Abstracts

The intention of our study was to assess Proton-MR Spectroscopy (¹H-MRS) as a non-invasive technique for grading degree of hippocampal sclerosis in patients with temporal lobe epilepsy (TLE). Quantified metabolite alterations in ¹H-MRS were correlated to hippocampal neuronal cell loss and degree of gliosis expressed by astroglial fibrillary acid protein (GFAP) expression., ¹H-MRS was carried out in hippocampal structures of 23 unilateral TLE patients scheduled for hippocampectomy. Neuronal cell numbers were performed with a microcomputer imaging system equipped to a BX51 microscope. Gliosis was detected by GFAP-staining. Correlation between hippocampal metabolite alterations and neuronal cell loss was calculated by Pearson Correlation Coefficient (PCC). Analysis between alterations of m-Ins and distribution of astroglial GFAP expression in the hippocampus was calculated by one-way ANOVA., Positive correlation was calculated between tNAA reduction and neuronal loss in hippocampal CA1- (p[lt]0,001), CA3- (p= 0,015), CA4 segment (p=0,031) (Figure 1) and dentate gyrus (p=0.006). Correlation between m-Ins and astroglial GFAP expression revealed a significant increased m-Ins levels in cases of diffuse astrogliosis (m-Ins = 6.4 [plusmn] 1.1) compared to gliosis restricted to isolated sectors of the hippocampus (i.e. hilus) (m-Ins=5.3 [plusmn] 1.2) (p=0.039). Negative correlation was found between m-Ins and neuronal loss in the CA4 segment of the hippocampus (p=0.012) (Figure 1).[figure1], Our results support ¹H-MRS as a valid, non-invasive method indicating hippocampal sclerosis preoperatively in patients with TLE. Degree of tNAA reduction in ¹H-MRS is correlated to neuronal loss. Furthermore absolute metabolite determination of m-Ins indicates amount of hippocampal astrocytosis displayed by GFAP expression., (Supported by Wilhelm Sander Foundation (Sachbeihilfeantrag-Nr. 2000.070.1).)