Naveed Ahmad, MD | RadQuiz.com

1. Anatomy & Imaging Studies

• Secondary Pulmonary Lobule Anatomy: The fundamental structural unit of the lung, bounded by interlobular septa. The core contains the centrilobular pulmonary arteriole and terminal bronchiole, while the periphery houses pulmonary veins and lymphatics within the septa.
• High-Resolution CT (HRCT) Technical Protocols: Thin-section collimation (1 mm or less) reconstructed with high-spatial-frequency (sharp) algorithms to maximize spatial resolution of reticular opacities and honeycombing. Expiratory acquisitions are vital for demonstrating air trapping (mosaic attenuation), while prone scans differentiate dependent atelectasis from true posterior interstitial fibrosis.

2. Definitions & Common Radiographic Signs

• Signet Ring Sign: A dilated bronchus paired with an adjacent, smaller pulmonary arteriole, characteristic of irreversible bronchiectasis.
• Reverse Halo Sign (Atoll Sign): A central area of ground-glass opacity surrounded by a denser rim of consolidation, highly suggestive of cryptogenic organizing pneumonia (COP).
• Tree-in-Bud Opacities: Centrilobular branching nodular opacities representing impacted, inflamed bronchioles filled with mucus, pus, or caseous material (hallmark of active infection, particularly nontuberculous mycobacteria and tuberculosis).
• CT Halo Sign & Air Crescent Sign: Ground-glass halo surrounding a pulmonary nodule or mass (invasive fungal infection like aspergillosis), versus an air crescent within a cavitary lesion (aspergilloma or resolving infarct cavitation).

3. ICU Chest Radiology, Lines, and Tubes

• Endotracheal Tube Placement: The distal tip must be positioned 3 to 5 cm above the carina with the patient’s head in neutral position, minimizing the risk of mainstem bronchial intubation or extubation during flexion/extension.
• Central Venous Catheters: Optimal placement places the distal catheter tip at the cavoatrial junction or lower superior vena cava (SVC), parallel to the vessel wall to prevent vascular erosion or tamponade.
• Swan-Ganz & Enteric Tubes: Pulmonary artery catheters should reside within the right or left main pulmonary artery without extending past the hilum. Nasogastric/feeding tubes must cross the gastroesophageal junction with the tip at least 10 cm into the stomach body.

4. Pleural, Mediastinal & Hilar Disorders

• Pleural Effusion & Decubitus Radiography: Lateral decubitus views confirm free-flowing fluid layers (thickness $> 1$ cm indicates safe thoracentesis volume). Complex loculations, pleural thickening $> 1$ cm, and split-pleura sign distinguish empyemas from simple transudative effusions.
• Mediastinal Compartmentalization: Anterior mediastinum lesions include thymoma, teratoma, thyroid, and lymphoma (the “4 T’s”). Middle mediastinum houses cysts and adenopathy, while posterior mediastinum lesions are predominantly neurogenic tumors or vertebral pathology.
• Hilar Evaluation & Symmetry: Differentiating true hilar enlargement (vascular congestion, lymphadenopathy, or neoplasm) from normal anatomic variants by evaluating the left hilum (higher than the right in 97% of normal individuals) and identifying the hilar point and overlay sign.

5. Airway & Interstitial Disease (ILD)

• Bronchiectasis Classifications: Morphologically divided into cylindrical (uniform dilatation), varicose (beaded contours), and cystic (ballooned, sac-like structures ending blindly) types.
• Usual Interstitial Pneumonia (UIP): Defined by subpleural and basilar predominance, honeycombing cysts, traction bronchiectasis, and fine reticular opacities in the relative absence of ground-glass attenuation.
• Non-Specific Interstitial Pneumonia (NSIP): Characterized by basilar predominance with classic subpleural sparing and extensive ground-glass opacity dominance over reticular fibrosis.
• Hypersensitivity Pneumonitis (HP): Demonstrates upper-to-mid lung predominance, poorly defined centrilobular nodules, and geographic mosaic attenuation with prominent air trapping on expiratory scans.

6. Inhalation Diseases & Occupational Lung Pathology

• Silicosis & Coal Worker’s Pneumoconiosis: Upper-lobe predominant small, well-defined centrilobular and subpleural nodules that can coalesce into progressive massive fibrosis (PMF), characterized by central retraction toward the hila.
• Asbestosis: Lower-lobe predominant interstitial fibrosis associated with pleural plaques (often calcified along the parietal pleura and diaphragm) and benign asbestos pleural effusions.

7. Pulmonary Nodules & Lung Cancer Staging (TNM 9th Edition)

• Fleischner Society & Lung-RADS v2022: Standardized risk-stratified algorithms governing follow-up intervals for solid, part-solid, and nonsolid incidental and screening nodules based on size thresholds and volume doubling times.
• TNM 9th Edition Nuances: Precise evaluation of T-descriptors (tumor size, visceral pleural invasion PL1/PL2, central airway/mediastinal structure invasion), N-stations (ipsilateral hilar N1 vs. mediastinal N2 vs. contralateral N3), and synchronous pulmonary lesions.

8. Trauma, Iatrogenic Injury & Congenital Disorders

• Traumatic Aortic Disruption & Pulmonary Contusion: Aortic injury at the aortic isthmus marked by widened mediastinum and left apical cap. Pulmonary contusions manifest as patchy non-segmental alveolar opacities appearing within hours of blunt trauma, independent of anatomical boundaries.
• Iatrogenic Complications: Post-biopsy tension pneumothorax and parenchymal hemorrhage. Barotrauma findings in mechanically ventilated patients include pneumomediastinum, subcutaneous emphysema, and pneumoperitoneum.
• Congenital Vascular & Airway Anomalies: Scimitar syndrome (partial anomalous pulmonary venous return), pulmonary sequestration (extralobar vs. intralobar with systemic arterial supply), and congenital lobar emphysema.

1. Anatomy & Imaging Studies

• Secondary Pulmonary Lobule Anatomy: The fundamental structural unit of the lung, bounded by interlobular septa. The core contains the centrilobular pulmonary arteriole and terminal bronchiole, while the periphery houses pulmonary veins and lymphatics within the septa.
• High-Resolution CT (HRCT) Technical Protocols: Thin-section collimation (1 mm or less) reconstructed with high-spatial-frequency (sharp) algorithms to maximize spatial resolution of reticular opacities and honeycombing. Expiratory acquisitions are vital for demonstrating air trapping (mosaic attenuation), while prone scans differentiate dependent atelectasis from true posterior interstitial fibrosis.

2. Definitions & Common Radiographic Signs

• Signet Ring Sign: A dilated bronchus paired with an adjacent, smaller pulmonary arteriole, characteristic of irreversible bronchiectasis.
• Reverse Halo Sign (Atoll Sign): A central area of ground-glass opacity surrounded by a denser rim of consolidation, highly suggestive of cryptogenic organizing pneumonia (COP).
• Tree-in-Bud Opacities: Centrilobular branching nodular opacities representing impacted, inflamed bronchioles filled with mucus, pus, or caseous material (hallmark of active infection, particularly nontuberculous mycobacteria and tuberculosis).
• CT Halo Sign & Air Crescent Sign: Ground-glass halo surrounding a pulmonary nodule or mass (invasive fungal infection like aspergillosis), versus an air crescent within a cavitary lesion (aspergilloma or resolving infarct cavitation).

3. ICU Chest Radiology, Lines, and Tubes

• Endotracheal Tube Placement: The distal tip must be positioned 3 to 5 cm above the carina with the patient’s head in neutral position, minimizing the risk of mainstem bronchial intubation or extubation during flexion/extension.
• Central Venous Catheters: Optimal placement places the distal catheter tip at the cavoatrial junction or lower superior vena cava (SVC), parallel to the vessel wall to prevent vascular erosion or tamponade.
• Swan-Ganz & Enteric Tubes: Pulmonary artery catheters should reside within the right or left main pulmonary artery without extending past the hilum. Nasogastric/feeding tubes must cross the gastroesophageal junction with the tip at least 10 cm into the stomach body.

4. Pleural, Mediastinal & Hilar Disorders

• Pleural Effusion & Decubitus Radiography: Lateral decubitus views confirm free-flowing fluid layers (thickness $> 1$ cm indicates safe thoracentesis volume). Complex loculations, pleural thickening $> 1$ cm, and split-pleura sign distinguish empyemas from simple transudative effusions.
• Mediastinal Compartmentalization: Anterior mediastinum lesions include thymoma, teratoma, thyroid, and lymphoma (the “4 T’s”). Middle mediastinum houses cysts and adenopathy, while posterior mediastinum lesions are predominantly neurogenic tumors or vertebral pathology.
• Hilar Evaluation & Symmetry: Differentiating true hilar enlargement (vascular congestion, lymphadenopathy, or neoplasm) from normal anatomic variants by evaluating the left hilum (higher than the right in 97% of normal individuals) and identifying the hilar point and overlay sign.

5. Airway & Interstitial Disease (ILD)

• Bronchiectasis Classifications: Morphologically divided into cylindrical (uniform dilatation), varicose (beaded contours), and cystic (ballooned, sac-like structures ending blindly) types.
• Usual Interstitial Pneumonia (UIP): Defined by subpleural and basilar predominance, honeycombing cysts, traction bronchiectasis, and fine reticular opacities in the relative absence of ground-glass attenuation.
• Non-Specific Interstitial Pneumonia (NSIP): Characterized by basilar predominance with classic subpleural sparing and extensive ground-glass opacity dominance over reticular fibrosis.
• Hypersensitivity Pneumonitis (HP): Demonstrates upper-to-mid lung predominance, poorly defined centrilobular nodules, and geographic mosaic attenuation with prominent air trapping on expiratory scans.

