Prediction of cerebral blood flow restoration after extracranial-intracranial bypass surgery using superficial temporal artery duplex ultrasonography (STDU)

Abstract

We investigated the availability of superficial temporal artery (STA) duplex ultrasonography (STDU) for evaluating the improvement of cerebral hemodynamics after extracranial-intracranial (EC-IC) bypass. This study included 56 consecutive patients who underwent EC-IC bypass for occlusive disease of their cerebral arteries. STA duplex ultrasonography (STDU) was performed to measure the flow velocity, pulsatility index, and diameter of ipsilateral STA before and 14 days after EC-IC bypass. Regional cerebral blood flow (rCBF) and acetazolamide (ACZ) reactivity of ipsilateral MCA territory were evaluated by quantitative single photon emission computed tomography. The mean flow velocities of ipsilateral STA were significantly higher (p < 0.0001) and PI value was significantly lower (p < 0.0001) 14 days after EC-IC bypass than before. The diameter of ipsilateral STA was also larger 14 days after EC-IC bypass than before (p < 0.0001). STA mean flow velocity was significantly correlated with the rCBF 14 days after EC-IC bypass (R = 0.55, p < 0.0001). The post-surgical STA mean flow velocity cut-off value over 58.2 cm/sec yielded the highest diagnostic accuracy (sensitivity, 75%; specificity, 74%) for excellent rCBF value (> or =40 ml/100 g/min) after EC-IC bypass. The ipsilateral STA mean blood flow velocity is a highly sensitive parameter for predicting rCBF in the ipsilateral MCA territory after EC-IC bypass.