scholarly journals Investigation of the BOLD-Based MRI Signal Time Course During Short Breath-Hold Periods for Estimation of the Cerebrovascular Reactivity

2020 ◽  
Vol 2 (9) ◽  
pp. 1551-1562
Author(s):  
Leonie Zerweck ◽  
Till-Karsten Hauser ◽  
Constantin Roder ◽  
Uwe Klose
Keyword(s):  
Healthy Subjects ◽  
Time Course ◽  
Clinical Diagnostics ◽  
Cerebrovascular Reactivity ◽  
Breath Hold ◽  
Bold Signal ◽  
Hold Period ◽  
Signal Changes ◽  
Short Breath ◽  
Breath Hold Duration

Abstract For the prognosis of stroke, patients with moyamoya disease (MMD) require the estimation of remaining cerebrovascular reactivity. For this purpose, CO2-triggered BOLD fMRI by use of short breath-hold periods seems to be a highly available alternative to nuclear medicine methods. Too long breath-hold periods are difficult to perform, too short breath-hold periods do not lead to sufficient BOLD signal changes. We aimed to investigate the required minimum breath-hold duration to detect distinct BOLD signals in the tissue of healthy subjects to find out how long the minimum breath-hold duration in clinical diagnostics of MMD should be. A prospective study was performed. Fourteen healthy subjects underwent fMRI during end-expiration breath-hold periods of different duration (3, 6, 9, and 12 s). Additionally, we compared the influence of paced and self-paced breathing altering the breath-hold periods. Data of a patient with MMD was evaluated to investigate whether the tested procedure is suitable for clinical use. Significant global BOLD signal increases were detected after breath-hold periods of 6, 9, and 12 s. The signals were significantly higher after breath-hold periods of 9 s than after 6 s, while not when the duration was extended from 9 to 12 s. Furthermore, we found additional BOLD signal changes before the expected signal increases, which could be avoided by paced respiratory instructions. This investigation indicates that end-expiration breath-hold period of at least 9 s might be used to measure the cerebrovascular reactivity. This time period resulted in distinct BOLD signal changes and could be performed easily.

scholarly journals Cerebrovascular reactivity assessment with O2-CO2 exchange ratio under brief breath hold challenge

2019 ◽  
Author(s):  
Suk Tak Chan ◽  
Karleyton C. Evans ◽  
Tian Yue Song ◽  
Juliett Selb ◽  
Andre van der Kouwe ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Partial Pressure ◽  
Cerebral Arteries ◽  
Blood Oxygenation ◽  
Cerebrovascular Reactivity ◽  
Breath Holding ◽  
Breath Hold ◽  
Bold Signal ◽  
Signal Changes

AbstractHypercapnia during breath holding is believed to be the dominant driver behind the modulation of cerebral blood flow (CBF). Here we showed that the cerebrovascular responses to brief breath hold epochs were coupled not only with increased partial pressure of carbon dioxide (PCO2), but also with a decrease in partial pressure of oxygen (PO2). We used transcranial Doppler ultrasound to evaluate the CBF changes during breath holding by measuring the cerebral blood flow velocity (CBFv) in the middle cerebral arteries, a pair of cerebral arteries that supply most parts of the brain. The regional CBF changes during breath hold epochs were mapped with blood oxygenation level dependent (BOLD) signal changes as surrogate of CBF changes using functional magnetic resonance imaging (fMRI) technique. Given the interdependence of the dynamic changes between PCO2 and PO2, we found that the breath-by-breath O2-CO2 exchange ratio (bER), namely the ratio of changes in PO2 (ΔPO2) to changes in PCO2 (ΔPCO2) between end inspiration and end expiration, was superior to either ΔPO2 or ΔPCO2 alone in coupling with the changes of CBFv and BOLD signals under breath hold challenge. The regional cerebrovascular reactivity (CVR) results derived by regressing BOLD signal changes on bER under breath hold challenge resembled those derived by regressing BOLD signal changes on end-tidal partial pressure of CO2 (PETCO2) under exogenous CO2 challenge. Our findings provide a novel insight on the potential of using bER to better quantify CVR changes under breath hold challenge, although the physiological mechanisms of cerebrovascular changes underlying breath hold and exogenous CO2 challenges are potentially different.

scholarly journals Shortening the preparation time of the single prolonged breath-hold for radiotherapy sessions

