BRAIN SINGLE-PHOTON EMISSION TOMOGRAPHY USING TC-99M BICISATE (ECD) IN A CASE OF COMPLEX PARTIAL SEIZURE

The clinical application of technetium-99m bicisate (ethyl cysteinate dimer, ECD) for ictal and interictal studies of regional cerebral bloo d flow (rCBF) in a patient suffering from medically intractable simple and complex partial seizures is reported. The interictal study was pe rformed 60 min p.i. and the ictal studies were performed at 60 min p.i . using an annular crystal single-photon emission tomography (SPET) sy stem dedicated for high-resolution brain SPET imaging. Visual evaluati on of the studies was carried out, as well as semiquantitative measure ment of regional tracer uptake. Magnetic resonance imaging (MRT) scans revealed atrophy of almost the complete left frontal lobe and the ven tral parts of the left temporal lobe, including in part the temporomes ial structures. The left parietal and occipital structures and the rig ht hemisphere were normal. The interictal study showed a large perfusi on defect involving the whole left frontal lobe as well as the left te mporal lobe with remaining Small areas of normal cortical tracer uptak e. The ictal studies detected circumscribed hyperperfusion within the left mesial temporal lobe (ventral part of the hippocampus). Additiona lly an increase in perfusion could be seen within the entire remaining left temporal lobe. Semiquantitative evaluation of tracer uptake comp aring both studies detected markedly increased uptake within the focus compared to the remaining left temporal lobe. On this basis the newly available tracer for studies of rCBF, Tc-99m-bicisate, seems to be of value for the detection of epileptogenic foci. Additionally, the valu e of ictal rCBF studies in the presurgical evaluation of those patient s presenting severe morphological alterations on MRI is clearly underl ined by this case.