Spinal nerve roots compression : the superadded diagnostic value of MR myelography

الملخص EN

MR provided a new method for generating a myelogram like images of the thecal sac following the conventional MR imaging and based on suppressing background signal using heavily T2 weighted sequences.

Forty two degenerative cases were included (group I)in our study (30 cases in the lumbar region, 12 cases in the cervical region and no degenerative case* in the dorsal region).

In addition 38 cases with non-degenerative spinal changes (group II) were included.

All cases were examined by conventional multiplanar MRI and MR myelography for detection of the degree of disc prolapse and the compression of the thecal sac and nerve roots.

MRI is very specific in determining the etiology of spinal cord compression using the T1,T2 and contrast enhanced sequences.

The sensitivity of conventional MRI in the demonstration of the nerve roots compression in our study was 87% in cases with lumbar and cervical disc lesions, 100% in the non degenerative lumbar cases and 87%in non degenerative cervical cases and 75% in dorsal lesions.

MR myelography is considered sensitive in 77% of lumbar non degenerative cases, 38% of dorsal non-degenerative cases and 75% in cervical non degenerative cases concerning the detection of the nerve roots compression .

Conclusion: MRM allowed a better overall view of the thecal sac and spinal nerve root sleeves making it easier to diagnose spinal canal stenosis and disc herniation.

MRM has the advantage of demonstration of the thecal sac and nerve root(s) distal to a complete block.

As with conventional myelography, MRM alone can not identify clearly the cause of nerve root compression and should only t performed as an adjunct to a conventional MR examination.