BRONCHIECTASIS - COMPARATIVE-ASSESSMENT WITH THIN-SECTION CT AND HELICAL CT

PURPOSE: To compare thin-section computed tomography (CT) and helical CT in the detection and assessment of the extent of bronchiectasis. MA TERIALS AND METHODS: Both thin-section and helical CT scans were obtai ned in 50 consecutive patients with clinical symptoms suggestive of br onchiectasis. Thin-section CT was performed with 1.5-mm collimation an d 10-mm intervals, and helical CT was performed with 3-mm collimation and a pitch of 1.6 during a 24-second breath hold. Three observers eva luated 593 segments on CT scans both independently and in consensus. R adiation dose was measured for both techniques. RESULTS: Bronchiectasi s was noted in 77 segments (22 patients) on thin-section CT scans comp ared with 90 segments (26 patients) on helical CT scans. No findings w ere positive for bronchiectasis on only thin-section CT scans. Interob server agreement was statistically significantly better (P < .05) in i dentification of segments that were positive for bronchiectasis on hel ical CT scans (kappa = 0.87) than on thin-section CT scans (kappa = 0. 71). Total skin dose of radiation delivered with helical CT was 3.4 ti mes greater than that delivered with thin-section CT. CONCLUSION: Heli cal scanning can improve CT depiction of bronchiectasis but with an in crease in radiation exposure to the patient. It should be used in pati ents considered for surgery or for thin-section CT scans that are diff icult to interpret.