Quantifying cerebral blood arrival times using hypoxia-mediated arterial BOLD contrast

Bhogal, Alex A.; Sayin, Ece Su; Poublanc, Julien; Duffin, James; Fisher, Joseph A.; Sobcyzk, Olivia; Mikulis, David

doi:10.1016/j.neuroimage.2022.119523

Cited by 10 publications

(10 citation statements)

References 58 publications

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“…This was followed by computation of global transit time as the sum of estimates of the arterial transit time (computed as the average of voxels with positive lag times relative to center) and the venous transit time (computed as the average of voxels with negative lag times relative to center), with the majority of global transit time estimates falling into the range of 4–6 s ( Aso et al, 2020 ). Additionally, Bhogal et al (2022) implemented a carpet method for computing global transit times using controlled hypoxia as a source of BOLD contrast, yielding an average global transit time of 4.5 s. Similar investigation of using hypoxia to induce BOLD contrast has been explored in ( Sayin et al, 2022 ). These alternative approaches demonstrate the feasibility of BOLD signal-based methods for computing global transit time which do not rely on induced hypercapnia.…”

Section: Discussionmentioning

confidence: 99%

“…However, it is a an invasive imaging technique and the side-effects of gadolinium-based agents remaining in the human body are still debatable ( Essig et al, 2013 ), highlighting the need for a safer and more convenient alternative. Several different alternative methods for measurement of hemodynamic metrics, based on blood oxygen level dependent (BOLD) MRI, have been proposed ( Aso et al, 2020 ; Bhogal et al, 2022 ; Sayin et al, 2022 ). Recently, an increasing number of studies have used elevated CO 2 levels as a regressor to estimate the CO 2 /blood arrival time via BOLD MRI ( Blockley et al, 2011 ; Thomas et al, 2013a ; Duffin et al, 2015 ; Donahue et al, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

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Using carpet plots to analyze blood transit times in the brain during hypercapnic challenge magnetic resonance imaging

Fitzgerald

Yao²,

Hocke³

et al. 2023

Front. Physiol.

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Blood arrival time and blood transit time are useful metrics in characterizing hemodynamic behaviors in the brain. Functional magnetic resonance imaging in combination with a hypercapnic challenge has been proposed as a non-invasive imaging tool to determine blood arrival time and replace dynamic susceptibility contrast (DSC) magnetic resonance imaging, a current gold-standard imaging tool with the downsides of invasiveness and limited repeatability. Using a hypercapnic challenge, blood arrival times can be computed by cross-correlating the administered CO2 signal with the fMRI signal, which increases during elevated CO2 due to vasodilation. However, whole-brain transit times derived from this method can be significantly longer than the known cerebral transit time for healthy subjects (nearing 20 s vs. the expected 5–6 s). To address this unrealistic measurement, we here propose a novel carpet plot-based method to compute improved blood transit times derived from hypercapnic blood oxygen level dependent fMRI, demonstrating that the method reduces estimated blood transit times to an average of 5.32 s. We also investigate the use of hypercapnic fMRI with cross-correlation to compute the venous blood arrival times in healthy subjects and compare the computed delay maps with DSC-MRI time to peak maps using the structural similarity index measure (SSIM). The strongest delay differences between the two methods, indicated by low structural similarity index measure, were found in areas of deep white matter and the periventricular region. SSIM measures throughout the remainder of the brain reflected a similar arrival sequence derived from the two methods despite the exaggerated spread of voxel delays computed using CO2 fMRI.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Using carpet plots to analyze blood transit times in the brain during hypercapnic challenge magnetic resonance imaging

Fitzgerald

Yao²,

Hocke³

et al. 2023

Front. Physiol.

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“…All subsequent dDSC processing was performed in MATLAB (MathWorks, Natick, MA). Signal contribution from pial veins was suppressed by eliminating voxels with higher signal amplitude than the 98th percentile ( Bhogal et al, 2022 ). Whole brain (WB), GM, and WM perfusion values was computed by averaging voxels within brain and tissue-specific masks in each subject’s functional native space.…”

Section: Methodsmentioning

confidence: 99%

“…The great cerebral veins not only have the largest signal intensity changes, but they have the longest delay relative to the global BOLD signal. Individual VOFs were obtained automatically by choosing 20 voxels with the highest integrated, rectified signal intensity ( Carroll et al, 2003 ) and delay greater than the 98th percentile ( Bhogal et al, 2022 ). To convert

to concentration-time curve

in both blood and tissue voxels, this manuscript assumed a linear relationship

, with coefficients

.…”

