title: Disappointing reliability of pulsatility indices to identify candidates for magnetic resonance imaging screening in population-based studies assessing prevalence of cerebral small vessel disease.
abstract: BACKGROUND
  Diagnosis of cerebral small vessel disease (SVD) is a challenge in remote areas where magnetic resonance imaging (MRI) is not available. Hospital-based studies in high-risk or stroke patients have found an association between the pulsatility index (PI) of intracranial arteries - as derived from transcranial Doppler (TCD) - and white matter hyperintensities (WMH) of presumed vascular origin. We aimed to assess the reliability of cerebral pulsatility indices to identify candidates for MRI screening in population-based studies assessing prevalence of SVD.
  
  
  METHODS
  A representative sample of stroke-free Atahualpa residents aged ≥65 years investigated with MRI underwent TCD. Using generalized linear models, we evaluated whether the PI of major intracranial arteries correlate with WMH (used as a proxy of diffuse SVD), after adjusting for demographics and cardiovascular risk factors.
  
  
  RESULTS
  Out of 70 participants (mean age 70.6 ± 4.6 years, 57% women), 28 (40%) had moderate-to-severe WMH. In multivariate models, there were no differences across categories of WMH in the mean PI of middle cerebral arteries (1.10 ± 0.16 vs. 1.22 ± 0.24, β: 0.065, 95% confidence interval (CI): -0.084-0.177, P = 0.474) or vertebrobasilar arteries (1.11 ± 0.16 vs. 1.29 ± 0.27, β: 0.066, 95% CI: -0.0024-0.156, P = 0.146).
  
  
  CONCLUSIONS
  Cerebral PI should not be used to identify candidates for MRI screening in population-based studies assessing the burden of SVD.
authors.affiliation: School of Medicine, Universidad Espiritu Santo - Ecuador, Ecuador.
authors.forename: Oscar H
authors.initials: OH
authors.lastname: Del Brutto
authors.affiliation: Department of Gastroenterology, Vanderbilt University, Nashville, TN.
authors.forename: Robertino M
authors.initials: RM
authors.lastname: Mera
authors.affiliation: Department of Neurology, Hospital Medica Sur, Mexico City, Mexico.
authors.forename: María de la Luz
authors.initials: Mde L
authors.lastname: Andrade
authors.affiliation: Mayo Clinic College of Medicine, Sleep Disorder Center, Jacksonville, Fl.
authors.forename: Pablo R
authors.initials: PR
authors.lastname: Castillo
authors.affiliation: Community Center, the Atahualpa Project, Atahualpa, Ecuador.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Zambrano
authors.affiliation: Department of Gastroenterology, Vanderbilt University, Nashville, TN.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Nader
keywords: Population-based studies; pulsatility index; small vessel disease; transcranial Doppler; white matter hyperintensities