MRI of the Perihemorrhagic Zone in a Rat ICH Model: Effect of Hematoma Evacuation

Abstract

We demonstrated vasogenic edema and mild perfusion reduction in the PHZ above the ischemic threshold. The existence of a perihemorrhagic "penumbra" indicating critically ischemic tissue analogous to ischemic stroke is unlikely.

Gross-total hematoma removal of hypertensive basal ganglia hemorrhages: A long-term follow-up

“…Orakcioglu found that, in a rat ICH model, clot evacuation is associated with normalization of perfusion [26]. Reversible perfusion reduction in this model indicates that early evacuation may help to reduce secondary neuronal changes [27].…”

Brain Natriuretic Peptide Improves Long-Term Functional Recovery after Acute CNS Injury in Mice

“…Interestingly, in mice injured with ICH, though there was a profound decrease in CBF by laser doppler flowmetry, we did not demonstrate any difference in CBF with nesiritide treatment, despite finding an improvement in outcome. Presumably this is due to the lack of the existence of a perihematomal penumbra in this disease state (Fainardi et al, 2008;Orakcioglu et al, 2008), but may FIG. 8.…”

Debate – does a reversible penumbra exist in intracerebral haemorrhage?

“…More recently, findings from imaging and regional blood flow studies in both animals and humans [7][8][9][10][11][12][13] have questioned the existence of an ischaemic penumbra in ICH. Perfusion computed tomography studies have suggested reduced perfusion and oedema in ICH have a common cause rather than presupposing one another.…”

“…PWI, on the other hand, provides a measure of relative cerebral perfusion. DWI and PWI studies in rat 10 have corroborated this opinion, although the model used to induce ICH has been criticised for not accurately replicating the clinical condition. Human imaging studies utilising single photon emission computed tomography (SPECT) found reduced blood flow in the perihaematomal region in the first 24 h following ICH, with normalisation of blood flow within 72 h. 11 Xenon computed tomography studies have shown that an ischaemic penumbra as defined by generally accepted cerebral blood flow thresholds does not exist in most ICH patients.…”