Chest Radiology Practice Questions

Q: Pulmonary embolism is best diagnosed by which imaging modality?

CT scan. **Explanation:** **CT Pulmonary Angiography (CTPA)** is currently the **gold standard and investigation of choice** for diagnosing Pulmonary Embolism (PE). It allows for direct visualization of the embolus as a filling defect within the pulmonary arteries. Its high sensitivity and specificity, combined with its ability to provide alternative diagnoses (like pneumonia or aortic dissection), make it the preferred first-line imaging modality in clinical practice. **Analysis of Incorrect Options:** * **Ultrasound:** While Lower Limb Doppler is used to detect Deep Vein Thrombosis (DVT), it cannot directly visualize a pulmonary embolus. It is an adjunct, not the primary diagnostic tool for PE. * **Chest X-ray:** Usually the first investigation performed, but it is often **normal** in PE. While it may show signs like *Hampton’s Hump* (wedge-shaped opacity) or *Westermark sign* (focal oligemia), these are rare and non-specific. Its main role is to rule out other causes of chest pain. * **Ventilation-Perfusion (V/Q) Scan:** Previously the investigation of choice, it is now reserved for patients with **contraindications to CTPA**, such as severe renal failure (due to contrast risk) or pregnancy. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** CT Pulmonary Angiography. * **Most Definitive (Invasive):** Conventional Pulmonary Angiography (rarely used now). * **ECG Finding:** Most common is Sinus Tachycardia; most specific is the **S1Q3T3 pattern**. * **Initial Screening Test:** D-Dimer (high negative predictive value). * **Investigation of choice in Pregnancy:** V/Q scan is often preferred to minimize maternal breast radiation, though protocols vary.

Q: Westermark sign is seen in which condition?

Pulmonary embolism. **Explanation:** **Westermark sign** is a classic, though infrequent, radiographic finding in **Pulmonary Embolism (PE)**. It refers to a focal area of increased lucency (hyperlucency) on a chest X-ray, caused by **oligemia** (reduced blood flow) distal to the occluded pulmonary artery. The lack of blood flow leads to a reduction in the caliber of peripheral vessels, making that segment of the lung appear darker than the surrounding tissue. **Analysis of Options:** * **Pulmonary Embolism (Correct):** In addition to Westermark sign, other X-ray signs include **Hampton’s Hump** (a wedge-shaped opacity representing pulmonary infarction) and **Palla’s sign** (enlarged right descending pulmonary artery). * **Pulmonary Sequestration:** This is a congenital anomaly where a segment of lung tissue lacks communication with the tracheobronchial tree and receives systemic arterial supply. It typically appears as a solid mass or cystic lesion, not focal oligemia. * **Pulmonary Alveolar Proteinosis:** Characterized by the accumulation of surfactant in alveoli. The classic radiographic finding is a **"Bat-wing" appearance** or "Crazy paving" pattern on CT. * **Pneumothorax:** While this also shows hyperlucency, it is characterized by the **absence of lung markings** and a visible visceral pleural line, rather than just reduced vessel caliber. **NEET-PG High-Yield Pearls:** * **Gold Standard Investigation for PE:** CT Pulmonary Angiography (CTPA). * **Most Common X-ray finding in PE:** A normal chest X-ray is the most common finding; however, **atelectasis** is the most common abnormality seen. * **ECG in PE:** Most common finding is **Sinus Tachycardia**; most specific is the **S1Q3T3 pattern**.

Q: Mounier-Kuhn syndrome is characterized on imaging by which finding?

