Department of Diagnostic Radiology and Nuclear Medicine, Tokyo Medical and Dental University.
Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University.
Magn Reson Med Sci. 2023 Jul 1;22(3):325-334. doi: 10.2463/mrms.mp.2021-0037. Epub 2022 May 10.
To quantify bowel motility shown on cine MRI using the classical optical flow algorithm and compare it with balloon-assisted enteroscopy (BAE) findings in patients with Crohn's disease (CD).
This retrospective study included 29 consecutive patients with CD who had undergone MR enterocolonography (MREC) and BAE between March and May 2017. We developed computer software to present motion vector magnitudes between consecutive cine MR images as bowel motility maps via a classical optical flow algorithm using the Horn-Schunck method. Cine MR images were acquired with a balanced steady-state free precession sequence in the coronal direction to capture small bowel motility. The small bowels were divided into three segments. In total, 63 bowel segments were assessed via BAE and MREC. Motility scores on the maps, simplified MR index of activity (sMaRIA), and MREC score derived from a 5-point MR classification were assessed independently by two radiologists and compared with the CD endoscopic index of severity (CDEIS). Correlations were assessed using Spearman's rank coefficient. The areas under the receiver-operating characteristic curve (AUCs) of motility score for differentiating CDEIS was calculated; a P value < 0.05 was considered statistically significant.
Motility score was negatively correlated with CDEIS (r = -0.59 [P < 0.001] and -0.54 [P < 0.001]), and the AUCs of motility scores for detecting CDEIS ≥ 3 were 88.2% and 78.6% for observers 1 and 2, respectively. There were no significant differences in the AUC for detecting CDEIS ≥ 3 and CDEIS ≥ 12 between motility and sMaRIA or MREC score.
The motility map was feasible for locally quantifying the bowel motility. In addition, the motility score on the map reflected the endoscopic inflammatory activity of each small bowel segment in patients with CD; hence, it could be used as a tool in objectively interpreting cine MREC to predict inflammatory activity in CD.
使用经典光流算法量化磁共振肠造影（MREC）电影图像上显示的肠道蠕动，并将其与克罗恩病（CD）患者的气囊辅助小肠镜（BAE）检查结果进行比较。
本回顾性研究纳入 2017 年 3 月至 5 月间接受 MREC 和 BAE 检查的 29 例连续 CD 患者。我们开发了计算机软件，通过 Horn-Schunck 经典光流算法，在冠状方向上连续的电影 MR 图像之间呈现运动矢量幅度，以生成肠道蠕动图。采用平衡稳态自由进动序列采集小肠蠕动的冠状位电影 MR 图像。将小肠分为 3 段。通过 BAE 和 MREC 共评估了 63 个肠段。由两位放射科医生独立评估地图上的运动评分、简化的活动磁共振指数（sMaRIA）和 5 分 MR 分类得出的 MREC 评分，并与 CD 内镜严重指数（CDEIS）进行比较。采用 Spearman 秩相关系数评估相关性。计算运动评分区分 CDEIS 的受试者工作特征曲线下面积（AUC）；P 值<0.05 认为有统计学意义。
运动评分与 CDEIS 呈负相关（r=-0.59[P<0.001]和-0.54[P<0.001]），观察者 1 和 2 检测 CDEIS≥3 的运动评分 AUC 分别为 88.2%和 78.6%。运动评分和 sMaRIA 或 MREC 评分在检测 CDEIS≥3 和 CDEIS≥12 方面的 AUC 无显著差异。
肠道蠕动图可用于局部量化肠道蠕动。此外，地图上的运动评分反映了 CD 患者各小肠段的内镜炎症活动度，因此可作为客观解读 Cine MREC 以预测 CD 炎症活动度的工具。
