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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.


MATERIALS AND METHODS
Both thin-section and helical CT scans were obtained in 50 consecutive patients with clinical symptoms suggestive of bronchiectasis. Thin-section CT was performed with 1.5-mm collimation and 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 evaluated 593 segments on CT scans both independently and in consensus. Radiation dose was measured for both techniques.


RESULTS
Bronchiectasis was noted in 77 segments (22 patients) on thin-section CT scans compared with 90 segments (26 patients) on helical CT scans. No findings were positive for bronchiectasis on only thin-section CT scans. Interobserver agreement was statistically significantly better (P < .05) in identification of segments that were positive for bronchiectasis on helical 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 times greater than that delivered with thin-section CT.


CONCLUSION
Helical scanning can improve CT depiction of bronchiectasis but with an increase in radiation exposure to the patient. It should be used in patients considered for surgery or for thin-section CT scans that are difficult to interpret.