Investigation of choice for Interstitial Lung Disease?

Ans. b (HRCT) (Ref. Harrison 18th/ p 1554)High Resolution Computerized Tomography # BASIC PRINCIPLE:- "Bone algorithm" (Basic Principle)0- Narrow beam collmation- 1 mm sections- Small field of view- Large matrix size# INDICATIONS (Investigation of choice for):- LUNGS:* Interstitial Lung Disease (ILD)* Bronchiectasis ("Signet-ring" sign)* Emphysema- PETROUS TEMPORAL BONE:* Cholesteatoma* Mastoiditis & Petrositis* Ossicular chain disruption* Congenital ear malformations* Facial canal fracture# Some Patterns of ILDs on HRCT:- "Groundglass" haziness is the earliest sign of almost all ILDs.0- "Honeycombing" correlates with end-stage disease.- "Tree in bud" apperance is seen in atypical mycobacterial infection/endobronchial TB.deg- "Crazy paving" is seen in several ILDs but is a distinct feature of Pulmonary Alveolar Proteiniosis.- Multiple discrete "lung cysts" and chylous pleural effusion in a postmenopausal women is chracteristic of lymphangioleomyomatosis.- "Mosaic perfusion" is also a feature of ILD.Also KnowDiseases with Predeliction for Upper Lung ZonesDiseases with Predeliction for Lower Lung ZonesExtrinsic allergic alveolitis (chronic hypersensitivity pneumonitis)Fibrosing alveolitisCWPAsbestosisLCHInterstitial pulmonary edemaAnkylosing spondylitisLymphangitis carcinomatosaSilicosis Sarcoidosis