Farhataziz Nabeel, Engels Jennifer E, Ramus Ronald M, Zaretsky Michael, Twickler Diane M
Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-8896, USA.
AJR Am J Roentgenol. 2005 Jun;184(6):1891-7. doi: 10.2214/ajr.184.6.01841891.
The purpose of our study was to assess the appearance of the colon and genitourinary tract in fetuses with respect to gestational age with T1- and T2-weighted MRI acquisitions and their applications to abnormalities in these systems.
Retrospective review of the fetal MRI database was performed to select studies in which both T1- and T2-weighted acquisitions were obtained. The signal characteristics of fluid in the fetal colon and urine in the fetal bladder were evaluated, and gestational age and fetal MRI diagnosis were recorded. A Mantel-Haenszel chi-square analysis was performed to evaluate the relationship of gestational age to MRI signal intensity. In fetuses with suspected colonic and genitourinary abnormalities, an assessment was made about whether the T1-weighted findings added information to the T2-weighted findings.
Eighty fetal MRI studies were reviewed. Forty-three studies showed normal findings, and 37 depicted genitourinary or gastrointestinal abnormalities. The mean gestational age was 27 weeks 6 days. The MRI signal characteristics of urine and meconium became significantly more conspicuous with increasing gestational age (urine bright on T2, p < 0.001; urine dark on T1, p < 0.001; meconium bright on T1, p < 0.001; meconium dark on T2, p < 0.001). Of the 37 cases with suspected problems of the gastrointestinal or genitourinary systems, the T1-weighted images added additional information in 23 cases.
The appearance of urine and meconium on T1- and T2-weighted images is significantly more apparent with increasing gestational age. T1-weighted images identified meconium in the colon beyond 24 weeks' gestation and aided in the diagnosis of complex abnormalities.
我们研究的目的是通过T1加权和T2加权磁共振成像（MRI）采集来评估不同孕周胎儿的结肠和泌尿生殖道表现，以及这些成像在这些系统异常情况中的应用。
对胎儿MRI数据库进行回顾性分析，以选择同时获得T1加权和T2加权图像的研究。评估胎儿结肠内液体及膀胱内尿液的信号特征，并记录孕周和胎儿MRI诊断结果。采用Mantel-Haenszel卡方分析评估孕周与MRI信号强度之间的关系。对于怀疑有结肠和泌尿生殖道异常的胎儿，评估T1加权图像结果是否能为T2加权图像结果提供更多信息。
共回顾了80例胎儿MRI研究。43例显示正常结果，37例显示泌尿生殖道或胃肠道异常。平均孕周为27周6天。随着孕周增加，尿液和胎粪的MRI信号特征变得更加明显（尿液在T2加权像上呈高信号，p<0.001；尿液在T1加权像上呈低信号，p<0.001；胎粪在T1加权像上呈高信号，p<0.001；胎粪在T2加权像上呈低信号，p<0.001）。在37例怀疑有胃肠道或泌尿生殖系统问题的病例中，T1加权图像在23例中提供了额外信息。
随着孕周增加，尿液和胎粪在T1加权和T2加权图像上的表现明显更清晰。T1加权图像可识别妊娠24周后结肠内的胎粪，并有助于复杂异常情况的诊断。
