Simultaneous ¹⁸F-FDG PET/MRI predicting favourable surgical outcome in refractory epilepsy patients

To evaluate the (1) successful surgery proportion in patients with clear structural lesions on MRI and single abnormality on ¹⁸F-fluorodeoxyglucose positron emission tomography/Magnetic resonance imaging (¹⁸F-FDG PET/MRI); (2) predictive value of ¹⁸F-FDG PET/MRI for postsurgical outcome in refractory epilepsy patients.

A retrospective study was conducted on 123 patients diagnosed with refractory epilepsy who underwent presurgical evaluation involving ¹⁸F-FDG PET/MRI and were followed for one-year post-surgery. Two neuroradiologists interpreted the PET/MRI images using visual analysis and an asymmetry index based on the standard uptake value. The Engel classification was used to assess surgical outcomes one-year post-surgery. Prognostic factors predicting post-surgical seizure outcomes were explored using univariate and binary logistic regression.

Definitely single lesion abnormality was observed in 35.0% (43/123) of the patients on the MRI portion of PET/MRI. The proportion increased to 74.0% (91/123) when 18 F-FDG PET portion was added. About 75% (69/91) of patients displaying a clear-cut lesion on 18 F-FDG PET/MRI were classified as Engel Class I one-year post-surgery. The proportion of Engel Class I patients was not significantly different when comparing MRI-single lesion patients with MRI-negative, PET-single lesion patients one year after surgery (81.4% vs. 70.0%, P = 0.24). Binary logistic regression analysis revealed that the detection of a clear single lesion on 18 F-FDG PET/MRI was a strong positive predictor of a favorable surgical outcome (OR 3.518, 95% CI 1.363-9.077, p = 0.009).

Single lesion detected on 18 F-FDG PET/MRI is useful to predict good surgical outcome for refractory epilepsy patients; Those patients should be considered as candidates for surgery.