MAGNETIC-RESONANCE IMAGING OF THE LUMBAR SPINE WITH CT CORRELATION

  • 1 January 1985
    • journal article
    • research article
    • Vol. 6  (2) , 237-245
Abstract
The results of magnetic resonance (MR) imaging and computed tomography (CT) in 18 patients with known degenerative disk disease of the lumbar spine were compared. In 60 intervertebral disk levels studied, there were 17 disks with degeneration and disk bulge and 15 herniated disks. Final diagnosis were based on several factors, with surgical confirmation in 5 patients. There was good correlation between the 2 methods at 51 of the 60 levels studied. There were major discrepancies in interpretation at 9 intervertebral disk levels. These included 3 false-positive MR imaging interpretations of a herniated disk and 1 false-negative herniated disk on MR imaging. MR imaging detected 1 case of disk herniation that was missed prospectively on CT. There were 4 presumed degenerated disks seen on MR scans that appeared normal on CT. The conus medullaris was imaged in 16 of 18 patients. The sagittal view proved best for demonstrating both disk abnormality and the conus medullaris. The transaxial view was sometimes helpful in localizing a disk herniation, but partial-volume averaging in the 7-mm slice thickness limited its usefulness. There were 5 disk herniations that could not be accurately localized on the MR scan. MR imaging proved more sensitive than CT in detecting early disk disease, which appeared as decreased signal intensity within the disk. In 3 postoperative cases, MR imaging was better able to distinguish between recurrent disk herniation and postoperative scar formation. CT was more specific in distinguishing herniated disk from disk bulge and proved far superior to MR imaging in localizing disk herniation. CT remains the preferred method for evaluation of lumbar spine degenerative disk disease. MR imaging is useful in clinical evaluation of lumbar disk disease as a complementary procedure. It may be valuable in postoperative patients and in equivocal cases where CT cannot differentiate between a small disk herniation and an asymmetric disk bulge. MR imaging should prove useful in evaluating patients with suspected lesions of the conus medullaris or the lumbar subarachnoid space. Further advances in MR imaging technology involving thinner sections, imaging coils with better signal-to-noise ratio and elimination of the interslice gap on the multislice technique can be expected to improve the utility of MR imaging in the lumbar spine.