The Value Of MRI And¹⁸F-FDG PET/CT In The Diagnosis Of Hippocampal Sclerosis

Part1The value of MRI in the diagnosis of hippocampal sclerosisBackground and purposeEpilepsy is a high incidence of neurological disease second only to cerebrovascular disease, in which the temporal lobe epilepsy account for60%～70%of the drug refractory epilepsy patients. The main reason of temporal lobe epilepsy is hippocampal sclerosis, it is related to all damage in infants and young children period (birth injury, trauma, high fever convulsion, etc.) which may lead to tissue hypoxia. Because the hippocampus structure is in growth and mature period in infants and young children period, at the same time due to fragility of hippocampal structure, hypoxia can cause metabolic abnormalities of hippocampal neuron cell, cell degeneration necrosis,loss, and astrocytes reactive hyperplasia. Andgrowth of the nerve cells lost stimulate the growth of residual neuron cell and abnomal nerve synaptic reorganization,it cause abnormal discharge, induce epilepsy. So the accurate diagnosis of hippocampal sclerosis plays a vital role to temporal lobe epilepsy surgery. MRI was considered the most sensitive method in the diagnosis of hippocampal sclerosis. Currently the imaging standard in the diagnosis of hippocampal sclerosis including hippocampal atrophy, T2WI signal increases, hippocampus shallow gully head disappear, isplater white matter atrophy, the temporal lobe atrophy, temporal angle of the lateral ventricle enlarged. Study found using MRI to measure the volume of hippocampal atrophy was consistent with the result of histologically loss of neurons. MRI diagnosis not only used for pathological changes of the hippocampus, but also be used to determine on the level of hippocampal sclerosis. This topic through the analysis of preoperative MRI in patients with hippocampal sclerosis, and to explore the qualitative and positioning diagnostic value of MRI to hippocampal sclerosis.Materials and methodsThe datas collected from clinical department of neurosurgery, zhujiang hospital, southern medical university hospital January2010to December2011, the patients was diagnosed as the inside of the temporal lobe epilepsy (TLE) cases, After comprehensive evaluation, we did surgical treatment for71patients, which were diagnosed as hippocampal sclerosis postoperative pathology. All patients with preoperative MRI, Based on presence of structure change on magnetic resonance imaging (MRI), the cases were devided into MRI negative group and the positive groups and analyze its sensitivity and specificity of hippocampal sclerosis.Result71cases in this study,43cases were positive group, positive rate was60.56%(43/71), negative group28cases, negative rate was39.44%(28/71).28cases were done accurate locating in43cases of hippocampal sclerosis with positive performance, the accurate locating rate was65.12%(28/43).(Note: Accurate locating refers to the examination showed pathological changes of temporal lobe, hippocampus, namely single focus; Multiple focuses to the examination showed lesions range in addition to the temporal lobe and hippocampus, frontal, cap, pillow and other areas have positive changes)Conclusion There were certain value of MRI in the diagnosis of hippocampal sclerosis. It reliable to detecte the apparent hippocampal sclerosis with organization structure. But hippocampal sclerosis has only mild structure changes, the false negative rate is high, it was certain limit. To the epilepsy patients with hippocampal sclerosis lesions, MRI can accurately locate lesions range, its specificity is higher. Part2The value of18F-FDG PET/CT in the diagnosis of hippocampal sclerosisBackground and purpose60%～90%of temporal lobe epilepsy can be controlled or cured with surgery, particularly for hippocampal sclerosis caused by epilepsy, effectiveness can reach90%, and the key to obtain ideal effect of surgery depends on preoperative accurate localization of epileptogenic zone. Traditional positioning of epileptogenic zone according to clinical manifestations and rely mainly on examination of electroencephalogram (EEG) and magnetic resonance imaging (MRI). With the development of molecular imaging techniques, positron emission tomography/computed tomography(PET/CT) can image and do quantitative analysis of epileptogenic zone from anatomy, metabolism, blood perfusion, biochemical, function, oxygen consumption, chemical neurotransmitters and neural receptors, and improve the detection rate,which makes it possible to accurate positioning of function and structure,and its application is more and more clinical attention. In general, in seizures, brain metabolism and