6. Inhalation Diseases & Occupational Lung Pathology

• Silicosis & Coal Worker’s Pneumoconiosis: Upper-lobe predominant small, well-defined centrilobular and subpleural nodules that can coalesce into progressive massive fibrosis (PMF), characterized by central retraction toward the hila.
• Asbestosis: Lower-lobe predominant interstitial fibrosis associated with pleural plaques (often calcified along the parietal pleura and diaphragm) and benign asbestos pleural effusions.

7. Pulmonary Nodules & Lung Cancer Staging (TNM 9th Edition)

• Fleischner Society & Lung-RADS v2022: Standardized risk-stratified algorithms governing follow-up intervals for solid, part-solid, and nonsolid incidental and screening nodules based on size thresholds and volume doubling times.
• TNM 9th Edition Nuances: Precise evaluation of T-descriptors (tumor size, visceral pleural invasion PL1/PL2, central airway/mediastinal structure invasion), N-stations (ipsilateral hilar N1 vs. mediastinal N2 vs. contralateral N3), and synchronous pulmonary lesions.

8. Trauma, Iatrogenic Injury & Congenital Disorders

• Traumatic Aortic Disruption & Pulmonary Contusion: Aortic injury at the aortic isthmus marked by widened mediastinum and left apical cap. Pulmonary contusions manifest as patchy non-segmental alveolar opacities appearing within hours of blunt trauma, independent of anatomical boundaries.
• Iatrogenic Complications: Post-biopsy tension pneumothorax and parenchymal hemorrhage. Barotrauma findings in mechanically ventilated patients include pneumomediastinum, subcutaneous emphysema, and pneumoperitoneum.
• Congenital Vascular & Airway Anomalies: Scimitar syndrome (partial anomalous pulmonary venous return), pulmonary sequestration (extralobar vs. intralobar with systemic arterial supply), and congenital lobar emphysema.

100 Pulmonary Radiology MCQs with Detailed Answer Explanations: Naveed Ahmad, MD

Section 1: Anatomy, Imaging Studies & Definitions (Q1–Q15)

Q1: Secondary Pulmonary Lobule Architecture

Scenario: A 45-year-old male undergoes high-resolution CT (HRCT) of the chest for evaluation of chronic cough. Which anatomical structure forms the core (center) of the secondary pulmonary lobule?

• A) Interlobular septa and pulmonary veins
• B) Centrilobular pulmonary arteriole and terminal bronchiole
• C) Visceral pleura and lymphatic channels
• D) Main bronchus and bronchial artery

Answer: B

• Explanation: The secondary pulmonary lobule is the smallest discrete unit of the lung surrounded by connective tissue septa. Its core houses the centrilobular pulmonary arteriole and terminal bronchiole, whereas the pulmonary veins and lymphatics reside in the periphery within the interlobular septa.

Q2: HRCT Scanning Technique

Scenario: When optimizing an HRCT protocol for suspected interstitial lung disease, which technical parameter is essential to maximize spatial resolution and detect subtle reticulation or honeycombing?

• A) Thick-section collimation (5 to 7 mm) with standard reconstruction algorithms
• B) Thin-section collimation (1 mm or less) with high-spatial-frequency (sharp) reconstruction algorithms
• C) Low-dose non-contrast screening protocols without breath-hold instructions
• D) Exclusively prone positioning during quiet tidal respiration

Answer: B

• Explanation: HRCT requires thin-section collimation ($\le 1\text{ mm}$) paired with high-spatial-frequency (sharp/bone) algorithms to maximize spatial resolution and accurately delineate fine structures such as interlobular septa, reticular opacities, and honeycombing.

Q3: Expiratory HRCT Utility

Scenario: An expiratory HRCT scan is acquired in a patient with suspected small airways disease. What is the primary physiological and imaging objective of this maneuver?

• A) To accentuate dependent posterior atelectasis and rule out fibrosis
• B) To demonstrate air trapping manifested as areas of persistent low attenuation (mosaic attenuation)
• C) To eliminate cardiac motion artifacts across the left lower lobe
• D) To dilate subsegmental bronchi for better lumen visualization

Answer: B

• Explanation: Expiratory HRCT scans allow air to empty from normal lung parenchyma. In small airways disease (e.g., bronchiolitis, hypersensitivity pneumonitis), affected lobules fail to empty normally, resulting in geographic areas of persistent lower attenuation (air trapping) that become more pronounced on expiration.

Q4: Prone HRCT Positioning

Scenario: A baseline supine HRCT demonstrates subtle dependent basilar ground-glass opacities in an elderly patient. A repeat scan in the prone position shows complete resolution of these opacities. How should this finding be interpreted?

• A) Cryptogenic organizing pneumonia in early remission
• B) Dependent atelectasis / normal dependent physiological density
• C) Early non-specific interstitial pneumonia (NSIP)
• D) Asbestosis with reversible pleural inflammation

Answer: B

• Explanation: Dependent dependent atelectasis is a common gravity-dependent phenomenon in the posterior dependent lung zones in the supine position. Prone scanning shifts the lung parenchyma, allowing radiologists to differentiate true interstitial lung disease from physiological dependent atelectasis, which resolves when prone.

Q5: Signet Ring Sign

Scenario: On a chest CT scan, a cross-sectional view of a subsegmental airway demonstrates a bronchiole whose internal lumen diameter is significantly larger than its accompanying adjacent pulmonary arteriole. What is this classic finding called?

• A) Fleischner sign
• B) Signet ring sign
• C) Westermark sign
• D) Hampton hump

Answer: B

• Explanation: The signet ring sign consists of a dilated, thick-walled bronchus paired with an adjacent, smaller pulmonary arteriole (which normally match in size). This is a classic hallmark of irreversible bronchiectasis.

Q6: Reverse Halo Sign (Atoll Sign)

Scenario: A 52-year-old immunocompromised patient presents with fever and cough. Chest CT reveals a focal area of ground-glass opacity surrounded by a dense, crescentic or complete rim of consolidation. What is this sign?

• A) Air crescent sign
• B) Reverse halo sign (atoll sign)
• C) CT halo sign
• D) Monod sign

Answer: B

• Explanation: The reverse halo sign (atoll sign) features a central area of ground-glass opacity bordered by a denser ring of consolidation. While initially considered highly specific for cryptogenic organizing pneumonia (COP), it can also be seen in invasive fungal infections and infarcts.

Q7: Tree-in-Bud Opacities

Scenario: High-resolution CT of a patient with productive cough demonstrates multiple centrilobular branching nodular opacities resembling budding trees in the peripheral lung zones. What pathological process do these represent?

• A) Interstitial edema confined to the interlobular septa
• B) Impacted, inflamed bronchioles filled with mucus, pus, or caseous material
• C) Focal pulmonary infarction secondary to septic emboli
• D) Perilymphatic tumor spread along the bronchovascular bundle

Answer: B

• Explanation: Tree-in-bud opacities represent centrilobular branching structures corresponding to bronchioles plugged with inflammatory exudate, mucus, pus, or caseous material. This is classically seen in infectious bronchiolitis, active tuberculosis, and nontuberculous mycobacterial (NTM) infection.

Q8: CT Halo Sign

Scenario: A neutropenic patient with acute leukemia undergoes chest CT, which demonstrates a pulmonary nodule surrounded by a halo of ground-glass attenuation. What does this ground-glass halo represent histopathologically?

• A) Perilesional hemorrhage and coagulative necrosis
• B) Compensatory alveolar hyperinflation
• C) Localized interstitial fibrosis
• D) Mucinous impaction within surrounding alveoli

Answer: A

• Explanation: In neutropenic patients, the CT halo sign—a zone of ground-glass opacity surrounding a nodule or mass—typically represents perilesional hemorrhage surrounding angioinvasive fungal infections such as invasive pulmonary aspergillosis or mucormycosis.

Q9: Air Crescent Sign

Scenario: A recovering neutropenic patient undergoes repeat chest CT. A pulmonary nodule previously surrounded by a halo now demonstrates a crescent-shaped collection of air separating the necrotic nodule from the surrounding parenchyma. What is this sign called?

• A) Westermark sign
• B) Air crescent sign
• C) Fleischner sign
• D) Rigler sign

Answer: B

• Explanation: The air crescent sign occurs when necrotic lung tissue (infarct or fungal ball) retracts within a cavity, leaving a crescent of air. In the setting of resolving invasive aspergillosis, it signifies neutrophil recovery and immune reconstitution.

Q10: Fleischner Sign in Pulmonary Embolism

Scenario: A chest radiograph in a patient with acute dyspnea demonstrates prominent enlargement of the right descending pulmonary artery accompanied by a sharp cutoff of peripheral branches. What is this classic chest radiograph sign?

• A) Westermark sign
• B) Fleischner sign
• C) Hampton hump
• D) Palla sign

Answer: B

• Explanation: The Fleischner sign refers to the radiographic appearance of dilatation of a pulmonary artery proximal to a large pulmonary embolus (often the right descending pulmonary artery), combined with downstream oligemia.

Q11: Westermark Sign

Scenario: A portable chest radiograph of a patient with an acute pulmonary embolism demonstrates a localized wedge-shaped region of decreased vascular markings and increased lucency in the lung periphery. What is this sign?

• A) Westermark sign
• B) Hampton hump
• C) Fleischner sign
• D) Chilaiditi sign

Answer: A

• Explanation: The Westermark sign represents focal oligemia (decreased vascular markings and hyperlucency) distal to a major pulmonary embolus. Though relatively specific, it has low sensitivity on plain radiographs.

Q12: Hampton Hump

Scenario: A chest radiograph demonstrates a pleural-based, wedge-shaped opacity in the right lower lobe with its apex pointing toward the hilum in a patient with pleuritic chest pain. What is this radiographic finding?

