PHOTOCHEMICALLY-INDUCED CEREBRAL INFARCTION IN THE RAT - COMPARISON OF NMR IMAGING AND HISTOLOGIC-CHANGES

The evolution of a photochemically induced cerebral thrombotic infarct ion was followed in rats during the first week after the insult by mea ns of NMR imaging and histology. Heavily T2-weighted images provided a n excellent lesion detection and a high specificity for the discrimina tion of different histological abnormalities. The T2-weighted images s howed a brain lesion evolving during the first 24h from a homogeneous hyperintense area, histologically corresponding to diffuse vasogenic a nd cytotoxic oedema with concomitant neuronal necrosis, to an iso-inte nse area with a hyperintense seam, which microscopically correlated wi th increased vascular permeability at the periphery of the lesion. The hyperintense seam was observed up to day 7, but at that time coincide d with gliomesodermal repair reaction which could be verified histoche mically and ultrastructurally. It may be concluded that NMR-micro-imag ing at a moderately high field, enables early detection and adequate f ollow-up of small cerebral infarctions in rats.