Cerebral FET uptake owing to epilepsy appears to be a rare phenomenon

Ziel/Aim:

A recent study reported (1) on high and reversible cerebral FET uptake in some patients due to epileptic seizures. We examined cerebral FET uptake in two chemical induced rat epilepsy models and in patients with focal epilepsy to further investigate whether this phenomenon represents a major pitfall in brain tumor diagnostics and whether FET PET may be a potential marker to localize epileptogenic foci.

Methodik/Methods:

Six rats (plus two controls) underwent kindling/sensitization with pentylenetetrazol (PTZ) 3x-8x/week over ten weeks and hence, class I increased to class IV seizures. Dynamic PET and standard multiparametric MRI were performed regularly on days with and without seizures. Five rats (plus two controls) underwent kainic acid titration to exhibit 3 – 3.5h of class IV-V motor seizures (status epilepticus, SE). Rats underwent PET and MR on days 3 – 4 as well as 9 – 10 days after SE. Four patients with epilepsy underwent FET PET for diagnostic purposes within one week after the last documented seizure.

Ergebnisse/Results:

In the PTZ model, no signal alterations in FET PET or MRI were noted during kindling and up to three weeks afterwards. In the SE kainic acid model, T₂-weighted signal alterations but no T₁-weighted with/without the contrast agent in MRI or FET accumulation were noted in the amygdala and hippocampus. No abnormalities of FET uptake were noted in the brain of epilepsy patients.

Schlussfolgerungen/Conclusions:

No abnormalities of cerebral FET uptake were observed in two different rat models of severe epilepsy and in patients with focal epilepsy. Thus, increased FET uptake due to epileptic seizures seems to be a very rare phenomenon and not a common pitfall in brain tumor diagnostics.

Literatur/References:

[1] Hutterer et al. Epileptic activity increases cerebral amino acid transport assessed by 18F-fluoroethyl-l-tyrosine amino acid PET: a potential brain tumor mimic. J Nucl Med. 2017;58:129 – 137