Abdomen: Angiography with 16-Detector CT—Comparison of Image Quality and Radiation Dose between Studies with 0.625-mm and those with 1.25-mm Collimation1

Purpose: To prospectively compare image quality and volume computed tomographic (CT) dose index (CTDIvol) of 16-detector CT angiograms of the abdomen acquired with 0.625-mm collimation with those of images acquired with 1.25-mm collimation. Materials and Methods: This study had institutional review board approval, and informed consent was obtained from all patients. Dual-phase contrast material–enhanced CT was performed in 78 patients (48 men and 30 women; age, 34–91 years; mean age, 64.8 years) by using a 16-detector CT scanner. Patients were prospectively randomized into two equal-sized groups: those who underwent CT with 0.625-mm collimation and nonoverlapped reconstruction and those who underwent CT with 1.25-mm collimation and 50% overlapped reconstruction. Scan acquisition time was 7.5 seconds in both groups. CTDIvol was recorded. Arterial phase volume-rendered, arterial phase multiplanar reformatted, and portal venous phase multiplanar reformatted CT angiograms were generated. Qualitative assessmen...