胎儿胸腺二维三径线预测胸腺体积的模型研究  

Study on the Model to Predict Thymus Volume with Two-dimensional Section Diameters among Fetuses

作　　者：康敏[1] 齐亚娜[2,3] 邵剑波[4] 马慧静[4] 郑楠楠[4] 

机构地区：[1]四川省妇女儿童医院放射科,成都610042 [2]四川大学华西公共卫生学院 [3]四川大学华西医院毕业后培训部 [4]武汉市妇女儿童医疗保健中心

出　　处：《华西医学》2016年第1期94-97,共4页West China Medical Journal

摘　　要：目的研究胎儿胸腺二维三径线为参考指标的胸腺体积预测模型。方法 2010年9月-2012年3月,对产前超声检查怀疑畸形的210例单胎孕妇行胎儿MRI检查,测量胎儿胸腺二维三径线并计算体积。以未见异常胎儿为标准,计算出不同孕周胎儿胸腺体积的理论正常值,经配对t检验比较胎儿胸腺体积与其理论正常值的差异,分成胸腺正常组和胸腺发育不良组以分别建立胸腺体积的预测模型。以胸腺上下径(d1)、前后径(d2)、左右径(d3)为自变量,胸腺体积自然对数值(ln V)为因变量建立线性回归模型。依据模型计算胸腺体积(ln V)预测值并计算误差率,误差率=(预测值-实际值)/实际值×100%,计算误差率绝对值与胎儿孕周的Pearson相关系数。结果胸腺体积预测模型:胸腺正常组ln V=0.016 d1+0.030 d2+0.086 d3+5.707+ε(R2=0.510),胸腺发育不良组ln V=0.048 d1+0.036 d2+0.016 d3+6.011+ε(R2=0.447)。模型预测误差率绝对值平均4.34%和5.34%(均接近5%),并随胎儿孕周增加而减小(胸腺正常组r=-0.264,P=0.007;胸腺发育不良组r=-0.182,P=0.060)。结论该模型预测效果欠佳,模型准确度随胎儿孕周增加有升高趋势,后期应开展大样本量研究建立正常胎儿不同孕周的胸腺体积预测模型。该建模思路具有一定的实用性和临床价值,可尝试应用于超声技术中。Objective To study the model to predict thymus volume with two-dimensional section diameters among fetuses.Methods From September 2010 to March 2012,210 singleton pregnant women suspected with fetal abnormality by prenatal ultrasonic testing were confirmed using MRI technology.Three two-dimensional section diameters of thymus were measured and the volume was calculated.No abnormal fetuses regarded as the standard,theoretical normal volume of fetal thymus was calculated.Paired t-test was used to compare the actual thymus volume with its corresponding theoretical normal value,and thus the fetuses were divided into two groups of normal and dysplasia so as to establish predictive model respectively.With two-dimensional section diameters as independent variables and thymus volume as dependent variable,the linear regression model was established.According to the model,the thymus volume was predicted and the error rate was calculated by formula：error rate=（predicted value-actual value） /actual valuex 100%.The Pearson correlation coefficient of error rate and fetal gestational age was calculated.Results The models of normal and dysplasia groups to predict thymus volume were In V= 0.016 d1 ＋ 0.030 d2 ＋ 0.086 d3 ＋ 5.707 ＋ε（R-2 = 0.510）and lnV= 0.048 d1 ＋ 0.036 d2 ＋ 0.016 d3 ＋ 6.011 ＋ε（R-2 = 0.447）.The average absolute values of predicted error rate were 4.34%and 5.34%and decreased with fetal gestational age（normal r=- 0.264,P= 0.007;dysplasia r=- 0.182,P= 0.060）.Conclusions The prediction effects of above models are not so good and the model accuracy increases with fetal gestational age.Normal fetuses＇ model of different gestational age should be established to predict thymus volume by conducting large sample size study in the future.The modeling approach has certain practicability and clinical value and can be applied in ultrasonic technique.

关 键 词：胎儿胸腺 体积 模型 磁共振成像 

分 类 号：R714.5[医药卫生—妇产科学] R445.2[医药卫生—临床医学]