Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.
Department of Radiology and Nuclear Medicine, St. Olavs hospital, Trondheim University Hostpital, Trondheim, Norway.
NMR Biomed. 2024 Aug;37(8):e5136. doi: 10.1002/nbm.5136. Epub 2024 Mar 21.
High acceleration factors in radial magnetic resonance fingerprinting (MRF) of the prostate lead to strong streak-like artefacts from flow in the femoral blood vessels, possibly concealing important anatomical information. Region-optimised virtual (ROVir) coils is a beamforming-based framework to create virtual coils that maximise signal in a region of interest while minimising signal in a region of interference. In this study, the potential of removing femoral flow streak artefacts in prostate MRF using ROVir coils is demonstrated in silico and in vivo. The ROVir framework was applied to radial MRF k-space data in an automated pipeline designed to maximise prostate signal while minimising signal from the femoral vessels. The method was tested in 15 asymptomatic volunteers at 3 T. The presence of streaks was visually assessed and measurements of whole prostate T, T and signal-to-noise ratio (SNR) with and without streak correction were examined. In addition, a purpose-built simulation framework in which blood flow through the femoral vessels can be turned on and off was used to quantitatively evaluate ROVir's ability to suppress streaks in radial prostate MRF. In vivo it was shown that removing selected ROVir coils visibly reduces streak-like artefacts from the femoral blood flow, without increasing the reconstruction time. On average, 80% of the prostate SNR was retained. A similar reduction of streaks was also observed in silico, while the quantitative accuracy of T and T mapping was retained. In conclusion, ROVir coils efficiently suppress streaking artefacts from blood flow in radial MRF of the prostate, thereby improving the visual clarity of the images, without significant sacrifices to acquisition time, reconstruction time and accuracy of quantitative values. This is expected to help enable T and T mapping of prostate cancer in clinically viable times, aiding differentiation between prostate cancer from noncancer and healthy prostate tissue.
高加速因子在前列腺的磁共振指纹成像（MRF）中导致来自股血管的流动的强条纹状伪影，可能隐藏重要的解剖信息。区域优化虚拟（ROVir）线圈是一种基于波束形成的框架，用于创建虚拟线圈，在感兴趣区域最大化信号，同时在干扰区域最小化信号。在这项研究中，在前列腺 MRF 中使用 ROVir 线圈去除股流条纹伪影的潜力在计算机模拟和体内进行了证明。ROVir 框架应用于径向 MRF k 空间数据，在自动化管道中设计为最大化前列腺信号，同时最小化来自股血管的信号。该方法在 15 名无症状志愿者中在 3T 进行了测试。通过目视评估条纹的存在，并检查存在和不存在条纹校正的整个前列腺 T、T 和信噪比（SNR）的测量值。此外，还使用专门构建的模拟框架，可以打开和关闭股血管中的血流，以定量评估 ROVir 抑制径向前列腺 MRF 中条纹的能力。在体内，结果表明，去除选定的 ROVir 线圈可明显减少来自股血流的条纹状伪影，而不会增加重建时间。平均而言，保留了 80%的前列腺 SNR。在计算机模拟中也观察到了类似的条纹减少，同时保留了 T 和 T 映射的定量准确性。总之，ROVir 线圈可有效地抑制径向 MRF 中血流的条纹伪影，从而提高图像的视觉清晰度，而不会对采集时间、重建时间和定量值的准确性有显著影响。这有望有助于在可行的临床时间内实现前列腺癌的 T 和 T 映射，帮助区分前列腺癌与非癌和健康前列腺组织。
