Diagnostic potential of contrast MRI in lumbar schwannomas.

Contrast enhancement in magnetic resonance imaging (MRI) is fast becoming a valuable means of diagnosing spinal pathology. The paramagnetic contrast agent, gadopentetate dimeglumine, used since 1986, delineates extradural, extramedullary intradural, as well as intramedullary lesions without myelography. However a combination of contrast MRI and water-soluble contrast myelography may prove especially useful in diagnosing mobile lesions in the lumbar region, particularly involving the cauda equina. Nerve root attachment (small spherical areas of void signal) and visualization of both the rounded cephalic and caudal ends were two other features delineated well on MRI. We report four cases of lumbar schwannomas where MRI was used alone or in conjunction with water-soluble contrast myelography to make the diagnosis.