2021 ◽  
Author(s):  
Michael John Parkes ◽  
Stuart Green ◽  
Jason Cashmore ◽  
Qamar Ghafoor ◽  
Thomas Clutton-Brock
Keyword(s):  
Healthy Subjects ◽  
Breath Hold ◽  
Preparation Time ◽  
The Mean ◽  
Original Preparation ◽  
Thoracic And Abdominal ◽  
Clinical Adoption ◽  
Ventilator Settings ◽  
Short Breath ◽  
Breath Hold Duration

Objective: Single prolonged breath-holds of >5 min can be obtained in cancer patients. Currently, however, the preparation time in each radiotherapy session is a practical limitation for clinical adoption of this new technique. Here, we show by how much our original preparation time can be shortened without unduly compromising breath-hold duration. Methods: 44 healthy subjects performed single prolonged breath-holds from 60% O2 and mechanically induced hypocapnia. We tested the effect on breath-hold duration of shortening preparation time (the durations of acclimatization, hyperventilation and hypocapnia) by changing these durations and or ventilator settings. Results: Mean original breath-hold duration was 6.5 ± 0.2 (standard error) min. The total original preparation time (from connecting the facemask to the start of the breath-hold) was 26 ± 1 min. After shortening the hypocapnia duration from 16 to 5 min, mean breath-hold duration was still 6.1 ± 0.2 min (ns vs the original). After abolishing the acclimatization and shortening the hypocapnia to 1 min (a total preparation time now of 9 ± 1 min), a mean breath-hold duration of >5 min was still possible (now significantly shortened to 5.2 ± 0.6 min, p < 0.001). After shorter and more vigorous hyperventilation (lasting 2.7 ± 0.3 min) and shorter hypocapnia (lasting 43 ± 4 s), a mean breath-hold duration of >5 min (5.3 ± 0.2 min, p < 0.05) was still possible. Here, the final total preparation time was 3.5 ± 0.3 min. Conclusions: These improvements may facilitate adoption of the single prolonged breath-hold for a range of thoracic and abdominal radiotherapies especially involving hypofractionation. Advances in knowledge: Multiple short breath-holds improve radiotherapy for thoracic and abdominal cancers. Further improvement may occur by adopting the single prolonged breath-hold of >5 min. One limitation to clinical adoption is its long preparation time. We show here how to reduce the mean preparation time from 26 to 3.5 min without compromising breath-hold duration

scholarly journals Different roles of the frontal and parietal regions in memory-guided saccade: A PCA approach on time course of BOLD signal changes

2004 ◽  
Vol 23 (3) ◽  
pp. 129-139 ◽  
Author(s):  
Motoaki Sugiura ◽  
Jobu Watanabe ◽  
Yasuhiro Maeda ◽  
Yoshihiko Matsue ◽  
Hiroshi Fukuda ◽  
...  
Keyword(s):  
Time Course ◽  
Bold Signal ◽  
Signal Changes

scholarly journals Conditioned Variation in Heart Rate During Static Breath-Holds in the Bottlenose Dolphin (Tursiops truncatus)

2020 ◽  
Vol 11 ◽  
Author(s):  
Andreas Fahlman ◽  
Bruno Cozzi ◽  
Mercy Manley ◽  
Sandra Jabas ◽  
Marek Malik ◽  
...  
Keyword(s):  
Heart Rate ◽  
Tursiops Truncatus ◽  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
Bubble Formation ◽  
Rate Of Change ◽  
Breath Hold ◽  
Short Breath ◽  
Breath Hold Duration ◽  
Spontaneous Breath

Previous reports suggested the existence of direct somatic motor control over heart rate (fH) responses during diving in some marine mammals, as the result of a cognitive and/or learning process rather than being a reflexive response. This would be beneficial for O2 storage management, but would also allow ventilation-perfusion matching for selective gas exchange, where O2 and CO2 can be exchanged with minimal exchange of N2. Such a mechanism explains how air breathing marine vertebrates avoid diving related gas bubble formation during repeated dives, and how stress could interrupt this mechanism and cause excessive N2 exchange. To investigate the conditioned response, we measured the fH-response before and during static breath-holds in three bottlenose dolphins (Tursiops truncatus) when shown a visual symbol to perform either a long (LONG) or short (SHORT) breath-hold, or during a spontaneous breath-hold without a symbol (NS). The average fH (ifHstart), and the rate of change in fH (difH/dt) during the first 20 s of the breath-hold differed between breath-hold types. In addition, the minimum instantaneous fH (ifHmin), and the average instantaneous fH during the last 10 s (ifHend) also differed between breath-hold types. The difH/dt was greater, and the ifHstart, ifHmin, and ifHend were lower during a LONG as compared with either a SHORT, or an NS breath-hold (P &lt; 0.05). Even though the NS breath-hold dives were longer in duration as compared with SHORT breath-hold dives, the difH/dt was greater and the ifHstart, ifHmin, and ifHend were lower during the latter (P &lt; 0.05). In addition, when the dolphin determined the breath-hold duration (NS), the fH was more variable within and between individuals and trials, suggesting a conditioned capacity to adjust the fH-response. These results suggest that dolphins have the capacity to selectively alter the fH-response during diving and provide evidence for significant cardiovascular plasticity in dolphins.

