Magnetic resonance imaging in occult spinal dysraphism.

A prospective study was carried out in 100 cases of suspected occult spinal dysraphic anomalies with Magnetic Resonance Imaging in order to determine its diagnostic efficacy as the initial imaging modality. MR imaging provided accurate preoperative information in 91 out of 92 cases (98.9%). Some of the unusual and interesting findings in the series were: presence of intrinsic cord abnormality in 19 out of 21 cases (90.4%) with a normal plain radiograph, 4 cases of diastematomyelia with a dermoid in the dorsal and lumbar region associated with syringohydromyelia, intradural fibrous/glial bands, syringohydromyelia/myelomalacia of the conus with tethered cord syndrome having a normally placed conus, and myelocystocele. It is concluded that MRI is an excellent primary diagnostic tool, together with a plain radiograph, for complete preoperative evaluation of mid-line spinal anomalies.