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.

White matter structural integrity and transcranial Doppler blood flow pulsatility in normal aging

“…Prior studies have reported inconsistent results for the association between PI and white matter measures (FA and/or WMHI) [7, 12, 13, 35]. Our results suggest that this may be due to the fact that PIs in different vessels carry different information and that prior studies employed different methods of PI and spatial averaging.…”

“…Because correlations among pulsatility indexes measured in each of the main cerebral arteries were modest (Table 1), analytic approaches that average their values across vessels to reduce noise, improve precision and/or to reduce the number of variables may dilute associations of PI and FA. Moreover, averaging may be performed in different ways yielding different effects on information: (i) average velocity time series across the vessels before extracting global PSV, EDV and MFV followed by applying the Gosling equation, (ii) average PSV, EDV and MFV extracted from each vessel prior to applying the Gosling equation and (iii) average PIs from each vessel [7, 12, 13, 35].…”

Pathogenesis and research progress in leukoaraiosis

“…While MBFv is a relative measure of the arterial perfusion integrity, PI reflects the resistance of the small vessels and the intracranial compliance (Baumgartner, 2006;Wagshul et al, 2011). Therefore, TCD is an inexpensive and feasible alternative to evaluate the cerebral hemodynamics, the arterial perfusion integrity, and the intracranial small vessel compliance (Wagshul et al, 2011;Brutto et al, 2015;Vinciguerra and Bosel, 2017).…”

“…However, a recent research shows that in a representative sample of older adults living in a rural Latin American population, the PI of major intracranial arteries do not correlate with LA severity after adjusting for confounding variables (Brutto et al, 2015). A high PI may not only reflect distal cerebrovascular resistance (and thus, LA) but may also occur as the result of large artery stiffness or other hemodynamic factors (Webb et al, 2012).…”

Development and validation of a priori risk model for extensive white matter lesions in people age 65 years or older: the Dijon MRI study

“…16 Moreover, access to and usage of MRI technology can be affected by factors such as rural location, patient health insurance, MRI contraindications and the preference for cheaper neuroimaging techniques. 17 18 Predictive clinical risk scores for brain imaging are therefore of major interest to improve clinical decision-making and patient outcomes, balancing overuse and underuse of imaging. Cerebral imaging risk scores have guided the use of CT for intracranial haematoma after minor head injuries.…”