Classification of Cerebral Arteriovenous Malformations and Intranidal Flow Patterns by Color-Encoded 4D-Hybrid-MRA

Patient 9. Inhomogeneous nidus perfusion (type 2). Inflow time point setting from 18 to 20 seconds in the first image to 21–27 seconds in the last image to generate the effect of blood flow. Diversion of the central inflow into the nidus can be observed to the lateral and medial sides.

Patient 6. Inhomogeneous nidus perfusion (type 3). Inflow time point setting from 18 to 20 seconds in the first image to 21–23 seconds in the last image to generate the effect of blood flow. Corresponding to different feeding territories, inflow is seen in the paraventricular region and in the MCA territory anteriorly and laterally (red arrows) with multidirectional flow diversion toward drainage (blue arrows).

Patient 23. Axial (A) and coronal (B) color-encoded images show the right (ipsilateral to the AVM) internal cerebral vein dilated with symmetric inflow time points. Note the early inflow in the deep venous system in comparison with the confluens sinuum (column 3). On DSA, a deep venous drainage is not seen (C). Also note the huge aneurysmal dilation of cortical drainage with relatively late filling from its medial portion.

Patient 4. A, Two dilated superficial draining veins can be seen, which drain early into the transverse sinus and superior sagittal sinus (pictures 1 and 4). On picture 5, a dilated vein with delayed drainage into the internal cerebral veins is seen. B, DSA shows faint and retarded drainage into the deep venous system (picture 5).