Magnetic resonance angiography with midsagittal saturation for the assessment of blood flow from superficial temporal artery-to-middle cerebral artery bypass

The purpose of this study was to evaluate the feasibility of magnetic resonance angiography (MRA) with midsagittal saturation for depiction of superficial temporal artery-to-middle cerebral artery bypass flow. Eleven patients undergoing bypass surgery in 13 regions were examined by external carotid artery angiography (ECAG) and 3-dimensional time-of-flight MRA with saturation pulse applied to the midsagittal plane covering the internal carotid arteries. We classified the extent of visualization of bypass flow into 4 types and examined the agreement of findings between them. The MRA revealed types of bypass flow in agreement with those observed on ECAG in 10 of the 13 regions. The MRA underestimated bypass flow in 2 regions and overestimated it in 1 region. The MRA with midsagittal saturation demonstrated bypass flow in agreement with ECAG in most cases. Application of MRA with midsagittal saturation permits noninvasive assessment of physiological flow from superficial temporal artery-to-middle cerebral artery bypass for a postoperative follow-up.