CT Myelography: How to Do It

The full digital presentation is available online.

An earlier incorrect version of this article appeared online. This article was corrected on December 18, 2023..

CT myelography is frequently used in the evaluation of spinal canal pathologic conditions when MRI is contraindicated and for the evaluation of cerebrospinal fluid (CSF) leaks. The accompanying slide presentation details the steps required to perform CT myelography, including needle and contrast material selection and techniques for cervical and lumbar punctures under fluoroscopic and CT guidance. The various image acquisition protocols for CT myelography are demonstrated, with description of specific techniques developed for the identification of CSF leaks. Potential complications associated with the procedure are reviewed, including postdural puncture headache. The main indications for CT myelography and the characteristic imaging findings are detailed, especially in the evaluation of spontaneous intracranial hypotension.

Performance of a lumbar or cervical puncture is a critical step in a CT myelography examination. The patient position is determined according to the acquisition technique and site of puncture. Lumbar puncture is preferred, and cervical puncture is mostly performed when the lumbar site is unavailable, is unsafe, or previous attempts were unsuccessful.

Image acquisition varies according to the indication. Conventional CT myelography is used for non-CSF leak pathologic conditions or as the first screening examination in cases of CSF leak. The patient is positioned in the lateral decubitus position, and a single acquisition is performed 3–10 minutes after contrast material injection. For dynamic CT myelography, multiple acquisitions are performed during and immediately after contrast material administration while the patient is in the Trendelenburg position. Suspicion for a fast CSF leak is the main indication for this type of CT myelography acquisition. Decubitus CT myelography is performed with the patient in the lateral decubitus Trendelenburg position to evaluate CSF-venous fistulas.

It is important to pay attention to the acquisition parameters used. Use of a dedicated diagnostic spine protocol instead of parameters usually preconfigured within the interventional protocols of interventional radiology suites is paramount.

One of the main indications for CT myelography is the evaluation of spontaneous intracranial hypotension, including the type and location of spinal CSF leaks (Fig 1). Use of the suitable image acquisition technique is crucial in characterization of such leaks (Fig 2). Other important indications include radiation treatment planning and spinal canal evaluation (if MRI is contraindicated). As MRI techniques have evolved, such as protocols for evaluation of the brachial plexus, some uses of CT myelography, such as in the assessment of nerve root avulsion, have become mostly obsolete.

Figure 1.

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Figure 2.

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CT myelography provides high spatial resolution, functional images, and delineation of the subarachnoid space and is a powerful tool when there is a contraindication for MRI and in the evaluation of CSF leak. Radiologists must be aware of the technical aspects of CT myelography and be able to perform the CT myelographic technique appropriate for each clinical suspicion.

Disclosures of conflicts of interest.—D.G.L.E. Institutional support received for license fee for professional illustrations. P.G.K. Medical advisory board member for Spinal CSF Leak Foundation. The other authors have disclosed no relevant relationships.