Usefullness of Routine MR-Myelography at MRI for Multiple Lumbar Stenosis / 대한정형외과학회잡지

ABSTRACT

PURPOSE: To determine if MR myelography (MRM) improves the interpretation of the severity of stenosis in patients with a multi-level lumbar stenosis. MATERIALS AND METHODS: Among the patients referred for MRI with MRM prospectively, 100 patients over 50 years old with multiple lumbar stenosis were enrolled in this study. The most severe stenotic level and the degree of stenosis at that level according to the extent of the remaining subarachnoidal space (1 normal to 50%, 2 over 50% but not a total block, 3 total block) were evaluated in a blinded manner by two observers. Conventional MRI (class A), MRM (class B) and MRI+MRM (class C) was evaluated independently and the interobserver and intraobserver reliability were assessed. RESULTS: In the selection of the most severe level and degree of stenosis, both observers showed a higher level of consensus with classes B and C than classes A and C. The interobserver k average values for the selection of the most severe level in classes A, B and C were 0.649, 0.782 and 0.832, respectively. In terms of the degree of stenosis, the average in classes A, B and C were 0.727, 0.771 and 0.784, respectively. The intraobserver k values for the above two items were the highest in class (B), followed by (C) and (A) in all observers and within the range of "almost perfect" (0.81< or =k< or =1) except for the selection of the level of one observer in clause A. CONCLUSION: MRM when used in routine practice can help improve the observer reliability in assessing the severity of stenosis in multiple lumbar stenosis.