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Published on: August 5, 2014
Contrast-enhanced perfusion and diffusion MRI accurately lateralize temporal lobe epilepsy: a pilot study
T J O'Brien1, E P David, C J Kilpatrick
1Department of Neurology, The Royal Melbourne Hospital, The University of Melbourne, Victoria, Australia. obrientj@unimelb.edu.au
Aims:
To undertake a pilot study to assess whether magnetic resonance (MR) contrast-enhanced perfusion imaging (CEPI) and diffusion-weighted imaging (DWI) provide lateralizing information in medically refractory temporal lobe epilepsy (TLE),and to compare this to standard quantitative hippocampal assessments (volumetric measurements and T2 relaxometry).
Methods:
Ten patients with 'non-lesional' TLE and 10 control subjects were studied. Quantification of the relative cerebral blood flow (rCBF) and apparent diffusion coefficient (ADC) was performed for the hippocampal regions. The ratios of the ipsilateral-to-contralateral side (to the EEG lateralization) were compared with the side-to-side ratios in the controls.
Results:
Six patients (60%) had an ADC ratio outside the control range (the larger ADC ipsilateral to the EEG lateralization in all cases). The CBF ratios were outside the control range in all eight patients (100%) in whom CEPI was performed (the lower value ipsilateral to the EEG lateralization in all cases). The magnitude of the hippocampal volume (HV) ratios showed no significant correlation with the magnitude of the ADC ratios (R=-0.03, p=0.93) or CBF ratios (R=0.36, p=0.39). There was a closer relationship with the T2 relaxometry ratios, but this was also not significant (R=-0.40, p=0.32; R=0.58, p=0.08).
Conclusions:
DWI and CEPI show potential as reliable tools for the lateralization of non-lesional TLE. Further studies with larger numbers are necessary to determine whether these techniques provide independent data to established MR quantitative measures.
Insights
Diffusion-weighted imaging (DWI) and contrast-enhanced perfusion imaging (CEPI) show promise for lateralizing non-lesional temporal lobe epilepsy (TLE). These advanced MRI techniques may offer new insights beyond traditional hippocampal volume and T2 relaxometry measures.
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.
