Active pulmonary TB can be diagnosed on CT-scan by following finding ?
Ans. is 'a' i.e., Tree in bud appearance(Ref Chapman 4n/e p.142,143; Fundamentals of radiology) Tree-in-bud sign or pattern describes the CT appearance of multiple areas of centrilobular nodules with a linear branching pattern.This is a characteristic sign of active pulmonary TB.Other impoant sign of pulmonary TB on CT is lymph nodes showing peripheral rim enhancement because of necrosis.
Tree in bud appearance
Honey comb appearance
Ground glass appearance
Signet ring sign