Artikel
Serial diffusion and perfusion MRI analysis of the perihemorrhagic zone in an experimental rat ICH model: Effect of stereotactic hematoma evacuation with rt-PA
Serielle Analyse der perihämorrhagische Zone im Tiermodell mittels diffusions- und perfusions-MRT: Effekte der stereotaktischen Evakuation
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Veröffentlicht: | 11. April 2007 |
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Gliederung
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Objective: An MRI evaluation of rMTT and ADC in the perihematomal zone(PHZ) of intracerebral hemorrhages (ICH) in rats was performed. Animals were examined within 3.5 hours after hemorrhage. Additionally, we investigated the effect of stereotactic evacuation of the hematoma after rt-PA induced lysis.
Methods: A 2.5T MRI compatible setup for rats in a double injection model was used to produce ICH with autologous arterial blood in the basal ganglia of 49 animals. Animals were divided into 2 groups; controls (gr1, n=27) and hematoma evacuation with rtPA after the first of 3 imaging time points (gr2, n=22). DWI and PWI sequences were generated. Diffusion (rADC) and perfusion (rMTT) characteristics were analyzed in 3 regions of interest surrounding the hematoma (ROI1-3).
Results: ADC map measurements based on DWI did not demonstrate ischemia but vasogenic edema in the PHZ of ICH. Mean rADC values in ROI1 and ROI2 ranged between 1.05 to 1.18 in both groups signifying vasogenic edema. Mean rADC values in ROI3 did not show any significant changes. A non-significant perfusion reduction was confirmed in comparison to the healthy hemisphere in the periphery (ROI1) and outer rim (ROI2). Mean rMTT values in ROI 1 were 1.1(gr1) vs. 1.09(gr2) at TP1, 1.06(gr1) vs. 0.97(gr2) at TP2 and 1.27(gr1) vs. 1.02(gr2) at TP3; in ROI2 rMTT values were 1.06(gr1) vs. 1.07(gr2) at TP1, 1.05(gr1) vs. 1.02(gr2) at TP2 and 1.16(gr1) vs. 0.97(gr2) at TP3. ROI3 did not show rMTT changes in both groups.
Conclusions: We demonstrate vasogenic edema and a non-significant perfusion reduction without ischemia in the PHZ as measured by MRI after ICH. The existence of a perihemorrhagic “penumbra” analogous to ischemic stroke is unlikely.