• A) Hampton hump
• B) Westermark sign
• C) Fleischner sign
• D) Golden S-sign

Answer: A

• Explanation: A Hampton hump is a pleural-based, wedge-shaped opacity with its apex directed toward the lung hilum, representing pulmonary infarction secondary to pulmonary embolism.

Q13: Palla Sign

Scenario: A patient with chronic pulmonary hypertension secondary to recurrent pulmonary emboli exhibits prominent enlargement of the right descending pulmonary artery measuring over 16 mm on chest radiography. What is this sign?

• A) Palla sign
• B) Westermark sign
• C) Hampton hump
• D) Luftsichel sign

Answer: A

• Explanation: The Palla sign refers to enlargement of the right descending pulmonary artery on chest radiographs, indicating pulmonary arterial hypertension and chronic right heart strain.

Q14: Luftsichel Sign

Scenario: A chest radiograph demonstrates left upper lobe collapse. A hyperlucent crescentic shadow is seen interposed between the aortic arch and the collapsed, retracted left upper lobe. What is this sign?

• A) Luftsichel sign
• B) Golden S-sign
• C) Water-lily sign
• D) Cumbo sign

Answer: A

• Explanation: The luftsichel sign (German for “air sickle”) represents compensatory hyperinflation and retrocardiac interposition of the superior segment of the left lower lobe around the collapsed left upper lobe.

Q15: Golden S-Sign (Golden S Sign of Spleen/Lobe)

Scenario: Right upper lobe collapse on a chest radiograph shows an S-shaped contour of the minor fissure, where the medial portion curves downward and the lateral portion curves upward. What does this S-shape typically indicate?

• A) Central obstructing bronchogenic carcinoma causing the lobar collapse
• B) Asbestos-related pleural mesothelioma with trapped lung
• C) Congenital pulmonary sequestration with aberrant arterial supply
• D) Tension pneumothorax with contralateral mediastinal shift

Answer: A

• Explanation: The Golden S-sign (or Golden S-sign of right upper lobe collapse) occurs when a central obstructing mass (such as a bronchogenic carcinoma) forms the central convex bulge of the “S,” while the collapsed lobe forms the concave outer curves.

Section 2: ICU Chest Radiology, Lines, and Tubes (Q16–Q30)

Q16: Endotracheal Tube Position

Scenario: An endotracheal tube (ETT) is placed in an intubated ICU patient. What is the ideal distance of the ETT distal tip above the carina on a neutral-position chest radiograph?

• A) 1 to 2 cm
• B) 3 to 5 cm
• C) 7 to 10 cm
• D) Exactly at the level of the aortic knob

Answer: B

• Explanation: The ETT tip should ideally lie 3 to 5 cm above the carina with the patient’s head in neutral position. This allows sufficient margin for tube displacement during flexion (moves down) and extension (moves up) of the neck.

Q17: Right Mainstem Intubation Risk

Scenario: Following emergency intubation, a portable chest radiograph demonstrates complete opacities and atelectasis of the entire left lung with hyperinflation of the right lung. What is the most likely cause?

• A) Mucus plugging of the left main bronchus
• B) Inadvertent selective intubation of the right mainstem bronchus
• C) Tension pneumothorax on the right side
• D) Esophageal intubation with aspiration

Answer: B

• Explanation: The right main bronchus arises at a more vertical angle from the trachea than the left. Inadvertent over-advancement of the ETT results in selective right mainstem bronchial intubation, leading to complete aeration of the right lung and atelectasis of the entire left lung.

Q18: Central Venous Catheter Tip Placement

Scenario: A central venous catheter (CVC) inserted via the right internal jugular vein is evaluated on a chest radiograph. Where should the optimal distal tip of the CVC be located?

• A) Mid-superior vena cava, above the level of the azygos arch
• B) At the cavoatrial junction or lower superior vena cava
• C) Within the mid-right atrium
• D) Inside the right ventricle

Answer: B

• Explanation: The ideal tip location for a central venous catheter is at the cavoatrial junction or the lower third of the superior vena cava, oriented parallel to the vessel wall to minimize risks of thrombosis, erosion, and cardiac arrhythmia.

Q19: Swan-Ganz Catheter Position

Scenario: A pulmonary artery (Swan-Ganz) catheter is placed in a critically ill cardiac patient. Where should the catheter tip reside to avoid distal pulmonary infarction or vessel rupture?

• A) Main pulmonary artery or proximal right/left pulmonary artery branches
• B) Distal subsegmental pulmonary arteriole wedged permanently
• C) Superior vena cava above the right atrium
• D) Left atrium via a patent foramen ovale

Answer: A

• Explanation: The Swan-Ganz catheter tip should lie within the right or left main pulmonary artery (or proximal lobar branches). It should not extend into the peripheral third of the lung fields, where “wedging” risks distal pulmonary infarction, pseudoaneurysm formation, or pulmonary artery rupture.

Q20: Enteric Feeding Tube Position

Scenario: A nasoenteric feeding tube is placed in an ICU patient. To ensure safe delivery of enteral nutrition and prevent aspiration, where must the distal radiopaque tip terminate?

• A) In the midesophagus, 5 cm above the gastroesophageal junction
• B) In the stomach body/antrum or past the pylorus into the duodenum
• C) In the proximal trachea before the main carina
• D) In the right mainstem bronchus

Answer: B

• Explanation: Enteric feeding tubes must cross the gastroesophageal (GE) junction and terminate well within the stomach (body or antrum) or extend past the pylorus into the duodenum/jejunum to prevent aspiration pneumonitis.

Q21: Pneumothorax in Mechanically Ventilated Patients

Scenario: A mechanically ventilated patient with acute respiratory distress syndrome (ARDS) experiences sudden oxygen desaturation and peak pressure alarms. A supine chest radiograph shows an unusually deep right costophrenic angle and sharp cardiac borders. What diagnosis must be excluded immediately?

• A) Hiatal hernia
• B) Tension pneumothorax (anterior/subpulmonic component in supine patient)
• C) Pneumoperitoneum
• D) Pulmonary embolism

Answer: B

• Explanation: In supine patients, free pleural air rises to the non-dependent anterior and basal recesses (the deep sulcus sign and hyperlucent upper quadrants/cardiac borders), masquerading as a subpulmonic or tension pneumothorax requiring emergent decompression.

Q22: Barotrauma Findings

Scenario: A patient on high-pressure mechanical ventilation develops crepitus in the neck. A chest radiograph demonstrates continuous linear gas lucencies outlining the heart border, aortic arch, and superior mediastinum. What is this finding?

• A) Pneumopericardium
• B) Pneumomediastinum
• C) Subcutaneous emphysema without mediastinal involvement
• D) Mackler triad

Answer: B

• Explanation: Pneumomediastinum results from alveolar rupture (the Macklin effect), where air tracks along the bronchovascular sheaths into the mediastinum, outlining mediastinal structures and often dissecting into the neck (subcutaneous emphysema).

Q23: Pneumopericardium vs. Pneumomediastinum

Scenario: A chest radiograph in a ventilated trauma patient shows a band of gas surrounding the heart. However, the gas does not extend above the level of the pericardial reflection on the great vessels. What is this diagnosis?

• A) Pneumomediastinum
• B) Pneumopericardium
• C) Tension pneumothorax
• D) Esophageal rupture

Answer: B

• Explanation: Pneumopericardium is characterized by gas confined within the pericardial sac. Unlike pneumomediastinum, pericardial reflections prevent air from extending superiorly around the great vessels above the heart base.

Q24: Intra-Aortic Balloon Pump (IABP) Position

Scenario: An intra-aortic balloon pump is placed via the femoral artery. Where should the radiopaque distal tip of the IABP be located on a chest/abdominal radiograph?

• A) In the ascending aorta, 2 cm above the aortic valve
• B) In the descending thoracic aorta, just distal to the origin of the left subclavian artery
• C) In the abdominal aorta below the renal arteries
• D) In the common iliac artery

Answer: B

• Explanation: The ideal position for an IABP tip is in the descending thoracic aorta, approximately 1 to 2 cm distal to the origin of the left subclavian artery (below the aortic arch and above the renal arteries).

Q25: Pacemaker Lead Placement

Scenario: A dual-chamber pacemaker is implanted. Where should the tip of the ventricular lead be positioned on a standard chest radiograph?

• A) Right atrial appendage
• B) Right ventricular apex or interventricular septum
• C) Coronary sinus
• D) Left ventricle via retrograde aortic access

Answer: B

• Explanation: In a dual-chamber pacemaker, the atrial lead tip is positioned in the right atrial appendage, while the ventricular lead tip is secured in the right ventricular apex (or increasingly the interventricular septum) with characteristic J-curve configuration for the atrium.

Q26: Chest Tube Positioning for Pneumothorax vs. Effusion

Scenario: A chest tube is placed for a loculated pleural effusion versus a large apical pneumothorax. Where should the tube be directed for an apical pneumothorax?

• A) Directed anteriorly and superiorly toward the apex
• B) Directed posteriorly and inferiorly toward the costophrenic angle
• C) Placed directly across the mediastinum into the contralateral pleural space
• D) Advanced through the diaphragm into the peritoneal cavity

Answer: A

• Explanation: For apical pneumothoraces, chest tubes are directed anteriorly and superiorly toward the apex where air naturally collects in supine or semi-upright patients. For effusions, tubes are directed posteriorly and inferiorly.

Q27: Pulmonary Interstitial Emphysema (PIE)

Scenario: A premature infant on mechanical ventilation develops hyperinflation and cystic lucencies radiating outward from the hila into the pulmonary parenchyma. What is this condition?

