Résumé
We evaluated MR imaging of spondylolytic spondylolisthesis degenerative spondylolisthesis and retrolisthesis in 14, 9 and 20 patients respectively. Sagittal and axial spin echo and gradient echo images were obtained with 25-30cm FOV and 5mm/0.5mm thickness/gap by using spine surface coil. Sagittal images showed defects of pars interarticularis just inside of the pedicles of spines in all the cases of spondylolytic spondylolisthesis with relatively variable signal intensity. Displaced vertebrae were commonly observed at L5 (8/14) in spondylolytic spondylolisthesis, at L4 (5/9) in degenerative spondylolisthesis and at variable locations in retrolisthesis. The mean length of displacement of vertebrae in spondylolytic spondylolisthesis was about 7mm and less displacement was onserved in degenerative spondylolisthesis and retrolisthesis. Seven, four and six cases of pseudobulging of disk at displaced level were observed in cases of spondylolytic spondylolisthesis, degenerative spondylolisthesis and retrolisthesis respectively. Seven, five and 14 cases of true disk lesions were onserved in cases of spondylolytic spondylolisthesis, degenertive spondylolisthesis and retrolisthesis respectively. Grade II neural foraminal stenoses (obliteration of one half epidural fat of neural foramen) were commonly (8/14) seen in spondylolytic spondylolisthesis, however the other two types showed less severe neural foraminal stenosis. In conclusion, MR imaging is a highly accurate method for the diagnosis and evaluation of spondylolisthesis and associated lesions of spine and disks.