TABLE 1.
Sample demographics. Values are summary and test statistics for all included participants with usable single and/or multi inflow time ASL data. Abbreviations: SCA, sickle cell anemia; sTI, single inflow time sequence; mTI, multi inflow time sequence; CBF, cerebral blood flow; BAT, bolus arrival time; iWSA, individual watershed areas; SD, standard deviation; IQR, interquartile range; p, probability values for between-group differences. Significant between-group differences are shown in bold.
| SCA (n = 94) | Control (n = 42) | between-group differences | ||
|---|---|---|---|---|
| Demographic Variables | Count (percentage)/Median (IQR) | |||
| Sex | 46 Male (48.94%) | 16 Male (38.10%) | p = 0.32, φ = 0.08 | |
| Age (yr) | 16.67 (13.32–19.89) | 17.33 (14.57–20.48) | p = 0.65, r = 0.04 | |
| Education Decile | 5 (4–7) | 5 (4–6) | p = 0.72, r = 0.03 | |
| Hematological Variables | 11.79 (10.39–12.92) | 17.69 (17.42–18.22) | p < 0.0001, r = 0.79 | |
| Arterial oxygen content (CaO2, mL/d) | ||||
| Radiological Variables | ||||
| Lesions | 45 | 10 | p = 0.0005, φ = 0.21 | |
| Lesion burden (1 mm3 voxels) | 75 (26–188.0) | 15 (4–34.5) | p = 0.006, 0.24 | |
| Cognitive Variables | Mean (SD)/Median (IQR) | |||
| Intelligence quotient (IQ) | 92.63 (13.44) | 98.10 (12.00) | p = 0.02, d = 0.43 | |
| Working memory index (WMI) | 91.73 (13.69) | 99.24 (13.48) | p = 0.004, d = 0,55 | |
| Processing speed index (PSI) | 89.49 (12.96) | 97.55 (13.17) | p = 0.001, d = 0.62 | |
| Hemodynamic Variables | Mean (SD)/Median (IQR) | |||
| sTI ASL | n = 89 | n = 42 | ||
| Grey Matter CBF (ml/100 g/min) | 54.06 (7.78) | 42.52 (7.13) | p < 0.0001, d = -1.55 | |
| White Matter—earlier arrival CBF (ml/100 g/min) | 34.12 (4.82) | 26.08 (4.85) | p < 0.0001, d = -1.66 | |
| White Matter—iWSA CBF (ml/100 g/min) | 24.11 (4.41) | 16.85 (3.95) | p < 0.0001, d = -1.73 | |
| mTI ASL | n = 80 | n = 36 | ||
| Grey Matter CBF (ml/100 g/min) | 129.02 (22.26) | 89.62 (11.83) | p < 0.0001, d = -2.21 | |
| White Matter—earlier arrival CBF (ml/100 g/min) | 73.80 (14.55) | 49.52 (8.39) | p < 0.0001, d = -2.04 | |
| White Matter—iWSA CBF (ml/100 g/min) a | 59.54 (14.61) | 55.13 (13.14) | p = 0.11, d = -0.32 | |
| Grey Matter BAT (s) | 0.72 (0.66–0.75) | 0.82 (0.77–0.89) | p < 0.0001, r = 0.53 | |
| White Matter—earlier arrival BAT (s) | 0.74 (0.70–0.80) | 0.85 (0.82–0.92) | p < 0.0001, r = 0.50 | |
| White Matter—iWSA BAT (s) | 1.51 (1.36–1.69) | 1.86 (1.71–2.05) | p < 0.0001, r = 0.53 | |
descriptive statistics and between-group differences in iWSA CBF reported with outlying control (Figure 5) excluded. Note that although including the outlier skews the mean in controls (m = 57.24, sd = 18.14), between-group differences remain non-significant (p = 0.51).