Barra Daniela de Abreu, Martins Wellington de Paula, Gallarretta Francisco Maximilliano, Nastri Carolina Oliveira, Nicolau Luis Guilherme, Mauad Filho Francisco
Departamento de Ginecologia e Obstetrícia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
Rev Bras Ginecol Obstet. 2008 Mar;30(3):142-8. doi: 10.1590/s0100-72032008005000004. Epub 2008 Feb 29.
to compare the intra and interobserver reproducibility of the total thickness measurement of the inferior uterine segment (IUS), through the abdominal route, and of the muscle layer measurement, through the vaginal route, using bi and tridimensional ultrasonography.
the IUS thickness measurement of 30 women, between the 36th and 39th weeks of gestation with previous caesarean section, done by two observers, was studied. Abdominal ultrasonography with the patient in both supine and lithotomy position was performed. In the sagittal section, the IUS was identified and four bidimensional images and two tridimensional blocks of the total thickness were collected through the abdominal route, and the same for the muscle layer, through the vaginal route. Tridimensional acquisitions were manipulated in the multiplanar mode. The time was measured with a chronometer. Reproducibility was evaluated by the computation of the absolute difference between measurements, the ratio of differences smaller than 1 mm, the intraclass coefficient (ICC), and the Bland and Altman's concordance limits.
the average bidimensional measurement of IUS thickness was 7.4 mm through the abdominal and 2.7 mm through the vaginal route, and the tridimensional measurement was 6.9 mm through the abdominal and 5.1 mm through the vaginal route. Intra- and interobserver reproducibility of vaginal versus abdominal route: smaller absolute difference (0.2-0.4 mm versus 0.8-1.5 mm), greater ratio of differences (85.8-97.8% versus 48.7-72,8%), with p<0,0001, higher ICC (0.8-0.9 versus 0.6-0.8) and lower concordance limits (-0.9 to 1.5 versus -3.8 to 4 mm) for the vaginal route. Tri versus bidimensional ultrasonography: lower absolute difference (0.2-1.4 versus 0.4-1.5 mm), higher ratio of differences (57.7-97.8% versus 48.7-91.7%) with p>0.05[A1] and similar lower concordance limits (-38 to 3.4 versus -3.6 to 4 mm) for tridimensional ultrasonography and ICC (0.6-0.9 versus 0.7-0.9).
from the above, we came to the conclusion that the measurement of the IUS muscle layer, through the vaginal route using tridimensional ultrasonography is more reproducible. Nevertheless, our results do not indicate that this measurement shows any clinical evidence to predict uterine tear, as that was not the aim of this study. The only work that has correlated the UIS thickness with risk of uterine tear, without interfering in the obstetrician behavior or anticipating delivery, was done by bidimensional abdominal measurements of the total thickness.
通过腹部途径比较子宫下段（IUS）总厚度测量以及通过阴道途径比较肌层测量的观察者内和观察者间的可重复性，采用二维和三维超声检查。
研究了30名既往有剖宫产史、孕周在36至39周之间的女性的IUS厚度测量情况，由两名观察者进行操作。让患者分别处于仰卧位和截石位进行腹部超声检查。在矢状切面中，识别出IUS，通过腹部途径采集4张二维图像和2个总厚度的三维数据块，通过阴道途径对肌层进行同样的操作。三维采集在多平面模式下进行。用秒表计时。通过计算测量值之间的绝对差值、小于1毫米的差值比例、组内相关系数（ICC）以及Bland和Altman一致性界限来评估可重复性。
IUS厚度的二维平均测量值通过腹部途径为7.4毫米，通过阴道途径为2.7毫米；三维测量值通过腹部途径为6.9毫米，通过阴道途径为5.1毫米。阴道途径与腹部途径的观察者内和观察者间可重复性比较：绝对差值更小（0.2 - 0.4毫米对0.8 - 1.5毫米），差值比例更大（85.8 - 97.8%对48.7 - 72.8%），p<0.0001，阴道途径的ICC更高（0.8 - 0.9对0.6 - 0.8），一致性界限更低（-0.9至1.5对-3.8至4毫米）。三维超声与二维超声比较：绝对差值更低（0.2 - 1.4对0.4 - 1.5毫米），差值比例更高（57.7 - 97.8%对48.7 - 91.7%），p>0.05，三维超声的一致性界限更低（-3.8至3.4对-3.6至4毫米）且ICC相似（0.6 - 0.9对0.7 - 0.9）。
综上所述，我们得出结论，通过阴道途径使用三维超声测量IUS肌层更具可重复性。然而，我们的结果并未表明该测量显示出任何预测子宫破裂的临床证据，因为这并非本研究的目的。唯一一项将子宫下段厚度与子宫破裂风险相关联且不干扰产科医生行为或提前分娩的研究是通过腹部二维测量总厚度完成的。
