**Core Concept**
High-resolution computed tomography (HRCT) of the chest is a critical diagnostic tool for detecting and characterizing interstitial lung disease (ILD). ILD encompasses a diverse group of lung disorders characterized by inflammation and fibrosis of the lung interstitium, which can lead to progressive lung damage and impairment of lung function.

**Why the Correct Answer is Right**
HRCT allows for the detailed visualization of lung parenchyma, bronchi, and blood vessels, providing a comprehensive assessment of ILD patterns, including ground-glass opacifications, reticular patterns, honeycombing, and traction bronchiectasis. The high spatial resolution of HRCT enables the identification of subtle changes in lung tissue, facilitating the diagnosis and differentiation of various ILD subtypes. The non-invasive nature of HRCT also makes it an ideal initial imaging modality for patients with suspected ILD.

**Why Each Wrong Option is Incorrect**
**Option A:** Chest X-ray is not sensitive or specific for detecting ILD, particularly in its early stages, and may not demonstrate any abnormalities until significant lung damage has occurred.
**Option B:** Pulmonary function tests (PFTs) are useful in assessing the functional impairment associated with ILD but do not provide direct visualization of lung tissue morphology.
**Option C:** Magnetic resonance imaging (MRI) may be used to evaluate the extent of pulmonary involvement in certain conditions, such as sarcoidosis, but is not the primary imaging modality for ILD.

**Clinical Pearl / High-Yield Fact**
When interpreting HRCT images in patients with suspected ILD, it is essential to consider the distribution and pattern of abnormalities, as well as the presence of any associated findings, such as pulmonary hypertension or mediastinal lymphadenopathy.

**Correct Answer: C. High-resolution computed tomography (HRCT) of the chest.