Abstract W P368: Longitudinal Change in fMRI Blood Oxygen Level Dependent Signal in Cerebral Amyloid Angiopathy

Introduction: Previous cross-sectional studies show that cerebral amyloid angiopathy (CAA) is associated with reduced blood oxygen level dependent (BOLD) signal change in response to a visual task, and that this reduction is due to impaired vascular reactivity. However, there are no data on the rate at which the BOLD signal changes over time in CAA. We hypothesized that fMRI activation would decline in CAA, representing progressively impaired vasoreactivity, and this decline would be associated with increased white matter hyperintensity (WMH) volume. Methods: fMRI BOLD amplitude was measured in response to a visual task (alternating checkerboard pattern) at study entry and 1-year follow-up for 18 patients with probable CAA by Boston criteria, and 15 healthy controls. fMRI data were matched to a canonical BOLD signal using a general linear model resulting in z-statistic images with a significance threshold of p<0.05 using FSL. The amplitude of the BOLD signal percent change from baseline was measured in the 200 most active voxels in the primary visual cortex. WMH were identified on fluid attenuated inversion recovery (FLAIR) images and the volume was measured using Quantomo software (Cybertrials Inc, Canada). Results: BOLD amplitude was lower at follow-up than baseline in CAA, but the difference was not significant (mean change -0.14±0.55, p=0.30). Mean BOLD amplitude was similar at baseline and follow-up in controls (mean change 0.20±0.49, p=0.14). The difference in rate of change over time between CAA and controls was borderline significant (p=0.04). fMRI was lower at follow-up than baseline in 11/18 CAA compared to 4/15 controls (p=0.08). In CAA patients, WMH increased over time (median 1.44 mL interquartile range -0.22 to 9.70mL, p=0.01). However, BOLD amplitude change and WMH change were not related (r=-0.01, p=0.96). Discussion: Although we did not see significant fMRI BOLD signal reduction from baseline to 1 year in CAA, we did see a difference in change over time between CAA and controls, consistent with our hypothesis that impaired vasoreactivity is a feature of CAA. Studies with larger numbers of patients, or longer duration of follow-up, are needed to more precisely determine the rate of change over time in reduction of fMRI BOLD amplitude in CAA.

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Kidney Functional Magnetic Resonance Imaging and Change in eGFR in Individuals with CKD

Clinical Journal of the American Society of Nephrology ◽

10.2215/cjn.13201019 ◽

2020 ◽

Vol 15 (6) ◽

pp. 776-783 ◽

Cited By ~ 1

Author(s):

Anand Srivastava ◽

Xuan Cai ◽

Jungwha Lee ◽

Wei Li ◽

Brett Larive ◽

...

Keyword(s):

Functional Mri ◽

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Functional Magnetic Resonance ◽

Resonance Imaging ◽

Blood Oxygen Level ◽

Time Interaction ◽

Over Time ◽

Egfr Slope

Background and objectivesKidney functional magnetic resonance imaging (MRI) requires further investigation to enhance the noninvasive identification of patients at high risk of CKD progression.Design, setting, participants, & measurementsIn this exploratory study, we obtained baseline diffusion-weighted and blood oxygen level–dependent MRI in 122 participants of the CKD Optimal Management with Binders and Nicotinamide trial, which was a multicenter, randomized, double-blinded, 12-month, four-group parallel trial of nicotinamide and lanthanum carbonate versus placebo conducted in individuals with eGFR 20–45 ml/min per 1.73 m2. Lower values of apparent diffusion coefficient (ADC) on diffusion-weighted MRI may indicate increased fibrosis, and higher values of relaxation rate (R2*) on blood oxygen level–dependent MRI may represent decreased oxygenation. Because there was no effect of active treatment on eGFR over 12 months, we tested whether baseline kidney functional MRI biomarkers were associated with eGFR decline in all 122 participants. In a subset of 87 participants with 12-month follow-up MRI data, we evaluated whether kidney functional MRI biomarkers change over time.ResultsMean baseline eGFR was 32±9 ml/min per 1.73 m2, and mean annual eGFR slope was −2.3 (95% confidence interval [95% CI], −3.4 to −1.1) ml/min per 1.73 m2 per year. After adjustment for baseline covariates, baseline ADC was associated with change in eGFR over time (difference in annual eGFR slope per 1 SD increase in ADC: 1.3 [95% CI, 0.1 to 2.5] ml/min per 1.73 m2 per year, ADC×time interaction P=0.04). This association was no longer significant after further adjustment for albuminuria (difference in annual eGFR slope per 1 SD increase in ADC: 1.0 (95% CI, −0.1 to 2.2) ml/min per 1.73 m2 per year, ADC×time interaction P=0.08). There was no significant association between baseline R2* and change in eGFR over time. In 87 participants with follow-up functional MRI, ADC and R2* values remained stable over 12 months (intraclass correlation: 0.71 and 0.68, respectively).ConclusionsBaseline cortical ADC was associated with change in eGFR over time, but this association was not independent of albuminuria. Kidney functional MRI biomarkers remained stable over 1 year.Clinical Trial registry name and registration numberCKD Optimal Management with Binders and Nicotinamide (COMBINE), NCT02258074.