• A) Congenital lobar emphysema
• B) Pulmonary interstitial emphysema (PIE)
• C) Bronchopulmonary dysplasia
• D) Scimitar syndrome

Answer: B

• Explanation: Pulmonary interstitial emphysema (PIE) occurs when air dissects into the pulmonary interstitium due to barotrauma in neonates, appearing as linear or cystic radiolucencies radiating from the hila.

Q28: Esophageal Rupture (Boerhaave Syndrome)

Scenario: A patient presents with severe chest pain and vomiting following a bout of retching. A chest radiograph reveals left-sided pleural effusion, pneumomediastinum, and subcutaneous emphysema. What is the diagnosis?

• A) Acute myocardial infarction
• B) Boerhaave syndrome (esophageal rupture)
• C) Dissecting aortic aneurysm
• D) Massive pulmonary embolism

Answer: B

• Explanation: Boerhaave syndrome is transmural barogenic rupture of the distal esophagus, classically presenting with vomiting, chest pain, hydropneumothorax (predominantly left-sided), and pneumomediastinum.

Q29: Malpositioned Thoracostomy Tube

Scenario: A post-operative chest radiograph shows a thoracostomy tube passing through the chest wall, but the side-hole (identified by the interrupted radiopaque line) lies outside the skin surface. What is the clinical implication?

• A) The tube will function normally via internal drainage
• B) Air or fluid will leak around the tube, rendering it ineffective and risking infection
• C) The tube has perforated the visceral pleura and entered the lung parenchyma
• D) The tube is positioned correctly in the pleural space

Answer: B

• Explanation: All side-holes of a thoracostomy tube must reside entirely within the pleural space. If a side-hole is extrathoracic, air will be sucked in through the hole, breaking the closed-system suction and failing to evacuate the pneumothorax or effusion.

Q30: Diaphragmatic Rupture

Scenario: A trauma patient involved in a high-speed motor vehicle collision undergoes a chest radiograph, which shows an abnormal focal contour elevation of the left hemidiaphragm with loops of bowel occupying the left hemithorax. What is the diagnosis?

• A) Phrenic nerve palsy
• B) Traumatic diaphragmatic rupture
• C) Bochdalek hernia
• D) Morgagni hernia

Answer: B

• Explanation: Traumatic diaphragmatic rupture occurs predominantly on the left side due to the cushioning effect of the liver on the right. CT or radiographs demonstrate herniation of abdominal contents into the thorax.

Section 3: Pleural, Mediastinal & Hilar Disorders (Q31–Q45)

Q31: Decubitus Radiography for Pleural Effusion

Scenario: A small pleural effusion is suspected on a supine chest radiograph. A lateral decubitus radiograph is performed with the affected side down. What thickness of fluid layer along the lateral chest wall is generally considered sufficient and safe for thoracentesis?

• A) Greater than 1 mm
• B) Greater than 10 mm (1 cm)
• C) Exactly 50 mm
• D) Only when it completely opacifies the hemithorax

Answer: B

• Explanation: A fluid layer measuring greater than 10 mm (1 cm) on a lateral decubitus radiograph indicates a sufficient volume of free-flowing fluid to safely perform thoracentesis under imaging guidance.

Q32: Empyema vs. Simple Effusion

Scenario: Contrast-enhanced chest CT in a patient with pneumonia and pleural fluid demonstrates smooth, enhancing parietal and visceral pleura separated by fluid, along with the split pleura sign. What is the diagnosis?

• A) Simple transudative effusion
• B) Empyema / complicated exudative effusion
• C) Malignant pleural mesothelioma
• D) Asbestos-related pleural plaque

Answer: B

• Explanation: The split pleura sign—characterized by intense enhancement and separation of thickened visceral and parietal pleura—is a hallmark of empyema or complicated exudative effusion requiring chest tube drainage or surgical decortication.

Q33: Malignant Pleural Mesothelioma

Scenario: A patient with a history of extensive occupational asbestos exposure presents with unremitting chest pain and dyspnea. CT demonstrates nodular, circumferential pleural thickening exceeding 1 cm, mediastinal pleural involvement, and encasement of the lung. What is the diagnosis?

• A) Fibrothorax
• B) Malignant pleural mesothelioma
• C) Loculated empyema
• D) Pleural lipoma

Answer: B

• Explanation: Malignant pleural mesothelioma is classically associated with asbestos exposure and presents with nodular, circumferential pleural thickening, fissural involvement, and hemithorax volume loss.

Q34: Anterior Mediastinal Masses (The 4 T’s)

Scenario: A 30-year-old female undergoes a routine chest radiograph, which reveals a well-circumscribed anterior mediastinal mass. Which differential diagnosis category applies to the “4 T’s” of anterior mediastinal masses?

• A) Thymoma, Teratoma (germ cell tumor), Thyroid (ectopic), Terrible lymphoma
• B) Thoracic duct cyst, Thymolipoma, Tracheal diverticulum, Tuberculosis
• C) Teratoma, Tuberculosis, Thrombosis, Transitional cell tumor
• D) Thymoma, Thyroglossal cyst, Thoracic meningocele, Traumatic hematoma

Answer: A

• Explanation: The classic mnemonic for anterior mediastinal masses is the 4 T’s: Thymoma, Teratoma (and other germ cell tumors), Thyroid (substernal goiter/ectopic thyroid), and Terrible lymphoma.

Q35: Middle Mediastinal Masses

Scenario: A patient has an incidental middle mediastinal cyst located near the carina. CT attenuation is near-water, and there is no contrast enhancement or calcification. What is the most likely diagnosis?

• A) Thymoma
• B) Bronchogenic cyst
• C) Neurogenic tumor (schwannoma)
• D) Esophageal leiomyoma

Answer: B

• Explanation: Bronchogenic cysts are congenital foregut duplication cysts located most commonly in the middle mediastinum near the carina or major bronchi. They typically demonstrate uniform fluid (water) attenuation on CT.

Q36: Posterior Mediastinal Masses

Scenario: A posterior mediastinal mass is identified in the paravertebral gutter of a 40-year-old patient. MRI reveals the lesion expanding through a neural foraminal opening in a dumbbell configuration. What is the most likely tumor?

• A) Thymic carcinoma
• B) Neurogenic tumor (schwannoma or neurofibroma)
• C) Pericardial cyst
• D) Sternal lipoma

Answer: B

• Explanation: Posterior mediastinal masses are predominantly neurogenic tumors arising from the sympathetic chain or intercostal nerves (e.g., schwannomas, neurofibromas, ganglioneuromas). Extension through the neural foramen creates the classic “dumbbell” shape.

Q37: Thymoma vs. Lymphoma in Anterior Mediastinum

Scenario: A 40-year-old male presents with myasthenia gravis and an anterior mediastinal mass that is homogeneous, encapsulated, and occasionally contains punctate calcifications. What is the most likely diagnosis?

• A) Hodgkin lymphoma
• B) Thymoma
• C) Teratoma containing bone and teeth
• D) Thymic carcinoma

Answer: B

• Explanation: Thymoma is the most common anterior mediastinal tumor in adults and is strongly associated with myasthenia gravis (present in 30-50% of patients). They are typically smooth, well-encapsulated masses with occasional cystic degeneration or calcification.

Q38: Teratoma Imaging Features

Scenario: An anterior mediastinal mass in a young adult contains macroscopic fat, fluid, and well-formed bone and teeth on CT. What is the definitive diagnosis?

• A) Thymic carcinoma
• B) Mature teratoma (dermoid cyst)
• C) Hodgkin lymphoma
• D) Liposarcoma

Answer: B

• Explanation: A mature teratoma is a germ cell tumor that frequently contains elements from all three germ cell layers, demonstrated on CT by the pathognomonic combination of fluid, fat, calcium, and teeth/bone.

Q39: Normal Hilar Anatomy & Asymmetry

Scenario: When evaluating a normal chest radiograph, which hilum is anatomically higher in the vast majority of individuals?

• A) Right hilum is higher in 97% of normal individuals
• B) Left hilum is higher in 97% of normal individuals
• C) Both hila are located at exactly the same vertical height
• D) Hilar height varies randomly with the cardiac cycle

Answer: B

• Explanation: The left hilum is anatomically higher than the right hilum in approximately 97% of normal individuals due to the superior course of the left pulmonary artery over the left main bronchus. The right main pulmonary artery branches earlier and lies lower.

Q40: Hilar Enlargement: Vascular vs. Adenopathy

Scenario: A chest radiograph demonstrates bilateral bulky hilar and mediastinal lymphadenopathy in a young asymptomatic patient, often described as “potato nodes” (symmetrical 1-2-3 sign). What is the most likely diagnosis?

• A) Bilateral bronchogenic carcinoma
• B) Sarcoidosis (Stage II)
• C) Pulmonary arterial hypertension
• D) Congestive heart failure

Answer: B

• Explanation: Sarcoidosis classically presents with symmetric bilateral hilar and right paratracheal lymphadenopathy (the classic 1-2-3 sign: right paratracheal, right hilar, and left hilar nodes), often referred to as “potato nodes.”

Q41: Right Paratracheal Stripe

Scenario: What is the normal upper limit of normal width for the right paratracheal stripe on a standard upright PA chest radiograph?

• A) 1 mm
• B) 4 mm
• C) 15 mm
• D) 30 mm

Answer: B

• Explanation: The normal right paratracheal stripe (formed by the interface between the right tracheal wall, mediastinal pleura, and lung) measures 4 mm or less in thickness. Widening greater than 4 mm indicates paratracheal adenopathy, tracheal pathology, or mediastinal hemorrhage.

Q42: Aortopulmonary Window Adenopathy

Scenario: A contrast-enhanced chest CT reveals a soft-tissue mass filling the concavity beneath the aortic arch and lateral to the ligamentum arteriosum. Which lymph node station is this?

