Quantitative positron emission tomography-guided magnetic resonance imaging postprocessing in magnetic resonance imaging-negative epilepsies

Summary Objective Detection of focal cortical dysplasia ( FCD ) is of paramount importance in epilepsy presurgical evaluation. Our study aims at utilizing quantitative positron emission tomography ( QPET ) analysis to complement magnetic resonance imaging ( MRI ) postprocessing by a morphometric analysis program ( MAP ) to facilitate automated identification of subtle FCD . Methods We retrospectively included a consecutive cohort of surgical patients who had a negative preoperative MRI by radiology report. MAP was performed on T1‐weighted volumetric sequence and QPET was performed on PET /computed tomographic data, both with comparison to scanner‐specific normal databases. Concordance between MAP and QPET was assessed at a lobar level, and the significance of concordant QPET ‐ MAP + abnormalities was confirmed by postresective seizure outcome and histopathology. QPET thresholds of standard deviations ( SDs ) of −1, −2, −3, and −4 were evaluated to identify the optimal threshold for QPET ‐ MAP analysis. Results A total of 104 patients were included. When QPET thresholds of SD = −1, −2, and −3 were used, complete resection of the QPET ‐ MAP + region was significantly associated with seizure‐free outcome when compared with the partial resection group ( P = 0.023, P < 0.001, P = 0.006) or the no resection group ( P = 0.002, P < 0.001, P = 0.001). The SD threshold of −2 showed the best combination of positive rate (55%), sensitivity (0.68), specificity (0.88), positive predictive value (0.88), and negative predictive value (0.69). Surgical pathology of the resected QPET ‐ MAP + areas revealed mainly FCD type I. Multiple QPET ‐ MAP + regions were present in 12% of the patients at SD = −2. Significance Our study demonstrates a practical and effective approach to combine quantitative analyses of functional ( QPET ) and structural ( MAP ) imaging data to improve identification of subtle epileptic abnormalities. This approach can be readily adopted by epilepsy centers to improve postresective seizure outcomes for patients without apparent lesions on MRI .