Purpose: To evaluate the role of the three dimensional (3D) MR myelography (MRM) in the diagnosis of the lumbar discogenic disease compared with conventional MR imaging.
Materials and methods: Fifty consecutive patients with clinical symptoms of lumbar disc herniation were enrolled for the study. Conventional MR imaging and coronal 3D MRM were performed on a 1.5 T MR system. At each disc space level, the presence and the location of disc herniation and nerve root compression were evaluated. Note was also made if MRM had additional contribution to the determination of most significant level in the cases of multilevel disc disease and lumbar spinal stenosis.
Results: Disc herniation was found in 60 disc space levels on conventional MR imaging and in 54 disc space levels on 3D-MRM imaging. As regards to disc herniation, the sensitivity, specificity, and accuracy of 3D-MRM was 90%, 100%, and 96%, respectively. Nerve root compression was seen in 91 levels on conventional MR images, as opposed to 98 on 3D-MRM. Regarding nerve root compression, the sensitivity, specificity, and accuracy of 3D-MRM was 100%, 97%, and 98%, respectively. In all of 13 patients with multilevel disc disease and lumbar spinal stenosis, 3D-MRM had additional contribution.
Conclusion: Scan time of 3D-MRM is short. It can be easily added to routine lumbar MR imaging. It may be a valuable modality in the diagnosis of the lumbar discogenic disease. The presence of false-negative and false-positive examinations necessitates caution in interpreting 3D-MRM images. 3D MRM technique may be useful in selected cases such as patients with multilevel disc abnormalities or lumbar spinal stenosis where it allows a rapid and easy appreciation of the level most likely to account for the pathology.