• A) Subcarinal station
• B) Aortopulmonary (AP) window station
• C) Right paratracheal station
• D) Subaortic station

Answer: B

• Explanation: The aortopulmonary (AP) window is bounded superiorly by the aortic arch, inferiorly by the left pulmonary artery, medially by the ligamentum arteriosum/left vagus nerve, and laterally by the mediastinal pleura. Adenopathy here is common in lung cancer, lymphoma, and sarcoidosis.

Q43: Subcarinal Lymphadenopathy

Scenario: On a chest CT, a soft-tissue mass is identified directly posterior and inferior to the tracheal bifurcation, separating the right and left main bronchi. What is the threshold diameter for considering a subcarinal lymph node abnormal?

• A) Greater than 5 mm
• B) Greater than 10 mm (1 cm) in short-axis diameter
• C) Greater than 30 mm
• D) Any visible subcarinal node is considered malignant

Answer: B

• Explanation: Lymph nodes in the mediastinum are generally considered radiologically abnormal if their short-axis diameter exceeds 10 mm (with exceptions for subcarinal and station 11 nodes, where threshold may be slightly lower, typically 10 mm).

Q44: Pleural Plaques

Scenario: A retired shipyard worker undergoes routine chest CT, which demonstrates well-defined, calcified plaque-like thickening along the posterolateral chest walls (between the 7th and 9th ribs) and the tendinous domes of the diaphragm. What is the exposure history?

• A) Coal dust exposure
• B) Asbestos exposure
• C) Silica dust exposure
• D) Beryllium exposure

Answer: B

• Explanation: Pleural plaques are the most common manifestation of prior asbestos exposure. They characteristically involve the parietal pleura along the lower chest wall and diaphragmatic domes, often sparing the costophrenic angles and apices.

Q45: Chylothorax

Scenario: A patient post-esophagectomy develops a milky-white pleural effusion. Thoracentesis reveals high triglyceride levels exceeding 110 mg/dL and chylomicrons. What is the diagnosis?

• A) Empyema
• B) Chylothorax (thoracic duct injury)
• C) Pseudochylous effusion
• D) Malignant mesothelioma

Answer: B

• Explanation: A chylothorax results from disruption of the thoracic duct (iatrogenic during surgery or traumatic), yielding milky fluid rich in triglycerides ($> 110\text{ mg/dL}$) and chylomicrons on lipoprotein electrophoresis.

Section 4: Airway, Interstitial & Idiopathic Disease (Q46–Q65)

Q46: Cylindrical vs. Cystic Bronchiectasis

Scenario: HRCT of a patient with chronic productive cough demonstrates dilated bronchi that maintain their caliber and fail to taper toward the periphery, resembling parallel tram tracks. What morphological type of bronchiectasis is this?

• A) Cylindrical bronchiectasis
• B) Varicose bronchiectasis
• C) Cystic (saccular) bronchiectasis
• D) Traction bronchiectasis

Answer: A

• Explanation: Cylindrical bronchiectasis is the mildest form, characterized by uniform tubular dilatation of bronchi without tapering. Varicose features irregular beading, and cystic features large balloon-like clusters.

Q47: Usual Interstitial Pneumonia (UIP) Pattern

Scenario: A 68-year-old male presents with progressive dyspnea and clubbing. HRCT demonstrates subpleural and basilar predominant reticular opacities, traction bronchiectasis, and honeycombing cysts. Ground-glass opacities are minimal. What is the diagnosis?

• A) Non-Specific Interstitial Pneumonia (NSIP)
• B) Usual Interstitial Pneumonia (UIP) / IPF
• C) Respiratory bronchiolitis-associated ILD (RB-ILD)
• D) Desquamative interstitial pneumonia (DIP)

Answer: B

• Explanation: The hallmark features of a definitive UIP pattern on HRCT are subpleural and basilar predominance, honeycombing, and traction bronchiectasis, with little ground-glass attenuation. This pattern is diagnostic of Idiopathic Pulmonary Fibrosis (IPF).

Q48: Non-Specific Interstitial Pneumonia (NSIP) Pattern

Scenario: A 50-year-old female presents with dry cough and fatigue. HRCT reveals bilateral symmetrical ground-glass opacities and reticular changes with basilar predominance, but notable subpleural sparing. What is the diagnosis?

• A) Usual Interstitial Pneumonia (UIP)
• B) Non-Specific Interstitial Pneumonia (NSIP)
• C) Hypersensitivity Pneumonitis (HP)
• D) Sarcoidosis

Answer: B

• Explanation: NSIP is characterized by basilar predominant ground-glass opacities and reticulation with characteristic subpleural sparing (unlike UIP, which clings to the subpleural space). NSIP carries a significantly better prognosis than UIP.

Q49: Hypersensitivity Pneumonitis (HP)

Scenario: A farmer presents with insidious dyspnea and weight loss. HRCT demonstrates upper-to-mid lung predominant centrilobular poorly defined nodules, patchy ground-glass attenuation, and geographic areas of decreased attenuation (air trapping) on expiratory scans. What is the diagnosis?

• A) Idiopathic pulmonary fibrosis
• B) Hypersensitivity pneumonitis (subacute/chronic)
• C) Desquamative interstitial pneumonia
• D) Pulmonary alveolar proteinosis

Answer: B

• Explanation: Hypersensitivity pneumonitis (HP) classically presents with upper-to-mid lung predominance, centrilobular nodularity, and mosaic attenuation/air trapping representing small airways inflammation and bronchiolitis (the headcheese sign on expiration).

Q50: Cryptogenic Organizing Pneumonia (COP)

Scenario: A patient with persistent non-resolving pneumonia failing antibiotics undergoes HRCT, which reveals patchy consolidation and ground-glass opacities with a peribronchovascular and subpleural distribution, accompanied by reverse halo signs. What is the diagnosis?

• A) Usual interstitial pneumonia
• B) Cryptogenic organizing pneumonia (COP) / Boeck sarcoid
• C) Pulmonary alveolar proteinosis
• D) Eosinophilic pneumonia

Answer: B

• Explanation: Cryptogenic organizing pneumonia (COP)—formerly BOOP—classically presents with patchy consolidations in a peribronchovascular and subpleural distribution, often demonstrating the reverse halo sign and dramatic response to corticosteroids.

Q51: Respiratory Bronchiolitis-Associated ILD (RB-ILD)

Scenario: A 35-year-old heavy cigarette smoker presents with mild dyspnea. HRCT reveals patchy centrilobular ground-glass nodules and bronchial wall thickening predominantly in the upper lobes. What is the diagnosis?

• A) Usual interstitial pneumonia
• B) Respiratory bronchiolitis-associated ILD (RB-ILD)
• C) Lymphocytic interstitial pneumonia
• D) Desquamative interstitial pneumonia (DIP)

Answer: B

• Explanation: RB-ILD and desquamative interstitial pneumonia (DIP) are smoking-related interstitial lung diseases. RB-ILD features centrilobular ground-glass nodules and upper-lobe predominance linked directly to tobacco smoke exposure.

Q52: Desquamative Interstitial Pneumonia (DIP)

Scenario: Another heavy smoker undergoes HRCT, which reveals diffuse, uniform, ground-glass opacities with a lower-lobe and subpleural predominance. Biopsy shows uniform filling of alveolar spaces by pigmented macrophages. What is this entity?

• A) RB-ILD
• B) Desquamative interstitial pneumonia (DIP)
• C) Acute interstitial pneumonia
• D) Lymphangitic carcinomatosis

Answer: B

• Explanation: DIP is the most extensive form of smoking-related interstitial lung disease, characterized by diffuse, homogeneous ground-glass opacities predominantly in the lower lobes and subpleural regions.

Q53: Lymphocytic Interstitial Pneumonia (LIP)

Scenario: A patient with Sjögren syndrome undergoes HRCT, which demonstrates thin-walled perivascular and subpleural cysts alongside ground-glass opacities and centrilobular nodules. What is the diagnosis?

• A) Pulmonary Langerhans cell histiocytosis
• B) Lymphocytic interstitial pneumonia (LIP)
• C) Birt-Hogg-Dubé syndrome
• D) Lymphangioleiomyomatosis (LAM)

Answer: B

• Explanation: LIP is a benign lymphoproliferative disorder strongly associated with autoimmune conditions such as Sjögren syndrome. HRCT reveals thin-walled cysts alongside ground-glass opacities and centrilobular nodules.

Q54: Pulmonary Langerhans Cell Histiocytosis (PLCH)

Scenario: A 25-year-old cigarette smoker presents with spontaneous pneumothorax. HRCT reveals bizarre-shaped, thick- and thin-walled cysts combined with centrilobular nodules exhibiting upper- and mid-lung predominance, sparing the costophrenic angles. What is the diagnosis?

• A) Lymphangioleiomyomatosis (LAM)
• B) Pulmonary Langerhans cell histiocytosis (PLCH)
• C) Emphysema
• D) Cystic fibrosis

Answer: B

• Explanation: PLCH is a smoking-related cystic lung disease occurring almost exclusively in young adults. It features bizarre, branching or lobulated cysts and centrilobular nodules with upper/mid-lung predominance and costophrenic angle sparing.

Q55: Lymphangioleiomyomatosis (LAM)

Scenario: A young female of childbearing age presents with chylous effusions and progressive dyspnea. HRCT demonstrates numerous diffuse, round, thin-walled cysts distributed uniformly throughout all lung zones, including the costophrenic angles, with normal intervening lung parenchyma. What is the diagnosis?

