A comparative study of magnetic resonance imaging and computed tomography-assisted myelography in spinal dysraphism.

Thirty-seven patients with a wide spectrum of spinal dysraphic lesions were studied by both magnetic resonance imaging (MRI) and myelography complemented by computed tomography (CT). Magnetic resonance imaging proved to be superior for tissue characterization, overall anatomical definition, topographical relationships of the cranio-cervical junction and demonstration of the presence and extent of hydrosyringomyelia. Demonstration by CT myelography of fine neural structures such as the filum terminale and nerve roots remains the superior technique; however, with constantly improving spatial resolution and thinner-slice imaging, MRI will become increasingly competitive in this respect. The osseous component of these lesions was best demonstrated by CT myelography. A high incidence of associated syrinx (8/15 cases) was found in the diastematomyelia group, with an overall incidence of 15 cases in all the dysraphic patients studied. The use of both T1- and T2-weighted sequences is required for tissue characterization. Whilst both imaging modalities proved complementary in the investigation of spinal dysraphism, we suggest that, with its superior tissue characterization and anatomical display of these lesions. MRI should be the primary imaging technique. Avoidance of an invasive procedure and use of ionizing radiation confers additional benefits upon MRI. The relative ease and shorter examination time of MRI makes this technique ideal for pre- and post-operative monitoring and assessment.