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Prognostication of Asymptomatic Penetrating Aortic Ulcers: A Modern Approach

Circulation ◽

10.1161/circulationaha.121.054710 ◽

2021 ◽

Author(s):

Charles DeCarlo ◽

Christopher A. Latz ◽

Laura T. Boitano ◽

Young Kim ◽

Adam Tanious ◽

...

Keyword(s):

Cumulative Incidence ◽

Radiographic Progression ◽

Intramural Hematoma ◽

Rate Of Change ◽

Change Over Time ◽

Modern Approach ◽

Ulcer Size ◽

Risk Of Death ◽

Over Time

Background: Literature detailing the natural history of asymptomatic penetrating aortic ulcers (PAU) is sparse and lacks long-term follow-up. This study sought to determine the rate of asymptomatic PAU growth over time and adverse events from asymptomatic PAU. Methods: A cohort of patients with asymptomatic PAU from 2005-2020 was followed. One ulcer was followed per patient. Primary endpoints were change in size over time and the composite of symptoms, radiographic progression, rupture, and intervention; cumulative incidence function estimated the incidence of the composite outcome. Ulcer size and rate of change were modeled using a linear mixed effects model. Patient and anatomic factors were evaluated as potential predictors of the outcomes. Results: There were 273 patients identified. Mean age was 75.5±9.6 years; 66.4% were male. The majority of ulcers were in the descending thoracic aorta (53.9%), followed by abdominal aorta (41.4%), and aortic arch (4.8%). Fusiform aneurysmal disease was present in 21.6% of patients at a separate location; 2.6% had an associated intramural hematoma; 23.6% had at least one other PAU. Symptoms developed in one patient who ruptured; 8 patients (2.9%) underwent an intervention for PAU (one for rupture, 2 for radiographic progression, 5 for size/growth) at a median of 3.1 years (IQR:1.0-6.5) after diagnosis. Five and 10-year cumulative incidence of the primary outcome, adjusted for competing risk of death, was 3.6% (95% CI: 1.6-6.9%) and 6.5% (95% CI: 3.1-11.4%), respectively. For 191 patients with multiple CT scans (760 total CT's) with median radiographic follow-up of 3.50 years (IQR:1.20-6.63 years), mean initial ulcer width, ulcer depth, and total diameter in millimeters (mm) was 13.6, 8.5, and 31.4, respectively. Small, but statistically significant change over time was observed for ulcer width (0.23 mm/year) and total diameter (0.24 mm/year); ulcer depth did not significantly change over time. Hypertension, hyperlipidemia, diabetes, initial ulcer width>20 mm, thrombosed PAU, and associated saccular aneurysm were associated with larger changes in ulcer size over time, however the magnitude of difference was small, ranging from 0.4-1.9 mm/year. Conclusions: Asymptomatic PAU displayed minimal growth and infrequent complications including rupture. Asymptomatic PAU may be conservatively managed with serial imaging and risk-factor modification.

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Blood-Oxygen-Level-Dependent (BOLD) Signal

Encyclopedia of Autism Spectrum Disorders ◽

10.1007/978-3-319-91280-6_550 ◽

2021 ◽

pp. 717-718

Author(s):

Kevin A. Pelphrey Harris

Keyword(s):

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Bold Signal ◽

Oxygen Level ◽

Blood Oxygen Level

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Variability in blood oxygen level dependent (BOLD) signal in patients with stroke-induced and primary progressive aphasia

NeuroImage Clinical ◽

10.1016/j.nicl.2015.03.014 ◽

2015 ◽

Vol 8 ◽

pp. 87-94 ◽

Cited By ~ 10

Author(s):

B. Bonakdarpour ◽

P.M. Beeson ◽

A.T. DeMarco ◽

S.Z. Rapcsak

Keyword(s):

Primary Progressive Aphasia ◽

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Bold Signal ◽

Oxygen Level ◽

Blood Oxygen Level ◽

Progressive Aphasia ◽

Primary Progressive

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Hemodynamic response function in resting brain: disambiguating neural events and autonomic effects

10.1101/028514 ◽

2015 ◽

Cited By ~ 1

Author(s):

Guorong Wu ◽

Daniele Marinazzo

Keyword(s):

Point Process ◽

Resting State ◽

Process Analysis ◽

Cardiac Activity ◽

Hemodynamic Response ◽

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Bold Signal ◽

Hemodynamic Response Function ◽

Blood Oxygen Level

It has been shown that resting state brain dynamics can be characterized by looking at sparse blood-oxygen-level dependent (BOLD) events, which can be retrieved by point process analysis. Cardiac activity can also induce changes in the BOLD signal, thus affect both the number of these events and the mapping between neural events and BOLD signal, namely the hemodynamic response. To isolate neural activity and autonomic effects, we compare the resting state hemodynamic response retrieved by means of a point process analysis with and without deconvolving the cardiac fluctuations. Brainstem and the surrounding cortical area (such as precuneus, insula etc.) are found to be significantly affected by cardiac pulses. Methodological and physiological implications are then discussed.

