Cerebrovascular Reactivity MRI Protocol - Figures

Pernet, Cyril R; Doubal, Fergus; Shi, Yulu; Marshall, Ian; Thrippleton, Michael; Waiter, Gordon; Schwarzbauer, Christian; Wardlaw, Joanna; Andrews, Peter JD; Blair, Gordon; Hamilton, Iona

Date Available

2017-08-08

Type

image

Data Creator

Thrippleton, Michael
Shi, Yulu
Blair, Gordon
Hamilton, Iona
Waiter, Gordon
Schwarzbauer, Christian
Pernet, Cyril R
Andrews, Peter JD
Marshall, Ian
Doubal, Fergus
Wardlaw, Joanna

Publisher

University of Edinburgh. Edinburgh Imaging

Metadata

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Citation

Thrippleton, Michael; Shi, Yulu; Blair, Gordon; Hamilton, Iona; Waiter, Gordon; Schwarzbauer, Christian; Pernet, Cyril; Andrews, Peter JD; Marshall, Ian; Doubal, Fergus; Wardlaw, Joanna M. (2017). Cerebrovascular Reactivity MRI Protocol - Figures, [image]. University of Edinburgh. Edinburgh Imaging. https://doi.org/10.7488/ds/2110.

Description

Figures describing an MRI protocol, including tolerability and reproducibility, for measurement of cerebrovascular reactivity.

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Supplementary Figure 1: Bland-Altman plots showing reproducibility of CVR for the 1-minute CO2 paradigm. Data points indicate the mean value obtained at the two visits (x-axis) and the difference between the two visits (value at visit 1 minus value at visit 2; y-axis); dashed lines show the mean difference between measurements and the mean difference ± 2 SD; the standard deviation of the differences is shown in parentheses. All quantities have units of %/mmHg. (160.6Kb)

Figure 1: (a) CVR MRI breathing circuit, designed by the University of Aberdeen and Intersurgical (Wokingham, UK). Red and blue arrows indicate the flow of inhaled and exhaled gas respectively. 1 = oxygen tubing for gas delivery; 2 = open-ended reservoir tube; 3 = anaesthetic face mask; 4,5 = one-way valve; 6 = exit port for exhaled gas; 7 = gas sampling line. (b) Photograph showing subject positioned in the head coil with the breathing circuit and patient monitoring equipment in place. (786.6Kb)

Figure 2: (a) Regions of interest for a healthy volunteer, (b) CVR magnitude (%/mmHg) and (c) CVR delay (s) parameters maps at the slice level shown by the right hand image in (a); both parameter maps were generated using BOLD data smoothed using a 4 mm full width at half maximum Gaussian kernel (note that ROI data were generated from unsmoothed data). (d-e) BOLD MRI signal (dotted line) and model fit (solid line) for the (d) right putamen and (e) right centrum semiovale ROIs. The signal drift visible in (d-e) is accounted for by a term in the model. (1.203Mb)

Figure 3: Tolerability of CVR scanning for healthy volunteers and patients. Charts indicate the tolerability ratings given at each visit by participants. (185.4Kb)

Figure 4: Mean (a) CVR and (b) CVR delay values in healthy volunteers for the 1-minute and 3-minute CO2 paradigms, averaged first over visits and secondly over subjects. (c-d) compare mean (c) CVR and (d) CVR delay values for healthy volunteers and patients, obtained using the 3-minute gas paradigm. (e-f) compare mean (e) CVR and (f) CVR delay for patients scanned using 4% (n=4) and 6% (n=10) CO2 gas mixtures. “*” indicates a significant difference (p < 0.05) between paradigms, between patients and volunteers, or between CO2 concentrations; error bars indicate the standard deviation after averaging over visits (part (a) only). Abbreviations: RPWM/LPWM, right/left posterior WM; RFWM/LFWM, right/left frontal WM; RPVWM/LPVWM, right/left periventricular WM; RCS/LCS, right/left centrum semiovale; RT/LT, right/left thalamus; RP/LP, right/left putamen; RCH/LCH, right/left caudate head; PCGM, posterior cortical GM; FCGM, frontal cortical GM. (824.0Kb)

Supplementary Figure 2: Bland-Altman plots showing reproducibility of CVR for the 3-minute CO2 paradigm. Data points indicate the mean value obtained at the two visits (x-axis) and the difference between the two visits (value at visit 1 minus value at visit 2; y-axis); dashed lines show the mean difference between measurements and the mean difference ± 2 SD; the standard deviation of the differences is shown in parentheses. All quantities have units of %/mmHg. (163.3Kb)

Supplementary Figure 3: Bland-Altman plots showing reproducibility of the CVR delay for the 1-minute CO2 paradigm. Data points indicate the mean value obtained at the two visits (x-axis) and the difference between the two visits (value at visit 1 minus value at visit 2; y-axis); dashed lines show the mean difference between measurements and the mean difference ± 2 SD; the standard deviation of the differences is shown in parentheses. All quantities have units of s. (135.3Kb)

Supplementary Figure 4: Bland-Altman plots showing reproducibility of the CVR delay for the 3-minute CO2 paradigm. Data points indicate the mean value obtained at the two visits (x-axis) and the difference between the two visits (value at visit 1 minus value at visit 2; y-axis); dashed lines show the mean difference between measurements and the mean difference ± 2 SD; the standard deviation of the differences is shown in parentheses. All quantities have units of s. (131.3Kb)

Supplementary Figure 5: BOLD MRI signal (dotted line) and model fit (solid line) for the left putamen ROI of a healthy volunteer using the 1-minute CO2 paradigm (LHS) with graphs showing the sum-of-squared residuals as a function of the time shift. At visit 1 (A), a positive CVR is fitted with a time shift of 5 s, while at visit 2 (B), a likely-erroneous negative CVR is fitted with a time shift of 62 s. This effect is not observed with the 3-minute CO2 paradigm due to the longer oscillation period. (1.307Mb)

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