癫痫病人MRI海马结构体积测定

Volume measurement of hippocampal formation using MRI in patients with epilepsy

目的测量正常成人及癫痫病人海马结构（ＨＦ）体积，探讨其在颞叶癫痫（ＴＬＥ）致痫灶定侧中的价值。材料与方法本组包括５２例正常成人及８９例癫痫病人，把病人分为三组：继发性癫痫４８例、特发颞叶外癫痫１５例、ＴＬＥ２６例，后者有２２例为顽固性癫痫。均作垂直于海马长轴的冠状位自旋回波（ＳＥ）序列Ｔ１加权像、ＴｕｒｂｏＳＥＴ２加权像，测量颞叶、ＨＦ体积和颞角、环池宽度，肉眼观察Ｔ２加权像海马信号强度改变。采用ＨＦ体积绝对值对ＴＬＥ定侧。结果获取了正常成人ＨＦ体积。２２例ＴＬＥＨＦ体积缩小，其中３例为双侧性；６例ＨＦ硬化经手术、病理证实，１例体积正常且致痫灶位于ＨＦ周围者ＨＦ硬化轻，８例其他类型癫痫病人ＨＦ体积略小，ＴＬＥ致痫灶定侧的敏感性为８５％，特异性为８７％。３例ＴＬＥ病人同侧前颞叶萎缩；部分ＴＬＥ病侧颞角、环池宽度增加；萎缩明显的ＨＦＴ２加权像信号弥漫性增高。结论ＨＦ体积缩小、Ｔ２加权像信号弥漫性增高是ＨＦ硬化萎缩的直接征象，与病变严重程度、致痫灶在颞叶的部位有关，前颞叶萎缩和颞角、环池增宽是ＨＦ硬化的辅助征象。ＨＦ萎缩不仅是颞叶癫痫的主要原因。

Purpose To measure the hippocampal volume in normal adults and patients with epilepsy, and discuss its value in lateralization of seizure focus in temporal lobe epilepsy(TLE). Materials and methods 52 normal adults and 89 epileptic patients were studied, the latter were subdivided into 3 groups: secondary epilepsy(48 cases), primary non temporal lobe epilepsy(15 cases), and TLE(26 cases),of which 22 were intractable epilepsy. The imaging protocal for volumetry of anterior temporal lobe (ATL) and hippocampus formation(HF), and measurement of the width of temporal horn and ambient cistern included SE T 1WI and Turbo SE T 2WI with the imaging plane perpendicular to the long axis of hippocampus. The signal intensity of hippocampus was investigated on the T 2WI. The lateralization of TLE was defined by absolute volume value of HF. Results The HF volume of normal adults was acquired.22 patients with TLE had volume loss of HF, 3 of them were bilateral, the hippocampal sclerosis(HS) in 6 cases was confirmed pathologically,1 patient with normal volume of HF had the seizure focus around HF and HS was mild. 8 with other kinds of epilepsy had slight volume loss of HF. The sensitivity of lateralization of TLE was 85%. The specificity was 87%. 3 with TLE had obviously atrophy of ipsilateral ATL. In some cases with TLE, the width of temporal horn and ambient cistern was enlarged. The atrophic hippocampus with significant volume loss presented diffuse increase in signal intensity on T 2WI. Conclusion The volume loss and diffuse increase of signal intensity on T 2WI of HF were direct findings of HS which was correlated with the degree of sclerosis and the position of seizure focus in temporal lobe. The widened temporal horn, ambient cistern and atrophic ATL were supplementary findings of HS. The authors considered that hippocampal atrophy was not only the main cause of TLE, but might also be the result of seizures of other kinds of epilepsy.