Tracheobronchomegaly. **Explanation:** **Mounier-Kuhn Syndrome**, also known as **Tracheobronchomegaly**, is a rare clinical entity characterized by marked dilation of the trachea and mainstem bronchi. The underlying pathophysiology involves the atrophy or absence of elastic fibers and smooth muscle within the tracheobronchial wall, leading to redundant, flaccid airways that collapse during expiration (tracheobronchomalacia). **Why Option B is correct:** On imaging (CT Chest), the diagnosis is confirmed when the transverse or anteroposterior diameter of the trachea exceeds **30 mm** (measured 2 cm above the aortic arch). The right and left mainstem bronchi are also dilated (>20 mm and >18 mm, respectively). A classic sign is the presence of **tracheal diverticulosis**, where the redundant mucosa herniates through the weakened muscular wall. **Why other options are incorrect:** * **A. Tracheal stenosis:** This refers to narrowing of the airway (e.g., post-intubation or Wegener’s), which is the opposite of the dilation seen in Mounier-Kuhn. * **C. Tracheal erosions:** These are typically seen in malignancy or chronic irritation (e.g., tracheostomy tubes) and are not a feature of this congenital connective tissue disorder. * **D. Sabre sheath trachea:** This refers to a trachea with a narrow transverse diameter and an increased AP diameter (ratio >2:1), characteristically associated with **COPD**, not Mounier-Kuhn. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Recurrent lower respiratory tract infections and bronchiectasis due to ineffective cough and impaired mucociliary clearance. * **Dynamic Imaging:** Expiratory CT is the gold standard to demonstrate dynamic airway collapse. * **Associations:** Often linked with Ehlers-Danlos syndrome or Marfan syndrome.

Q: What is the earliest chest X-ray finding in cystic fibrosis?

Hyperinflation. **Explanation:** Cystic Fibrosis (CF) is a multisystem disorder characterized by thick, viscous secretions. In the lungs, these secretions lead to small airway obstruction and air trapping long before structural damage occurs. **1. Why Hyperinflation is the correct answer:** The earliest radiological manifestation of CF is **hyperinflation**. This occurs due to the "ball-valve" effect, where thick mucus plugs allow air to enter during inspiration but prevent it from exiting during expiration. On a chest X-ray, this is visualized as flattened diaphragms, an increased retrosternal clear space, and horizontal ribs. **2. Analysis of Incorrect Options:** * **Ring shadows:** These represent thickened bronchial walls seen end-on or dilated bronchi (bronchiectasis). While classic for CF, they indicate established structural damage and appear later than hyperinflation. * **Marked increase in bronchovascular markings:** This is a non-specific finding often associated with chronic bronchitis or early inflammation, but it typically follows the initial phase of air trapping. * **Prominent right descending pulmonary artery:** This is a sign of **pulmonary hypertension**, which is a late-stage complication of CF resulting from chronic hypoxia and cor pulmonale. **3. NEET-PG High-Yield Pearls:** * **Earliest Sign:** Hyperinflation. * **Most Common Pattern:** Bronchiectasis, typically involving the **upper lobes** (unlike idiopathic bronchiectasis, which often affects the lower lobes). * **Finger-in-glove sign:** Represents mucoid impaction in dilated bronchi. * **Gold Standard Diagnosis:** Sweat Chloride Test (>60 mEq/L). * **Common Pathogens:** *Staphylococcus aureus* (early childhood) and *Pseudomonas aeruginosa* (most common in adults).

Q: Obliteration of the right cardiac silhouette on a chest X-ray suggests pathology involving which of the following structures?

Right middle lobe. This question tests the concept of the **Silhouette Sign**, a fundamental principle in chest radiology. ### **The Concept: Silhouette Sign** The silhouette sign occurs when two structures of similar radiographic density (e.g., soft tissue and fluid/consolidation) are in direct anatomical contact. This results in the loss of the distinct border or "silhouette" between them. 1. **Why Right Middle Lobe (RML) is correct:** Anatomically, the RML lies anteriorly and is in direct contact with the **right heart border (Right Atrium)**. Therefore, any pathology that increases the density of the RML (like pneumonia or collapse) will obliterate the right heart border. 2. **Why Right Lower Lobe (RLL) is incorrect:** The RLL is located posteriorly. It does not touch the heart border but sits on the diaphragm. Pathology in the RLL obliterates the **right hemidiaphragm** but leaves the heart border visible. 3. **Why Right Atrium/Ventricle are incorrect:** These are the structures that *form* the silhouette, not the lung segments causing the obliteration. The right heart border is formed by the right atrium, while the right ventricle is an anterior structure that does not form a border on a standard PA view. ### **High-Yield Clinical Pearls for NEET-PG** * **Right Heart Border:** Obliterated by **Right Middle Lobe** lesions. * **Right Hemidiaphragm:** Obliterated by **Right Lower Lobe** lesions. * **Left Heart Border:** Obliterated by **Lingula** (Left Upper Lobe) lesions. * **Left Hemidiaphragm:** Obliterated by **Left Lower Lobe** lesions. * **Aortic Knuckle:** Obliterated by **Left Upper Lobe (Posterior segment)** or mediastinal masses. * **Descending Aorta:** Obliterated by **Left Lower Lobe** lesions.

