title: Assessment of diffusion and perfusion deficits in patients with small subcortical ischemia.
abstract: OBJECTIVE
  Using perfusion- and diffusion-weighted MR imaging in acute ischemic stroke of the middle cerebral artery (MCA), previous studies have shown a typical pathophysiologic pattern that is characterized by a perfusion deficit larger than the diffusion lesion (mismatch), with the final lesion usually comprising the initial diffusion lesion (core) plus parts of the initial mismatch area. Little is known about underlying pathophysiology in small ischemic stroke. In this study, we used perfusion- and diffusion-weighted MR imaging to investigate the underlying pathophysiology of small subcortical ischemia.
  
  
  METHODS
  Six consecutive patients (age range, 42-76 years) with small subcortical ischemia were examined by using a 1.5-T MR system 2-5, 22-55, and 144-392 hours after the onset of symptoms. T2-weighted, diffusion-weighted imaging at b=0 s/mm2 and b=1000 s/mm2, and bolus-track perfusion-weighted imaging were performed. Lesion sizes were determined on the basis of T2-weighted findings as well as those of apparent diffusion coefficient (ADC) maps and CBF.
  
  
  RESULTS
  In every patient, the initial CBF lesion was smaller than the initial ADC lesion. Both the CBF lesion and the ADC lesion increased in size from first to second examination. In all instances, however, the CBF lesion remained smaller than the ADC lesion. The CBF lesion observed during the acute phase and the one seen on the following days were both smaller than the final T2 lesion.
  
  
  CONCLUSIONS
  Our data suggest that in contrast to previous findings in MCA ischemia in small subcortical infarcts tissue damage may spread beyond the area of the initial perfusion disturbance. In light of the small number of patients, further studies will have to address the relevance of this observation.
authors.affiliation: Department of Neurology, Humboldt University, Charité, Berlin, Germany.
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Doege
authors.forename: Christian M
authors.initials: CM
authors.lastname: Kerskens
authors.forename: Berenice I
authors.initials: BI
authors.lastname: Romero
authors.forename: Peter
authors.initials: P
authors.lastname: Brunecker
authors.forename: Jan
authors.initials: J
authors.lastname: Junge-Hülsing
authors.forename: Wolfram
authors.initials: W
authors.lastname: von Pannwitz
authors.forename: Bianca
authors.initials: B
authors.lastname: Müller
authors.forename: Arno
authors.initials: A
authors.lastname: Villringer
mesh_terms: D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005858:Germany; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies