“…Similar to the previously reported 4D-CTA of AVM and AVF [6] , [7] , [8] , [9] , [10] , 4D-CTA of CPA visualized the hemodynamics as well as DSA. Moreover, 4D-CTA exhibited the abnormal vessels in higher contrast than right internal carotid angiography due to high spatial and time resolution, whereas the left external carotid angiography visualized the transdural supply, which is one of the characteristic findings of CPA [ 1 , [3] , [4] , [5] ], more clearly than 4D-CTA due to high vascular selectivity. Therefore, the high contrast of 4D-CTA and the high vascular selectivity of DSA play complementary roles in assessing the hemodynamics of CPA.…”