Hybrid imaging techniques in the assessment of epileptic foci: A clinical case

Introduction. Localization of an epileptic focus (EF) in patients with pharmacoresistant focal epilepsy can be a challenging task, and the detection of multiple EFs limits the possibilities of surgical treatment. A more accurate description of the structure and metabolism of EFs may provide additional information for managing such patients. Clinical case description. A 35-year-old patient suffered from pharmacoresistant focal epilepsy, which debuted at the age of 24 with grand mal seizures followed by focal episodes with fading and tonic tension of the left arm. The MRI revealed bilateral mesial temporal sclerosis with more pronounced changes on the left; however, the EEG revealed epileptiform activity in the right temporal region, which created diagnostic difficulties in determining the primary epileptogenic zone. To clarify the location of the lesion, a comprehensive examination was performed, including PET/MRI, which revealed pronounced hypometabolism in the right temporal lobe (with a difference of up to 31% compared with the contralateral side) while maintaining symmetrical accumulation of RPh in the hippocampus. Additionally, diffusion kurtosis imaging (DKI) was performed, which showed a significant decrease in radial and median kurtosis, as well as axonal water fraction in the right temporal lobe (up to 1.33 SD from normal). Invasive EEG monitoring confirmed the bilateral nature of epileptogenicity with a predominance of right-hemisphere seizure initiation. Conclusions. The combined use of PET/MRI and DKI increases the accuracy of detection of epileptogenic foci in pharmacoresistant epilepsy. Hybrid imaging allows for a comprehensive assessment of metabolic and microstructural changes, which is important for planning surgical treatment. Data integration helps differentiate primary and secondary foci, thus optimizing patient management tactics. The introduction of automated analysis for standardization of diagnostics is promising.