Q: A chest X-ray shows a homogenous opacity on the right side with a shift of the mediastinum to the opposite side. What is the most probable diagnosis?

Pleural effusion. ### Explanation The key to solving chest radiology questions in NEET-PG lies in identifying the **opacity** and the **position of the mediastinum**. **1. Why Pleural Effusion is Correct:** A large pleural effusion presents as a **homogenous opacity** (radiopacity) because fluid absorbs more X-rays than air-filled lung tissue. Since fluid occupies space in the pleural cavity, it exerts **positive pressure**, pushing the mobile mediastinal structures (like the trachea and heart) toward the **opposite (contralateral) side**. The classic radiological sign is the obliteration of costophrenic angles and a meniscus sign. **2. Analysis of Incorrect Options:** * **Collapse (A):** While it also shows a homogenous opacity, collapse involves a loss of lung volume. This creates negative pressure, **pulling** the mediastinum toward the **same (ipsilateral) side**. * **Pneumothorax (C):** This presents as an area of **hyperlucency** (increased blackness) due to air in the pleural space, not an opacity. While it can shift the mediastinum to the opposite side (Tension Pneumothorax), the density description does not match. * **Consolidation (D):** This appears as an ill-defined opacity (often with air bronchograms). Crucially, consolidation does not typically exert mass effect, so the **mediastinum remains central**. **3. NEET-PG High-Yield Pearls:** * **Shift to Same Side:** Collapse, Pneumonectomy, Agenesis. * **Shift to Opposite Side:** Large Pleural Effusion, Tension Pneumothorax, Large Diaphragmatic Hernia. * **No Shift:** Consolidation, Pulmonary Infarction, Small Effusion/Collapse. * **Meniscus Sign:** Characteristic of a moderate pleural effusion on an erect CXR.

Q: What is the earliest feature of pulmonary venous hypertension?

Upper lobar diversion of vessels. **Explanation:** Pulmonary venous hypertension (PVH) is most commonly caused by left-sided heart failure or mitral valve disease. The progression of PVH follows a predictable sequence on chest X-ray based on the Pulmonary Capillary Wedge Pressure (PCWP). **1. Why "Upper lobar diversion" is correct:** Also known as **Cephalization** or the **Antler sign**, this is the **earliest** radiological sign of PVH, occurring when PCWP rises to **10–15 mmHg**. In a normal upright individual, lower lobe vessels are more prominent due to gravity. In PVH, interstitial edema causes perivascular pressure to rise, leading to the constriction of lower lobe vessels and a compensatory shunting of blood to the upper lobes. **2. Analysis of Incorrect Options:** * **Kerley B lines:** These represent thickening of the interlobular septa due to fluid. They indicate **interstitial edema** and typically appear when PCWP reaches **15–20 mmHg**. This is a later stage than cephalization. * **Left atrial enlargement:** While often present in chronic conditions like mitral stenosis, it is a sign of the *underlying cause* rather than a feature of pulmonary venous hypertension itself. * **Pleural effusion:** This occurs during the **alveolar edema** stage when PCWP exceeds **25 mmHg**. It is a late finding. **High-Yield Clinical Pearls for NEET-PG:** * **Stages of PVH:** 1. **Stage 1 (Redistribution):** PCWP 10-15 mmHg → Cephalization. 2. **Stage 2 (Interstitial Edema):** PCWP 15-25 mmHg → Kerley lines, Peribronchial cuffing, Hazy hila. 3. **Stage 3 (Alveolar Edema):** PCWP >25 mmHg → Bat-wing appearance, Pleural effusion. * **Kerley B lines** are best seen at the **costophrenic angles** (perpendicular to the pleura).

