Translational Imaging Group, CMIC, University College London, London, United Kingdom; Epilepsy Society MRI Unit, Chalfont St Peter, United Kingdom; Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), University College London, London, United Kingdom.
Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom.
J Neuroradiol. 2018 Oct;45(6):368-373. doi: 10.1016/j.neurad.2018.02.007. Epub 2018 Mar 2.
T2-FLAIR is the single most sensitive MRI contrast to detect lesions underlying focal epilepsies but 3D sequences used to obtain isotropic high-resolution images are susceptible to motion artefacts. Prospective motion correction (PMC) - demonstrated to improve 3D-T1 image quality in a pediatric population - was applied to high-resolution 3D-T2-FLAIR scans in adult epilepsy patients to evaluate its clinical benefit. Coronal 3D-T2-FLAIR scans were acquired with a 1mm isotropic resolution on a 3T MRI scanner. Two expert neuroradiologists reviewed 40 scans without PMC and 40 with navigator-based PMC. Visual assessment addressed six criteria of image quality (resolution, SNR, WM-GM contrast, intensity homogeneity, lesion conspicuity, diagnostic confidence) on a seven-point Likert scale (from non-diagnostic to outstanding). SNR was also objectively quantified within the white matter. PMC scans had near-identical scores on the criteria of image quality to non-PMC scans, with the notable exception that intensity homogeneity was generally worse. Using PMC, the percentage of scans with bad image quality was substantially lower than without PMC (3.25% vs. 12.5%) on the other five criteria. Quantitative SNR estimates revealed that PMC and non-PMC had no significant difference in SNR (P=0.07). Application of prospective motion correction to 3D-T2-FLAIR sequences decreased the percentage of low-quality scans, reducing the number of scans that need to be repeated to obtain clinically useful data.
T2-FLAIR 是检测局灶性癫痫相关病变的最敏感的 MRI 对比剂，但用于获得各向同性高分辨率图像的 3D 序列容易受到运动伪影的影响。前瞻性运动校正（PMC）——已被证明可改善儿科人群的 3D-T1 图像质量——被应用于成人癫痫患者的高分辨率 3D-T2-FLAIR 扫描，以评估其临床益处。在 3T MRI 扫描仪上采集具有 1mm 各向同性分辨率的冠状 3D-T2-FLAIR 扫描。两位专家神经放射科医生对 40 例无 PMC 和 40 例基于导航器的 PMC 的扫描进行了回顾。视觉评估采用七点李克特量表（从非诊断到出色）对图像质量的六个标准（分辨率、SNR、WM-GM 对比度、强度均匀性、病变显著性、诊断信心）进行评估。还在白质内对 SNR 进行了客观量化。PMC 扫描在图像质量标准上的评分与非-PMC 扫描几乎相同，唯一的例外是强度均匀性通常较差。使用 PMC，具有不良图像质量的扫描百分比明显低于无 PMC（分别为 3.25%和 12.5%），在其他五个标准中也是如此。定量 SNR 估计表明，PMC 和非-PMC 在 SNR 方面没有显著差异（P=0.07）。前瞻性运动校正的应用降低了低质量扫描的百分比，减少了获得临床有用数据所需重复扫描的次数。
