Evaluation of renal artery stenosis on CT-angiography: Comparison of various rendering techniques (AXIAL, MPR, MIP, SSD).

Purpose: To evaluate the various reconstruction methods of helical-CT angio graphy for the assessment of hemodynamically relevant renal artery stenoses in comparison to i.a. DSA. Methods: In 76 renal arteries the reconstructio n modalities AXIAL, MRP, MIP and SSD of helical-CT angiography were compare d with the results of i.a. DSA for the determination of the grade and locat ion of the stenosis, Results: The highest accuracy of stenosis grading was 76% with AXIAL reconstruction. In 8% of the cases grading of the stenosis w as not evaluable by the AXIAL reconstruction, In these cases, a higher sens itivity in the detection of hemodynamically relevant stenoses (>grade II, > 50%) was achieved with the reconstruction mode MPR (96%) than with MIP (92 %), In 51% of the cases the reconstruction mode SSD was not suitable for an y diagnosis of renal artery stenosis because of overlying calcified plaques . Conclusions: The evidence of hemodynamically relevant stenosis in helical -CT angiography in comparison to i.a. DSA succeeds most reliable by using t he reconstruction modality AXIAL in combination with MPR. The MIP reconstru ction provides information about the anatomy of the renal arteries within o ne image.