k-t-Space Accelerated Myocardial Perfusion

Purpose: To investigate the performance of the recently introduced spatiotemporal parallel imaging technique called parallel MRI with extended and averaged generalized autocalibrating partially parallel acquisitions (GRAPPA) kernels (PEAK-GRAPPA) for myocardial perfusion measurements. Materials and Methods: A study with 11 patients with myocardial infarction was performed to compare nonaccelerated perfusion imaging, i.e., fully acquired k-space data, with the results of conventional GRAPPA and PEAK-GRAPPA with a net acceleration factor of 2.4 to 3.4. Signal time courses reflecting the passage of the contrast agent bolus in different regions of the heart were evaluated for these different reconstruction methods. Results: Reconstruction with PEAK-GRAPPA demonstrated considerably improved image quality compared to conventional GRAPPA. In addition, signal time courses for PEAK-GRAPPA demonstrated an excellent agreement compared to full k-space data, which is necessary for an accurate qualitative and quantitative assessment of myocardial perfusion. Conclusion: Qualitative and quantitative results of patient measurements illustrate that the temporal fidelity of nonperiodic processes such as myocardial perfusion are preserved with PEAK-GRAPPA up to net acceleration factors of more than 3 while showing a superior image quality compared to conventional GRAPPA and a sliding-window reconstruction.