Fushimi Yasutaka, Okada Tomohisa, Kikuchi Takayuki, Yamamoto Akira, Okada Tsutomu, Yamamoto Takayuki, Schmidt Michaela, Yoshida Kazumichi, Miyamoto Susumu, Togashi Kaori
Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawaharacho, Sakyoku, Kyoto, Japan.
Human Brain Research Center, Kyoto University Graduate School of Medicine, 54 Shogoin Kawaharacho, Sakyoku, Kyoto, Japan.
NMR Biomed. 2017 Nov;30(11). doi: 10.1002/nbm.3774. Epub 2017 Aug 10.
Compressed sensing (CS) MRI has just been introduced to research areas as an innovative approach to accelerate MRI. CS is expected to achieve higher k-space undersampling by exploiting the underlying sparsity in an appropriate transform domain. MR angiography (MRA) provides high spatial resolution information on arteries; however, a relatively long acquisition time is necessary to cover a wide volume. Reduction of acquisition time by CS for time-of-flight (TOF) MR angiography (Sparse-TOF) is beneficial in clinical examinations; therefore, the clinical validity of Sparse-TOF needs to be investigated. The aim of this study was to compare the diagnostic capability of TOF MRA between parallel imaging (PI)-TOF with an acceleration factor of 3 (annotated as 3×) and Sparse-TOF (3× and 5×) in patients with cerebral aneurysms. PI-TOF (3×) and Sparse-TOF (3× and 5×) imaging were performed in 20 patients using a 3 T MRI system. Aneurysms in PI-TOF (3×) and Sparse-TOF (3× and 5×) were blindly rated as visible or scarcely visible by neuroradiologists. The neck, height and width of aneurysms were also measured. Twenty-six aneurysms were visualized and rated as visible in PI-TOF (3×) and Sparse-TOF (3× and 5×), with excellent agreement between two raters. No significant differences were found in measured neck, height or width of aneurysms among them. Sparse-TOF (3× and 5×) were acquired and reconstructed within 6 min, and cerebral aneurysms were visible in both of them with equivalent quality to PI-TOF (3×). Sparse-TOF (5×) is a good alternative to PI-TOF (3×) to visualize cerebral aneurysms.
压缩感知（CS）磁共振成像（MRI）作为一种加速MRI的创新方法刚刚被引入研究领域。CS有望通过利用适当变换域中的潜在稀疏性来实现更高的k空间欠采样。磁共振血管造影（MRA）可提供有关动脉的高空间分辨率信息；然而，要覆盖较大体积需要相对较长的采集时间。通过CS减少飞行时间（TOF）磁共振血管造影（稀疏TOF）的采集时间在临床检查中是有益的；因此，需要研究稀疏TOF的临床有效性。本研究的目的是比较并行成像（PI）-TOF（加速因子为3，标注为3×）和稀疏TOF（3×和5×）在脑动脉瘤患者中TOF MRA的诊断能力。使用3T MRI系统对20例患者进行了PI-TOF（3×）和稀疏TOF（3×和5×）成像。神经放射科医生对PI-TOF（3×）和稀疏TOF（3×和5×）中的动脉瘤进行盲法评级，判断其是否可见或几乎不可见。还测量了动脉瘤的颈部、高度和宽度。26个动脉瘤在PI-TOF（3×）和稀疏TOF（3×和5×）中均被显示并评级为可见，两位评级者之间具有良好的一致性。它们之间在测量的动脉瘤颈部、高度或宽度方面未发现显著差异。稀疏TOF（3×和5×）在6分钟内完成采集和重建，其中的脑动脉瘤均可见，质量与PI-TOF（3×）相当。稀疏TOF（5×）是PI-TOF（3×）用于显示脑动脉瘤的良好替代方法。
