Evolution of early perihemorrhagic changes--ischemia vs. edema: an MRI study in rats.
OBJECTIVE
Cerebral ischemia has been proposed as a contributing mechanism to secondary neuronal injury after intracranial hemorrhage (ICH). The search for surrogate parameters that allow treatment stratification for spontaneous ICH continues. We aimed to examine perihemorrhagic ischemic changes with an animal experimental MRI study.


METHODS
A high field MRI compatible setup for male Wistar rats was established using a double injection model. ICH was stereotactically placed into the right basal ganglia of 29 Wistar rats. Coronal T2-WI, T2*-WI and DWI were generated with a 2.35 T animal MRI scanner 15 min, 60 min and 210 min after ICH. Clot signal characteristics, clot volumes and normalized ADC values were analyzed in four hematoma regions (core, periphery, outer rim, healthy ipsilateral tissue) in all sequences.


RESULTS
T2*-WI and DWI reliably demonstrated ICH in 100% with only small deviation from the applied volume (-20% to +26%) whereas T2-WI failed to conspicuously show ICH. There were no perihemorrhagic ADC decreases consistent with ischemic cytotoxic edema but a mild vasogenic edema surrounding the ICH could be observed.


CONCLUSIONS
T2*-WI and DWI are accurate for the diagnosis of hyperacute ICH. According to serial and crossectional ADC analysis, there is no hint towards the existence of a perihemorrhagic ischemic area that might be saved by early intervention. Future studies should focus on perfusion and metabolic/neurotoxic studies of this particular area and neurotoxic properties of the surrounding edema.
Orakcioglu
Berk
B
Department of Neurology, University of Heidelberg, Germany; Department of Neurosurgery, University of Heidelberg, Germany.
Fiebach
Jochen B
JB
Steiner
Thorsten
T
Kollmar
Rainer
R
Jüttler
Eric
E
Becker
Kristina
K
Schwab
Stefan
S
Heiland
Sabine
S
Meyding-Lamadé
Uta K
UK
Schellinger
Peter D
PD
D000818:Animals; D001479:Basal Ganglia / Q000473:pathology; D002543:Cerebral Hemorrhage / Q000150:complications / Q000401:mortality / Q000473:pathology*; D004058:Diffusion; D004195:Disease Models, Animal; D004487:Edema / Q000209:etiology / Q000473:pathology*; D006406:Hematoma / Q000473:pathology; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007511:Ischemia / Q000209:etiology / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors