Helical computed tomography of the abdomen: evaluation of image quality using 1.0, 1.3, and 1.5 pitches.

BACKGROUND The purpose of this study was to investigate whether trained radiologists can distinguish minor differences among computed tomography (CT) images of extended helical pitches of 1.0 to 1.5. METHODS Between September 2000 and February 2001, 72 patients were randomized into 1 of 3 equal groups: helical pitches of 1.0, 1.3, and 1.5. The imaging parameters of all patients were kept constant. Twelve of the 72 patients were excluded because of various pathological conditions. In a total, 60 examinations were enrolled in the evaluation study. Three radiologists blinded to the image parameters were asked to independently evaluate 9 normal structures and overall images of 60 studies using a scale from 1 (worst) to 5 (best). RESULTS There were no statistically significant differences in evaluation of image quality among helical pitches 1.0, 1.3, and 1.5 of abdominal CT when assessing 9 normal structures and overall images independently (p > 0.05). CONCLUSIONS Abdominal CT performed with helical pitches of 1.0, 1.3, and 1.5 were equivalent in this study. With the use of a helical pitch greater than 1, clinicians can benefit from increased scan coverage in less time and with less radiation than can be achieved with standard helical pitch-1.0 protocols.