title: Quantitative microstructural deficits in chronic phase of stroke with small volume infarcts: A diffusion tensor 3-D tractographic analysis.
abstract: Non-infarct zone white matter wallerian degeneration is well-documented in large volume territorial infarctions. However to what extent these abnormalities exist in small volume infarction is not known, particularly since routine T2/FLAIR MR images show minimal changes in such cases. We therefore utilized DTI based quantitative 3D tractography for quantitative assessment of white matter integrity in chronic phase of small volume anterior circulation infarcts.
  
  
  
  Eleven chronic stroke subjects with small anterior circulation large vessel infarcts (≤10cm(3) volume of primary infarct) were compared with 8 age matched controls. These infarcts had negligible to mild gliosis and encephalomalacia in the primary infarct territory without obvious wallerian degeneration on conventional MRI. Quantitative Diffusion Tensor 3-D tractography was performed for CST, genu and splenium of corpus callosum. Tract based Trace and fractional anisotropy (FA) were compared with age matched controls.
  
  
  
  On univariate analysis, Chronic stroke subjects had significant elevation in Trace measurement in genu of corpus callosum (GCC), ipsilesional and contralesional CST, (p<0.05), compared to controls. After adjusting for smoking, hypertension (HTN) and non-specific white matter hyperintensities, (WMHs), there was significant elevation in trace within the ipsilesional CST (p=0.05). Contralesional CST FA correlated significantly with walking speed, r=0.67, p=0.03.
  
  
  
  Stroke subjects with small volume infarcts demonstrate significant quantitative microstructural white matter abnormalities in chronic phase, which are otherwise subthreshold for detection on routine imaging. Ability to quantify these changes provides an important marker for assessing non-infarct zone neuroaxonal integrity in the chronic phase even in the setting of small infarction.
authors.affiliation: Department of Radiology, Mount Sinai Medical Center, Miami Beach, FL and Center for Comparative NeuroImaging, University of Massachusetts Medical School, Worcester, MA. Electronic address: prachi.dubey@umassmed.edu.
authors.forename: Prachi
authors.initials: P
authors.lastname: Dubey
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Vasileios-Arsenios
authors.initials: VA
authors.lastname: Lioutas
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Rafeeque
authors.initials: R
authors.lastname: Bhadelia
authors.affiliation: Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Brad
authors.initials: B
authors.lastname: Manor
authors.affiliation: Department of Neurology, University of Massachusetts Medical School, Worcester, MA.
authors.forename: Peter
authors.initials: P
authors.lastname: Novak
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Magdy
authors.initials: M
authors.lastname: Selim
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Vera
authors.initials: V
authors.lastname: Novak
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D003337:Corpus Callosum / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000000981:diagnostic imaging* / Q000503:physiopathology*
keywords: Chronic stroke; Diffusion tensor imaging; Quantitative imaging; Tractography