In-vitro-Versuche zur Stenosegradbestimmung mit der Spiral-CT-Angiographie

UNLABELLED: Aim of the study was to evaluate the influence of different spiral-CT parameters for the visualisation of vascular stenoses, especially of the renal arteries. MATERIAL AND METHODS: Models with a density equivalent to that of fat, filled with diluted contrast agent, and an inner lumen of 4, 6, 8 mm were scanned in x-, y- and z-direction. Data were acquired in up to 24 second long spiral-CT scans using different spiral-CT parameters (collimation, table speed, reconstruction algorithm, tube current). Detection of the degree of stenosis was achieved by assessment of the axial images and 3D reconstructions. RESULTS: The best correlation between real and measured degree of stenosis was seen by using a small collimation, a low table increment and assessment of the axial images reconstructed in standard algorithm. The stenosis degrees of models directed in x- and y-direction were overestimated and those in z-direction were underestimated depending on the spiral-CT parameters. CONCLUSION: For optimal imaging of renal artery stenoses, collimation of 2 mm (pitch = 1-2 and a reconstruction interval of 1 mm is recommended.