Q: Based on the provided image, what is the most likely diagnosis?

Emphysema. ***Emphysema*** - Classic chest X-ray features include **hyperinflation** with **flattened diaphragms**, **barrel chest** appearance, and **hyperlucent lung fields** with **attenuated vascular markings**. - The **increased anteroposterior diameter** and **reduced cardiac silhouette** are characteristic findings in advanced emphysema. *Pneumothorax* - Would show **absent lung markings** in the affected area with a visible **visceral pleural line** separating collapsed lung from pleural space. - Typically presents with **sudden onset chest pain** and **dyspnea**, not the chronic progressive pattern seen in emphysema. *Bronchiectasis* - Characterized by **tramline shadows** (parallel lines representing dilated bronchi) and **ring shadows** (dilated bronchi seen end-on). - Often shows **increased markings** and **honeycombing** rather than the hyperlucent fields typical of emphysema. *Cardiomegaly* - Defined by **cardiothoracic ratio >0.5** with an enlarged cardiac silhouette on chest X-ray. - The heart shadow would be **prominently enlarged**, which contrasts with the **small heart** appearance often seen in emphysema due to hyperinflation.

Question 1

Pulmonary embolism is best diagnosed by which imaging modality?

Accepted Answer

CT scan

Answer

Ultrasound

Answer

Chest X-ray

Answer

Ventilation-Perfusion scan

Question 2

Which of the following statements regarding signs of pulmonary embolism are TRUE or FALSE?

Accepted Answer

McConnell sign is seen in CT pulmonary angiography as a filling defect. Westermark sign is an area of regional oligemia seen on x-ray. Polo mint sign is seen in echocardiography as regional motion abnormality. IOC in a pregnant patient is V/Q scan. Chang sign is an abrupt change in diameter of the right descending pulmonary artery.

Answer

McConnell sign is seen in CT pulmonary angiography as a filling defect. Westermark sign is an area of regional oligemia seen on x-ray. Polo sign is seen in echocardiography as regional motion abnormality. IOC in a pregnant patient is V/Q scan. Chang sign is an abrupt change in diameter of the right descending pulmonary artery.

Question 3

Westermark sign is seen in which condition?

Accepted Answer

Pulmonary embolism

Answer

Pulmonary sequestration

Answer

Pulmonary alveolar proteinosis

Answer

Pneumothorax

Question 4

Mounier-Kuhn syndrome is characterized on imaging by which finding?

Accepted Answer

Tracheobronchomegaly

Answer

Tracheal stenosis

Answer

Tracheal erosions

Answer

Sabre sheath trachea

Question 5

All of the following statements about Pneumococcal Pneumonia are true, except?

Accepted Answer

Non-segmental Consolidation

Answer

Air Bronchogram Absent

Answer

Usually confined to one lobe

Answer

Cavitation is rare

Question 6

What is the earliest chest X-ray finding in cystic fibrosis?

Accepted Answer

Hyperinflation

Answer

Ring shadows

Answer

Marked increase in bronchovascular markings

Answer

Prominent right descending pulmonary artery

Question 7

Obliteration of the right cardiac silhouette on a chest X-ray suggests pathology involving which of the following structures?

Accepted Answer

Right middle lobe

Answer

Right lower lobe

Answer

Right atrium

Answer

Right ventricle

Question 8

A chest X-ray shows a homogenous opacity on the right side with a shift of the mediastinum to the opposite side. What is the most probable diagnosis?

Accepted Answer

Pleural effusion

Answer

Collapse

Answer

Pneumothorax

Answer

Consolidation

Question 9

What is the earliest feature of pulmonary venous hypertension?

Accepted Answer

Upper lobar diversion of vessels

Answer

Kerley B lines

Answer

Left atrial enlargement

Answer

Pleural effusion

Question 10

Based on the provided image, what is the most likely diagnosis?

Accepted Answer

Emphysema

Answer

Pneumothorax

Answer

Bronchiectasis

Answer

Cardiomegaly

Chest Radiology — MCQs

Chest Radiology — MCQs

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