Contrast‐agent‐free state‐of‐the‐art MRI on cerebral small vessel disease—part 1. ASL, IVIM, and CVR

Abstract

Cerebral small vessel disease (cSVD), a common cause of stroke and dementia, is traditionally considered the small vessel equivalent of large artery occlusion or rupture that leads to cortical and subcortical brain damage. Microvessel endothelial dysfunction can also contribute to it. Brain imaging, including MRI, is useful to show the presence of lesions of several types, although the association between conventional MRI measures and clinical features of cSVD is not always concordant. We assessed the additional contribution of contrast‐agent‐free, state‐of‐the‐art MRI techniques such as arterial spin labeling (ASL), diffusion tensor imaging, functional MRI, and intravoxel incoherent motion (IVIM) applied to cSVD in the existing literature. We performed a review following the PICO Worksheet and Search Strategy, including original papers in English, published between 2000 and 2022. For each MRI method, we extracted information about their contributions, in addition to those established with traditional MRI methods and related information about the origins, pathology, markers, and clinical outcomes in cSVD. This paper presents the first part of the review, which includes 37 studies focusing on ASL, IVIM, and cerebrovascular reactivity (CVR) measures. In general, they have shown that, in addition to white matter hyperintensities, alterations in other neuroimaging parameters such as blood flow and CVR also indicate the presence of cSVD. Such quantitative parameters were also related to cSVD risk factors. Therefore, they are promising, noninvasive tools to explore questions that have not yet been clarified about this clinical condition. However, protocol standardization is essential to increase their clinical use.

Visualizing Cerebral Small Vessel Degeneration During Aging and Diseases Using Magnetic Resonance Imaging

“…2). A variety of MRI methods enable the noninvasive evaluation of cerebral vascular functions 24 . In addition to the widely used arterial spin labeling method that assesses cerebral blood flow, 25 novel methods are being continuously developed.…”

“…A variety of MRI methods enable the noninvasive evaluation of cerebral vascular functions. 24 In addition to the widely used arterial spin labeling method that assesses cerebral blood flow, 25 novel methods are being continuously developed. Oxygen extraction fraction 26 and cerebral vascular reactivity 27 could detect perfusion deficits at an earlier disease stage.…”

Assessment of Microvascular Disease in Heart and Brain by MRI: Application in Heart Failure with Preserved Ejection Fraction and Cerebral Small Vessel Disease

“…Perfusion abnormalities are a common finding in CSVD, with an probable inverse relationship between CBF and CSVD severity [ 98 ]. There is ongoing debate as to whether reduced CBF is a cause or consequence [ 38 ] of CSVD, as loss of neural tissue could result in decreased metabolic demand and therefore reduced CBF; conversely, reduced perfusion may lead to tissue damage.…”

Integrated intravoxel incoherent motion tensor and diffusion tensor brain MRI in a single fast acquisition

“…A cerebral pathology that appears highly suitable for the evaluation of the combined IVIM-DTI analysis is cerebral small vessel disease (cSVD). 18,19 cSVD is characterized by alterations in brain parenchyma such as white matter with hyperintensities (WMH), lacunes, and microbleeds. [20][21][22] An increasing number of studies suggest that chronic cerebral hypoperfusion is involved in the etiology of cSVD, [23][24][25][26] while evidence from DTI-based studies demonstrates loss of microstructural integrity of the WM in cSVD.…”

“…A cerebral pathology that appears highly suitable for the evaluation of the combined IVIM–DTI analysis is cerebral small vessel disease (cSVD) 18,19 . cSVD is characterized by alterations in brain parenchyma such as white matter with hyperintensities (WMH), lacunes, and microbleeds 20–22 .…”