Interactive spinal computed tomography angiography-guided spinal digital subtraction angiography and embolization for thoracolumbar epidural arteriovenous fistulas: illustrative case

Abstract

Background: Spinal digital subtraction angiography (sDSA) is the gold standard for examining spinal arteriovenous fistulas; however, thorough sDSA evaluations of spinal arteriovenous fistulas require a long procedure, which may increase the radiation exposure time.

Observations: A 72-year-old man presented with progressive myelopathy due to a spinal epidural arteriovenous fistula. Spinal computed tomography angiography (sCTA) showed an epidural arteriovenous fistula fed by the left L3 segmental artery. To prepare for sDSA, the sCTA images were modified to mark the segmental artery bifurcations from T5 to L5 with multicolored markers. These modified sCTA images were loaded onto the multiwindow DSA display. The sCTA images were interactively modulated during sDSA. This sCTA-guided sDSA identified 18 segmental arteries within 47 minutes. The total radiation exposure was 1,292 mGy. Subsequently, transarterial embolization resolved the epidural arteriovenous fistula with clinical improvement.

Lessons: Three-dimensional sCTA can provide detailed anatomical information before sDSA. Modified sCTA images with segmental artery bifurcation marking can provide interactive guidance on multipanel DSA displays. sCTA-guided sDSA is useful for accurate catheterization and reduction of procedure time.

Keywords: computed tomography angiography; digital subtraction angiography; spinal epidural arteriovenous fistula.

FIG. 1.

Preoperative radiological images. A: Sagittal short tau inversion recovery MRI sequence shows spinal cord edema from the T6 to T12 level. The conus medullaris is also edematous. Multiple flow voids are identified. B: Sagittal CTA image shows vascular enhancement on the ventral and dorsal surface of the thoracolumbar spinal cord.

FIG. 2.

Preoperative preparation using CTA and sDSA images in representative segmental arteries. White arrows indicate the bifurcation of the right T11 segmental artery; white arrowheads, the left L3 segmental artery; black arrow, artery of Adamkiewicz; black arrowhead, epidural arteriovenous fistula. The bifurcation of the segmental arteries from the aorta is marked on axial CTA images (A and B). C: The markers for bifurcations are merged with vascular and spine images. The markers and segmental arteries are shown in different colors. D and E: The pointed bifurcation and structure of the right T11 radicular artery are fused with the vertebral structures. F and G: The feeder and drainer of the spinal epidural arteriovenous fistula were reconstructed and fused, respectively. The same method was applied to all segmental arteries. Fusion and intraprocedural images. H: The sDSA was performed, referring to the fusion image. I–K: The intraprocedural and fusion images were shown on the screen. sDSA shows canulation and angiography of the right T11 segmental artery. The right T11 segmental artery was selected based on the fusion image and the bony structure. The artery of Adamkiewicz branches from the right T11 radicular artery. L–N: sDSA showing canulation and angiography of the left L3 segmental artery. The left L3 segmental artery was selected based on the fusion image. An epidural spinal arteriovenous fistula was also identified. The same method was applied to all segmental arteries.

FIG. 3.

The epidural arteriovenous fistula is fed by the right L2 (A) and left L2 (B) and L3 (C) segmental arteries and is drained into the radiculomedullary vein (black arrowheads).

FIG. 4.

Postoperative radiological images. A: Sagittal short tau inversion recovery MRI sequence shows that the flow voids resolved and spinal cord edema decreased. B: Sagittal CTA image shows that vascular enhancement on the ventral and dorsal surface of the thoracolumbar spinal cord disappeared.