TABLE 2.
MRI Results
| Subject | Cell concentration | Cell infusion location/duration | Saline infusion location/duration | MR findings | MRI notes |
|---|---|---|---|---|---|
| Canine 1 | 2 × 106 cells/20 mL | 32 min 0 s L ICA | 17 min 0 s; R ICA | normal | |
| Canine 2 | 1 × 107 cells/20 mL | 40 min 50 s; L ICA | 15 min 28 s; R ICA | left thalamic/left brainstem infarct | Infarct uncorrelated with cell infusion; technical issue, related to access |
| Canine 3 | 2 × 107 cells/20 mL | 22 min 21 s; L ICA | 20 min 34 s; R ICA | normal | |
| Canine 4 | 1 × 108 cells/20 mL | 21 min 0 s; R ICA | 17 min 0 s; L ICA | normal | |
| Canine 5 | 1 × 108 cells/20 mL | 21 min 34 s; L PCA | 18 min 0 s; R PCA | left cerebellar infarct, IVH | Left PCA cell infusion, likely access-related stroke |
| Canine 6 | 1 × 108 cells/10 mL | 11 min 26 s; L PCA | 10 min 12 s; R PCA | diffuse stroke, IVH | Left PCA cell infusion, likely access-related stroke |
| Canine 7 | Positive stroke control | R PCA particles Positive control #1 |
no injection | diffuse stroke, IVH, SAH | Right PCA PVA particle embolization, but likely access-related stroke |
| Canine 8 | Positive stroke control | R ICA particles Positive control #2 |
no injection | diffuse stroke | Right ICA Lumi particle embolization; penetrated bilaterally |
| Canine 9 | 1 × 108 cells/10 mL | R ICA | L ICA | normal | Survival |
| Canine 10 | 1 × 108 cells/10 mL | L ICA | R ICA | normal | Survival |
The stroke in subject 2 was in the contralateral posterior circulation territory relative to the cell infusion; thus it was determined (independently by the reading radiologist) that it was likely related to access rather than cell infusion. The remaining MRI-detected complications occurred in posterior circulation access cases. Quantitative analysis of MRI results is shown in Table 3. MRI was found to be sensitive to hemorrhagic and ischemic complications in the 2 positive control subjects (7 and 8), which were accessed via the right PCA and ICA, respectively. The PCA infusion subject had embolic particles in the vessel infused and had diffuse ischemic stroke, but also intraventricular hemorrhage (IVH) and SAH, which would be attributable to microcatheterization of the posterior circulation rather than the particles themselves. Subject 8 had a more characteristic global ischemic caused from right ICA infusion of embolic particles. This confirmed the sensitivity of MRI to detect hemorrhagic as well as ischemic complications.