cerebral blood flow were significantly increased,18F-FDG PET was Characterized by regional cerebral with high metabolism,and while in interphase, brain metabolism and cerebral blood flow decreases, PET was Characterized by regional cerebral with low metabolism. To explore qualitative, positioning diagnostic value of hippocampal sclerosis of18F-FDG PET/CT,this topic performed analysis on patients with F-FDG PET/CT performance of hippocampal sclerosis preoperatively.Materials and methodsThe datas collected from clinical department of neurosurgery, zhujiang hospital, southern medical university hospital from January2010to December2011, the patients was diagnosed as temporal lobe epilepsy (TLE) cases, After comprehensive evaluation, we did surgical treatment for71patients, which were diagnosed as hippocampal sclerosis postoperative pathology. All patients with preoperative18F-FDG PET/CT, Based on presence of structure change on18F-FDG PET/CT, the cases were devided into F-FDG PET/CT negative group and the positive groups and analyze its sensitivity and specificity of hippocampal sclerosis.Result71cases in this study,61cases were positive group, positive rate was85.92%(61/71), negative group10cases, negative rate was14.08%(10/71).24cases were done accurate locating in61cases of hippocampal sclerosis with positive performance, the accurate locating rate was39.34%(24/61).(Note: Accurate locating refers to the examination showed pathological changes of temporal lobe, hippocampus, namely single focus; Multiple focuses to the examination showed lesions range in addition to the temporal lobe and hippocampus, frontal, cap, pillow and other areas have positive changes)Conclusion18F-FDG PET/CT has high value to the diagnosis of hippocampal sclerosis, and with high sensitivity, but for larger lesions of people with epilepsy,18F-FDG PET/CT can not accurate locating, and has certain limitations because of its poor specificity. Part3The value of MRI and18F-FDG PET/CT in the diagnosis of hippocampal sclerosisBackground and purposeEpilepsy is a chronic nervous system diseases caused by multiple causes, treatment-resistant epilepsy accounted for about20%of the total people with epilepsy, and temporal lobe epilepsy accounts for a large proportion. Surgery was widely used in clinic because it has obvious control effect to epileptic seizures or cure rate. And accurate preoperative localization is the basis of trying to maximize surgical curative effect and minimize complications after the operation. The main pathological changes of temporal lobe epilepsy was hippocampal sclerosis, and the main characterized by lossing of neurons and glial cells proliferation. So accurate diagnosis of hippocampal sclerosis in temporal lobe epilepsy plays a vital role in surgery. The diagnosis of hippocampal sclerosis relies mainly on symptoms, history, EEG, magnetic resonance imaging (MRI, MRS), nuclear medicine (PET/CT, SPECT) Currently.Materials and methodsThe datas collected from clinical department of neurosurgery, zhujiang hospital, southern medical university hospital from January2010to December2011, the patients was diagnosed as temporal lobe epilepsy (TLE) cases, After comprehensive evaluation, we did surgical treatment for71patients, which were diagnosed as hippocampal sclerosis postoperative pathology. All patients with preoperative MRI and18F-FDG PET/CT, Based on the changes, compare their sensitivity and specificity of hippocampal sclerosis. According to SPSS13.0statistical software, use x2test and consistency test analyse the sensitivity and specificity of MRI and18F-FDG PET/CT to hippocampal sclerosis.ResultIn this study, MRI of hippocampal sclerosis has positive performance in43cases (43/71,60.56%), accurate locating in28cases (28/43,65.12%),18F-FDG PET/CT of hippocampal sclerosis has positive in61cases(61/71,85.92%), accurate locating in24cases (24/61,39.34%). The positive rate of18F-FDG PET/CT of hippocampal sclerosis was higher than that of MRI, But accurate locating rate was lower than that of MRI, with the difference was statistically significant (chi-square=4.68, P=0.031.)(Note: Accurate locating refers to the examination showed pathological changes of temporal lobe, hippocampus, namely single focus; Multiple focuses to the examination showed lesions range in addition to the temporal lobe and hippocampus, frontal, cap, pillow and other areas have positive changes)ConclusionThis study found that, The positive rate of18F-FDG PET/CT of hippocampal sclerosis was higher than that of MRI and with higher the sensitivity(P<0.05), while the accurate locating rate of MRI is higher than that of18F-FDG PET/CT and with higher specificity.