In vivo detection of developing vessel occlusion in photothrombotic ischemic brain lesions in the rat by iron particle enhanced MRI.

The aim of our study was to visualize developing vessel occlusion in focal cerebral ischemia in vivo. Cortical photothrombosis (PT) was induced in rats, which in addition received superparamagnetic iron oxide (SPIO) particles intravenously. When SPIO particles were applied simultaneously during illumination of the brain for induction of PT, animals showed a markedly hypointense cortical lesion on T2-weighted (T2-w) magnetic-resonance images (MRI).

In vivo monitoring of macrophage infiltration in experimental ischemic brain lesions by magnetic resonance imaging.

Although macrophages represent the major inflammatory cells in cerebral ischemia, the kinetics of macrophage infiltration are largely unknown. To address this issue, we injected superparamagnetic iron oxide (SPIO) particles into the circulation of rats at different time points after focal photothrombotic cerebral infarction and performed magnetic resonance imaging (MRI) 24 hours later. Infarcts appeared as hyperintense lesions on T2-w and CISS MR images during all stages.