THE USE OF MAGNETIC-RESONANCE ANGIOGRAPHY IN STEREOTAXIC NEUROSURGERY

The authors discuss the advantages and disadvantages of the use of mag netic resonance (MR) angiography images in stereotactic neurosurgery. Current computer programs designed to assist the neurosurgeon in the p lanning of stereotactic neurosurgical interventions use intraarterial digital subtraction angiography images to visualize the blood vessels. Magnetic resonance angiography is a recent technique with a number of advantages over the digital subtraction method: it is less invasive a nd less prone to complications; it provides truly three-dimensional da ta sets that can be viewed from any direction; and it can visualize bo th stationary and flowing tissues with the same imaging device and loc alizer frame. Although digital subtraction images are still superior i n contrast and vascular detail, state-of-the-art high-resolution MR an giography sequences provide sufficient vascular detail for planning su rgery. Contrast-enhanced MR angiography images were acquired using ada pted gradient-echo sequences to compensate for now-induced distortions ; postacquisition distortion correction was not necessary. Five method s to integrate and inspect a possible trajectory in the MR angiography data are discussed. Initial clinical experience with eight patients l ed to the conclusion that MR angiography is a valuable imaging modalit y that can be integrated reliably into a stereotactic neurosurgery pla nning procedure.