Heterogeneity and Penumbra of White Matter Hyperintensities in Small Vessel Diseases Determined by Quantitative MRI.

Background: White matter hyperintensities (WMHs) are established structural imaging markers of cerebral small vessel disease. The pathophysiologic condition of brain tissue varies over the core, the vicinity, and the subtypes of WMH and cannot be interpreted from conventional magnetic resonance imaging. We aim to improve our pathophysiologic understanding of WMHs and the adjacently injured normal-appearing white matter in terms of microstructural and microvascular alterations using quantitative magnetic resonance imaging in patients with sporadic and genetic cerebral small vessel disease.

Diffusion-derived intravoxel-incoherent motion anisotropy relates to CSF and blood flow.

Unlabelled: This study investigates the feasibility of multi-b-value, multi-directional diffusion MRI for assessing the anisotropy of the cerebral pseudo-diffusion (D*)-tensor. We examine D*-tensor's potential to (1) reflect CSF and blood flow, and (2) detect microvascular architectural alterations in cerebral small vessel disease (cSVD) and aging.

Methods: Multi-b-value diffusion MRI was acquired in 32 gradient directions for 11 healthy volunteers, and in six directions for 29 patients with cSVD and 14 controls at 3 T.

Blood-Brain Barrier Integrity Decreases With Higher Blood Pressure: A 7T DCE-MRI Study.

Background: Blood-brain barrier (BBB) integrity is presumed to be impaired in hypertension, resulting from cerebral endothelial dysfunction. Hypertension precedes various cerebrovascular diseases, such as cerebral small vessel disease, and is a risk factor for developing neurodegenerative diseases for which BBB disruption is a preceding pathophysiological process. In this cross-sectional study, we investigated the relation between hypertension, current blood pressure, and BBB leakage in human subjects.

The neurovascular unit and its correlation with cognitive performance in patients with cerebral small vessel disease: a canonical correlation analysis approach.

Growing evidence indicates an important role of neurovascular unit (NVU) dysfunction in the pathophysiology of cerebral small vessel disease (cSVD). Individually measurable functions of the NVU have been correlated with cognitive function, but a combined analysis is lacking. We aimed to perform a unified analysis of NVU function and its relation with cognitive performance.

Imaging Interstitial Fluid With MRI: A Narrative Review on the Associations of Altered Interstitial Fluid With Vascular and Neurodegenerative Abnormalities.

Interstitial fluid (ISF) refers to the fluid between the parenchymal cells and along the perivascular spaces (PVS). ISF plays a crucial role in delivering nutrients and clearing waste products from the brain. This narrative review focuses on the use of MRI techniques to measure various ISF characteristics in humans.

Improving microstructural integrity, interstitial fluid, and blood microcirculation images from multi-b-value diffusion MRI using physics-informed neural networks in cerebrovascular disease.

Purpose: To obtain better microstructural integrity, interstitial fluid, and microvascular images from multi-b-value diffusion MRI data by using a physics-informed neural network (PINN) fitting approach.

Methods: Test-retest whole-brain inversion recovery diffusion-weighted images with multiple b-values (IVIM: intravoxel incoherent motion) were acquired on separate days for 16 patients with cerebrovascular disease on a 3.0T MRI system.

Evaluation of Microvascular Rarefaction in Vascular Cognitive Impairment and Heart Failure (CRUCIAL): Study Protocol for an Observational Study.

Introduction: Microvascular rarefaction, the functional reduction in perfused microvessels and structural reduction of microvascular density, seems to be an important mechanism in the pathophysiology of small blood vessel-related disorders including vascular cognitive impairment (VCI) due to cerebral small vessel disease and heart failure with preserved ejection fraction (HFpEF). Both diseases share common risk factors including hypertension, diabetes mellitus, obesity, and ageing; in turn, these comorbidities are associated with microvascular rarefaction. Our consortium aims to investigate novel non-invasive tools to quantify microvascular health and rarefaction in both organs, as well as surrogate biomarkers for cerebral and/or cardiac rarefaction (via sublingual capillary health, vascular density of the retina, and RNA content of circulating extracellular vesicles), and to determine whether microvascular density relates to disease severity.

Retinal microvascular function is associated with the cerebral microcirculation as determined by intravoxel incoherent motion MRI.

Background And Aims: The easily accessible retinal vessels provide a unique opportunity to study a proxy for cerebral small vessels. Associations between retinal vessel diameters and macrostructural brain white matter changes have already been demonstrated. Alterations in microvascular function, likely precede these structural abnormalities.

Semi-automated Computed Tomography Volumetry as a Proxy for Intracranial Pressure in Patients with Severe Traumatic Brain Injury: Clinical Feasibility Study.

Introduction: Traumatic brain injury (TBI) is associated with high mortality due to intracranial pressure (ICP). Whether computed tomography (CT) scanning of the brain within the first 24 h is indicative of intracranial hypertension is largely unknown. We assessed the feasibility of semi-automated CT segmentation in comparison with invasive ICP measurements.

Time-efficient measurement of subtle blood-brain barrier leakage using a T mapping MRI protocol at 7 T.

Purpose: Blood-brain barrier (BBB) disruption is commonly measured with DCE-MRI using continuous dynamic scanning. For precise measurement of subtle BBB leakage, a long acquisition time (>20 minutes) is required. As extravasation of the contrast agent is slow, discrete sampling at strategic time points might be beneficial, and gains scan time for additional sequences.

Spectral Diffusion Analysis of Intravoxel Incoherent Motion MRI in Cerebral Small Vessel Disease.

Background: Cerebral intravoxel incoherent motion (IVIM) imaging assumes two components. However, more compartments are likely present in pathologic tissue. We hypothesized that spectral analysis using a nonnegative least-squares (NNLS) approach can detect an additional, intermediate diffusion component, distinct from the parenchymal and microvascular components, in lesion-prone regions.