Abstract:
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Purpose: Preliminary diffusion MRI studies have shown that apparent diffusion coefficient (ADC) values may lateralize the epileptogenic lesion in patients with epilepsy. We sought to determine if ADC measurements in patients with temporal lobe epilepsy (TLE) are predictive of performance on neuropsychological testing.
Methods and Materials: 19 patients with TLE and 19 age and sex matched normal controls underwent an MRI of the brain at 1.5 T. ADC region of interest measurements were taken by a blinded reader in the bilateral hippocampi and parahippocampal gyri as well as ADC values of the whole brain. All patients completed neuropsychological testing as part of a routine presurgical work-up. In addition, video EEG, WADA, and surgical pathology results were collected where available. Statistical comparisons were made of ADC values in TLE patients versus normal controls. The Mann-Whitney test was used to compare TLE patients and controls with respect to each ADC measure. The Wilcoxon Signed Rank Test was used to compare ipsilateral versus contralateral regions of interest in the temporal lobes in patients as determined by seizure focus. Spearman Rank correlation coefficient and least squares regression analyses were conducted to determine if a relationship existed between ADC values and scores on neuropsychological tests in TLE patients.
Results: The seizure focus was determined by video EEG; right side = 10 patients and left side = 9 patients. Compared to normal controls, patients with TLE demonstrated higher ADC values on whole brain (p<0.005) as well as hippocampal (p<0.0005) and parahippocampal measurements (p< 0.0005). In patients with TLE, ADC values were higher in the hippocampus and parahippocampal gyrus ipsilateral to the seizure focus (p< 0.0005). Significant positive correlations were seen between visual retention and ADC values in the left > right hippocampal structures. There was a trend towards negative correlations between the remaining memory measures and ADC values; however, these did not reach statistical significance.
Conclusion: Quantitative diffusion measurements imply microstructural abnormalities of the hippocampal structures and whole brain in patients with TLE; however, there is no simple relationship between ADC values and memory performance.
Questions about this event email: luiy01@med.nyu.edu
Lui MD, Y,
Correlation of Apparent Diffusion Coefficient with Neuropsychological Testing in Temporal Lobe Epilepsy. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3102554.html
