A patient presents with a cavitatory lesion in right upper lobe of lung. The best investigation is?
**Core Concept**
A cavitatory lesion in the lung refers to a hollow area within the lung tissue, often resulting from necrosis or tissue destruction. This condition can be associated with infections, such as tuberculosis or fungal infections, or non-infectious causes like cancer. The investigation of choice should aim to identify the underlying cause and extent of the lesion.
**Why the Correct Answer is Right**
The best investigation for a cavitatory lesion in the lung is a high-resolution computed tomography (HRCT) scan of the chest. HRCT provides detailed images of the lung tissue, allowing for the visualization of the cavitary lesion and its surrounding structures. This modality is particularly useful in detecting small lesions and assessing the extent of lung involvement. Additionally, HRCT can help differentiate between infectious and non-infectious causes of cavitary lesions.
**Why Each Wrong Option is Incorrect**
* **Option A:** Chest X-ray, while useful for initial evaluation, is not sufficient for detailed assessment of cavitary lesions. It may not provide the necessary resolution to detect small lesions or assess lung involvement.
* **Option B:** Positron Emission Tomography (PET) scan is more useful for assessing metabolic activity within lesions, rather than providing detailed anatomical information.
* **Option D:** Magnetic Resonance Imaging (MRI) is not typically used for lung imaging due to its limited ability to penetrate through lung tissue.
**Clinical Pearl / High-Yield Fact**
When evaluating a patient with a cavitary lesion in the lung, it is essential to consider both infectious and non-infectious causes, and to obtain a detailed history and physical examination to inform the choice of investigation.
**Correct Answer: C. HRCT scan of the chest.**