Investigation of choice for interstitial disease is

High-resolution computed tomography is superior to the plain chest X-ray for early detection and confirmation of suspected ILD(interstitial lung disease).In addition,HRCT allows better assessment of the extent and distribution of disease,and it is especially useful in the investigation of patients with a normal chest radiograph.Co-existing disease is best often recognised on HRCT scanning.e.g.,mediastinal adenopathy,carcinoma,or emphysema.When a lung biopsy is needed,HRCT scanning is useful for determining the most appropriate area from which biopsy sample should be taken. References:Harrison.