3D MRI of the cervical spine: low flip angle FISP vs. Gd-DTPA TurboFLASH in degenerative disk disease.

The authors undertook this study to compare bright and dark CSF three-dimensional (3D) gradient-echo (GE) MR techniques to answer the following questions: Could a single Gd-DTPA enhanced T1-weighted GE volume sequence (with multiplanar reformats) be diagnostically equivalent for degenerative cervical disk disease to a standard sequence consisting of sagittal T1-weighted spin echo and axial low flip angle volume GE images (with reformatted images)? Does performing oblique coronal reformats perpendicular to the course of exiting cervical nerve roots improve diagnostic confidence over axial images alone? Thirty-one consecutive patients received a "routine" MR examination consisting of a sagittal T1-weighted spin echo and axial low flip angle volume sequence (FISP) [(35/7/5), 64 slices, 2 mm slice thickness, 192 x 256 matrix, 7.2 min]. Each patient was then given 0.1 mmol/kg Gd-DTPA intravenously, and reimaged with a T1-weighted volume GE sequence [(13/6/12), acquired as 128-1.2 mm coronal partitions, 192 x 256 matrix, 5.5 min]. Sequences were reconstructed on the standard diagnostic console in 1 mm increments. Sets of examinations (routine vs T1-weighted volume) were independently interpreted by three neuroradiologists for location, type, and severity of extradural degenerative disease. There was no strong or consistent trend for increased detection of disease by one imaging sequence over the other. For lateral disk disease, only 3% of the observations were in discordance. For disk disease, there was close agreement in the severity scores. All readers indicated that additional information was provided by the reformatted images more frequently with TurboFLASH (fast low angle shot) than with FISP. All readers indicated that increased confidence was provided by the reformatted images more frequently with TurboFLASH than with FISP. A single 3D contrast-enhanced TurboFLASH sequence is diagnostically equivalent to a set of two-dimensional T1-weighted sagittal spin echo and 3D axial low flip angle sequences for assessing the location and degree of cervical extradural degenerative disease. A screening examination of the cervical spine could be performed with a single contrast-enhanced 5.2 min study, and then relying on computer postprocessing to provide additional imaging planes.