Lumbar herniated disk disease: comparison of MRI, myelography, and post-myelographic CT scan with surgical findings.

One hundred eighty patients with suspected lumbar disk disease were evaluated preoperatively with magnetic resonance imaging (MRI), myelography, and post-myelogram computerized tomography (CT) scan. Sixty patients underwent surgery on 102 disk levels, allowing for anatomic confirmation of the diagnosis. Eight negative explorations were performed. The correlation between preoperative interpretations of each test and the observed surgical findings was analyzed statistically. Based on this analysis, MRI accurately predicted the operative findings in 98 of 102 disk levels (96%), while the accuracy of myelography (81%) and post-myelogram CT scan (57%) was significantly less. When myelography and CT scan were utilized jointly, the accuracy was 84%, a significant improvement over either test alone, as a diagnostic modality. There was only one false positive MRI study in the evaluation of lumbar herniated disk. The results of this study reflect that MRI is a clinically superior diagnostic test in the evaluation of patients with suspected lumbar disk herniation, and that it should be the diagnostic study of choice when available. Its noninvasive nature, multiplanar capabilities, and the lack of ionizing radiation are particularly desirable for patient and physician.