• A) Pulmonary Langerhans cell histiocytosis
• B) Lymphangioleiomyomatosis (LAM)
• C) Tuberous sclerosis-associated cystic lung disease
• D) Emphysema

Answer: B

• Explanation: LAM occurs almost exclusively in women of childbearing age (sporadic or associated with tuberous sclerosis). It manifests as diffuse, uniform, round, thin-walled parenchymal cysts from apices to bases, often complicated by chylothorax or pneumothorax.

Q56: Pulmonary Alveolar Proteinosis (PAP)

Scenario: A patient presents with dyspnea and “milky” bronchoalveolar lavage fluid. HRCT demonstrates smooth interlobular septal thickening superimposed upon widespread ground-glass opacities, producing a crazy-paving pattern. What is the diagnosis?

• A) Pulmonary alveolar proteinosis (PAP)
• B) Adult respiratory distress syndrome (ARDS)
• C) Pneumocystis jirovecii pneumonia (PCP)
• D) Pulmonary hemorrhage

Answer: A

• Explanation: The crazy-paving pattern (superimposed interlobular septal thickening on a background of ground-glass opacity) is highly characteristic of pulmonary alveolar proteinosis (PAP), though it can also be seen in ARDS, PCP, and hemorrhage.

Q57: Birt-Hogg-Dubé Syndrome

Scenario: A patient with recurrent spontaneous pneumothoraces and multiple cutaneous fibrofolliculomas undergoes chest CT, which demonstrates thin-walled, multiseptated, or lenticular (lens-shaped) cysts located predominantly in the medial basilar lung zones and lung bases. What is the syndrome?

• A) Marfan syndrome
• B) Birt-Hogg-Dubé syndrome
• C) Ehlers-Danlos syndrome
• D) Neurofibromatosis

Answer: B

• Explanation: Birt-Hogg-Dubé syndrome is an autosomal dominant condition characterized by skin fibrofolliculomas, renal tumors, and characteristic medial basilar-predominant lenticular cysts.

Q58: Acute Interstitial Pneumonia (AIP – Hamman-Rich Syndrome)

Scenario: A previously healthy patient presents with rapidly progressive acute respiratory failure mimicking ARDS without an identifiable secondary cause. HRCT demonstrates bilateral dependent airspace consolidation and extensive ground-glass opacities with architectural distortion. What is the diagnosis?

• A) Idiopathic pulmonary fibrosis
• B) Acute interstitial pneumonia (AIP / Hamman-Rich syndrome)
• C) Respiratory bronchiolitis-ILD
• D) Desquamative interstitial pneumonia

Answer: B

• Explanation: AIP (Hamman-Rich syndrome) is a fulminant, rapidly progressive form of idiopathic interstitial pneumonia leading to acute respiratory failure with diffuse alveolar damage (DAD) histology.

Q59: Sarcoidosis Imaging Stages

Scenario: A chest radiograph demonstrates bilateral hilar adenopathy and right paratracheal adenopathy without parenchymal lung involvement. According to the Scadding staging system for sarcoidosis, what stage is this?

• A) Stage 0
• B) Stage I
• C) Stage II
• D) Stage III

Answer: B

• Explanation: Scadding staging for sarcoidosis: Stage I = lymphadenopathy alone; Stage II = adenopathy plus pulmonary infiltrates; Stage III = pulmonary infiltrates alone without adenopathy; Stage IV = advanced fibrosis with honeycombing.

Q60: Bronchial Atresia

Scenario: An incidental finding on a chest CT in an asymptomatic young adult reveals a blind-ended, mucus-filled bronchus (bronchomucocele) surrounded by a focal area of hyperlucent, hyperinflated lung parenchyma due to collateral air drift (Kohn pores). What is this congenital anomaly?

• A) Bronchial atresia
• B) Congenital lobar emphysema
• C) Intralobar sequestration
• D) Scimitar syndrome

Answer: A

• Explanation: Bronchial atresia is a focal congenital occlusion of a segmental or subsegmental bronchus, leading to a mucus plug (bronchomucocele) and surrounding hyperlucent, hyperinflated lung due to collateral air drift.

Q61: Mucoid Impaction / Allergic Bronchopulmonary Aspergillosis (ABPA)

Scenario: An asthmatic patient presents with fleeting infiltrates and central bronchiectasis. CT demonstrates high-attenuation mucus plugs (“glove-finger” or “V-shaped” opacities) within dilated central bronchi. What is the diagnosis?

• A) Tuberculosis
• B) Allergic bronchopulmonary aspergillosis (ABPA)
• C) Bronchogenic carcinoma
• D) Cystic fibrosis

Answer: B

• Explanation: ABPA is an immunologic reaction to Aspergillus fumigatus colonization in asthmatics, classically presenting with central bronchiectasis and high-attenuation mucus plugs within dilated airways.

Q62: Kartagener Syndrome (Primary Ciliary Dyskinesia)

Scenario: A patient presents with chronic sinusitis, bronchiectasis, and situs inversus totalis. What is the clinical syndrome?

• A) Young syndrome
• B) Kartagener syndrome
• C) Mounier-Kuhn syndrome
• D) Swyer-James syndrome

Answer: B

• Explanation: Kartagener syndrome is a triad of primary ciliary dyskinesia consisting of situs inversus, chronic sinusitis, and bronchiectasis.

Q63: Mounier-Kuhn Syndrome (Tracheobronchomegaly)

Scenario: A chest CT demonstrates marked abnormal dilatation of the trachea and mainstem bronchi, with tracheal transverse diameter exceeding 30 mm and recurrent lower respiratory tract infections. What is this condition?

• A) Williams-Campbell syndrome
• B) Mounier-Kuhn syndrome (tracheobronchomegaly)
• C) Tracheomalacia
• D) Saber-sheath trachea

Answer: B

• Explanation: Mounier-Kuhn syndrome (tracheobronchomegaly) is characterized by congenital atrophy of elastic and smooth muscle fibers in the trachea and main bronchi, leading to massive airway dilation and ineffective clearance.

Q64: Williams-Campbell Syndrome

Scenario: A patient presents with cystic bronchiectasis affecting the subsegmental and distal bronchi (4th through 6th generations) due to congenital cartilage deficiency, while the trachea and main bronchi remain normal. What is this syndrome?

• A) Mounier-Kuhn syndrome
• B) Williams-Campbell syndrome
• C) Swyer-James syndrome
• D) Young syndrome

Answer: B

• Explanation: Williams-Campbell syndrome is characterized by cartilage deficiency distal to the main bronchi, leading to distal bronchiectasis, whereas Mounier-Kuhn involves the trachea and main bronchi.

Q65: Swyer-James Syndrome (Macleod Syndrome)

Scenario: A pediatric patient presents with a hyperlucent, small unilateral lung following a severe viral bronchiolitis in infancy. Ventilation-perfusion scan shows matched reduction in ventilation and perfusion. What is this condition?

• A) Congenital lobar emphysema
• B) Swyer-James (Macleod) syndrome
• C) Scimitar syndrome
• D) Intralobar sequestration

Answer: B

• Explanation: Swyer-James syndrome is post-infectious obliterative bronchiolitis acquired in childhood, resulting in a hyperlucent, hypoplastic lung due to impaired vascular development and air trapping.

Section 5: Inhalation Diseases, Nodules & Lung Cancer (Q66–Q85)

Q66: Silicosis

Scenario: A stonecutter presents with progressive dyspnea. HRCT demonstrates upper-lobe predominant small, well-defined centrilobular and subpleural nodules, with occasional “eggshell” calcification of hilar lymph nodes. What is the occupational exposure?

• A) Asbestos
• B) Silica dust (silicosis)
• C) Beryllium
• D) Coal dust

Answer: B

• Explanation: Silicosis results from inhaling free silica dust. It features upper-lobe predominant small nodules and characteristic eggshell calcification of lymph nodes.

Q67: Progressive Massive Fibrosis (PMF)

Scenario: A coal worker’s pneumoconiosis patient develops large, symmetric, rubbery, coalescent upper-lobe masses that migrate toward the hila over time, surrounded by emphysematous spaces. What is this advanced stage called?

• A) Caplan syndrome
• B) Progressive massive fibrosis (PMF)
• C) Silicotuberculosis
• D) Asbestosis

Answer: B

• Explanation: Progressive massive fibrosis (PMF) represents complicated pneumoconiosis (coal worker’s or silicosis), where small nodules coalesce into large masses measuring $> 1\text{ cm}$ with surrounding emphysema and central retraction.

Q68: Caplan Syndrome

Scenario: A coal miner with rheumatoid arthritis develops rapidly enlarging, well-defined peripheral pulmonary nodules measuring 0.5 to 5 cm. What is this association?

• A) Caplan syndrome
• B) Felty syndrome
• C) Lofgren syndrome
• D) Goodpasture syndrome

Answer: A

• Explanation: Caplan syndrome is the combination of rheumatoid arthritis and pneumoconiosis (coal worker’s or silicosis), characterized by necrobiotic rheumatoid nodules in the lung periphery that can rapidly cavitate or calcify.

Q69: Berylliosis (Chronic Beryllium Disease)

• Scenario: An aerospace worker presents with non-caseating granulomatous lung disease histologically identical to sarcoidosis, following occupational exposure to a specific light metal. What metal is responsible?
• A) Asbestos
• B) Beryllium (chronic beryllium disease)
• C) Talc
• D) Silica

Answer: B

• Explanation: Chronic beryllium disease results from beryllium exposure and is clinically, radiographically, and histologically indistinguishable from sarcoidosis, requiring a lymphocyte proliferation test for definitive diagnosis.

Q70: Fleischner Society Guidelines for Solid Nodules

Scenario: A 60-year-old heavy smoker has an incidental solid pulmonary nodule measuring 5 mm in maximum diameter on a chest CT. Prior chest CTs are unavailable. According to Fleischner Society guidelines for high-risk patients, what is the recommended follow-up?

