Region-specific associations between dual-Layer spectral detector CT-derived carotid plaque parameters and white...

White matter hyperintensities (WMH) exhibit region-specific characteristics. Whether dual-layer spectral detector CT (DLSCT)-derived plaque parameters associate with WMH burden region-specifically remains unclear.

This cross-sectional study enrolled 213 patients with carotid atherosclerotic plaques who underwent carotid CTA and brain MRI within 30 days. Seven DLSCT parameters were measured; WMH was segmented into juxtaventricular, periventricular, deep, and juxtacortical subregions. Multivariable linear regression assessed associations with total WMH burden (FDR correction). Nested models evaluated incremental value. Linear mixed-effects models with region-by-parameter interactions assessed region-specific associations.

In the primary model (Model 2), Z-Zeff was significantly negatively associated with total WMH burden (β = -0.205, 95 % CI: -0.299 ∼ -0.111, FDR-q < 0.001). Adding Z-Zeff to the clinical model significantly increased explained variance (ΔR² = 0.070, p < 0.001, ΔAIC = -15.09), whereas conventional CTA parameters did not (ΔR² = 0.001, p = 0.938). Significant region interactions were observed for Z-Zeff, age, and LDL-C. Z-Zeff was negatively associated with all subregions, strongest in periventricular (β = -0.254) and deep (β = -0.172) WMH. Age was most strongly associated with periventricular WMH (β = 0.436). LDL-C and diabetes were associated only with periventricular WMH (β = -0.111 and -0.221, respectively).

DLSCT-derived Z-Zeff was independently associated with WMH burden in a region-specific manner, with the strongest associations in periventricular and deep white matter, and provided incremental value beyond clinical and conventional CTA parameters. These findings support Z-Zeff as a potential imaging biomarker linking carotid plaque composition to regional cerebral small vessel disease.