We evaluate the feasibility of HR-VWI for diagnosing PICA dissection. Our results demonstrated that HR-VWI could effectively diagnose arterial dissection even in PICA, small diameter vessel. The dissection flap with outer wall enlargement on T2W HR-VWI was most confident sign for diagnosing PICAD. Isolated PICAD is not a rare cause of ischemic stroke in posterior circulation. Therefore, in case of PICA territory infarction of uncertain origin, differentiating PICAD using HR-VWI is necessary for proper treatment of patients, and T2WI should be included in HR-VWI.