In vivo mapping of cerebral small-vessel abnormalities in Parkinson's disease patients using USPIO-MRI at 3T

Conventional imaging techniques lack the resolution and sensitivity to adequately characterize cerebral small-vessel abnormalities (CSVA) in vivo. This study aimed to overcome these limitations and evaluate the feasibility of a novel MRI technique called Microvascular In-vivo Contrast Revealed Origins (MICRO), which uses an ultrasmall superparamagnetic iron oxide (USPIO) contrast agent (Ferumoxytol) to resolve the cerebral microvascular architecture with a level of anatomical and physiological detail not previously achievable in vivo. Fifty-nine Parkinson's disease (PD) patients underwent MICRO MRI based on susceptibility-weighted imaging (SWI). Three independent raters identified and categorized CSVAs as large developmental venous anomalies (DVAs), micro DVAs, engorged vessels, and diminished vessels. The location of each CSVA was documented, and its association with white matter hyperintensities (WMHs) was assessed. The MICRO imaging protocol demonstrated excellent inter-rater agreement for identifying these CSVAs. Our findings show a high prevalence of CSVAs in PD patients, with engorged vessels being the most common type (49.06% of subjects). Both engorged vessels (72.41%) and micro DVAs (81.82%) were highly associated with WMHs. CSVAs were most frequently observed in the periventricular white matter (n = 28), deep white matter (n = 32), and putamen (n = 14), suggesting a regional distribution pattern of detectable CSVAs. This work establishes MICRO as a feasible, reliable platform for in vivo microvascular mapping with potential applications in neurovascular research.