Three-dimensional rotational myelography

Abstract

Three-dimensional (3D) rotational radiography, initially developed to visualize intracranial aneurysms, is applied to the cervical spine after conventional myelography. We call this process 3D rotational myelography. 3D reconstruction and then postprocessing allows imaging in multiple planes. Spinal or nerve root sheath alterations caused by bony or soft tissue can be visualized and differentiated by using this technique.

Fig 1.

Images from the case of a 60-year-old man who presented with severe cervicobrachialgia and dysesthesia on the right side. A, Lateral myelogram shows multiple anterior defects that indicate general narrowing of the spinal canal with ventral bony spurs and a steep vertebral column. At disk level C5–C6, an additional disk protrusion can only be assumed. B, Anteroposterior myelogram shows right-sided local compression of root sleeves C6 and C7, with a major defect at C6 (arrows).

Fig 2.

Real-time 3D reconstruction of cervical spine, with differentiation of the contrast column from bone, shows relationship between thecal sac and bony structures. This oblique projection, similar to a conventional myelogram, shows the filling defect in the neural foramen of C5–C6 (arrow), indicating major deficit at this level.

Fig 3.

Coronal multiplanar reformatting. A, Lateral reconstruction localizer in the multiplanar reformatting mode indicates coronal curved planes of reconstruction (see C), following the physiological lordosis of the spine. B, Image shows multiplanar reformatting with coronal plane of reconstruction. This plane is straight and limits the visualization and comparison of the root sleeves. Because of the physiological lordosis of the cervical spine, the nerve root sheaths are mostly out of the cutting plane and thus are difficult to compare for evaluation of maximum nerve root compression (arrows). C, Image shows reformatting with curved coronal planes of reconstruction, following the physiological lordosis of the spine. The visualization of several nerve root sheaths is possible in the same plane (arrows), allowing simultaneous assessment of multilevel abnormalities. By comparison, straight coronal plane multiplanar reformatting shows only two nerve roots sheaths (see B, arrows).

Fig 4.

Parasagittal multiplanar reformatting. A, Right-sided parasagittal reconstruction of the spine in multiplanar reformatting modus is shown. The defect of the contrast column at the C5–C6 level indicates nerve root sheath compression and also allows distinction between the compressing disk material and the vertebra (arrow). Inset, multiplanar reformatting with axial orientation of the reconstruction plane at the C5–C6 level shows a narrowing of the neural foramen on the right side. The contrast medium is asymmetrically distributed within the spinal canal, indicating a right paramedian soft disk protrusion with compression of the thecal sac and the spinal cord (arrow). White line marks reconstruction plane in relation to spinal canal. B, Multiplanar reformatting in oblique parasagittal projection obtained perpendicular to the course of the nerve root canal allows assessment of narrowing of the foramen (arrows). As the inset in A shows (white line shows reconstruction plane), an evaluation of the neural foramen along its course is possible, allowing determination of maximum stenosis.