Gonçalves-Pereira P M, Oliveira E, Insausti R
Departamento de Imaginología, Hospital de Pedro Hispano, Matosinhos, Portugal.
Rev Neurol. 2006;42(12):713-22.
Atrophy of the hippocampus, amygdala and entorhinal cortex can be found in neurodegenerative diseases, head trauma and epilepsy and are expressed by means of volume reductions. The ability to detect these changes quantitatively depends on accurate comparisons with normative databases.
To present standard magnetic resonance imaging (MRI) volumes of the mesio-temporal lobe structures and an objective statistical methodology for contrasting pathological states.
Volumes of the right and left hippocampi, amygdalae and entorhinal cortex were measured from MRI in 34 right-handed healthy volunteers, aged 19-52 years. Data were normalized for the individual variation in total intracranial volume. Reproducibility was confirmed by intra/inter-observer tests. The statistical analyses included asymmetry comparisons, correlations between volumes and tests to assess the influence of age, gender and general morphometry (body mass index and height). For each volume, we further defined a normative interval by means of 99% confidence ellipses, accordingly to Hotteling's method.
Right-left asymmetry in the volumes of the hippocampus and entorhinal cortex was a normal finding. Structures located in the right hemisphere were larger than the left by a small but statistically significant amount. No asymmetry was found in the amygdala. There was no correlation in-between these volumes. Gender differences were exclusively noted in the absolute amygdala volumes (male > female) but were eliminated by the normalization procedure. No effect of age or morphometry was seen in the absolute or normalized volumes (except for a milder correlation between hippocampal volumes and height). Confidence ellipses were built for every structure and provided a precise reading of the data. Particularly, it allowed for a clear distinction of pathological asymmetries and bilateral cases.
These normative volumes serve as a reference for the assessment of pathologic groups within similar age-range. The use of a single graphic representation simplifies the clinical interpretation and enhances the precision of the results.
海马体、杏仁核和内嗅皮质萎缩在神经退行性疾病、头部创伤和癫痫中均可发现，且通过体积缩小表现出来。定量检测这些变化的能力取决于与标准数据库的准确比较。
呈现内侧颞叶结构的标准磁共振成像（MRI）体积，并提供一种用于对比病理状态的客观统计方法。
对34名年龄在19至52岁之间的右利手健康志愿者进行MRI扫描，测量其左右海马体、杏仁核和内嗅皮质的体积。数据针对颅内总体积的个体差异进行了标准化处理。通过观察者内/间测试确认了可重复性。统计分析包括不对称性比较、体积之间的相关性以及评估年龄、性别和一般形态学（体重指数和身高）影响的测试。对于每个体积，我们根据霍特林方法通过99%置信椭圆进一步定义了一个标准区间。
海马体和内嗅皮质体积的左右不对称是正常现象。位于右半球的结构比左半球稍大，但具有统计学意义。杏仁核未发现不对称性。这些体积之间没有相关性。仅在杏仁核绝对体积上发现了性别差异（男性>女性），但通过标准化程序消除了这种差异。在绝对或标准化体积中未观察到年龄或形态学的影响（除了海马体体积与身高之间存在较弱的相关性）。为每个结构构建了置信椭圆，并提供了对数据的精确解读。特别是，它能够清晰地区分病理性不对称和双侧病例。
这些标准体积可作为评估相似年龄范围内病理组的参考。使用单一图形表示简化了临床解释并提高了结果的准确性。
