Investigation of choice for bronchiectasis is-

Ans. is 'd' i.e., HRCT * HRCT is the investigation of choice for bronchiectesis* The CT criteria for diagnosis include 'signet -ring' sign (bronchus being larger than accompanying vessel), bronchial wall thickening, and bronchi visible within 1 cm of the pleura.* Three types are described according to Their appearance :-A. Cylindrical:- Mild diffuse dilatation of the bronchi. Radiologically there is Tram - Trank appearance, i.e. lack of peripheral tapering.B. Varicose:- Cystic bronchial dilatation interrupted by focal areas of narrowing, giving radiological appearance of'String of pearl (string of beads).C. Saccular (cystic):- Clusters of bronchi with marked saccular dilatation. Cystic bronchiectasis in any region is easily recognized as clusters of rounded lucencies, often containing air - fluid levels; this appearance has been linked to a 'cluster of grapes'.Investigations of choice in respiratory systemDiseaseInvestigation* Interstitial lung disease* HRCT* Bronchiectasis* HRCT (1st choice)* Bronchography (2nd choice)* Pulmonary embolism* CT with i.v. Contrast (1st choice)* V/Q scan (2nd choice)* Solitary pulmonary nodule* CT scan* Calcification* CT scan* Pulmonary malignancy* CT scan (except in superior sulcus or pancoast tumor)* Superior sulcus or pancoast tumor* MRI