Imaging of cerebral blood flow in epileptic patients using 99mTc-HMPAO SPECT

In this preliminary study with young patients suffering from partial or generalised epileptic seizures, the regional HMPAO distribution (n=74) was taken by means of a regional index (RI), and the absolute HMPAO uptake was determined, expressed in percentage of injected dose/100 ml brain tissue (n=46). Both values were also determined in a standard group of young persons (n=51), and data obtained for this group revealed a clear, significant right-preponderance of regional blood circulation. In 59.3% of scans in patients with partial seizures either enhanced or decreased RIs were measured, but only in 20% of the scans made in patients with generalised seizures. There was no significant difference to be found in %-HMPAO uptake/100 ml of the age-equivalent control group and of the epileptic patient group (n=46), but the right-preponderance was clearly less marked in the latter group. The study showed that a visual evaluation of SPECT data has to take into account normally occurring asymmetries of HMPAO uptake in order to avoid malinterpretations. The less marked regional right-preponderance may be one reason responsible for the interiktal behaviour of some epileptic patients. (orig.)