MRI of lumbar spondylosis: a comparison of sagittal T2 weighted and three sequence examinations.

The aim of this study was to determine whether a single T2 weighted sagittal sequence could replace the conventional three sequence examination of the lumbar spine. The T2 weighted sagittal image of 79 lumbar spine MRI examinations were retrospectively reported by three radiologists. Features relating to degenerative disease were recorded and an assessment made of whether further sequences were likely to add information. On a separate occasion the T1 weighted and T2 weighted sagittal and T2 weighted axial sequences were reported blind in relation to the initial assessment. Areas of disagreement were resolved by consensus opinion. The T2 weighted sequence was compared with the three sequences, taking the three sequence examination as the standard. Disc protrusions were diagnosed from the T2 weighted sagittal images with a sensitivity of 38% and a specificity of 97%. 22 discs reported as a disc bulge on the T2 weighted sequence were re-classified as a disc protrusion on axial images because of their focal nature. Central canal stenosis was diagnosed on the T2 weighted sagittal sequence with a sensitivity of 60% and a specificity of 95%. After assessing the T2 weighted sequence, it was thought unlikely that further sequences would add extra information in 60% of cases (48/79). However, further information was obtained in 21% of these cases (10/48) when all the sequences were assessed. The extra information gained by using all three sequences was considered to be of greater benefit than the time saved by using a single T2 sagittal sequence. Other diagnoses where the additional sequences proved helpful are discussed.