Woermann F G, Barker G J, Birnie K D, Meencke H J, Duncan J S
The MRI Unit, Institute of Neurology and National Society for Epilepsy, Chelfont St Peter, Bucks, UK.
J Neurol Neurosurg Psychiatry. 1998 Nov;65(5):656-64. doi: 10.1136/jnnp.65.5.656.
The principal MRI features of hippocampal sclerosis are volume loss and increased T2 weighted signal intensity. Minor and localised abnormalities may be overlooked without careful quantitation. Hippocampal T2 relaxation time (HT2) can be quantified, but previously has only been measured on a few thick coronal slices with interslice gaps. In this study HT2 was measured along the entire length of the hippocampus on contiguous slices and used, with quantitative measures of hippocampal volume (HV) and distribution of atrophy, to better define the range of hippocampal sclerosis.
Thirty patients with temporal lobe epilepsy, 10 patients with extratemporal localisation related epilepsy and extratemporal lesions, and 20 control subjects were studied using MRI T2 relaxometry and volumetry.
In controls and patients, HT2 was higher in the anterior than the posterior hippocampus. Using HV, morphometric, and HT2 data, patients with temporal lobe epilepsy were classified as unilateral diffuse hippocampal sclerosis (n=16), unilateral focal (n=6), bilaterally affected (n=6), and normal (n=2). In patients with unilateral hippocampal sclerosis, the anterior hippocampus was always affected. In three patients with normal HV, HT2 measurements disclosed unilateral focal abnormalities that corresponded to the EEG lateralisation of epileptic activity. Patients with bilateral hippocampal involvement had an earlier onset of epilepsy than patients with unilateral hippocampal sclerosis.
Measurement of regional abnormalities of HT2 along the length of the hippocampus provides further refinement to the MRI assessment of the hippocampi in patients with temporal lobe epilepsy and is complementary to volumetric and morphological data.
海马硬化的主要磁共振成像（MRI）特征是体积缩小和T2加权信号强度增加。若不进行仔细定量分析，轻微和局部的异常可能会被忽视。海马T2弛豫时间（HT2）可以定量，但此前仅在少数有层间距的厚冠状切片上进行测量。在本研究中，我们在连续切片上沿海马全长测量HT2，并结合海马体积（HV）的定量测量和萎缩分布情况，以更好地界定海马硬化的范围。
对30例颞叶癫痫患者、10例颞外定位相关癫痫及颞外病变患者和20名对照者进行了MRI T2弛豫测量和容积测量研究。
在对照者和患者中，海马前部的HT2高于后部。利用HV、形态计量学和HT2数据，将颞叶癫痫患者分为单侧弥漫性海马硬化（n = 16）、单侧局灶性（n = 6）、双侧受累（n = 6）和正常（n = 2）四类。在单侧海马硬化患者中，海马前部总是受累。在3例HV正常的患者中，HT2测量显示出与癫痫活动脑电图侧化相对应的单侧局灶性异常。双侧海马受累的患者癫痫发作起始时间比单侧海马硬化患者更早。
沿海马长度测量HT2的区域异常，为颞叶癫痫患者海马的MRI评估提供了进一步的细化，并且是对容积和形态学数据的补充。
