TC-99M-HM-PAO BRAIN SPECT IN SUBARACHNOID HEMORRHAGE

Cerebral blood flow (CBF) in subarachnoid haemorrhage (SAH) has been extensively studied using xenon-133. CBF can be imaged by SPECT using HM-PAO: this technique is much easier to perform, but true quantitative data are not available and different diagnostic criteria have to be used. This study investigates the role of HM-PAO SPECT in SAH. Twenty-six HM-PAO SPECT studies were recorded on 24 patients. Fifteen patients were in Hunter and Hess clinical grades I and II and nine were in clinical grades III, IV and V. HM-PAO SPECT showed derangements of brain perfusion in 16 patients. Focal hypoperfusion was observed in 15 patients and focal hyperperfusion in one patient. One patient studied twice had a diffuse hypoperfusion in the first study and focal hypoperfusion in the second. HM-PAO SPECT was more sensitive than transmission computed tomography (CT) in detecting ischaemic complications in the first week (p = 0.064) and in the first two weeks (p = 0.016) after SAH. HM-PAO SPECT also showed altered tissue perfusion in four patients in which not only CT, but also angiography and transcranial Doppler flowmetry were normal. The results obtained lead to the following conclusions: (1) CBF derangements are observed in a high percentage of SAH patients; this percentage is higher among patients with more severe disease (p = 0.048) with focal hypoperfusion being the most common finding; (2) HM-PAO SPECT is more sensitive than CT in evaluating ischaemic complications (p = 0.016) and it can show ischaemia even if no complicating factor, as evaluated by usual neuroradiological procedures, is present; (3) HM-PAO results are associated with the prognosis of the patient (p = 0.155). © 1990 Chapman and Hall Ltd.