Phase-contrast MR angiography of the lower extremity. Comparison of methods and clinical application

Purpose: To investigate whether phase-contrast MRA is a clinically suited approach to examine arteries of the pelvis and lower extremities. Methods: The study was divided into two parts, a volunteer study and patient study. Three MRA techniques - 2D TOF with venous saturation, 3D magnitude contrast and 2D phase contrast with EGG triggering were intraindividually compared in 15 volunteers and evaluated by three blinded readers. Subsequently, a total of 230 vessel segments of 45 MRA studies using EGG-triggered phase contrast were compared with intraarterial DSA. All vessel segments were scored by three blinded readers using a five-point scale with DSA serving as the gold standard. Results: EGG-triggered phase contrast provided better image quality than the other MRA techniques as assessed by the Friedman test. Clinical studies demonstrated a significant correlation of DSA and MRA as assessed by the Spearman correlation and kappa statistics for individual readers. Conclusion: MRA of the pelvis and lower extremities may be performed with 2D ECG-triggered phase-contrast MRA within a reasonable time frame (< 30 min). MRA slabs provide orientation similar to that with DSA projections and good to very good correlation of vessel pathology as shown by kappa statistics.