Cerebrovascular reactivity over time course in healthy subjects

2006 ◽  
Vol 249 (2) ◽  
pp. 135-139 ◽  
Author(s):  
N. Schwertfeger ◽  
P. Neu ◽  
P. Schlattmann ◽  
H. Lemke ◽  
I. Heuser ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Time Course ◽  
Cerebrovascular Reactivity ◽  
Over Time

Cerebrovascular Reactivity Assessment during Carbon Dioxide Inhalation Using SPECT

2021 ◽  
Vol 11 (3) ◽  
pp. 1161
Author(s):  
Yeong-Bae Lee ◽  
Chang-Ki Kang
Keyword(s):  
Carbon Dioxide ◽  
Healthy Subjects ◽  
Healthy Aging ◽  
Single Photon ◽  
Photon Emission ◽  
Clinical Diagnostics ◽  
Cerebrovascular Reactivity ◽  
Emission Computed Tomography ◽  
Brain Vessels ◽  
Quantitative Spect

Background: Perfusion single-photon emission computed tomography (SPECT) using an acetazolamide is an important clinical tool used to assess cerebrovascular reactivity (CVR) in patients, but its use has been limited to clinical diagnostics. This study aimed to preliminarily evaluate the feasibility of perfusion SPECT using carbon dioxide (CO2). Methods: Ten healthy subjects participated in two consecutive SPECT scans using CO2 inhalation. To evaluate brain perfusion after preprocessing, the voxel-by-voxel CVR values were averaged in 13 subgroup regions of interest (ROIs) based on a template. Subsequently, averaged CVR values of each ROI were analyzed based on both cerebellar hemispheres. Results: CVR values in the eight subgroup ROIs, which included vermis, both insula/cingulate, and frontal cortices, showed significant changes (p < 0.05). CVR values were higher in vermis and right insula/cingulate by 3.34% and 3.15%, respectively. Conclusions: This study showed that quantitative SPECT with CO2 inhalation could be used to evaluate the voxel-based CVR in healthy subjects, which could be beneficial for elucidating induced hypercapnic states and for longitudinally investigating the healthy aging in brain vessels. Furthermore, the cerebrovascular hemodynamic parameters induced by CO2 could play an important role as a biomarker to evaluate treatment progress in patients with cerebrovascular disease.

Regional Frontal Lobe Response Magnitudes During Affective Shifting Covary With Resting Heart Rate Variability in Healthy Volunteers

2016 ◽  
Vol 30 (4) ◽  
pp. 165-174 ◽  
Author(s):  
Ryan Smith ◽  
John J.B. Allen ◽  
Julian F. Thayer ◽  
Richard D. Lane
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Subjects ◽  
Emotional Reactivity ◽  
Bold Signal ◽  
Resting Heart Rate ◽  
Functional Magnetic Resonance ◽  
Absolute Value ◽  
Cardiac Vagal Control ◽  
Resting Heart Rate Variability

Abstract. We hypothesized that in healthy subjects differences in resting heart rate variability (rHRV) would be associated with differences in emotional reactivity within the medial visceromotor network (MVN). We also probed whether this MVN-rHRV relationship was diminished in depression. Eleven healthy adults and nine depressed subjects performed the emotional counting stroop task in alternating blocks of emotion and neutral words during functional magnetic resonance imaging (fMRI). The correlation between rHRV outside the scanner and BOLD signal reactivity (absolute value of change between adjacent blocks in the BOLD signal) was examined in specific MVN regions. Significant negative correlations were observed between rHRV and average BOLD shift magnitude (BSM) in several MVN regions in healthy subjects but not depressed subjects. This preliminary report provides novel evidence relating emotional reactivity in MVN regions to rHRV. It also provides preliminary suggestive evidence that depression may involve reduced interaction between the MVN and cardiac vagal control.

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