MR Findings of Large Schmorl's Nodes

ABSTRACT

PURPOSE: To demonstrate the MR findings of large Schmorl's nodes(>1 cm). Method and Materials: Six hundredpatients underwent MRI and the results were retrospectively analysed. Eleven patients(1.83%) had 12 largeSchmorl's nodes. We analyzed the size, contour, location, signal changes and enhancement of these, as well asmarrow changes in adjacent vertebral bodies. RESULTS: Twelve large Schmorl's nodes were found in eleven of 600patients(1.83%) with a mean age of 46.1 years and a female : male ratio of 4 : 7. Their mean size was 1.35 cm(AP)x 0.99 cm(height) x 1.23 cm(transverse), and they were observed at various sites, namely lower(n=7) and upperend-plate locations(n=5). Central locations(n=8) on end-plates were most common. A semi-lunar appearance was notedin seven cases, and in most, a well-demarcated irregular margin was seen. All large Schmorl's nodes were enhanced; peripheral forms(n=8) were more common than diffuse(n=4). Adjacent discs showed no intranuclear enhancement butin seven cases there was flat-contoured enhancements in the annulus fibrosus. In disks with large Schmorl's nodes,degeneration was noted on T2WI regardless of the degree of diskal herniation. In nearly all cases, signalintensity on T1WI was low, but on T2WI, this was variable. Large Schmorl's nodes showed characteristic marrowchange in adjacent vertebral bodies ; the most common pattern was fatty and sclerotic(n=8). Especially onT1-weighted axial images, target appearances were visible in ten cases. CONCLUSION: MR findings of Schmorl'snodes will be very useful for differentiating nodes from other vertebral or diskal lesions, especially spondylitiscombined with diskitis or vertebral body tumor.