Improvement of FDG PET/CT and MRI concordance in temporal lobe epilepsy pre-surgical assessment using statistical...

This retrospective study evaluates the diagnostic performance of statistical parametric mapping (SPM) analysis of interictal F18-fluoro-deoxy-D-glucose positron emission tomography computed tomography (FDG PET/CT) in temporal lobe epilepsy (TLE) patients, aiming to enhance image reporting consistency and correlation between magnetic resonance imaging (MRI) and FDG PET/CT findings and boost confidence in the surgical decision-making.

Forty-nine TLE patients undergoing MRI and FDG PET/CT imaging at a tertiary epilepsy service were included. Images were visually interpreted by an experienced radiologist and nuclear medicine physician. SPM-based quantitative analysis for FDG PET/CT including Z score asymmetric index (ZAI) was performed. Statistical analyses include receiver operating characteristic curve and Cohen's k statistics.

Significant differences in the standardised uptake value (SUV) ratio and ZAI were observed among left TLE, nonepilepsy, and right TLE (p < 0.01). The areas under the curves for left/nonleft and right/nonright groups were 0.838 and 0.780, respectively. The cutoff value to separate left TLE from nonepilepsy and right TLE was 0.305 with 89.7% sensitivity, 80.0% specificity, 94.6% positive predictive value (PPV), 66.7% negative predictive value (NPV), and a 0.697 Youden index for diagnosis. It was 0.190 to separate right TLE from the other 2 with 87.5% sensitivity, 75.6% specificity, 41.2% PPV, 96.9% NPV, and a 0.631 Youden index for diagnosis. The intermethod agreement between MRI and SUV ratio was moderate (k = 0.48; 95% CI, 0.32-0.65) and that between FDG PET/CT qualitative assessment and ZAI was moderate (k = 0.43; 95% CI, 0.10-0.76).

FDG PET/CT-based SUV ratios and ZAI show promising diagnostic value in TLE patients, facilitating the integration of FDG PET/CT practice into presurgical assessment for medically refractory epilepsy.