ORIGINAL ARTICLE - NEUROSURGERY - EPILEPSY
Double match of
F-fluorodeoxyglucose-PET and iomazenil-SPECT
improves outcomes of focus resection surgery
Received: 10 March 2018 /Accepted: 23 May 2018
Springer-Verlag GmbH Austria, part of Springer Nature 2018
Background When the results of electroencephalography (EEG), magnetic resonance imaging (MRI), and seizure semiology are
discordant or no structural lesion is evident on MRI, single-photon emission computed tomography (SPECT) and positron
emission tomography (PET) are important examinations for lateralization or localization of epileptic regions. We hypothesized
that the concordance between interictal 2-[
FDG)-PET and iomazenil (IMZ)-SPECT could
suggest the epileptogenic lobe in patients with non-lesional findings on MRI.
Method Fifty-nine patients (31 females, 28 males; mean age, 29 years; median age, 27 years; range, 7–56 years) underwent
subdural electrode implantation followed by focus resection. All patients underwent
FDG-PET, IMZ-SPECT, and focus
resection surgery. Follow-up was continued for ≥ 2 years. We evaluated surgical outcomes as seizure-free or not and analyzed
correlations between outcomes and concordances of low-uptake lobes on PET, SPECT, or both PET and SPECT to the resection
lobes. We used uni- and multivariate logistic regression analyses.
Results In univariate analyses, all three concordances correlated significantly with seizure-free outcomes (PET, p = 0.017;
SPECT, p = 0.030; both PET and SPECT, p = 0.006). In multivariate analysis, concordance between resection and low-uptake
lobes in both PET and SPECT correlated significantly with seizure-free outcomes (p = 0.004). The odds ratio was 6.0.
Conclusion Concordance between interictal
FDG-PET and IMZ-SPECT suggested that the epileptogenic lobe is six times
better than each examination alone among patients with non-lesional findings on MRI. IMZ-SPECT and
complementary examinations in the assessment of localization-related epilepsy.
When planning epilepsy surgery for patients with intractable
epilepsy, presurgical examinations to detect the estimated ep-
ilepsy foci are requested. After eliciting a detailed history,
seizure semiology captured by long-term video-electroen-
cephalography (EEG), high-resolution magnetic resonance
imaging (MRI), magnetoencephalography (MEG), dense-
array EEG, etc., are performed and evaluated prior to surgery.
When the results of EEG, MRI, and seizure semiology are
discordant or no structural lesion is evident on MRI, single-
photon emission computed tomography (SPECT) and posi-
tron emission tomography (PET) are important examinations
for lateralization or localization of the epileptic region and
providing guidance for subsequent subdural electrode (SE)
placement in cases of intractable epilepsy [4, 11, 19].
The expected image pattern of 2-[
FDG)-PET in the epileptogenic region is hypo-
metabolic . The reported sensitivity of
FDG-PET for detect-
ing an epileptogenic brain region is 85–90% in temporal lobe
epilepsy and lower (45–92%) in extratemporal epilepsy .
During the ictal state, as blood flow in the epileptic region
increases depending on the electrical hyperactivity, brain per-
fusion radiopharmaceuticals are used for SPECT . Ictal or
peri-ictal perfusion SPECT thus offers high sensitivity for
focus detection . Sarikaya  reported meta-analytic
* Ayataka Fuj imoto
Comprehensive Epilepsy Center, Seirei Hamamatsu General
Hospital, 2-12-12 Sumiyoshi, Nakaku,
Hamamatsu, Shizuoka 430-8558, Japan
Department of Radiology, Seirei Hamamatsu General Hospital,