Peripheral pulmonary arteries: optimization of the spiral CT acquisition protocol.

PURPOSE

To analyze the influence of collimation on identification of segmental and subsegmental pulmonary arteries on spiral computed tomographic (CT) scans.

MATERIAL AND METHODS

Contrast material-enhanced spiral CT scans were retrospectively analyzed. Patients in group A (n = 20) underwent CT with 3-mm collimation, 1.00 second per revolution, and pitch of 1.7; those in group B (n = 20) underwent CT with 2-mm collimation, 0.75 second per revolution, and pitch of 2.0. A total of 800 segmental (20 arteries per patient) and 1,600 subsegmental (40 arteries per patient) arteries were assessed.

RESULTS

The mean number of analyzable segmental arteries per patient was greater in group B patients (18.6 of 20.0 [93%]) than that in group A patients (17.0 of 20.0 [85%]) (P < .001). The mean number of analyzable subsegmental arteries per patient was greater in group B patients (24.6 of 40.0 [61%]) than that in group A patients (14.8 of 40.0 [37%]) (P < .0001). Frequency of identification on CT scans of 13 of the 40 subsegmental arteries was improved in group B compared with group A patients (P < .0001).

CONCLUSION

Spiral CT with 2-mm collimation at 0.75 second per revolution enables marked improvement in the analysis of segmental and subsegmental pulmonary arteries.