This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory, Subject name: Medicine
Non contrast ct is investigation of choice for 
Select and explain. 
A. Mediastinal mass, B. Lung mass, C. Nodular thickening of pleura, D. Interstitial lung disease
D: Interstitial lung disease
Answer: D: Interstitial lung disease 
Explanation: 16 (D) (Interstitial lung disease) (707- Davidson 22nd)High resolution CT is superior to the plain chest x ray for early defection and confirmation of suspected ILD (2163-H 18TH).Clinical assessment including chest x-ray, pulmonary function test, haematology, biochemical andimmunological investigations | High -resolution CT||| |Appearances consistent with usual interstitial pneumonia Inconsistent clinical or CT appearances Appearances consistent with another diffuse parenchymal lung disease e,g, sarcoid| | |Diagnose idiopathic pulmonary fibrosis Further investigations, e,g, bronchoalveolar lavage, transbronchial biopsy, surgical biopsy Diagnose and treat accordinglyAlgorithm for the investigation of patients with interstitial lung disease following initial clinical and chest X-ray examination.