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Evaluating Cognitive Relationships with Resting-State and Task-driven Blood Oxygen Level-Dependent Variability

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01645 ◽

2021 ◽

Vol 33 (2) ◽

pp. 279-302

Author(s):

Peter R. Millar ◽

Beau M. Ances ◽

Brian A. Gordon ◽

Tammie L. S. Benzinger ◽

John C. Morris ◽

...

Keyword(s):

Task Performance ◽

Resting State ◽

Attentional Control ◽

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Bold Signal ◽

Oxygen Level ◽

Blood Oxygen Level ◽

Age Related ◽

And Task

Recent functional magnetic resonance imaging studies have reported that moment-to-moment variability in the blood oxygen level-dependent (BOLD) signal is positively associated with task performance and, thus, may reflect a behaviorally sensitive signal. However, it is not clear whether estimates of resting-state and task-driven BOLD variability are differentially related to cognition, as they may be driven by distinct sources of variance in the BOLD signal. Moreover, other studies have suggested that age differences in resting-state BOLD variability may be particularly sensitive to individual differences in cardiovascular, rather than neural, factors. In this study, we tested relationships between measures of behavioral task performance and BOLD variability during both resting-state and task-driven runs of a Stroop and an animacy judgment task in a large, well-characterized sample of cognitively normal middle-aged to older adults. Resting-state BOLD variability was related to composite measures of global cognition and attentional control, but these relationships were eliminated after correction for age or cardiovascular estimates. In contrast, task-driven BOLD variability was related to attentional control measured both inside and outside the scanner, and importantly, these relationships persisted after correction for age and cardiovascular measures. Overall, these results suggest that BOLD variability is a behaviorally sensitive signal. However, resting-state and task-driven estimates of BOLD variability may differ in the degree to which they are sensitive to age-related, cardiovascular, and neural mechanisms.

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Human non-REM sleep and the mean global BOLD signal

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x18791070 ◽

2018 ◽

Vol 39 (11) ◽

pp. 2210-2222 ◽

Cited By ~ 5

Author(s):

Mark P McAvoy ◽

Enzo Tagliazucchi ◽

Helmut Laufs ◽

Marcus E Raichle

Keyword(s):

Blood Flow ◽

Rem Sleep ◽

Brain Activity ◽

Oxygen Metabolism ◽

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Bold Signal ◽

Blood Oxygen Level ◽

The Mean ◽

Uniform Manner

A hallmark of non-rapid eye movement (REM) sleep is the decreased brain activity as measured by global reductions in cerebral blood flow, oxygen metabolism, and glucose metabolism. It is unknown whether the blood oxygen level dependent (BOLD) signal undergoes similar changes. Here we show that, in contrast to the decreases in blood flow and metabolism, the mean global BOLD signal increases with sleep depth in a regionally non-uniform manner throughout gray matter. We relate our findings to the circulatory and metabolic processes influencing the BOLD signal and conclude that because oxygen consumption decreases proportionately more than blood flow in sleep, the resulting decrease in paramagnetic deoxyhemoglobin accounts for the increase in mean global BOLD signal.

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The variability of functional MRI brain signal increases in Alzheimer's disease at cardiorespiratory frequencies

Scientific Reports ◽

10.1038/s41598-020-77984-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Timo Tuovinen ◽

Janne Kananen ◽

Zalan Rajna ◽

Johannes Lieslehto ◽

Vesa Korhonen ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Blood Oxygen Level Dependent ◽

Present Observation ◽

Blood Oxygen ◽

Bold Signal ◽

Blood Oxygen Level ◽

Brain Hemodynamics ◽

Fluid Convection ◽

Signal Variability

AbstractBiomarkers sensitive to prodromal or early pathophysiological changes in Alzheimer’s disease (AD) symptoms could improve disease detection and enable timely interventions. Changes in brain hemodynamics may be associated with the main clinical AD symptoms. To test this possibility, we measured the variability of blood oxygen level-dependent (BOLD) signal in individuals from three independent datasets (totaling 80 AD patients and 90 controls). We detected a replicable increase in brain BOLD signal variability in the AD populations, which constituted a robust biomarker for clearly differentiating AD cases from controls. Fast BOLD scans showed that the elevated BOLD signal variability in AD arises mainly from cardiovascular brain pulsations. Manifesting in abnormal cerebral perfusion and cerebrospinal fluid convection, present observation presents a mechanism explaining earlier observations of impaired glymphatic clearance associated with AD in humans.

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