title: Temporal evolution of ischemic lesions in nonhuman primates: a diffusion and perfusion MRI study.
abstract: OBJECTIVE
  Diffusion-weighted imaging (DWI) and perfusion MRI were used to examine the spatiotemporal evolution of stroke lesions in adult macaques with ischemic occlusion.
  
  
  METHODS
  Permanent MCA occlusion was induced with silk sutures through an interventional approach via the femoral artery in adult rhesus monkeys (n = 8, 10-21 years old). The stroke lesions were examined with high-resolution DWI and perfusion MRI, and T2-weighted imaging (T2W) on a clinical 3T scanner at 1-6, 48, and 96 hours post occlusion and validated with H&E staining.
  
  
  RESULTS
  The stroke infarct evolved via a natural logarithmic pattern with the mean infarct growth rate = 1.38 ± 1.32 ml per logarithmic time scale (hours) (n = 7) in the hyperacute phase (1-6 hours). The mean infarct volume after 6 hours post occlusion was 3.6±2.8 ml (n = 7, by DWI) and increased to 3.9±2.9 ml (n = 5, by T2W) after 48 hours, and to 4.7±2.2ml (n = 3, by T2W) after 96 hours post occlusion. The infarct volumes predicted by the natural logarithmic function were correlated significantly with the T2W-derived lesion volumes (n = 5, r = 0.92, p = 0.01) at 48 hours post occlusion. The final infarct volumes derived from T2W were correlated significantly with those from H&E staining (r = 0.999, p < 0.0001, n = 4). In addition, the diffusion-perfusion mismatch was visible generally at 6 hours but nearly diminished at 48 hours post occlusion.
  
  
  CONCLUSIONS
  The infarct evolution follows a natural logarithmic pattern in the hyperacute phase of stroke. The logarithmic pattern of evolution could last up to 48 hours after stroke onset and may be used to predict the infarct volume growth during the acute phase of ischemic stroke. The nonhuman primate model, MRI protocols, and post data processing strategy may provide an excellent platform for characterizing the evolution of acute stroke lesion in mechanistic studies and therapeutic interventions of stroke disease.
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America.
authors: Xiaodong
authors: X
authors: Zhang
authors: Department of Radiology, School of Medicine, Emory University, Atlanta, Georgia 30322, United States of America.
authors: Frank
authors: F
authors: Tong
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America.
authors: Chun-Xia
authors: CX
authors: Li
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America.
authors: Yumei
authors: Y
authors: Yan
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America.
authors: Doty
authors: D
authors: Kempf
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America; Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, Georgia 30322, United States of America.
authors: Govind
authors: G
authors: Nair
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America.
authors: Silun
authors: S
authors: Wang
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America; Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, Georgia 30322, United States of America.
authors: E Chris
authors: EC
authors: Muly
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America; Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, Georgia 30322, United States of America; Atlanta Veterans Affairs Medical Center, Decatur, Georgia 30033, United States of America.
authors: Stuart
authors: S
authors: Zola
authors: Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, United States of America; Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, Georgia 30322, United States of America.
authors: Leonard
authors: L
authors: Howell
mesh_terms: D000818:Animals; D020520:Brain Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D008253:Macaca mulatta; D018810:Magnetic Resonance Angiography; D008297:Male; D011859:Radiography; D020521:Stroke / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D013997:Time Factors