Myelography in the Age of MRI: Why We Do It, and How We Do It

Abstract

Myelography is a nearly ninety-year-old method that has undergone a steady development from the introduction of water-soluble contrast agents to CT myelography. Since the introduction of magnetic resonance imaging into clinical routine in the mid-1980s, the role of myelography seemed to be constantly less important in spinal diagnostics, but it remains a method that is probably even superior to MRI for special clinical issues. This paper briefly summarizes the historical development of myelography, describes the technique, and discusses current indications like the detection of CSF leaks or cervical root avulsion.

Figure 1

The myelography workplace. The table is tiltable by more than 90° so that a head-down position can be achieved.

Figure 2

Volunteer demonstrating the patient position for the lumbar tap.

Figure 3

Standard projections in prone position. From left to right: a.p., about 25° left and right to show the lumbar nerve roots. Taking these images under fluoroscopic control makes sure that even with stabilizing material on three levels the roots are visible from their origin to the foramen.

Figure 4

Diagnostic value of additional upright/functional views. (a) Extension (left) shows marked narrowing of the sagittal dural sac diameter directly above the stabilization. The finding in flexed position (right) is normal. This information cannot be obtained in the prone position alone. (b) Oblique views, top: prone position, bottom: patient standing upright. Shortening of the left L4 root and compression of the left L5 origin are only visible in the upright position.

Figure 5

Cervical myelography (prone position). With the patient's head reclined, there is sufficient time to acquire images that show the cervical nerve roots in high detail without losing contrast. (Standard projections as Figure 3).

Figure 6

Development of myelography exams at the authors' institution 1999–2009.

Figure 7

Cervical root avulsion after motorcycle accident. (a) Myelography shows traumatic pseudoceles C7-D1. Rootlets are not discernible. (b) Thin-section (1.25 mm) myelo-CT and reformatted coronal images clearly show complete avulsion of ventral and dorsal rootlets.

Figure 8

Spinal CSF leak causing subdural hematoma. (a) Left: contrast leakage to the left at the level of the D11 root. Right: 45 seconds later, contrast has flown around the dural sac and is exiting the spinal canal to the right. The dynamic series easily allows to study these flow dynamics and avoids misinterpretations. (b) Sagittal (left) and coronal (right) reformatted images from the subsequent myelo-CT show leakage in the left D11/12 foramen and contrast leakage to the right one segment above. This static study does not allow to exactly determine how contrast flows in and around the dural sac.