J Neurol Surg A Cent Eur Neurosurg 2014; 75 - p64
DOI: 10.1055/s-0034-1383793

Magnet Resonance Imaging in Experimental Mouse Subarachnoid Hemorrhage

C. Muroi 1, Y. Kashiwakgi 2, T. Rokugawa 2, T. Yamada 2, A. Obata 2, M. Fujioka 2, K. Abe 3
  • 1Department of Neurosurgery, Kantonsspital Aarau, Aarau, Switzerland
  • 2Department of Innovative Drug Discovery Technologies, Innovative Drug Discovery Research Laboratories, Shionogi & Co., Ltd., Osaka, Japan
  • 3Department of Neurosurgery, Wakasuka Daiichi Hospital, Osaka, Japan
  • 4Department of Emergency and Critical Care Medicine, Nara Medical University, Kashihara, Japan

Aims: Experimental subarachnoid hemorrhage (SAH) in mice is becoming increasingly popular to elucidate the molecular pathogenesis of delayed neuronal injury. The filament perforation model (FPM) is currently most often used. Reports about MRI in experimental mouse SAH are virtually nonexistent. The aim of this study is the evaluation of experimental SAH in mice using the FPM by magnet resonance imaging (MRI).

Methods: A total of 23 male C57Bl/6J mice weighting 21-25 g were used. In 17 animals, SAH was induced using the FPM. For comparison, 2 animals were subjected to transient focal cerebral ischemia by middle cerebral artery occlusion (MCAo). Another 4 mice were used as controls. MRI examinations were performed using a Varian 7T small animal scanner. T1 weighted-spin echo (SE), T2-SE, T2* weighted gradient echo (GE) and apparent diffusion coefficient (ADC) map were evaluated at various time points (range: day 0-6 after SAH).

Results: Hemorrhage could be confirmed best in T2*-GE sequences. However, due to tiny cerebrospinal compartments in mice, the interpretation was difficult in mild SAH. Degree of hemorrhage varied. In one animal, severe SAH with ventricle tamponade could be seen. The majority of animals (92%) evaluated ≥2d showed signs of hydrocephalus, which was best seen in T2-SE sequences. SAH did not lead to visible “territorial ischemia” in contrast to MCAo. Marked hypointense cortical veins were visible in the peracute (≤30 minute) and delayed (≥3d) phase after SAH in the T2*-GE sequences. This phenomenon might reflect increased oxygen extraction fraction due to altered cerebral blood flow (CBF).

Conclusions: MRI evaluation in mouse SAH is feasible. T2* sequences are seemingly best for hemorrhage detection, as previously reported in clinical case reports. Occurrence of hydrocephalus could be documented. The heterogeneity in degree of hemorrhage in FPM could be confirmed. However, neuronal injury could not be detected by MRI after SAH in contrast to MCAo. CBF studies are warranted, for example using arterial spin labeling.

Acknowledgment C.M. was supported by a personal research grant from the Swiss Foundation for Grants in Biology and Medicine (under the patronage of the Swiss national Science Foundation).