Magnetic resonance imaging(MRI) is clearly more reliable than computer tomography and myelography in radiological diagnosis of lumbar herniated intervertebral disc. Moreover, MRI can also detect degenerative changes of intervertebral discs. The purpose of this study was to determine the utility and accuracy of MRI in conjuntion with the diagnosis of lumbar herniated intervertebral disc and to compare findings with operative findings.

Comparisons of operative findings and MRI were done in 133 cases. Each patients had been diagnosed by MRI as having lumbar herniated intervertebral disc. MRI findings included those of spin echo T1-weighted images and T2-weighted images, gradient echo T1-weighted images and T2-weighted images, and gadolinium-DTPA enhancement when needed.

In 32 protrusion disc cases diagnosed by MRI, 28 cases were confirmed by operation and four were actually extrusion disc. In 77 cases diagnosed by MRI as extrusion disc, 72 cases were confirmed by operative findings, while 5 cases were found to be protrusion disc. 4 cases of sequestration disc diagnosed by MRI were confirmed by operative findings. Specific dimensions of MRI use yielded the following results: protrusion disc indicated 84.8% in sensitivity, 95% specificity, 87.5% in accuracy; extrusion disc showed 94.7%, 86.5%, 93.5%, respectively; and sequestration disc revealed 100% in all categories. In this study, the average accuracy of lumbar herniated intervertebral disc diagnosed by MRI was 93.6% on average.

Accordingly, MRI has shown itself to be a good diagnostic tool for determining anatomical and biological change in lumbar herniated intervertebral disc.

Chronic progressive radiation myelopathy(CPRM) is a rare but serious complication of radiation therapy. It's exact cause is unknown and the diagnosis is usually made based on the exclusion of other causes of myelopathy. Magnetic resonance imaging(MRI) with gadolinium- diethylenetriamine pentaacetic acid(DTPA) enhancement seems to be useful for the diagnosis of CPRM. There is no known effective treatment and the complication is irreversible.

We report a case of CPRM after radiation therapy for subglottic cancer which was not respond to high-dose steroid therapy with review of literature.