RT Journal Article
SR Electronic
T1 Epileptic Activity Increases Cerebral Amino Acid Transport Assessed by <sup>18</sup>F-Fluoroethyl-<span class="sc">l</span>-Tyrosine Amino Acid PET: A Potential Brain Tumor Mimic
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 129
OP 137
DO 10.2967/jnumed.116.176610
VO 58
IS 1
A1 Markus Hutterer
A1 Yvonne Ebner
A1 Markus J. Riemenschneider
A1 Antje Willuweit
A1 Mark McCoy
A1 Barbara Egger
A1 Michael Schröder
A1 Christina Wendl
A1 Dirk Hellwig
A1 Jirka Grosse
A1 Karin Menhart
A1 Martin Proescholdt
A1 Brita Fritsch
A1 Horst Urbach
A1 Guenther Stockhammer
A1 Ulrich Roelcke
A1 Norbert Galldiks
A1 Philipp T. Meyer
A1 Karl-Josef Langen
A1 Peter Hau
A1 Eugen Trinka
YR 2017
UL http://jnm.snmjournals.org/content/58/1/129.abstract
AB O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) PET is a well-established method increasingly used for diagnosis, treatment planning, and monitoring in gliomas. Epileptic activity, frequently occurring in glioma patients, can influence MRI findings. Whether seizures also affect 18F-FET PET imaging is currently unknown. The aim of this retrospective analysis was to investigate the brain amino acid metabolism during epileptic seizures by 18F-FET PET and to elucidate the pathophysiologic background. Methods: Ten patients with 11 episodes of serial seizures or status epilepticus, who underwent MRI and 18F-FET PET, were studied. The main diagnosis was glioma World Health Organization grade II–IV (n = 8); 2 patients suffered from nonneoplastic diseases. Immunohistochemical assessment of LAT1/LAT2/CD98 amino acid transporters was performed in seizure-affected cortex (n = 2) and compared with glioma tissues (n = 3). Results: All patients exhibited increased seizure-associated strict gyral 18F-FET uptake, which was reversible in follow-up studies or negative shortly before and without any histologic or clinical signs of tumor recurrence. 18F-FET uptake corresponded to structural MRI changes, compatible with cortical vasogenic and cytotoxic edema, partial contrast enhancement, and hyperperfusion. Patients with prolonged postictal symptoms lasting up to 8 wk displayed intensive and widespread (≥ 1 lobe) cortical 18F-FET uptake. LAT1/LAT2/CD98 was strongly expressed in neurons and endothelium of seizure-affected brains and less in reactive astrocytosis. Conclusion: Seizure activity, in particular status epilepticus, increases cerebral amino acid transport with a strict gyral 18F-FET uptake pattern. Such periictal pseudoprogression represents a potential pitfall of 18F-FET PET and may mimic brain tumor. Our data also indicate a seizure-induced upregulation of neuronal, endothelial, and less astroglial LAT1/LAT2/CD98 amino acid transporter expression.