Vitro examinations for detection of vascular stenoses using spiral CT angiography.

Purpose: This experimental study investigates the suitability of spiral CT angiography for detection of stenoses. Material and methods: Three vessel phantoms of 4, 7, and 10 mm diameter were scanned with spiral CT several times using different scanning parameters each time. Axial scans were viewed in different ways. Stenoses were adjusted axial, oblique, and parallel to the scan plane, and in between. 7 radiologists had to make a total of 630 decisions about the detectability of stenoses. Results: Adequate scan- and reconstructional parameters improve detection of stenoses significantly. 100% recognition can be reached with 5 mm layer thickness and table feed and 2 mm reconstructional interval provided axial scans are viewed in cine mode on a monitor. Vessels running parallel to the layer plane show better results than vessels axial to the plane, which in turn show better results than those running oblique. Vessels of 4 to 10 mm diameter are almost equally suitable. Conclusions: Viewing axial scans, the detectability is rather influenced by different locations of stenoses than by varying vessel diameters.