Evaluation of myelography and computed tomography in clinically diagnosed patients of lumbar disc herniation.

Forty patients with dinical diagnosis of lumbar disc herniation were evaluated with myelography and CT scan. Myelography diagnosed lumbar disc hemiation at 59 levels in 40 patients, while CT diagnosed disc hemiation at 64 levels. Lumbar disc hemiation was confirmed peroperatively in 30 out of 40 patients at 48 levels. Myelography correctly diagnosed 43 levels out of 48 levels and thus had a sensitivity of 89.6 per cent. CT diagnosed all the 48 levels correctly with a sensitivity of 100 per cent. Thus CT is super to conventional myelography in the diagnosis of lumbar disc herniation. However, conventional myelography supplements CT examination by limiting the number of scans to the level of interest and thus reduces radiation exposure.