title: MRI-based Algorithm for Acute Ischemic Stroke Subtype Classification.
abstract: OBJECTIVE
  In order to improve inter-rater reliability and minimize diagnosis of undetermined etiology for stroke subtype classification, using a stroke registry, we developed and implemented a magnetic resonance imaging (MRI)-based algorithm for acute ischemic stroke subtype classification (MAGIC).
  
  
  METHODS
  We enrolled patients who experienced an acute ischemic stroke, were hospitalized in the 14 participating centers within 7 days of onset, and had relevant lesions on MR-diffusion weighted imaging (DWI). MAGIC was designed to reflect recent advances in stroke imaging and thrombolytic therapy. The inter-rater reliability was compared with and without MAGIC to classify the Trial of Org 10172 in Acute Stroke Treatment (TOAST) of each stroke patient. MAGIC was then applied to all stroke patients hospitalized since July 2011, and information about stroke subtypes, other clinical characteristics, and stroke recurrence was collected via a web-based registry database.
  
  
  RESULTS
  The overall intra-class correlation coefficient (ICC) value was 0.43 (95% CI, 0.31-0.57) for MAGIC and 0.28 (95% CI, 0.18-0.42) for TOAST. Large artery atherosclerosis (LAA) was the most common cause of acute ischemic stroke (38.3%), followed by cardioembolism (CE, 22.8%), undetermined cause (UD, 22.2%), and small-vessel occlusion (SVO, 14.6%). One-year stroke recurrence rates were the highest for two or more UDs (11.80%), followed by LAA (7.30%), CE (5.60%), and SVO (2.50%).
  
  
  CONCLUSIONS
  Despite several limitations, this study shows that the MAGIC system is feasible and may be helpful to classify stroke subtype in the clinic.
authors.affiliation: Department of Neurology, Eulji University Hospital, Eulji University, Daejeon, Korea.
authors.forename: Youngchai
authors.initials: Y
authors.lastname: Ko
authors.affiliation: Department of Neurology, Eulji University Hospital, Eulji University, Daejeon, Korea.
authors.forename: SooJoo
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Neurology, Cerebrovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Chung
authors.affiliation: Department of Neurology, Cerebrovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Moon-Ku
authors.initials: MK
authors.lastname: Han
authors.affiliation: Department of Neurology, Eulji General Hospital, Eulji University, Seoul, Korea.
authors.forename: Jong-Moo
authors.initials: JM
authors.lastname: Park
authors.affiliation: Department of Neurology, Eulji General Hospital, Eulji University, Seoul, Korea.
authors.forename: Kyusik
authors.initials: K
authors.lastname: Kang
authors.affiliation: Department of Neurology, Seoul Medical Center, Seoul, Korea.
authors.forename: Tai Hwan
authors.initials: TH
authors.lastname: Park
authors.affiliation: Department of Neurology, Seoul Medical Center, Seoul, Korea.
authors.forename: Sang-Soon
authors.initials: SS
authors.lastname: Park
authors.affiliation: Department of Neurology, Ilsan Paik Hospital, Inje University, Goyang, Korea.
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Cho
authors.affiliation: Department of Neurology, Ilsan Paik Hospital, Inje University, Goyang, Korea.
authors.forename: Keun-Sik
authors.initials: KS
authors.lastname: Hong
authors.affiliation: Department of Neurology, Soonchunhyang University Hospital, Seoul, Korea.
authors.forename: Kyung Bok
authors.initials: KB
authors.lastname: Lee
authors.affiliation: Department of Neurology, Yeungnam University Hospital, Daegu, Korea.
authors.forename: Jun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Dong-Eog
authors.initials: DE
authors.lastname: Kim
authors.affiliation: Department of Neurology, Dong-A University Hospital, Busan, Korea.
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Department of Neurology, Dong-A University Hospital, Busan, Korea.
authors.forename: Jae-Kwan
authors.initials: JK
authors.lastname: Cha
authors.affiliation: Department of Neurology, Chonnam National University Hospital, Gwangju, Korea.
authors.forename: Joon-Tae
authors.initials: JT
authors.lastname: Kim
authors.affiliation: Department of Neurology, Jeju National University Hospital, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Jay Chol
authors.initials: JC
authors.lastname: Choi
authors.affiliation: Department of Neurology, Chungbuk National University College of Medicine, Cheongju, Korea.
authors.forename: Dong-Ick
authors.initials: DI
authors.lastname: Shin
authors.affiliation: Biostatistical Consulting Unit, Soonchunhyang University Medical Center, Seoul, Korea.
authors.forename: Ji Sung
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Biostatistics, Korea University College of Medicine, Seoul, Korea.
authors.forename: Juneyoung
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Neurology, Hallym University Sacred Heart Hospital, Anyang, Korea.
authors.forename: Kyung-Ho
authors.initials: KH
authors.lastname: Yu
authors.affiliation: Department of Neurology, Hallym University Sacred Heart Hospital, Anyang, Korea.
authors.forename: Byung-Chul
authors.initials: BC
authors.lastname: Lee
authors.affiliation: Department of Neurology, Cerebrovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Hee-Joon
authors.initials: HJ
authors.lastname: Bae
keywords: Algorithm; Classification; Magnetic resonance imaging; Stroke