title: Transcranial Doppler pulsatility indices as a measure of diffuse small-vessel disease.
abstract: OBJECTIVE
  Elevation in pulsatility indices (PIs) as measured by transcranial Doppler (TCD) have been postulated to reflect downstream increased vascular resistance caused by small-vessel ischemic disease.
  
  
  METHODS
  The authors retrospectively compared TCD PIs and magnetic resonance imaging (MRI) manifestations of small-vessel disease in 55 consecutive patients who underwent TCD studies and brain MRI within 6 months of each other during a 2-year period.
  
  
  RESULTS
  Correlations between TCD middle cerebral artery PIs and MRI measures were as follows: periventricular hyperintensity (PVH) = 0.52 (P < .0001), deep white matter hyperintensity (DWMH) = 0.54 (P < .0001), lacunar disease = 0.31 (P = .02), and combined PVH/DWMH/lacunes = 0.54 (P < .0001). Correlation between pontine ischemia and vertebrobasilar PIs was 0.46 (P = .0004). Univariate analysis showed that age, elevated PI, and hypertension strongly correlated with white matter disease measures. After adjusting for these factors in a multivariate Poisson regression analysis, PI remained an independent predictor of white matter disease. Receiver operator curve analyses identified PI cut points that allowed discrimination of PVH with 89% sensitivity and 86% specificity and discrimination of DWMH with 70% sensitivity and 73% specificity.
  
  
  CONCLUSIONS
  Elevation in PIs as measured by TCD shows strong correlation with MRI evidence of small-vessel disease. TCD may be a useful physiologic index of the presence and severity of diffuse small-vessel disease.
authors.affiliation: Stroke Center, Department of Neurology, 710 Westwood Plaza, UCLA Medical Center, Los Angeles, CA 90095, USA. ckidwell@ucla.edu
authors.forename: C S
authors.initials: CS
authors.lastname: Kidwell
authors.forename: S
authors.initials: S
authors.lastname: el-Saden
authors.forename: Z
authors.initials: Z
authors.lastname: Livshits
authors.forename: N A
authors.initials: NA
authors.lastname: Martin
authors.forename: T C
authors.initials: TC
authors.lastname: Glenn
authors.forename: J L
authors.initials: JL
authors.lastname: Saver
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D011673:Pulsatile Flow; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D017585:Ultrasonography, Doppler, Transcranial; D014655:Vascular Resistance