**Question:** The best method to diagnose bronchiectasis:

A. Chest radiography
B. High-resolution computed tomography (HRCT) scan
C. Bronchoscopy and bronchoalveolar lavage (BAL)
D. Endobronchial ultrasound (EBUS)

**Correct Answer:** B. High-resolution computed tomography (HRCT) scan

**Core Concept:** Bronchiectasis is a condition characterized by irreversible dilation and distortion of the bronchi, usually resulting from chronic inflammation, infection, or obstruction. Diagnosis involves identifying these changes on imaging studies.

**Why the Correct Answer is Right:**

High-resolution computed tomography (HRCT) scan is the most accurate and sensitive method for diagnosing bronchiectasis due to its superior spatial resolution and ability to visualize small bronchiectatic changes. HRCT can detect both central and peripheral abnormalities, as well as the distribution, severity, and pattern of bronchiectasis.

**Why Each Wrong Option is Incorrect:**

A. Chest radiography (x-ray) is less sensitive and specific than HRCT scan for detecting bronchiectasis, especially in its early stages. It is less detailed and fails to identify peripheral or small bronchiectatic changes.

B. Bronchoscopy and bronchoalveolar lavage (BAL) are procedures used to diagnose respiratory infections and inflammation but are not diagnostic tools for bronchiectasis. They provide information about the lower respiratory tract and are not specific for bronchiectasis.

C. Endobronchial ultrasound (EBUS) is a procedure used for sampling lymph nodes and mediastinal lesions, not specifically for diagnosing bronchiectasis. While EBUS may reveal associated findings in bronchiectasis patients, it is not dedicated to diagnose bronchiectasis itself.

**Clinical Pearl:** HRCT scan is a crucial tool for diagnosing bronchiectasis due to its high sensitivity and specificity. Early diagnosis allows for appropriate management, such as antibiotics, mucolytics, bronchodilators, and physiotherapy to prevent complications like lung parenchyma destruction, chronic cough, and recurrent infections.