Painful lumbar disk derangement: Relevance of endplate abnormalities at MRimaging

PURPOSE: To investigate the predictive value of magnetic resonance (MR) ima ging of abnormalities of the lumbar intervertebral disks, particularly with adjacent endplate changes, to predict symptomatic disk derangement, with d iscography as the standard. MATERIALS AND METHODS: Fifty patients aged 28-50 years with chronic low bac k pain and without radicular leg pain underwent prospective clinical examin ation and sagittal T1- and T2-weighted and transverse T2-weighted MR imagin g. Subsequently, patients underwent lumbar discography with a pain provocat ion test (116 disks). MR images were evaluated for disk degeneration, a hig h-signal-intensity zone, and endplate abnormalities. Results of pain provoc ation at discography were rated independently of the image findings as conc ordant or as nonconcordant or painless. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the clinical relevance of MR abnormalities. RESULTS: Normal disks on MR images were generally not painful at provocativ e discography (NPV, 98%). Disk degeneration (sensitivity, 98%; specificity, 59%; PPV, 63%) and a high-signal-intensity zone (sensitivity, 27%; specifi city, 85%; PPV, 56%) were not helpful in the identification of symptomatic disk derangement. When only moderate and severe type I and type II endplate abnormalities were considered abnormal, all injected disks caused concorda nt pain with provocation (sensitivity, 38%; specificity, 100%; PPV, 100%). CONCLUSION: Moderate and severe endplate abnormalities appear be useful in the prediction of painful disk derangement in patients with symptomatic low back pain.