Contrast-enhanced perfusion and diffusion MRI accurately lateralize temporal lobe epilepsy: a pilot study

Area of Science:

• Neuroimaging
• Epilepsy Research
• Medical Diagnostics

Background:

• Medically refractory temporal lobe epilepsy (TLE) presents diagnostic challenges, particularly in non-lesional cases.
• Accurate lateralization is crucial for guiding treatment strategies in TLE.
• Standard MRI quantitative assessments like volumetric measurements and T2 relaxometry have limitations in non-lesional TLE.

Purpose of the Study:

• To evaluate magnetic resonance (MR) contrast-enhanced perfusion imaging (CEPI) and diffusion-weighted imaging (DWI) for lateralizing information in medically refractory TLE.
• To compare the efficacy of CEPI and DWI with standard quantitative hippocampal assessments.
• To assess the potential of advanced MR techniques in identifying the seizure focus in TLE.

Main Methods:

• A pilot study involving 10 patients with non-lesional TLE and 10 controls.
• Quantification of relative cerebral blood flow (rCBF) using CEPI and apparent diffusion coefficient (ADC) using DWI in hippocampal regions.
• Comparison of ipsilateral-to-contralateral side ratios with control group ratios, correlated with EEG lateralization.

Main Results:

• 60% of TLE patients showed abnormal ADC ratios, with larger ADC ipsilateral to EEG lateralization.
• 100% of patients undergoing CEPI demonstrated abnormal CBF ratios, with lower values ipsilateral to EEG lateralization.
• No significant correlation was found between hippocampal volume ratios and ADC or CBF ratios, nor a significant relationship with T2 relaxometry ratios.

Conclusions:

• DWI and CEPI demonstrate potential as reliable tools for lateralizing non-lesional TLE.
• These advanced MR techniques may provide complementary information to established quantitative MR measures.
• Larger studies are needed to confirm the independent diagnostic value of DWI and CEPI in TLE lateralization.