title: Acute and chronic stroke: navigated spin-echo diffusion-weighted MR imaging.
abstract: OBJECTIVE
  The authors evaluated a phase-navigated spin-echo (SE) motion-correction sequence for use at diffusion-weighted (DW) magnetic resonance (MR) imaging after cerebral infarction.
  
  
  METHODS
  Twenty-nine patients underwent 32 conventional T2-weighted fast SE and SE DW imaging after stroke (n=25), transient ischemic attack (n=3), or reversible ischemic neurologic deficit (n=1). Imaging was performed in a standard head holder with standard padding. Apparent diffusion coefficient (ADC) maps were constructed.
  
  
  RESULTS
  DW images depicted high signal intensity compatible with localization of the ischemic symptoms in all cases. Lesions were depicted more clearly on DW than on T2-weighted images. On DW images, acute infarct ADC values were uniformly low (mean, 0.401x10(-5) cm2/sec =+/- 0.143 [standard deviation]) compared with control ADC values (mean, 0.754x10(-5) cm2/sec +/- 0.201). ADC values of chronic infarcts were supranormal (mean, 1.591x10(-5) cm2/sec +/- 0.840) compared with control values (mean, 0.788x10(-5) cm2/sec +/- 0.166). DW imaging did not show a change after transient ischemic attack. with reversible ischemic neurologic deficit, however, hyperintensity on DW images and low ADC resolved after symptoms abated.
  
  
  CONCLUSIONS
  Clinical phase-navigated SE DW imaging improved early diagnosis of stroke and helped differentiate acute from chronic stroke. Changes on DW images are reversed after symptoms resolve.
authors.affiliation: Department of Radiology, Stanford University Medical Center, Stanford, CA 94305-5105, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Marks
authors.forename: A
authors.initials: A
authors.lastname: de Crespigny
authors.forename: D
authors.initials: D
authors.lastname: Lentz
authors.forename: D R
authors.initials: DR
authors.lastname: Enzmann
authors.forename: G W
authors.initials: GW
authors.lastname: Albers
authors.forename: M E
authors.initials: ME
authors.lastname: Moseley
mesh_terms: D000208:Acute Disease; D000368:Aged; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000175:diagnosis*; D002544:Cerebral Infarction / Q000175:diagnosis*; D002560:Cerebrovascular Circulation; D002908:Chronic Disease; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002546:Ischemic Attack, Transient / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D013997:Time Factors