Value and Limitations of Contrast-Enhanced MR Angiography in Spinal Arteriovenous Malformations and Dural Arteriovenous Fistulas

SDAVF in a 69-year-old male patient visualized by MRA and DSA. Demonstration of a normal spinal cord supplying artery and arterialized veins of a SDAVF supplied from the same segmental artery.

A, The sagittal T2-weighted image reveals a signal intensity increase of the thoracolumbar cord and some flow voids at the dorsal aspect of the spinal cord raising the suspicion of a vascular spinal cord abnormality (small white arrows).

B, Sagittal MIP of the MRA examination showing the overview and localization of the dilated veins (small black arrows).

C, The coronal target MRA MIP demonstrates the feeding segmental artery of the SDAVF at the first lumbar level (L1; gray arrow).

D, The localization of this origin is confirmed by DSA. In addition to the fistula with dilated veins (small black arrows), DSA shows an anterior spinal cord supplying artery (white arrow) originating from the same segmental vessel.

E, On the targeted MPR image of the MRA examination, the anterior radiculomedullary artery could be visualized retrospectively (white arrow) and localized at the first lumbar level (L1). Please note that the normal spinal cord supplying artery, which is not involved in the AV-shunt, is very thin on both the DSA and MRA image.

F, This anterior spinal artery (white arrow) is also demonstrated on the oblique sagittal target MRA MIP and can be separated from the abnormal veins of the SDAVF lying posteriorly (small black arrows).

The corresponding DSA projections of the early (G) and late phase (H) for comparison.

Sacral SDAVF in a 64-year-old male patient visualized by MRA and DSA. Advantage of MRA in demonstrating vascular abnormality in a large FOV.

A, Sagittal T2-weighted image showing extensive spinal cord edema and only some enlarged vessels raising the suspicion of a vascular spinal cord abnormality (small white arrows).

B, Sagittal MIP of the MRA examination showing the overview and localization of an early filled and dilated vein (small black arrows).

C, In the enlarged view, the dilated vein of the filum terminale is more clearly depicted (black arrows).

The coronal target MRA MIP shows the arterialized filum vein (D, small black arrows) in the same projection in which DSA (E) could confirm the localization of the very small shunt at the first sacral level (gray arrow).

SDAVF in a 61-year-old male patient visualized by MRA and DSA. Misinterpretation of the segmental level of origin on MRA.

A, Sagittal T2-weighted image showing spinal cord edema (small white arrows).

B, Sagittal MIP of the MRA examination showing the overview and localization of the dilated vein (small black arrows).

C, In the coronal target MRA MIP the feeding segmental artery of the SDAVF was falsely localized by just 1 level at the seventh thoracic level (T7; black arrow).

D, DSA shows that the feeding segmental artery (gray arrow) originates from the sixth thoracic level (T6).

E, Selective injection of segmental artery T7 (black arrow) shows no supply to the SDAVF. Retrospectively, the correct level (gray arrow) could be identified on the target MRA MIP (C).

Perimedullary SAVM in a 43-year-old woman visualized by MRA and DSA. Problem of separating arteries from veins by MRA and of superimpositions in nonselective angiograms.

A, Sagittal T2-weighted image showing increased signal intensity of the thoracolumbar cord and enlarged perimedullary and infraconal vessels raising the suspicion of a vascular spinal cord abnormality (small white arrows).

B, Sagittal MIP of the MRA examination showing the overview and localization of the dilated vessels (small black arrows).

C, In the coronal target MRA MIP a mixture of enhanced tortuous arteries and veins is observed.

D, On the selective DSA, the AP projection of the early phase shows filling of the largest SAVM-feeding radiculomedullary artery (white arrow), which is derived from the first lumbar level (L1).

E, In the late phase the draining veins can clearly be distinguished from the artery (E) which was not possible with MRA (C).

F, Because of the overprojection and the MPR postprocessing, the origin of the large anterior radiculomedullary artery was first falsely localized at the twelfth thoracic level (T12) on the MRA image (black arrow).

G, Retrospectively, the correct level could be localized at L1 (black arrow).

H, The T12 level gives rise to an additional posterior feeder of the SAVM, only localized by selective DSA (gray arrow).