Figure 1.
Laser speckle flowmetry (LSF) imaging and ‘macrosphere' model. (A) Photo of field of view (around 12 × 7 mm2) after thinning the left frontal, parietal, and temporal bones. The cortex can be seen through thinned bone and intact dura mater. (B) Distribution of cerebral arteries and artery-to-artery anastomoses shown after transcardial perfusion and staining with Latex/black ink is shown. The cortex in the field of view used for LSF imaging was mainly supplied by the left middle cerebral artery (MCA). Many collateral branches from the anterior and posterior cerebral arteries are marked by filled or open circles (colors depict individual animals). (C) Speckle contrast image including 25 regions of interest (ROIs) (A–Y), which were used for regional analysis. (D) Post mortem view of the base of the brain showing the position of a macrosphere (white particle, see black arrow) at the bifurcation of MCA and anterior cerebral artery (ACA) blocking the anterograde blood flow into the MCA. (E) Triphenyltetrazolium chloride (TTC)-stained brain sections showing infarction 1 day after embolization of the MCA that was caused by injection of one macrosphere. These sections confirm that arterial occlusion with one macrosphere has the potential to induce a large infarction. Please note that the example shows a large, almost hemispheric infarction, and does not derive from the analyzed experiments, which were terminated 3 hours after macrosphere injection. Arrowheads indicate that the field of view covered mainly the ischemic penumbra and only part of the core region of the MCA territory. (F) Example of the coincidence of DC shift and cerebral blood flow (CBF) alteration caused by spreading depolarization occurring spontaneously after injection of a macrosphere and subsequent occlusion of the MCA.