for AVMs located close to, or within, motor, sensory, speech or visual areas.
A recent study  described image-guided AVM surgery based on CT angiography rather than on MRI. Segmentation and 3D reconstruction of the AVM allowed exact definition of the nidus, as well as the draining veins and feeding arteries, in relation to the underlying brain tissue. Manipulation of the reconstruction through rotation and subtraction allowed multi-angle viewing of the relationships of the AVM vessels. Preliminary image-guided temporary clipping of the sulcal feeding arteries led to decompression of the AVM nidus in most cases, rendering easier the subsequent step of dissection along the previously localized draining veins. However, temporary clipping prior to complete feeder dissection is associated with a low risk of clipping en-passant vessels. Another limitation of this study was that only vessels larger than 3 mm in size could be identified -a direct result of the resolution limit of the segmentation process.
By demonstrating the configuration and margins of the nidus, image guidance decreases the risk of inadvertent surgical entry into the AVM. The plane between the AVM and the surrounding brain tissue can be readily identified, minimizing tissue manipulation and decreasing intraoperative bleeding.
It is still unclear, however, whether image-guided surgery for AVMs does in fact result in a lower morbidity when compared with standard, free-hand techniques.
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