Click on image to view larger version.
Fig 9. SAVM of the filum terminale in a 61-year-old male patient visualized by MR and catheter angiography: the problem of differentiation between this rare type of SAVM and spinal dural AV fistulas is due to difficult shunt localization and vessel identification in present MR angiography. A, Sagittal T2-weighted image showing enlarged infraconal vessels raising the suspicion of a vascular spinal cord abnormality (small white arrows); no signal intensity abnormality of the spinal cord is visible. B, Sagittal MIP of the MR angiography data showing the overview and localization of the dilated vessels (small black arrows). C, The blood vessel demonstrated on the coronal target MR angiography MIP could, retrospectively, be identified to be an enlarged AKA (white arrow) and ASA, with origin from the 11th thoracic level (T11). D, Catheter angiography for comparison. E–G, The continuation of this ASA to the filum terminale (white arrowheads) is the feeding artery for this type of AVM situated at the level of L4 in this individual case (gray arrow). Differentiation of the feeding artery that is running downward (white arrowheads) and the arterialized vein (black arrowheads) that is running upward is only possible with a good time resolution of the selective angiogram, as shown on the catheter angiography images in early (F) and late phases (G).41
