title: Interhemispheric cerebral blood flow balance during recovery of motor hand function after ischemic stroke--a longitudinal MRI study using arterial spin labeling perfusion.
abstract: BACKGROUND
  Unilateral ischemic stroke disrupts the well balanced interactions within bilateral cortical networks. Restitution of interhemispheric balance is thought to contribute to post-stroke recovery. Longitudinal measurements of cerebral blood flow (CBF) changes might act as surrogate marker for this process.
  
  
  OBJECTIVE
  To quantify longitudinal CBF changes using arterial spin labeling MRI (ASL) and interhemispheric balance within the cortical sensorimotor network and to assess their relationship with motor hand function recovery.
  
  
  METHODS
  Longitudinal CBF data were acquired in 23 patients at 3 and 9 months after cortical sensorimotor stroke and in 20 healthy controls using pulsed ASL. Recovery of grip force and manual dexterity was assessed with tasks requiring power and precision grips. Voxel-based analysis was performed to identify areas of significant CBF change. Region-of-interest analyses were used to quantify the interhemispheric balance across nodes of the cortical sensorimotor network.
  
  
  RESULTS
  Dexterity was more affected, and recovered at a slower pace than grip force. In patients with successful recovery of dexterous hand function, CBF decreased over time in the contralesional supplementary motor area, paralimbic anterior cingulate cortex and superior precuneus, and interhemispheric balance returned to healthy control levels. In contrast, patients with poor recovery presented with sustained hypoperfusion in the sensorimotor cortices encompassing the ischemic tissue, and CBF remained lateralized to the contralesional hemisphere.
  
  
  CONCLUSIONS
  Sustained perfusion imbalance within the cortical sensorimotor network, as measured with task-unrelated ASL, is associated with poor recovery of dexterous hand function after stroke. CBF at rest might be used to monitor recovery and gain prognostic information.
authors.affiliation: Support Center for Advanced Neuroimaging (SCAN), Institute for Diagnostic and Interventional Neuroradiology, University Hospital Inselspital and University of Bern, Bern, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Wiest
authors.affiliation: Support Center for Advanced Neuroimaging (SCAN), Institute for Diagnostic and Interventional Neuroradiology, University Hospital Inselspital and University of Bern, Bern, Switzerland; Department of Neurology, University Hospital Inselspital and University of Bern, Bern, Switzerland.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Abela
authors.affiliation: Paul Scherrer Institute, Laboratory of Biomolecular Research, Villigen, Switzerland.
authors.forename: John
authors.initials: J
authors.lastname: Missimer
authors.affiliation: Support Center for Advanced Neuroimaging (SCAN), Institute for Diagnostic and Interventional Neuroradiology, University Hospital Inselspital and University of Bern, Bern, Switzerland.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schroth
authors.affiliation: Department of Neurology, University Hospital Inselspital and University of Bern, Bern, Switzerland.
authors.forename: Christian W
authors.initials: CW
authors.lastname: Hess
authors.affiliation: Department of Neurology, University Hospital Inselspital and University of Bern, Bern, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Sturzenegger
authors.affiliation: Department of Neurology, Ahmanson-Lovelace Brain Mapping Center, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: Danny J J
authors.initials: DJ
authors.lastname: Wang
authors.affiliation: Support Center for Advanced Neuroimaging (SCAN), Institute for Diagnostic and Interventional Neuroradiology, University Hospital Inselspital and University of Bern, Bern, Switzerland; Department of Neurology, Kantonsspital St. Gallen, St. Gallen, Switzerland; Department of Neurology, University Hospital Inselspital and University of Bern, Bern, Switzerland.
authors.forename: Bruno
authors.initials: B
authors.lastname: Weder
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Psychiatry and University of Bern, Bern, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Federspiel
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology; D002560:Cerebrovascular Circulation; D003430:Cross-Sectional Studies; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011446:Prospective Studies; D011597:Psychomotor Performance; D020127:Recovery of Function; D012039:Regional Blood Flow; D020521:Stroke / Q000473:pathology* / Q000503:physiopathology*