De macro-nachtvlinderfauna (Lepidoptera) van Zandig-Vlaanderen tussen brugge en Gent en van de scheldepolders in het Meetjesland (1969/1983 - 2010)

Volume: 38Start Page: 129End Page: 14

Value of single-voxel proton MR spectroscopy in temporal lobe epilepsy

PURPOSE: To study the value of different parameters derived from single-voxel proton MR spectroscopy of the mesial temporal lobes in the lateralization of the epileptogenic zone in patients with temporal lobe epilepsy, METHODS: We studied 12 healthy volunteers and 21 patients with temporal lobe epilepsy refractory to medical treatment, which was clearly lateralized with electroencephalography (EEG) and MR imaging, The mesial temporal lobes were investigated with single-voxel proton MR spectroscopy using a point-resolved spectroscopic sequence with an echo time of 135 milliseconds, The normalized concentration of N-acetylaspartate (NAA), creatine (Cr), and choline-containing compounds (Cho), and the metabolite ratios NAA/Cho+Cr, NAA/Cr, Cho/Cr, and NAA/Cho were calculated from the spectra. Using these values and an asymmetry index, we assigned the patients to one of five lateralization categories, RESULTS: The most consistent MR spectroscopic parameter for clear lateralization was the NAA/Cho+Cr ratio, followed by the NAA ratio, But with an adequate asymmetry index, the epilepsy in 17 (81%) of 21 patients could be lateralized by EEC and MR imaging with both parameters concordantly. Symmetric bilateral abnormalities were found in four of the 21 patients with NAA/Cho+Cr and in only one of the 21 patients with NAA. With both parameters, no contradictory lateralization was found; however, this was indeed the case with the remaining ratios, NAH/Cr, Cho/Cr, and NAA/Cho, in two, three, and one of the patients, respectively. A statistically significant decrease in NAA was found on the epileptic side, but also on the contralateral side. CONCLUSION: With an adequate asymmetry index, NAA/Cho+Cr and NAA are equally sensitive in predicting the side of involvement in patients with unilateral temporal lobe epilepsy

An MR protocol for presurgical evaluation of patients with complex partial seizures of temporal-lobe origin

PURPOSE: To find an optimal diagnostic protocol for the presurgical MR evaluation of patients with temporal lobe epilepsy, METHODS: MR imaging in 14 healthy subjects and 25 consecutive patients with temporal lobe epilepsy was performed in paracoronal sections perpendicular to the hippocampi with T1-weighted inversion recovery and T2 weighting. Volume measurements of the hippocampus/amygdala complex were performed and a multiecho sequence yielded T2-calculated images. RESULTS: Hippocampal disease was seen in 22 of 25 temporal lobe epilepsy patients on paracoronal T1-weighted inversion recovery images. Four had bilateral abnormalities. Characteristic for hippocampal disease were features such as volume loss, decreased signal, and loss of internal morphology. Only 17 of 25 patients demonstrated hippocampal pathology on T2-weighted images, and in one patient this was bilateral. Patients with only minimal structural loss on T1-weighted inversion recovery had normal T2-weighted images, T2 calculation was no more sensitive than visual assessment on the T2-weighted images. Volume measurements were normal in one patient and misleading in two patients. Lateralization, as compared with clinical and electroencephalographic findings, was most confidently done with paracoronal T1-weighted inversion recovery images and volume measurements. CONCLUSIONS: An optimum MR protocol for temporal lobe epilepsy patients is proposed. Its essential feature is that the hippocampus be evaluated by paracoronal T1-weighted inversion recovery images and volume measurements. T2-weighted imaging can be omitted

Single-voxel proton MR spectroscopy and positron emission tomography for lateralization of refractory temporal lobe epilepsy

PURPOSE: We compared the metabolic information obtained from single-voxel proton MR spectroscopy and positron emission tomography (PET) in patients with temporal lobe epilepsy. METHODS: Twenty-nine patients,vith temporal lobe epilepsy were screened for metabolic abnormalities with both proton MR spectroscopy and PET. Lateralization with MR spectroscopy was possible by using NAA/(Cho+Cr) and an asymmetry index. Hypometabolism as determined by PET was classified as typical or complex. RESULTS: Twenty-four (96%) of 25 patients whose seizure onset could be lateralized to one temporal lobe showed ipsilateral lateralization with either MR spectroscopy or PET, whereas concordant lateralization with both techniques was possible only in 14 (56%) of the 25 patients. MR spectroscopy showed 42 abnormal temporal lobes whereas PET showed only 25 lobes with decreased metabolism. All temporal lobes with hypometabolism at PET also had a low NAA/(Cho+Cr). Five patients (20%) with negative PET studies had seizures lateralized correctly with MR spectroscopy. CONCLUSION: Proton MR spectroscopy is more sensitive in depicting metabolic abnormalities than is PET in patients with temporal lobe epilepsy. Patients with negative PET studies will benefit from MR spectroscopy for the purpose of lateralizatio