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METHODS article

Front. Physiol.
Sec. Vascular Physiology
Volume 15 - 2024 | doi: 10.3389/fphys.2024.1437973

Comparing Single-and Multi-Post Labeling Delays for the Measurements of Resting Cerebral and Hippocampal Blood Flow for Cerebrovascular Testing in Midlife Adults

Provisionally accepted
Kevin Decker Kevin Decker Faria Sanjana Faria Sanjana Nick Rizzi Nick Rizzi Mary K. Kramer Mary K. Kramer Alexander M. Cerjanic Alexander M. Cerjanic Curtis Johnson Curtis Johnson Christopher R. Martens Christopher R. Martens *
  • University of Delaware, Newark, United States

The final, formatted version of the article will be published soon.

    Objectives: To assess the reliability and validity of measuring resting cerebral blood flow (CBF) and hippocampal CBF using a single-post-labeling delay (PLD) and a multi-PLD pseudocontinuous arterial spin labeling (pCASL) protocol for cerebrovascular reactivity (CVR) testing.: 25 healthy, midlife adults (57 ± 4 years old) were imaged in a Siemens Prisma 3T magnetic resonance imaging (MRI) scanner. Resting CBF and hippocampal CBF were assessed using two pCASL protocols, our modified single-PLD protocol (pCASL-MOD) to accommodate the needs for CVR testing and the multi-PLD Human Connectome Project (HCP) Lifespan protocol to serve as the reference control (pCASL-HCP). During pCASL-MOD, CVR was calculated as the change in CBF from rest to hypercapnia (+9 mmHg increase in end-tidal partial pressure of carbon dioxide [PETCO2]) and then normalized for PETCO2. The reliability and validity in resting gray matter (GM) CBF, white matter (WM) CBF, and hippocampal CBF between pCASL-MOD and pCASL-HCP protocols were examined using correlation analyses, paired t-tests, and Bland Altman plots. Results: The pCASL-MOD and pCASL-HCP protocols were significantly correlated for resting GM CBF [r = 0.72; F (1, 23) = 25.24, p < 0.0001], WM CBF [r = 0.57; F (1, 23) = 10.83, p = 0.003], and hippocampal CBF [r = 0.77; F (1, 23) = 32.65, p < 0.0001]. However, pCASL-MOD underestimated resting GM CBF (pCASL-MOD: 53.7 ± 11.1 v. pCASL-HCP: 69.1 ± 13.1ml/100g/min; p < 0.0001), WM CBF (pCASL-MOD: 32.4 ± 4.8 v. pCASL-HCP: 35.5 ± 6.9 ml/100g/min; p = 0.01), and hippocampal CBF (pCASL-MOD: 50.5 ± 9.0 v. pCASL-HCP: 68.1 ± 12.5 ml/100g / min; p < 0.0001). PETCO2 increased by 8.0 ± 0.7 mmHg to induce CVR (GM CBF: 4.8 ± 2.6%; WM CBF 2.9 ± 2.5%; and hippocampal CBF: 3.4 ± 3.8%).Our single-PLD pCASL-MOD protocol reliably measured CBF and hippocampal CBF at rest given the significant correlation with the multi-PLD pCASL-HCP protocol. Despite the lower magnitude relative to pCASL-HCP, we recommend using our pCASL-MOD protocol for CVR testing in which an exact estimate of CBF is not required such as the assessment of relative change in CBF to hypercapnia.

    Keywords: Brain health, cerebral blood flow (CBF), Cerebrovascular reactivity (CVR), magnetic resonance imaging (MRI), and Arterial Spin Labeling (ASL) MRI

    Received: 24 May 2024; Accepted: 17 Sep 2024.

    Copyright: © 2024 Decker, Sanjana, Rizzi, Kramer, Cerjanic, Johnson and Martens. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Christopher R. Martens, University of Delaware, Newark, United States

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