• A) Immediate video-assisted thoracoscopic surgery (VATS) resection
• B) 3-month follow-up CT
• C) No routine follow-up required (or optional 12-month follow-up)
• D) PET/CT scan immediately

Answer: C

• Explanation: Under Fleischner Society guidelines for incidental solid nodules $< 6\text{ mm}$, low-risk patients require no routine follow-up, while high-risk patients warrant an optional 12-month follow-up CT.

Q71: Fleischner Guidelines for Nodules 6–8 mm

Scenario: An incidental solid nodule measuring 7 mm is detected in a high-risk patient. According to Fleischner Society guidelines, what is the recommended management?

• A) No follow-up required
• B) CT at 6 to 12 months, then consider 18 to 24 month CT
• C) Immediate biopsy
• D) Annual screening for 10 years

Answer: B

• Explanation: For solid nodules measuring 6 to 8 mm in high-risk patients, Fleischner guidelines recommend initial follow-up CT at 6 to 12 months, followed by a subsequent scan at 18 to 24 months.

Q72: Lung-RADS v2022 Category 3

Scenario: Under Lung-RADS v2022 guidelines for lung cancer screening, what management is recommended for a newly identified solid nodule measuring 7 mm (Category 3)?

• A) Routine annual screening (Category 1)
• B) 6-month low-dose CT follow-up
• C) Immediate PET/CT and tissue biopsy
• D) 12-month low-dose CT follow-up

Answer: B

• Explanation: Under Lung-RADS v2022, a solid nodule measuring 6 mm to $< 8\text{ mm}$ (or new solid nodule) is Category 3 (Probably Benign), requiring a 6-month low-dose CT follow-up.

Q73: Part-Solid Pulmonary Nodules

Scenario: A persistent part-solid nodule measuring 12 mm overall with a solid component of 4 mm is identified in the right upper lobe. What is the primary differential diagnosis?

• A) Granulomatous infection or focal infarct
• B) Lepidic predominant adenocarcinoma (formerly adenocarcinoma in situ or minimally invasive adenocarcinoma)
• C) Hamartoma with fat and calcification
• D) Round atelectasis

Answer: B

• Explanation: Persistent part-solid nodules carry a high likelihood of malignancy, specifically lung adenocarcinoma with lepidic growth (adenocarcinoma in situ or minimally invasive adenocarcinoma). The size of the solid component dictates the invasive fraction and staging.

Q74: TNM 9th Edition T-Descriptor: Tumor Size

Scenario: Under the TNM 9th Edition staging system for non-small cell lung cancer, what is the T category for a primary tumor measuring 5.5 cm in maximum dimension without invasion of vital mediastinal structures?

• A) T1b
• B) T2b
• C) T3
• D) T4

Answer: B

• Explanation: TNM 9th Edition T descriptors for tumor size: $\le 1\text{ cm}$ (T1a), $> 1-2\text{ cm}$ (T1b), $> 2-3\text{ cm}$ (T1c), $> 3-4\text{ cm}$ (T2a), $> 4-5\text{ cm}$ (T2b), $> 5-7\text{ cm}$ (T3), and $> 7\text{ cm}$ (T4). Thus, 5.5 cm is T2b.

Q75: TNM 9th Edition: Visceral Pleural Invasion

Scenario: A lung cancer measuring 2.5 cm is proven histologically to invade beyond the elastic layer of the visceral pleura (PL1). What is the minimum T category assigned based on this pleural invasion?

• A) T1c
• B) T2a
• C) T3
• D) T4

Answer: B

• Explanation: Visceral pleural invasion (PL1 or PL2) upstages a tumor to at least T2 (specifically T2a if the tumor is $\le 3\text{ cm}$), regardless of its small size.

Q76: TNM 9th Edition: Separate Ipsilateral Nodule

Scenario: A primary lung cancer is located in the left upper lobe, and a separate tumor nodule is identified in the left lower lobe (same ipsilateral lung). What is the T descriptor?

• A) T3
• B) T4
• C) M1a
• D) M1b

Answer: A

• Explanation: A separate tumor nodule in a different lobe of the same ipsilateral lung is classified as T3. If the nodule is in the contralateral lung, it is classified as M1a.

Q77: Mediastinal Lymph Node Stations (N2)

Scenario: During staging of a right lung cancer, an enlarged lymph node is identified in the subcarinal station (Station 7). What N descriptor is assigned?

• A) N1
• B) N2
• C) N3
• D) M1

Answer: B

• Explanation: Ipsilateral mediastinal and subcarinal lymph nodes (including station 7) are classified as N2 disease. Contralateral mediastinal or scalene nodes are N3.

Q78: Pancoast Tumor (Superior Sulcus Tumor)

Scenario: A patient presents with right shoulder and arm pain, Horner syndrome (ptosis, miosis, anhidrosis), and a mass in the superior sulcus of the right lung apex. What is the diagnosis?

• A) Thymoma
• B) Pancoast tumor (superior sulcus NSCLC)
• C) Bronchogenic cyst
• D) Neurogenic schwannoma

Answer: B

• Explanation: A Pancoast tumor is a bronchogenic carcinoma arising in the superior sulcus of the lung apex, classically presenting with Pancoast syndrome (shoulder pain, brachial plexopathy C8-T2, and Horner syndrome from sympathetic chain invasion).

Q79: Superior Vena Cava (SVC) Syndrome

Scenario: A patient with a right upper lobe lung mass presents with facial swelling, distended neck veins, and upper extremity plethora. CT reveals obstruction of the superior vena cava. What T stage feature is this?

• A) T3
• B) T4 (mediastinal/great vessel invasion)
• C) N3
• D) M1c

Answer: B

• Explanation: Invasion of the superior vena cava, heart, or great vessels by a lung cancer constitutes T4 disease (mediastinal structure invasion), frequently resulting in SVC syndrome.

Q80: Bronchial Carcinoid Tumor

Scenario: A 30-year-old non-smoker presents with recurrent hemoptysis and obstructive pneumonia. Bronchoscopy reveals a smooth, hypervascular, polypoid endobronchial mass that enhances avidly on contrast-enhanced CT. What is the diagnosis?

• A) Squamous cell carcinoma
• B) Typical / Atypical bronchial carcinoid tumor
• C) Adenocarcinoma
• D) Small cell lung cancer

Answer: B

• Explanation: Bronchial carcinoid tumors are neuroendocrine neoplasms that typically present as centrally located, highly vascular endobronchial masses in younger patients, frequently causing hemoptysis, atelectasis, and post-obstructive pneumonia.

Q81: Pulmonary Hamartoma

Scenario: A 60-year-old asymptomatic patient has an incidental 2 cm pulmonary nodule. CT demonstrates foci of macroscopic fat and “popcorn” calcifications within the nodule. What is the diagnosis?

• A) Granuloma
• B) Pulmonary hamartoma
• C) Adenocarcinoma
• D) Squamous cell carcinoma

Answer: B

• Explanation: Pulmonary hamartoma is the most common benign lung tumor. Pathognomonic CT features include macroscopic fat attenuation and coarse “popcorn” calcifications.

Q82: Round Atelectasis

Scenario: A patient with a history of asbestos exposure has a rounded, pleural-based mass in the lower lobe with converging blood vessels and bronchi diving into the mass (the comet tail sign). What is this entity?

• A) Bronchogenic carcinoma
• B) Round atelectasis (folded lung)
• C) Pulmonary infarct
• D) Aspergilloma

Answer: B

• Explanation: Round atelectasis (folded lung) is a benign pseudotumor resulting from pleural effusion or inflammation causing infolding of lung parenchyma. The hallmark is the comet tail sign of bronchovascular bundles curving into the mass.

Q83: Pulmonary Metastases

Scenario: A patient with known renal cell carcinoma undergoes chest CT, which demonstrates multiple well-circumscribed, varying-sized “cannonball” nodules scattered throughout both lung fields, predominantly in the lower lung zones. What is the diagnosis?

• A) Septic emboli
• B) Pulmonary metastases (“cannonball” lesions)
• C) Sarcoidosis
• D) Coal worker’s pneumoconiosis

Answer: B

• Explanation: Pulmonary metastases—classically referred to as “cannonball” metastases when large and well-circumscribed from primaries like renal cell carcinoma or choriocarcinoma—spread hematogenously and predominate in the periphery and lower lung bases.

Q84: Septic Pulmonary Emboli

Scenario: An IV drug user presents with fever, pleuritic chest pain, and multiple peripheral nodular opacities, several of which demonstrate central cavitation. What is the diagnosis?

• A) Metastatic carcinoma
• B) Septic pulmonary emboli
• C) Rheumatoid nodules
• D) Wegener granulomatosis (GPA)

Answer: B

• Explanation: Septic pulmonary emboli arise from infected thrombi (e.g., endocarditis, IV drug use, infected lines), presenting as multiple peripheral, subpleural nodules that frequently undergo cavitation.

Q85: Granulomatosis with Polyangiitis (GPA)

Scenario: A patient presents with sinusitis, hematuria, and multiple cavitating pulmonary nodules and masses of varying sizes on chest CT. Antineutrophil cytoplasmic antibodies (c-ANCA) are positive. What is the diagnosis?

• A) Goodpasture syndrome
• B) Granulomatosis with polyangiitis (GPA / Wegener)
• C) Churg-Strauss syndrome (EGPA)
• D) Metastatic squamous cell carcinoma

Answer: B

• Explanation: GPA is an autoimmune vasculitis associated with c-ANCA positivity. It classically presents with upper airway destruction, glomerulonephritis, and multiple cavitating pulmonary nodules and masses.

