchyma
b) Associated lymphadenopathy
c) No pleural effusion
d) Discrete round or oval lesion
e) Calcified margins

Answer: b) Associated lymphadenopathy

Comment (Correct Answer):
SPNs are characterized by their isolation within normal lung parenchyma and lack of systemic features such as lymphadenopathy, pleural effusion, or other adjacent abnormalities. Presence of lymphadenopathy suggests malignancy or systemic disease, excluding the lesion from being classified as an SPN.
“By definition, solitary pulmonary nodules are isolated and lack mediastinal adenopathy or pleural effusion.” (Fleischner Society Guidelines)

Incorrect Answers:

• a) Surrounding normal lung parenchyma:
  “SPNs are defined as discrete, well-circumscribed lesions surrounded by normal lung parenchyma.” (Radiopaedia)
• c) No pleural effusion:
  “Absence of pleural effusion is a hallmark feature of SPNs, differentiating them from advanced disease.” (Radiopaedia)
• d) Discrete round or oval lesion:
  “SPNs are typically round or oval, with well-defined or slightly irregular margins.” (Radiopaedia)
• e) Calcified margins:
  “Calcifications, especially central or laminated types, can be seen in benign SPNs.” (Radiopaedia)

L1 Question 3: Which calcification pattern is most suggestive of malignancy in SPNs?

a) Central/popcorn
b) Eccentric/stippled
c) Diffuse
d) Lamellated
e) None of the above

Answer: b) Eccentric/stippled

Comment (Correct Answer):
Eccentric or stippled calcifications are highly suspicious for malignancy, as they indicate uneven growth and potential infiltration of surrounding tissue.
“Eccentric or stippled calcifications are highly suspicious for malignancy.” (Radiographics)

Incorrect Answers:

• a) Central/popcorn:
  “Central or popcorn calcifications are typically associated with benign lesions such as hamartomas.” (Radiopaedia)
• c) Diffuse:
  “Diffuse calcifications suggest benignity, often due to granulomas.” (Radiopaedia)
• d) Lamellated:
  “Lamellated calcifications are usually benign and associated with healed granulomas.” (Radiographics)
• e) None of the above:
  “Option b correctly identifies a malignancy-associated calcification pattern.” (Fleischner Society Guidelines)

L1 Question 4: Single ground-glass nodule (GGN) greater than 3 mm and less than 3 cm with well-defined borders is classified as:

a) Masses
b) Micronodules
c) Single Pulmonary Nodules (SPNs)
d) Benign nodules
e) Tumors

Answer: c) Single Pulmonary Nodules (SPNs)

Comment (Correct Answer):
GGNs greater than 3 mm with well-defined borders and measuring less than 3 cm are classified as SPNs if solitary and not associated with lymphadenopathy, effusion, or other abnormalities. This distinction allows for appropriate risk stratification and management.
“GGNs greater than 3 mm with well-defined borders are classified as SPNs if solitary and not associated with other abnormalities.” (Fleischner Society Guidelines)

Incorrect Answers:

• a) Masses:
  “Masses are lesions larger than 30 mm.” (Radiopaedia)
• b) Micronodules:
  “Micronodules are defined as lesions smaller than 3 mm.” (Radiopaedia)
• d) Benign nodules:
  “The term does not inherently classify nodules as benign.” (Radiopaedia)
• e) Tumors:
  “Tumors are not a direct classification of GGNs or SPNs.” (Radiopaedia)

L2 Question 5: What is the Fleischner Society recommendation for follow-up of a 6-8 mm solid SPN in a low-risk patient?

a) No follow-up required
b) Follow-up CT at 6-12 months
c) Immediate PET/CT
d) Biopsy
e) Annual surveillance for 5 years

Answer: b) Follow-up CT at 6-12 months

Comment (Correct Answer):
For solid SPNs measuring 6-8 mm in low-risk patients, the Fleischner Society recommends a follow-up CT at 6-12 months, and additional imaging at 18-24 months if no growth is observed.
“Solid nodules 6-8 mm in low-risk patients require follow-up CT at 6-12 months, then optional CT at 18-24 months.” (Fleischner Society Guidelines)

Incorrect Answers:

• a) No follow-up required:
  “Nodules greater than 6 mm require surveillance imaging in both low- and high-risk individuals.” (Radiopaedia)
• c) Immediate PET/CT:
  “PET/CT is typically reserved for nodules greater than 8 mm or those with a high pretest probability of malignancy.” (Radiopaedia)
• d) Biopsy:
  “Biopsy is usually considered for SPNs with concerning growth patterns or malignancy features on imaging.” (Radiographics)
• e) Annual surveillance for 5 years:
  “Annual surveillance is appropriate for subsolid nodules, not for solid SPNs in this size range.” (Fleischner Society Guidelines)

L2 Question 6: What is the next step in management for a subsolid nodule >6 mm?

a) Biopsy immediately
b) Follow-up CT at 6-12 months, then annually for 5 years
c) Perform PET/CT
d) Ignore the nodule as benign
e) Perform MRI

Answer: b) Follow-up CT at 6-12 months, then annually for 5 years

Comment (Correct Answer):
Subsolid nodules >6 mm require close monitoring to detect slow malignant transformation. Follow-up involves imaging at 6-12 months and annual CT scans for at least 5 years.
“Subsolid nodules greater than 6 mm necessitate follow-up imaging at regular intervals for 5 years.” (Fleischner Society Guidelines)

Incorrect Answers:

• a) Biopsy immediately:
  “Immediate biopsy is not indicated for subsolid nodules unless there is substantial evidence of malignancy.” (Radiopaedia)
• c) Perform PET/CT:
  “PET/CT is less reliable in subsolid nodules due to their low metabolic activity.” (Radiographics)
• d) Ignore the nodule as benign:
  “Ignoring subsolid nodules is inappropriate as they carry a higher risk of malignancy over time.” (Radiopaedia)
• e) Perform MRI:
  “MRI is not a standard modality for evaluating pulmonary nodules.” (Radiopaedia)

