Spinal Dural Arteriovenous Fistula: Imaging Features and Its Mimics

Abstract

Spinal dural arteriovenous fistula (SDAVF) is the most common spinal vascular malformation, however it is still rare and underdiagnosed. Magnetic resonance imaging findings such as spinal cord edema and dilated and tortuous perimedullary veins play a pivotal role in the confirmation of the diagnosis. However, spinal angiography remains the gold standard in the diagnosis of SDAVF. Classic angiographic findings of SDAVF are early filling of radicular veins, delayed venous return, and an extensive network of dilated perimedullary venous plexus. A series of angiograms of SDAVF at different locations along the spinal column, and mimics of serpentine perimedullary venous plexus on MR images, are demonstrated. Thorough knowledge of SDAVF aids correct diagnosis and prevents irreversible complications.

Keywords: Central nervous system vascular malformations; Spinal cord diseases; Spine.

Fig. 1. Illustration of SDAVF at lower thoracic level.

Arteries are labeled with black background, while veins are labeled with white background. a = aorta, b = intercostal artery, c = dorsal branch of spinal artery, d = ventral branch of spinal artery, e = ventral epidural arcade, f = dural branch of ventral spinal artery, g = radicular artery, h = radiculomedullary artery, i = radiculopial artery, j = anterior spinal artery, k = dural branches of radiculopial artery, l = radial vein, m = perimedullary venous plexus, n = posterior radicular vein, o = anterior radicular vein, p = intervertebral vein, q = epidural venous plexus.

Fig. 2. Characteristic diagnostic clues of SDAVF on MRI.

A. On sagittal T2-weighted spinal MR image, spinal cord hyperintensity (hollow arrows), and serpentine and dilated perimedullary venous plexus (white arrows) as flow voids are striking characteristics. B. On sagittal T1-weighted spinal MR image, tortuous and dilated perimedullary venous plexus is barely recognized (white arrows). C. Sagittal T1-weighted MR image with gadolinium enhancement clearly reveals tortuous and dilated perimedullary venous plexus (white arrows). SDAVF = spinal dural arteriovenous fistula

Fig. 3. Intracranial dural arteriovenous fistula with arterial feeding from meningeal branch of left vertebral artery of 47-year-old man with progressive quadriparesis associated with urinary and fecal incontinence and impotency.

A. Sagittal T1-weighted spinal MR image with gadolinium enhancement shows serpentine enhancement at anterior and posterior surfaces of cervical spinal cord and brainstem, as well as at tonsils (arrowheads). B. Lateral view of left vertebral arteriogram demonstrates engorged inferior vermian vein (white arrows), which connects to veins at lower brainstem to drain into anterior and posterior spinal veins (hallow arrows). Reproduced with permission from Chen et al. Neuroradiology 1998;40:393-397 (64).

Fig. 4. Cervical SDAVF with feeding artery from right vertebral artery of 84-year-old man as incidental finding.

A. Right verterbral angiogram in frontal view at early phase demonstrates suspicious SDAVF (white arrows) with feeding artery directly from right vertebral artery (hallow arrow). B. Dilated and tortuous draining vein is prominent at late phase (black arrows). SDAVF = spinal dural arteriovenous fistula

Fig. 5. Lumbar SDAVF with arterial feeding from left L2 lumbar artery of 53-year-old man presenting with bilateral weakness in lower extremities and urinary bladder frequency.

A. Sagittal T2-weighted spinal MR image reveals hyperintensity (hollow arrows) with flow voids (white arrows) mostly at posterior surface of spinal cord. B. Superselective angiography evidently shows feeding artery (hallow arrow), SDAVF (white arrow) and tortuous draining vein (black arrow). SDAVF = spinal dural arteriovenous fistula C. Angiogram of left L2 lumbar artery in frontal view before treatment demonstrates fistula (white arrow) and tortuous vein (hollow arrow). D. Angiogram of left L2 lumbar artery in frontal view after treatment reveals result of successful endovascular embolization without opacification of fistula or tortuous vein.

Fig. 6. Sacral SDAVF with arterial feeding from left internal iliac artery of 67-year-old male suffering from progressive numbness, soreness and muscle cramps in bilateral lower extremities for 2 years.

Left internal iliac angiogram in frontal view shows sacral SDAVF (white arrow) draining toward spinal canal via dilated filum terminale vein (arrowheads). Reproduced with permission from Chen et al. Eur J Radiol 2002;44:152-155 (65). SDAVF = spinal dural arteriovenous fistula

Fig. 7. 76-year-old man with lower legs numbness was diagnosed with severe canal stenosis at L3/4 and L4/5 and moderate canal stenosis at L2/3.

A. MR myelography displays engorged and tortuous vein (white arrows) across only about 2 vertebrae along with tangle of flow voids (arrowheads), which are possibly redundant nerves and vessels, just proximal to level of stenosis. These findings are distinguishable from that of Figure 2A. B. Sagittal T2-weighted spinal MR image shows annular bulging at L2/3 to L4/5, causing moderate and severe spinal canal stenosis (white arrows) without spinal cord edema.

Fig. 8. 60-year-old man presenting with bilateral leg soreness for several months was diagnosed with SEAVF.

A. Axial T2-weighted spinal MR image shows engorged flow void structure (white arrow) at left anterolateral epidural space at L3 level, which is probably epidural venous lake. B. Angiography of left lumbar artery at L3 shows arteriovenous shunts (hollow arrow) that drain into prominent, diamond-shaped epidural venous plexus (white arrows) cross midline and delayed intradural venous drainage (black long arrows). Turning point (small black arrows) where retrograde drainage of intradural vein arises from epidural venous plexus is clearly exhibited. SEAVF = spinal extradural arteriovenous fistulas

Fig. 9. 13-year-old girl presented with nonspecific intermittent back pain.

No definite diagnosis was established. Sagittal T2-weighted spinal MR image shows bulky and discontinuous signal loss (white arrows) at thoracic level without spinal cord edema.

Fig. 10. Prominent anterior spinal artery mimics SDAVF.

A. Sagittal gadolinium-enhanced MR image demonstrates prominent vessels on anterior surface of spinal cord (white arrows). B, C. Lateral (B) and frontal (C) views of left T12 intercostal arteriogram reveal prominent artery in middle of anterior surface of spinal cord (black arrows) with characteristic hairpin turn, which is anterior spinal artery supplying from artery of Adamkiewicz. No SDAVF was found based on this study. SDAVF = spinal dural arteriovenous fistula

Fig. 11. Prominent left posterior spinal artery mimics SDAVF.

A. Left L1 lumbar arteriogram shows longitudinal artery without hairpin turn. B, C. On coronal (B) and sagittal (C) three-dimensional CT angiograms, artery is paramedian and dorsal to spinal cord (hollow arrow), proven to be prominent left posterior spinal artery. White dotted line demonstrates midline. SDAVF = spinal dural arteriovenous fistula

Fig. 12. SDAVF with arterial feeding from artery of Adamkiewicz of 29-year-old woman presenting with progressive tingling and paresthesia in lower extremities for 6 months.

T5 intercoastal arteriogram at early phase demonstrates that artery of Adamkiewicz (white arrow) ascends first then joins anterior spinal artery after characteristic hairpin turn (hollow arrows). Simultaneous appearance of serpentine and tortuous perimedullary venous plexus (black arrows) implies common origin with artery of Adamkiewicz. SDAVF = spinal dural arteriovenous fistula