Table 1. Summary of demographic characteristics of the animals used in 8 experiments performed, and (B) details of MRI protocols and acquisition parameters for evaluation of the brain CSF and ISF spaces, employed in the current study.
Legend: CryoProbe – cryogenically-cooled MR coil; TA - time of acquisition; Tx/Rx - transmit/receive; TR - time to repetition; TE - time to echo; FA - flip angle; FOV - field of view; Av. / Rep. – averages for image formation or independently repeated acquisitions; FISP - steady-state free precession sequence; TrueFISP - true balanced steady-state free precession sequence; EPI - echo-planar imaging sequence; VTR – variable TR; VFA – variable flip angle; CM – cisterna magna; p - statistical p-value from Mann-Whitney U-test; N/A – data not available; NS - statistically not significant finding (p>>0.05).
| A | No.of animals | Age [weeks] | Body weight [g] | Respiration [bpm] | |||||
|---|---|---|---|---|---|---|---|---|---|
| KO | WT | Male [%] | Overall (mean ±SD) | p | Overall (mean ±SD) | p | Overall (mean ±SD) | p | |
| 3D-CISS volumetry | 5 | 6 | 72.7 | 13.8±1.8 | NS | 27.3±2.1 | NS | 176±30 | NS |
| MR-DWI | 6 | 6 | 41.7 | 10.4±0.7 | NS | 22.4±3.0 | NS | 175±11 | NS |
| DCE-MRI | 5 | 6 | 45.5 | 13.4±1.6 | NS | 27.3±2.2 | NS | 182±14 | NS |
| AQP4 expression | - | 4 | 50 | 10.0±0.0 | NS | 25–30 | N/A | - | - |
| Vascular density | 6 | 6 | 0 | 14.6±1.0 | NS | 24.3±4.6 | NS | - | - |
| CSF production | 5 | 6 | 45.5 | 15.4±0.5 | NS | 28.7±4.2 | NS | - | - |
| ISF space volume estimation using TMA | 8 | 20 | 55 | 10.0±0.0 | NS | 25–30 | N/A | - | - |
| Brain water content | 3 | 5 | 62.5 | 12.0±1.0 | NS | 25–30 | N/A | - | - |
| B | MR sequences and acquisition parameters | ||||||||
| Sequence (Tx/Rx coil; slice orientation) | TR [ms] | TE [ms] | FA [deg] | Av./Rep. | Voxel size [mm3](interpolation) | Bandwidth [Hz/pix] | Matrix size | TA | |
| MR CSF space volumetry | |||||||||
| 3D-TrueFISP (CryoProbe; sagittal) | 5.2 | 2.6 | 50 | 2 | 0.033×0.033×0.033 (2.0×1.6×1.0) | 260 | 19.2×12.8×12.8 | 27 min | |
|
MR-DWI (in vivo and ex vivo) (δ=3 and Δ=10ms for gradient duration and separation times) *(b-values (Av.>1)): 40, 50, 59, 70, 92, 113, 165, 197, 238, 342, 445, 649, 854, 1057 (2), 1564 (2), 2071 (2), 3081 (2) s2/mm | |||||||||
| 2D-EPI (volumetric; axial) | 3600 | 30 | 90 | 3 | 0.15×0.15×0.5 (0.2 mm gap, 16 slices) | 3307 | 16.2×14.4×11.2 | 20–30 min (respiratory-gated) | |
| DCE-MRI via CM-injection | |||||||||
| 3D-FISP (CryoProbe; sagittal) | 3.26 | 1.63 | 15 | 1 | 0.1×0.1×0.1 | 781 | 19.2×12.8×12.8 | 90 min | |
|
Microbeads phantom ex vivo - T1 mapping (VTR: 12000, 9000, 6500, 4000, 2000, 1000, 800, 500, 300, 100, 80, 50, 15ms) (VFA: 45° and 90°) |
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| 2D-RARE (volumetric; axial) | VTR | 3.1 | 90 | 2 | 0.1×0.1×3.0 | 671 | 16.2×16.2×1 | 3 h 20 min | |
| 2D-RARE (volumetric; axial) | 12000 | 3.1 | VFA | 3 | 0.1×0.1×3.0 | 671 | 16.2×16.2×1 | 1 hr 40 min | |
Presented averages of measured values from 3 diffusion encoding directions are slightly higher than the set-up, due to gradient preparation time.