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Baseline NAWM structural integrity and CBF predict periventricular WMH expansion over time
Nutta-On Promjunyakul1, Hiroko H Dodge2, David Lahna2
1From the Department of Neurology (N.P., H.H.D., D.L., E.L.B., J.A.K., L.C.S.) and Advanced Imaging Research Center (W.D.R.), Oregon Health & Science University, Portland; Department of Neurology (H.H.D.), University of Michigan, Ann Arbor; and Department of Neurology (J.A.K., L.C.S.), Veterans Affairs Medical Center, Portland, OR. promjuny@ohsu.edu.
Neurology
|May 18, 2018
Summary
Low cerebral blood flow and specific diffusion tensor imaging measures, particularly mean diffusivity, predict white matter hyperintensity growth. Diffusion tensor imaging is more sensitive than cerebral blood flow for predicting this progression.
Area of Science:
- Neuroimaging
- Cerebrovascular disease
- White matter integrity
Background:
- White matter hyperintensities (WMH) are common in aging and associated with cognitive decline.
- Understanding the progression of WMH is crucial for developing neuroprotective strategies.
- The periventricular white matter hyperintensity (PVWMH) penumbra represents a region of potential WMH growth.
Purpose of the Study:
- To compare baseline cerebral blood flow (CBF) and microstructural characteristics of normal-appearing white matter (NAWM) in the PVWMH penumbra.
- To determine the predictive value of these measures for WMH growth over time.
- To identify the most sensitive imaging marker for WMH progression.
Main Methods:
- Serial brain MRI including pulsed arterial spin labeling (for CBF) and diffusion tensor imaging (DTI) in 52 elderly patients.
- Identification of new WMH and persistent NAWM voxels in relation to the WMH penumbra at follow-up.
- Statistical analyses using paired t tests and generalized estimating equations to assess associations between baseline imaging measures and WMH growth.
Main Results:
- Low baseline CBF, fractional anisotropy, and high mean diffusivity (MD) were associated with new PVWMH.
- Mean diffusivity (MD) emerged as the strongest predictor of WMH growth.
- Radial diffusivity showed a stronger relationship with WMH growth than CBF and axial diffusivity.
Conclusions:
- Both CBF and DTI measures independently predict WMH growth.
- DTI, particularly MD, is a more sensitive predictor of WMH progression than CBF.
- WMH progression may be driven by demyelinating injury secondary to hypoperfusion, supporting MD's use in future trials.
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