Right coronary artery flow velocity and volume assessment with spiral K ‐space sampled breathhold velocity‐encoded MRI at 3 tesla: Accuracy and reproducibility

Purpose: To evaluate accuracy and reproducibility of flow velocity and volume measurements in a phantom and in human coronary arteries using breathhold velocity‐encoded (VE) MRI with spiral k ‐space sampling at 3 Tesla. Materials and Methods: Flow velocity assessment was performed using VE MRI with spiral k ‐space sampling. Accuracy of VE MRI was tested in vitro at five constant flow rates. Reproducibility was investigated in 19 healthy subjects (mean age 25.4 ± 1.2 years, 11 men) by repeated acquisition in the right coronary artery (RCA). Results: MRI‐measured flow rates correlated strongly with volumetric collection (Pearson correlation r = 0.99; P < 0.01). Due to limited sample resolution, VE MRI overestimated the flow rate by 47% on average when nonconstricted region‐of‐interest segmentation was used. Using constricted region‐of‐interest segmentation with lumen size equal to ground‐truth luminal size, less than 13% error in flow rate was found. In vivo RCA flow velocity assessment was successful in 82% of the applied studies. High interscan, intra‐ and inter‐observer agreement was found for almost all indices describing coronary flow velocity. Reproducibility for repeated acquisitions varied by less than 16% for peak velocity values and by less than 24% for flow volumes. Conclusion: 3T breathhold VE MRI with spiral k ‐space sampling enables accurate and reproducible assessment of RCA flow velocity. J. Magn. Reson. Imaging 2010;31:1215–1223. © 2010 Wiley‐Liss, Inc.