犬正常腰椎间盘的动态增强MRI特征

Dynamic contrast-enhanced-MRI of lumbar intervertebral disc in normal canine

中文关键词:  动态增强MRI  椎间盘  终板  犬

英文关键词:Dynamic contrast-enhanced MRI  Intervertebral disc  Cartilage endplate  Canine

中文摘要:

  【摘要】 目的：研究犬正常腰椎间盘的动态增强MRI特点。方法：选取2岁龄健康杂种犬6只，麻醉后，对腰椎进行常规MRI T1WI、T2WI及X线片检查，排除退变或畸形腰椎间盘。MRI常规扫描结束后，静脉注射对比增强剂（钆喷酸葡胺），并在注射增强剂后2min、5min、10min、30min、1h、1.5h、2h、2.5h、3h、3.5h、4h行T1WI扫描。动态扫描结束后，选取每个腰椎间盘的上下椎体、上下终板、上下周围髓核及中央髓核为感兴趣区，分别测量增强前及注射增强剂后各时间点腰椎各感兴趣区的信号强度值，计算增强率，绘制时间-信号曲线及峰值出现时间，观察感兴趣区的信号变化特点。结果：注射对比增强剂后5min、1h、1h、1.5h，正常犬腰椎椎体、终板区域、周围髓核、中央髓核分别达到第1个峰值，信号增强率分别为（172.7±14.6）%、（197.6±39.5）%、（234.2±56.3）%、（253.5±37.3）%。注射对比增强剂后3.5h各区域信号强度达到达到第2个峰值，信号增强率分别为（122.5±18.2）%、（164.7±36.0）%、（200.6±23.6）%、（220.9±15.2）%。各感兴趣区的第2个峰值均低于第1个峰值，差异均有统计学意义（P<0.05）。结论：犬正常腰椎间盘的动态增强MRI表现具有“终板延迟”现象及“双峰”特征。

英文摘要:

  【Abstract】 Objectives: To investigate the characteristics of lumbar intervertebral disc in normal canine on dynamic contrast-enhanced-MRI images. Methods: Six mongrel adult canines(2 years old) were included in this study. After anesthesia, ordinary MRI T1WI, T2WI and X-Ray were performed at first for exclusion of intervertebral discs which had degeneration and deformity. Injection of Gadopentetate dimeglumine(Gd-DTPA) was applied after ordinary MRI scan, and T1WI scan would be done at 2min, 5min, 10min, 30min, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h after enhancement. Following the completion of dynamic scan, the superior and inferior vertebral body, endplate as same as peripheral and central nucleus pulposus were selected as regions of interest(ROI) for measurement. Signal intensity before and after enhancement of each ROI will be included to calculate enhancement percentage, to plot time-intensity curve, to find the peak time and to investigate the character of signal intensity change. Results: The first peak time of enhancement of vertebral body, endplate zone, peripheral nucleus and central nucleus was 5min, 1h, 1h, and 1.5h, respectively with the peak value of (172.7±14.6)%, (197.6±39.5)%, (234.2±56.3)%, and (253.5±37.3)%, respectively. Then the curves declined gradually, as time went by, each TIC started rising again. All ROIs reached the second peaks at 3.5h, with the peak value of (122.5±18.2)%, (164.7±36.0)%, (200.6±23.6)%, (220.9±15.2)% respectively, which were relatively lower than those of first peaks(P<0.05). Conclusions: The "endplate delay" effect and "double peak" phenomenon are the key character of the performance of normal canine intervertebral disc on dynamic contrast enhanced-MRI.