Department of Radiology (L.S., R.C., A.B.), di Cagliari - Polo di Monserrato s.s, Cagliari, Italy. Azienda Ospedaliero Universitaria (A.O.U.), Department of Cardiovascular Medicine (V.N.), Mayo Clinic, Rochester, MN. Department of Radiology (A.G.), Weill Cornell Medicine, New York, New York. Department of Neurology (H.K.), Weill Cornell Medicine, New York, New York. Stroke Diagnosis and Monitoring Division, AtheroPoint LLC, Roseville, CA (J.S.S.). Department of Pathology (T.C., D.F., G.C., G.F.), di Cagliari - Polo di Monserrato s.s, Cagliari, Italy. Department of Radiology, University of Otago, Christchurch, New Zealand (A.P.H.B., S.G.). Department of Vascular Surgery (R.S.), di Cagliari - Polo di Monserrato s.s, Cagliari, Italy. Department of Radiology (IDI), Hospital Universitari de Girona, Spain (J.P.). Xuanwu Hospital, Capital Medical University, Xicheng District, Beijing, China (Q.Y.). IRCSS SDN, Naples, Italy (L.M.). Department of Neurologic Surgery (G.L.), Mayo Clinic, Rochester, MN.