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

English Keywords:Dynamic contrast-enhanced MRI  Intervertebral disc  Cartilage endplate  Canine

English Abstract:

  【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.