Section: Methodsmentioning

confidence: 99%

“…Since the signal at each voxel was a sinusoid, whose phase could be estimated, TD was computed as the phase delay of tissue:

where

is the fundamental frequency of the sinusoidal stimulus and

is the phase of the sine wave ( Blockley et al, 2011 ) calculated from the Fourier transform of the BOLD signal with respect to time. The venous phase

was estimated by forming a histogram of phase delays across all voxels within the brain for each subject and selecting the 98th percentile, thus removing observer bias to obtain more consistent phase estimates ( Bhogal et al, 2022 ).…”

Section: Methodsmentioning

confidence: 99%

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Sinusoidal CO2 respiratory challenge for concurrent perfusion and cerebrovascular reactivity MRI

Xu²,

Gonzalez-Zacarias³

et al. 2023

Front. Physiol.

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Introduction: Deoxygenation-based dynamic susceptibility contrast (dDSC) has previously leveraged respiratory challenges to modulate blood oxygen content as an endogenous source of contrast alternative to gadolinium injection in perfusion-weighted MRI. This work proposed the use of sinusoidal modulation of end-tidal CO2 pressures (SineCO2), which has previously been used to measure cerebrovascular reactivity, to induce susceptibility-weighted gradient-echo signal loss to measure brain perfusion.Methods:SineCO2 was performed in 10 healthy volunteers (age 37 ± 11, 60% female), and tracer kinetics model was applied in the frequency domain to calculate cerebral blood flow, cerebral blood volume, mean transit time, and temporal delay. These perfusion estimates were compared against reference techniques, including gadolinium-based DSC, arterial spin labeling, and phase contrast.Results: Our results showed regional agreement between SineCO2 and the clinical comparators. SineCO2 was able to generate robust CVR maps in conjunction to baseline perfusion estimates.Discussion: Overall, this work demonstrated feasibility of using sinusoidal CO2 respiratory paradigm to simultaneously acquire both cerebral perfusion and cerebrovascular reactivity maps in one imaging sequence.

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An Investigation of Cerebral Vascular Functional Properties in Middle‐to‐Old Age Community People With High Vascular Risk Profiles

Zhang,

Hong

et al. 2024

Magnetic Resonance Imaging

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BackgroundVascular degeneration is an important cause of brain damage in aging. Assessing the functional properties of the cerebral vascular system may aid early diagnosis and prevention.PurposeTo investigate the relationships between potential vascular functional markers and vascular risks, brain parenchymal damage, and cognition.Study TypeRetrospective.SubjectsTwo hundred two general community subjects (42–80 years, males/females: 127/75).Field Strength/Sequence3 T, spin echo T1W/T2W/FLAIR, resting‐state functional MRI with an echo‐planar sequence (rsfMRI), pseudo‐continuous arterial spin labeling (pCASL) with a three‐dimensional gradient‐spin echo sequence.AssessmentCerebral blood flow (CBF) in gray matter calculated using pCASL, blood transit times calculated using rsfMRI, and the SD of internal carotid arteries signal (ICAstd) calculated using rsfMRI; visual assessment for lacunes; quantification of white matter hyperintensity volume; permutation test for quality control; collection of demographic and clinical data, Montreal Cognitive Assessment, Mini‐Mental State Examination.Statistical TestsKolmogorov–Smirnov test; Spearman rank correlation analysis; Multivariable linear regression analysis controlling for covariates; The level of statistical significance was set at P < 0.05.ResultsAge was negatively associated with ICAstd (β = −0.180). Diabetes was associated with longer blood transit time from large arteries to capillary bed (β = 0.185, adjusted for age, sex, and intracranial volume). Larger ICAstd was associated with less presence of lacunes (odds ratio: 0.418, adjusted for age and sex). Higher gray matter CBF (β = 0.154) and larger ICAstd (β = 0.136) were associated with better MoCA scores (adjusted for age, sex, and education).Data ConclusionProlonged blood transit time, decreased ICAstd, and diminished CBF were associated with vascular dysfunction and cognitive impairment. They may serve as vascular functional markers in future studies.Evidence Level3Technical EfficacyStage 3

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Quantifying cerebral blood arrival times using hypoxia-mediated arterial BOLD contrast

Cited by 10 publications

References 58 publications

Using carpet plots to analyze blood transit times in the brain during hypercapnic challenge magnetic resonance imaging

Using carpet plots to analyze blood transit times in the brain during hypercapnic challenge magnetic resonance imaging

Sinusoidal CO2 respiratory challenge for concurrent perfusion and cerebrovascular reactivity MRI

An Investigation of Cerebral Vascular Functional Properties in Middle‐to‐Old Age Community People With High Vascular Risk Profiles

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