Semi-automated Segmentation and Quantification of Perivascular Spaces at 7 Tesla in COVID-19, 2022, Langan et al

Semi-automated Segmentation and Quantification of Perivascular Spaces at 7 Tesla in COVID-19
Langan MT, Smith DA, Verma G, Khegai O, Saju S, Rashid S, Ranti D, Markowitz M, Belani P, Jette N, Mathew B, Goldstein J, Kirsch CFE, Morris LS, Becker JH, Delman BN, Balchandani P

While COVID-19 is primarily considered a respiratory disease, it has been shown to affect the central nervous system. Mounting evidence shows that COVID-19 is associated with neurological complications as well as effects thought to be related to neuroinflammatory processes. Due to the novelty of COVID-19, there is a need to better understand the possible long-term effects it may have on patients, particularly linkage to neuroinflammatory processes.

Perivascular spaces (PVS) are small fluid-filled spaces in the brain that appear on MRI scans near blood vessels and are believed to play a role in modulation of the immune response, leukocyte trafficking, and glymphatic drainage. Some studies have suggested that increased number or presence of PVS could be considered a marker of increased blood-brain barrier permeability or dysfunction and may be involved in or precede cascades leading to neuroinflammatory processes.

Due to their size, PVS are better detected on MRI at ultrahigh magnetic field strengths such as 7 Tesla, with improved sensitivity and resolution to quantify both concentration and size. As such, the objective of this prospective study was to leverage a semi-automated detection tool to identify and quantify differences in perivascular spaces between a group of 10 COVID-19 patients and a similar subset of controls to determine whether PVS might be biomarkers of COVID-19-mediated neuroinflammation.

Results demonstrate a detectable difference in neuroinflammatory measures in the patient group compared to controls. PVS count and white matter volume were significantly different in the patient group compared to controls, yet there was no significant association between PVS count and symptom measures. Our findings suggest that the PVS count may be a viable marker for neuroinflammation in COVID-19, and other diseases which may be linked to neuroinflammatory processes.

Link | PDF (Frontiers in Neurology)

 

See also —

• Automated Methods for Detecting and Quantitation of Enlarged Perivascular spaces on MRI (2023)
• Perivascular spaces and brain waste clearance systems: relevance for neurodegenerative and cerebrovascular pathology (2021)
• Perivascular spaces as a marker of psychological trauma in depression: A 7-Tesla MRI study (2022)

 

I won't make a separate thread, but this paper shows that enlarged perivascular spaces are more often associated with arteries, in the basal ganglia.

Enlarged perivascular spaces in the basal ganglia are associated with arteries not veins (2024)
Jan Oltmer; Hendrik Mattern; Julia Beck; Renat Yakupov; Steven M Greenberg; Jaco JM Zwanenburg; Tine Arts; Emrah Düzel; Susanne J van Veluw; Stefanie Schreiber; Valentina Perosa

Enlarged perivascular spaces (EPVS) are common in cerebral small vessel disease (CSVD) and have been identified as a marker of dysfunctional brain clearance. However, it remains unknown if the enlargement occurs predominantly around arteries or veins.

We combined in vivo ultra-high-resolution MRI and histopathology to investigate the spatial relationship of veins and arteries with EPVS within the basal ganglia (BG). Furthermore, we assessed the relationship between the EPVS and measures of blood-flow (blood-flow velocity, pulsatility index) in the small arteries of the BG. Twenty-four healthy controls, twelve non-CAA CSVD patients, and five probable CAA patients underwent a 3 tesla [T] and 7T MRI scan, and EPVS, arteries, and veins within the BG were manually segmented. Furthermore, the scans were co-registered. Six autopsy-cases were also assessed.

In the BG, EPVS were significantly closer to and overlapped more frequently with arteries than with veins. Histological analysis showed a higher proportion of BG EPVS surrounding arteries than veins. Finally, the pulsatility index of BG arteries correlated with EPVS volume. Our results are in line with previous works and establish a pathophysiological relationship between arteries and EPVS, contributing to elucidating perivascular clearance routes in the human brain.

Link | PDF (Journal of Cerebral Blood Flow & Metabolism)