Level 2 Question 7: Which of the following features can differentiate pseudocavitation from true cavitation in an SPN?

a) Presence of thick walls in the cavity
b) Multiple small lucencies without thick walls
c) Association with adenocarcinoma
d) Smooth, uniform cavity margins
e) Central necrosis with air-fluid levels

Answer: b) Multiple small lucencies without thick walls and c) Association with adenocarcinoma

Comment (Correct Answer):
Pseudocavitation refers to small lucencies within a nodule, typically associated with adenocarcinoma, and does not involve thick walls. In contrast, true cavitation, often seen in squamous cell carcinoma, shows thicker walls and may feature air-fluid levels.
“Pseudocavitation is often associated with adenocarcinoma and appears as small lucencies within the nodule.” (Radiopaedia)
“True cavitation typically shows thick walls and is more characteristic of squamous cell carcinoma.” (Radiographics)

Incorrect Answers:

• a) Presence of thick walls in the cavity:
  “Thick-walled cavities are associated with true cavitation, not pseudocavitation.” (Radiographics)
• d) Smooth, uniform cavity margins:
  “Smooth cavity margins are not characteristic of pseudocavitation or true cavitation in malignancies.” (Radiopaedia)
• e) Central necrosis with air-fluid levels:
  “Air-fluid levels and central necrosis are hallmarks of true cavitation, often seen in infections or squamous cell carcinoma.” (Radiopaedia)

Level 2 Question 8: Which density and enhancement characteristics help differentiate benign from malignant SPNs?

a) Low attenuation on CT (<15 Hounsfield units)
b) Peripheral enhancement on contrast CT
c) Lack of enhancement on contrast CT
d) Central necrosis with irregular enhancement
e) Uniform enhancement >20 Hounsfield units

Answer: a) Low attenuation on CT (<15 Hounsfield units) and e) Uniform enhancement >20 Hounsfield units

Comment (Correct Answer):
Low attenuation on CT (<15 Hounsfield units) is indicative of benign lesions such as hamartomas. Uniform enhancement >20 Hounsfield units suggests malignancy due to vascularity.
“Low attenuation suggests benignity, particularly in fat-containing nodules like hamartomas.” (Radiopaedia)
“Enhancement >20 HU often indicates malignancy, reflecting increased vascular supply.” (Radiographics)

Incorrect Answers:

• b) Peripheral enhancement on contrast CT:
  “Peripheral enhancement is more typical of infectious processes or abscesses.” (Radiopaedia)
• c) Lack of enhancement on contrast CT:
  “Lack of enhancement can be seen in benign fibrotic or calcified nodules.” (Radiographics)
• d) Central necrosis with irregular enhancement:
  “Central necrosis and irregular enhancement are features of advanced malignancy or infections.” (Radiopaedia)

• Level 2 Question 9: Match the following diseases with their characteristic calcification patterns.

  Diseases:

  • Hamartoma
  • Amyloidosis
  • Castleman disease
  • Scar carcinoma
  • Mucinous metastases

  Calcification Patterns:

  • a) Eccentric calcification
  • b) Lobulated calcification
  • c) Psammomatous calcifications
  • d) Diffuse calcification
  • e) Popcorn calcification

  Correct Matches:

  1: Hamartoma – e) Popcorn calcification
  “Hamartomas are known for their central and popcorn calcification patterns.” (Radiopaedia)

  2: Amyloidosis – b) Lobulated calcification
  “Amyloidosis may present with lobulated calcifications due to abnormal protein deposition.” (Radiographics)

  3: Castleman disease – d) Diffuse calcification
  “Castleman disease rarely demonstrates diffuse calcifications but may be seen in certain cases.” (Radiopaedia)

  4: Scar carcinoma – a) Eccentric calcification
  “Eccentric calcifications are suspicious for malignancy, as seen in scar carcinoma.” (Radiographics)

  5: Mucinous metastases – c) Psammomatous calcifications
  “Psammomatous calcifications are characteristic of central deposits often associated with specific malignancies.” (Radiopaedia)

Level 2 Question 10: A 55-year-old male presents with a stroke and is incidentally found to have a solitary pulmonary nodule. What is the most likely explanation for the findings?

a) Pulmonary arteriovenous malformation (AVM)
b) Pseudoaneurysm caused by Swan-Ganz catheter
c) Pulmonary artery aneurysm
d) Left atrial myxoma
e) None of the above

Answer: a) Pulmonary arteriovenous malformation (AVM) and d) Left atrial myxoma

Comment (Correct Answers):
Pulmonary AVMs can cause paradoxical embolism, leading to stroke due to right-to-left shunting. Similarly, left atrial myxomas can embolize into the systemic circulation, causing strokes and mimicking vascular anomalies. Both conditions can present as incidental findings of SPNs.
“Pulmonary AVMs are a common cause of paradoxical embolism, leading to stroke or systemic emboli.” (Radiopaedia)
“Left atrial myxomas are known to embolize, often causing systemic embolic events including stroke.” (Radiographics)

Incorrect Answers:

• b) Pseudoaneurysm caused by Swan-Ganz catheter:
  “Pseudoaneurysms are post-traumatic and usually do not cause systemic embolism.” (Radiographics)
• c) Pulmonary artery aneurysm:
  “Pulmonary artery aneurysms are rare and not typically associated with stroke.” (Radiopaedia)
• e) None of the above:
  “Both pulmonary AVMs and left atrial myxomas can explain the findings in this case.” (Radiopaedia)