Table 5.
Findings of repeatability of CVR estimates.
| References | MRI technique | Repeatability | Population | Results |
|---|---|---|---|---|
| Thrippleton et al. (2018) | BOLD; fixed inhaled CO2 | Within-day repeatability | 15 HC | - Inter-session CV of GM CVR: 7.9–15.4% for a 3 min and 11.7–70.2% for a 1 min challenge - Inter-session CV of WM CVR: 16.1–24.4% for a 3 min and 27.5–141.0% for a 1 min challenge |
| Sobczyk et al. (2016), Leung et al. (2016b) and Dengel et al. (2017) | BOLD; EtCO2 targeting | Within- (Leung et al., 2016b; Dengel et al., 2017) and between-day repeatability (Leung et al., 2016b; Sobczyk et al., 2016; Dengel et al., 2017) and within-day consecutive intra-scan repeatability (Dengel et al., 2017) | 15 (Sobczyk et al., 2016),11 (Dengel et al., 2017), and 10 (Leung et al., 2016b) HC | - Within-day intra-scan ICC of GM CVR (Dengel et al., 2017): 0.84 - Within-day intra-scan CV of GM CVR (Dengel et al., 2017): 5.70% - Within-day inter-scan ICC CVR in GM: 0.78 (Dengel et al., 2017), 0.86 (Leung et al., 2016b); WM: 0.90 (Leung et al., 2016b) - Within-day inter-scan CV of GM CVR (Dengel et al., 2017): 6.62% - Between-day ICC CVR in GM: 0.69 (Dengel et al., 2017), 0.78 (Leung et al., 2016b); WM: 0.72 (Leung et al., 2016b) - Between-day CV CVR in GM: 7.87% (Dengel et al., 2017), 7.3% (Sobczyk et al., 2016); WM: 10.3% (Sobczyk et al., 2016) |
| Bright and Murphy (2013), Dlamini et al. (2018), and Peng et al. (2020) | BOLD; BH | Within-day (Dlamini et al., 2018; Peng et al., 2020), between-day (Peng et al., 2020), inter-regressors (Bright and Murphy, 2013) and intra-subject (Bright and Murphy, 2013) repeatability | 20 SOD (Dlamini et al., 2018). 9 (Peng et al., 2020), 12 (Bright and Murphy, 2013) HC | - Within-day ICC of whole brain CVR: 0.7 (Dlamini et al., 2018), >0.4 (Peng et al., 2020) - Within-day CV of positive GM CVR: 9.1% (Dlamini et al., 2018), <33% (Peng et al., 2020) - Within-day CV of negative GM CVR (Dlamini et al., 2018): 22.5% - Inter-regressor ICC of GM CVR (Bright and Murphy, 2013): <0.4 for ramp regressor and 0.82 for EtCO2 regressor - Intra-subject ICC of GM CVR (Bright and Murphy, 2013): 1.03% for EtCO2 regressor |
| Sousa et al. (2014) | BOLD; paced deep breathing | Test-retest and inter-subject repeatability | 9 HC | - Inter-subject CV of GM CVR: 20% - Intra-subject CV of GM CVR: 8% - Intra-subject ICC of GM CVR: 1.04 |
| Kassner et al. (2010) | BOLD; EtCO2 forcing | Within, between-day and inter-subject repeatability | 19 HC | - ICC of GM CVR: 0.92 within-day, 0.81 between-day - ICC of WM CVR: 0.88 within-day, 0.66 between-day - CV of GM CVR: 4.2% within-day, 6.8% between-day, 20% inter-subject - CV of WM CVR: 6.3% within-day, 9.9% between-day, 21.8% inter-subject |
| Liu et al. (2017a) and Taneja et al. (2019) | Resting-state BOLD | Within-day (Liu et al., 2017a) and between-day (Taneja et al., 2019) repeatability | 6 stroke (Taneja et al., 2019), 10 HC (Liu et al., 2017a) |
- Within-day ICC (Liu et al., 2017a): 0.91 - Between-day correlation of lesion CVR (Taneja et al., 2019): r2 = 0.91 - Between-day correlation of contralateral-to-lesion CVR (Taneja et al., 2019): r2 = 0.79 |
| Heijtel et al. (2014) | ASL; fixed inhaled CO2 | Within- and between-day repeatability | 16 HC | - Within-day RI: 18.2%; Between-day RI: 25.1% for baseline CBF, 24.8% for hypercapnia CBF - CV of inter-subject variability: 12.9% for baseline CBF, 15.6% for hypercapnia CBF |
| Merola et al. (2018) | Dual-echo ASL/BOLD; fixed inhaled CO2 | Within- and between-day repeatability | 26 HC | - Correlation with coefficient of determination of GM CVR variability: 0.57 for within-day inter-scan, 0.41 for within-day inter-session, 0.02 for between-day - CV of inter-subject variability of GM CVR: 17.5% for within-day, 25% for between-day - CV of intra-subject variability for GM CVR: 9.5% for within-day inter-scan, 12.5% for within-day inter-session, 17.5% between-day |
| Grandin et al. (2005) | DSC; ACZ | Inter-scan repeatability | 13 HC | - Repeatability using the SD of the mean difference in CBF between scans: 22.4% - Repeatability using the SD of the mean difference in CBV between scans: 18.2% |
BH, breath-hold; BOLD, blood oxygen level-dependent; ACZ, acetazolamide; CC, correlation coefficient; CV, coefficient of variation; GM, grey matter; DSC, dynamic susceptibility contrast; ICC, intraclass CC; HC, healthy controls; SOD, steno-occlusive disease; SD, standard deviation; RI, repeatability index.