Section 6: Trauma, Iatrogenic, Congenital & Procedures (Q86–Q100)

Q86: Traumatic Aortic Injury (TAI)

Scenario: A high-speed motor vehicle collision victim undergoes chest CT. Traumatic aortic injury is identified. What is the most common anatomical location for TAI?

• A) Ascending aorta near the aortic valve
• B) Aortic isthmus (just distal to the left subclavian artery attachment near the ligamentum arteriosum)
• C) Abdominal aorta at the level of the renal arteries
• D) Aortic arch between the brachiocephalic and left common carotid arteries

Answer: B

• Explanation: Over 90% of traumatic aortic injuries occur at the aortic isthmus due to rapid deceleration forces placing maximal shearing stress where the mobile aortic arch transitions into the fixed descending aorta.

Q87: Pulmonary Contusion vs. Hematoma

Scenario: A trauma patient sustains blunt chest wall impact. CT demonstrates a patchy, non-segmental alveolar opacity that appears within minutes of trauma, respecting no anatomical boundaries, and clears within 48 to 72 hours. What is this?

• A) Pulmonary laceration
• B) Pulmonary contusion
• C) Aspiration pneumonia
• D) Fat embolism syndrome

Answer: B

• Explanation: Pulmonary contusion represents alveolar hemorrhage and edema from blunt trauma. Unlike lobar pneumonia or aspiration, it appears immediately, does not respect anatomical boundaries, and resolves rapidly within days.

Q88: Pulmonary Laceration (Traumatic Pneumatocele)

Scenario: Following chest trauma, a patient’s CT scan demonstrates a round, air-filled cyst within a contused lung. Over the next week, it fills with fluid. What is this lesion?

• A) Bronchogenic cyst
• B) Pulmonary laceration / traumatic pneumatocele
• C) Hydatid cyst
• D) Lung abscess

Answer: B

• Explanation: A pulmonary laceration is a tear in the lung parenchyma resulting from shear forces, filling with air (traumatic pneumatocele) or blood (pulmonary hematoma).

Q89: Post-Biopsy Pneumothorax

%Scenario: A patient undergoes CT-guided percutaneous core needle biopsy of a peripheral lung nodule. Immediate post-procedural scanning reveals a small pneumothorax. Which factor increases the risk of pneumothorax most significantly?

• A) Increasing depth of the lesion from the pleural surface and presence of underlying emphysema
• B) Biopsy of central hilar lesions rather than peripheral ones
• C) Patient positioning in the prone rather than supine position
• D) Use of coaxial 18-gauge automated cutting needles

Answer: A

• Explanation: The primary risk factors for pneumothorax following percutaneous lung biopsy are increased depth of pleural traversal, traversal of emphysematous lung parenchyma, and smaller nodule size.

Q90: Scimitar Syndrome (PAPVR)

Scenario: A pediatric chest radiograph reveals a hypoplastic right lung and a curved, scimitar-shaped tubular opacity descending toward the inferior vena cava along the right heart border. What is this syndrome?

• A) Swyer-James syndrome
• B) Scimitar syndrome (partial anomalous pulmonary venous return)
• C) Intralobar sequestration
• D) Congenital lobar emphysema

Answer: B

• Explanation: Scimitar syndrome is a form of partial anomalous pulmonary venous return (PAPVR) where right pulmonary veins drain directly into the IVC, resembling a Turkish sword (scimitar) on radiographs, associated with right lung hypoplasia and systemic arterial supply.

Q91: Pulmonary Sequestration: Intralobar vs. Extralobar

Scenario: A congenital non-functioning mass of lung tissue has its own visceral pleural envelope and receives its arterial blood supply directly from the thoracic aorta. What type of sequestration is this?

• A) Intralobar sequestration
• B) Extralobar sequestration
• C) Bronchogenic sequestration
• D) Horseshoe lung

Answer: B

• Explanation: Extralobar sequestration possesses its own distinct visceral pleural envelope and drains into systemic veins (azygos/hemiazygos). Intralobar sequestration shares the visceral pleura of the adjacent normal lung and typically drains into pulmonary veins.

Q92: Congenital Lobar Emphysema (CLE)

Scenario: A neonate presents with severe respiratory distress. Chest radiograph reveals marked hyperinflation of the left upper lobe with compressive atelectasis of the remaining ipsilateral lung and mediastinal shift. What is the diagnosis?

• A) Tension pneumothorax
• B) Congenital lobar emphysema (CLE)
• C) Diaphragmatic hernia
• D) Cystic adenomatoid malformation (CPAM)

Answer: B

• Explanation: CLE is a developmental anomaly characterized by overexpansion of a lung lobe (most commonly the left upper lobe) due to bronchial cartilage dysplasia acting as a ball-valve mechanism.

Q93: Congenital Pulmonary Airway Malformation (CPAM / CCAM)

%Scenario: A prenatal ultrasound and postnatal CT demonstrate a multiseptated cystic lung mass composed of multiple large cysts (Type I CPAM) replacing normal lung parenchyma in an infant. What is the diagnosis?

• A) Bronchogenic cyst
• B) Congenital pulmonary airway malformation (CPAM)
• C) Pulmonary sequestration
• D) Lobar emphysema

Answer: B

• Explanation: CPAM (formerly CCAM) is a hamartomatous developmental malformation of the lower respiratory tract classified by cyst size (Stocker classification Types 0 through 4), often requiring surgical resection to prevent infection and malignant transformation.

Q94: Fat Embolism Syndrome

Scenario: A patient with multiple long bone fractures 48 hours prior develops petechial rash, neurological symptoms, and bilateral diffuse ground-glass opacities and consolidations on chest CT. What is the diagnosis?

• A) Septic emboli
• B) Fat embolism syndrome
• C) Thromboembolic pulmonary embolism
• D) Aspiration pneumonitis

Answer: B

• Explanation: Fat embolism syndrome typically occurs 24 to 72 hours after long bone fractures, presenting with the classic triad of respiratory distress, neurological impairment, and petechial rash, with CT showing ground-glass opacities and consolidations.

Q95: Amniotic Fluid Embolism

Scenario: A parturient during labor experiences sudden cardiovascular collapse, disseminated intravascular coagulation (DIC), and acute pulmonary edema. What is the pathophysiology?

• A) Massive fat embolism
• B) Amniotic fluid embolism
• C) Septic shock
• D) Eclampsia

Answer: B

• Explanation: Amniotic fluid embolism is a catastrophic obstetric complication characterized by entry of amniotic fluid into the maternal circulation, triggering anaphylactoid reactions, severe vasospasm, cor pulmonale, and DIC.

Q96: Tracheobronchial Foreign Body Aspiration

Scenario: A toddler presents with sudden wheezing and coughing. Expiratory chest radiograph demonstrates marked hyperinflation of the right lung. Where is an aspirated foreign body most frequently lodged?

• A) Left main bronchus
• B) Right mainstem bronchus
• C) Trachea directly above the carina
• D) Esophagus

Answer: B

• Explanation: Due to the more vertical orientation and larger caliber of the right mainstem bronchus, aspirated foreign bodies lodge predominantly in the right bronchial tree, producing ball-valve air trapping and hyperinflation of the right lung on expiration.

Q97: Tracheomalacia

Scenario: Dynamic expiratory CT scans of the trachea demonstrate greater than 50% reduction in tracheal luminal cross-sectional area during forced expiration, accompanied by excessive anterior bowing of the posterior membranous wall. What is this condition?

• A) Tracheobronchomegaly
• B) Tracheomalacia
• C) Saber-sheath trachea
• D) Relapsing polychondritis

Answer: B

• Explanation: Tracheomalacia is characterized by weakness of the tracheal walls and supporting cartilage, resulting in excessive expiratory collapse ($> 50\%$ luminal narrowing) due to inward bulging of the posterior membrane.

Q98: Saber-Sheath Trachea

Scenario: A chest radiograph in a patient with severe chronic obstructive pulmonary disease (COPD) demonstrates coronal narrowing of the trachea with compensatory widening in the sagittal plane, along with tracheal calcification. What is this finding?

• A) Tracheomalacia
• B) Saber-sheath trachea
• C) Relapsing polychondritis
• D) Amyloidosis of the trachea

Answer: B

• Explanation: Saber-sheath trachea is a pathognomonic sign of chronic obstructive pulmonary disease (COPD), characterized by coronal narrowing and sagittal elongation of the intrathoracic trachea accompanied by cartilaginous calcification.

Q99: Relapsing Polychondritis

Scenario: A patient presents with hoarseness, upper airway obstruction, and recurrent chondritis of the ears and nose. CT of the trachea demonstrates diffuse thickening and calcification of the tracheal cartilage rings with sparing of the posterior membranous wall. What is the diagnosis?

• A) Tracheomalacia
• B) Relapsing polychondritis
• C) Tracheobronchopathia osteochondroplastica
• D) Amyloidosis

Answer: B

• Explanation: Relapsing polychondritis is an autoimmune inflammatory disorder affecting cartilaginous structures. On CT, tracheal involvement shows thickening and calcification of the anterior and lateral cartilaginous rings with characteristic sparing of the posterior membranous wall (unlike tracheomalacia or amyloidosis).

Q100: Tracheobronchopathia Osteochondroplastica

Scenario: Bronchoscopy and CT of a patient with chronic cough reveal numerous small, hard, nodular osseous and cartilaginous projections studding the anterior and lateral walls of the trachea, with sparing of the posterior membranous wall. What is this benign condition?

• A) Relapsing polychondritis
• B) Tracheobronchopathia osteochondroplastica
• C) Papillomatosis
• D) Amyloidosis

Answer: B

• Explanation: Tracheobronchopathia osteochondroplastica is a rare, benign condition characterized by submucosal cartilaginous and bony nodules projecting into the lumen of the trachea and major bronchi, classically sparing the posterior membranous wall.