Photochemically-induced cerebral infarction in the rat: Comparison of NMR imaging and histologic changes

Abstract

The evolution of a photochemically induced cerebral thrombotic infarction was followed in rats during the first week after the insult by means of NMR imaging and histology. Heavily T2-weighted images provided an excellent lesion detection and a high specificity for the discrimination of different histological abnormalities. The T2-weighted images showed a brain lesion evolving during the first 24 h from a homogeneous hyperintense area, histologically corresponding to diffuse vasogenic and cytotoxic oedema with concomitant neuronal necrosis, to an iso-intense area with a hyperintense seam, which microscopically correlated with increased vascular permeability at the periphery of the lesion. The hyperintense seam was observed up to day 7, but at that time coincided with gliomesodermal repair reaction which could be verified histochemically and ultrastructurally. It may be concluded that NMR-micro-imaging at a moderately high field, enables early detection and adequate follow-up of small cerebral infarctions in rats.

In Vivo Detection of Developing Vessel Occlusion in Photothrombotic Ischemic Brain Lesions in the Rat by Iron Particle Enhanced MRI

“…show that in PT vessel occlusion is still ongoing despite cessation of illumination, and spreads from the core of the lesion to the 'penumbra'. Thus, ongoing thrombosis as shown here provides a partial explanation and possible mechanism for secondary infarct growth in the PT model documented by several groups (Grome et al, 1988;Verlooy et al, 1993;Lee et al, 1996; this study). The concept of an early thrombotic lesion core surrounded by a zone of ongoing vessel thrombosis in the periphery as revealed by iron-enhanced MRI in the present study further substantiates previous findings on the temporal profile of hemodynamic alterations after PT.…”

The blood–brain barrier in trauma, stroke and edema

“…To recognize and counteract problems that may arise in the neurosurgery clinic, we have been looking for answers in the laboratory of experimental neuropathology. Many years of experience with animal models of stroke and neurotrauma [1][2][3][4][5][6][7] provided insight in specific morphologic mechanisms and revealed a strong similarity in neurodegenerative processes between stroke and trauma, especially with regard to dynamic progression and endpoint parameters. The therapeutic goal certainly is protection of neurons, but to our opinion this cannot be achieved without counteracting secondary phenomena such as edema formation which in conditions of stroke as well as trauma appear in the very acute phase.…”

Evidence for a Neuroprotective Effect of Pyrid-3-yl-sulphonylurea in Photochemically Induced Focal Ischaemia in Rats: Magnetic Resonance Imaging Evaluation

“…As the focal ischaemic cerebral lesion is associated with brain oedema, magnetic resonance imaging is ideally suited to investigating the phenomena of infarct growth. This method enables non-invasive, real time quanti®cation of the extent of the cerebral oedema from T2-weighted spinecho images (Verlooy et al 1993;Lee et al 1996;Loubinoux et al 1997;Mottet et al 1997). Figure 1) was synthesized as previously described (Masereel et al 1992) and dissolved in dimethylsulphoxide (5 mg mL À1 ).…”