**Core Concept**
The patient in this scenario is presenting with symptoms suggestive of pulmonary disease, such as recurrent hemoptysis and purulent sputum, despite a normal chest X-ray. This situation highlights the limitations of conventional radiography in detecting certain pulmonary abnormalities, especially those that are not easily visible on a standard chest X-ray.

**Why the Correct Answer is Right**
High-Resolution Computed Tomography (HRCT) is the next best investigation for Rampal due to its superior ability to visualize the lung parenchyma and bronchial tree. HRCT can detect subtle abnormalities in lung structure and function, such as bronchiectasis, bronchial dilation, and mucoid impaction, which may be responsible for the patient's symptoms. The high-resolution images provided by HRCT enable accurate assessment of lung morphology and aid in diagnosing conditions like cystic fibrosis, primary ciliary dyskinesia, and chronic bronchiectasis.

**Why Each Wrong Option is Incorrect**
**Option A:** CT-guided angiography is not typically used as a first-line investigation for recurrent hemoptysis, as it is more invasive and usually reserved for cases where a specific vascular lesion is suspected.
**Option B:** Angiography is also not the next best investigation, as it is primarily used to visualize the blood vessels and diagnose vascular abnormalities, which may not be the primary concern in this case.
**Option D:** Spiral CT (also known as helical CT) is a rapid scanning technique that provides a better overview of the lung parenchyma but lacks the high-resolution detail of HRCT, making it less suitable for detecting subtle abnormalities.

**Clinical Pearl / High-Yield Fact**
In patients with recurrent hemoptysis and a normal chest X-ray, HRCT is often the best initial imaging modality to evaluate the lung parenchyma and bronchial tree, helping to identify underlying conditions that may be causing symptoms.

**✓ Correct Answer: A. HRCT**