Jordaan H V, Dunn L J
Obstet Gynecol. 1978 Jun;51(6):659-65.
When fetal brain weight (BrW) is expressed as a modified exponential function of total body weight (BW), there is close agreement (p = 0.9841) between measured and calculated values (Sy = 6.16 g). Fetal BrW in utero can be determined from the neurocranial cross-sectional area (CSA) of the fronto-parieto-occipital plane. The standard error of the estimate is Sy = 8.03 g. The estimation of BW from the abdominal circumference and BrW from the CSA is the basis of two indexes which reflect the BrW:BW relationship. By definition, the brain size index (BSI) is 100 in the normally growing fetus. In a given case, a value greater than 100 denotes the amount by which measured BrW exceeds the BrW which is appropriately for a normal fetus of the same BW. The somatic retardation index (SRI) expresses as a percentage the amount by which total fetal weight lags behind normal ponderal growth in cases of IUGR. The indexes provide quantitative data on relative brain and body weights and serve as a ratio scale of the severity of the pathology in IUGR.
当胎儿脑重（BrW）表示为总体重（BW）的修正指数函数时，测量值与计算值之间具有高度一致性（p = 0.9841）（Sy = 6.16 g）。子宫内胎儿的BrW可根据额顶枕平面的神经颅横截面积（CSA）来确定。估计的标准误差为Sy = 8.03 g。根据腹围估计BW以及根据CSA估计BrW是反映BrW:BW关系的两个指标的基础。根据定义，正常生长胎儿的脑大小指数（BSI）为100。在特定情况下，大于100的值表示测量的BrW超过相同BW的正常胎儿应有的BrW的量。躯体发育迟缓指数（SRI）以百分比表示在宫内生长受限（IUGR）情况下胎儿总体重落后于正常体重增长的量。这些指标提供了关于相对脑重和体重的定量数据，并作为IUGR中病理严重程度的比率尺度。
