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[In vitro studies to determine the degree of stenosis using spiral CT angiography]
G Wittenberg1, G Lenk, M Jenett
1Institut für Röntgendiagnostik, Universität Würzburg.
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.