Quantitative measurement of cerebral blood flow by Tc-99m-HMPAO SPECT in acute ischaemic stroke: usefulness in determining therapeutic options

Objective-Early recanalisation by thrombolysis is a conclusive therapy for acute ischaemic stroke. But this therapy may increase the risk of intracere bral haemorrhage or severe brain oedema. The purpose was to evaluate useful ness of quantitative measurement of cerebral blood flow by single photon em ission computed tomography (SPECT) in predicting the risk of haemorrhage or oedema, and determining the therapeutic options in acute hemispheric ischa emic stroke. Methods-The relation was studied retrospectively between initial regional c erebral blood flow (rCBF) quantitatively measured by technetium-99m-labelle d hexamethylpropyleneamine oxime (Tc-99m-HMPAO) SPECT and final clinical an d radiological outcome in 20 patients who presented hemispheric ischaemic s troke and were treated conservatively or received early recanalisation by l ocal intraarterial thrombolysis. The non-invasive Patlak plot method was us ed for quantitative measurement of rCBF by SPECT. Results-Regions where residual rCBF was preserved over 35 ml/100 g/min had a low possibility of infarction without recanalisation and regions where re sidual rCBF was preserved over 25 ml/100 g/min could be recovered by early recanalisation. However, regions where residual rCBF was severely decreased (< 20 ml/100 g/min) had a risk of intracerebral haemorrhage and severe oed ema. Conclusions-A quantitative assessment of residual rCBF by Tc-99m-HMPAO SPEC T is useful in predicting the risk of haemorrhage or severe oedema in acute ischaemic stroke. Therapeutic options should be determined based on the re sults of rCBF measurement.