Can transcranial Doppler ultrasound be used for screening cerebral small vessel diseases in the community?

Abstract

Objectives: Elderly persons harbouring severe white matter hyperintensity (WMH), a radiological manifestation of cerebral small vessel disease (SVD), have an increased risk of dementia, stroke and poor functional outcomes. A simple screening tool will enhance their recruitment into preventive trials for SVD. We explored the clinical utility of the pulsatility index (PI) of the middle cerebral artery (MCA), obtained from transcranial Doppler ultrasound (TCD), in identifying severe WMH among community elderly persons with vascular risk factors.

Methods: Three hundred and thirty-one dementia- and stroke-free community elderly subjects with hypertension and/or diabetes mellitus underwent TCD to obtain the MCA PI. The WMH volume on 3.0 Tesla MRI was quantified and normalized to each subject's brain volume. The normalized WMH volumes were classified as low (<14.5 ml, 1 standard deviation [SD] above the mean, 84th percentile) or high (≥14.5 ml). The severity of WMH was also rated visually with the Fazekas score. Logistic regression and receiver-operator characteristics (ROC) analysis were performed to evaluate the association between the MCA PI and the severity of WMH.

Results: The MCA PI was not an independent predictor of severe WMH. An MCA PI ≥1.095 detected high normalized WMH volumes with an area under the curve (AUC) of 0.553 (95% CI 0.473-0.633), sensitivity of 0.556, and specificity of 0.523. ROC analysis of the MCA PI in predicting high Fazekas scores yielded similar findings.

Conclusion: In stroke- and dementia-free elderly persons with vascular risk factors, the MCA PI was unable to identify severe WMH. (Word count: 260).

Keywords: Screening; Small vessel diseases; Transcranial Doppler ultrasound; Vascular dementia; White matter hyperintensity.