Antenatal hydronephrosis: negative predictive value of normal postnatal ultrasound--a 5-year study

AIM: To determine whether normal postnatal ultrasound, as part of a strict screening protocol for the detection and follow-up of antenatal hydronephrosis, effectively excludes the majority of babies with congenital urinary tract abnormalities that would otherwise present with a urinary tract infection. MATERIALS AND METHODS: We retrospectively reviewed all babies who had postnatal follow-up of antenatally detected hydronephrosis over a 5-year period at our institution, a district general Trust with a specialist paediatric unit. We then studied all babies presenting with urinary tract infection before their first birthday to our institution over the same period. By cross-referencing these two study groups we were able to determine which babies developed a urinary tract infection having been previously discharged after normal postnatal ultrasound. RESULTS: Four hundred and twenty-five babies had postnatal follow-up of antenatal hydronephrosis. Of these, 284 were investigated with ultrasound alone. In the same 5-year period, 230 babies presented with urinary tract infection before their first birthday. Only three of these babies had been previously discharged after normal postnatal ultrasound. The negative predictive value of a normal postnatal ultrasound was therefore 98.9% (281/284) for babies who subsequently presented with a urinary tract infection before their first birthday. CONCLUSION: Careful antenatal and postnatal ultrasound with strict protocols is effective in detecting congenital renal tract abnormalities. Infants discharged after normal postnatal ultrasound are highly unlikely to still have an undetected urinary tract abnormality. We suggest that all babies with antenatal hydronephrosis are started on prophylactic antibiotics at birth, pending further investigation. All babies without features of severe obstruction antenatally should have their postnatal ultrasound delayed for a month. We recommend selective use of micturating cystourethrogram (MCUG), and delaying this investigation until the baby is 3 to 4 months old to allow for spontaneous resolution of vesicoureteric reflux. We do not believe that all babies with antenatal hydronephrosis require MCUG, providing a clear protocol is followed.     

胎儿畸形产前超声筛查在基层医院开展的可行性研究

目的按照产前超声检查技术规范的标准,探讨基层医院胎儿畸形产前超声筛查可行性及其意义。方法收集2004年3月至2009年4月,10 630例孕妇接受胎儿畸形产前超声检查资料,以产后最终诊断为标准,评估产前超声诊断的价值。结果超声诊断胎儿先天性畸形共266例,畸形的发生率约为2.50%(266/10 630),畸形检出率88.96%(266/299),单发畸形228例,复合畸形38例;漏诊33例,其中小畸形和复杂畸形漏诊29例。结论基层医院在严格执行产前超声筛查技术规程同时,加强自身技术和服务能力,能有效地降低畸形儿的出生率及漏诊率。     

超声筛查胎儿心脏畸形

目的: 探讨超声筛查胎儿先天性心脏畸形的可行性及应用价值.材料和方法: 对5000例产前超声检查者常规观察胎儿心脏四个切面,即四腔心、左室流出道、右室流出道、三血管平面,疑有异常者行超声心动图检查.结果: 超声检查发现25例先天性心脏畸形,其中22例引产尸解证实,3例出生后超声心动图复查证实.漏诊室间隔缺损3例,房间隔缺损3例.结论: 胎儿心脏四个切面筛查能发现绝大部分先天性心脏畸形,包括大血管畸形,但易漏诊小的室间隔缺损及房间隔缺损.     

Prenatal diagnosis and postnatal management of congenital unilateral hydrocephalus for stenosis of the foramen of Monro

Congenital hydrocephalus and ventriculomegaly can be diagnosed reliably with prenatal ultrasound and Magnetic Resonance Imaging (MRI). Unilateral hydrocephalus is uncommon, and the prognosis depends on etiology and postnatal management. Here, we present a case of a 32-years-old woman with prenatal diagnosis of unilateral hydrocephalus associated with stenosis of the foramen of Monro. Unilateral hydrocephalus is an uncommon feature that can be detected prenatally on ultrasound and MRI. In case of isolated stenosis of the foramen of Monro prognosis is good.     

Pre and postnatal diagnosis of fetus-in-fetu

Differentiation of abdominal masses detected on prenatal ultrasound is difficult and requires careful characterization of the mass and precise localization. Differentiation is required in order to distinguish benign from potentially malignant conditions. We describe a case of fetus-in-fetu with pre- and postnatal imaging.     

Foetal cystic abdominal masses

Foetal abdominal cysts are frequently found on routine antenatal ultrasound. Various sonographic features might help in their differential diagnosis. However, a definitive diagnosis is often not made until postnatal life, and detection of an intra-abdominal cyst antenatally rarely alters obstetric management. A review of possible causes of a foetal abdominal cyst is presented.     

Congenital lobar emphysema: antenatal diagnosis and follow up

The case of an echogenic mass in the right lung that apparently resolved spontaneously prior to delivery is reported here. Postnatal investigations revealed congenital lobar emphysema. To the knowledge of the authors, this is the first reported case of spontaneous, apparently complete resolution of an echogenic lung mass on antenatal ultrasound due to lobar emphysema. The routine use of ultrasound to screen for foetal anomalies has led to the discovery of a number of incidental findings, such as an echogenic foetal lung mass, that pose a challenge to diagnosis and management. The importance of appropriate counselling and postnatal follow-up are highlighted.     

超声联合MRI在胎儿胸部异常诊断中的应用

目的 对比分析产前超声和MRI在胎儿胸部发育异常中的诊断价值及各自的优、劣势,并初步探讨两者联合应用在胎儿胸部异常中的临床价值.方法 回顾性分析胸部异常胎儿的产前超声和MRI图像,94例产前超声诊断胸部异常的胎儿,征其家属同意后,于检查后1 d或2 d内行MRI检查.所有病例均经产后尸检或生后随访证实.结果 94例胸部异常包括先天性肺囊腺瘤48例,隔离肺33例,膈疝10例,原发性肺发育不良3例.超声正确诊断78例,诊断符合率约82.98%;超声联合MRI正确诊断88例,诊断符合率约93.62%.超声联合MRI诊断胎儿胸腔病变与单一超声相比差异有统计学意义(P<0.05).结论 超声和MRI均能较好地诊断胎儿胸部异常,但其各有优、劣势.两者联合应用能够提高产前诊断敏感性和准确性,在诊断胎儿胸部发育异常方面更具优势.     

A 5-year audit of 778 neonatal renal scans (Part 2). Miscellaneous anomalies in 59 infants: a pictorial presentation

In this 5-year review of 778 neonatal renal scans seen in an obstetric hospital, Mercy Hospital for Women, Melbourne, most infants were referred because of antenatal ultrasound findings. Ninety-two percent of these had fetal pyelectasis. The results were classified on the ultrasound findings. The majority of neonates (76%) had a normal postnatal scan. A number had vesicoureteric reflux found on micturating cystourethrogram. Persisting mild/moderate pyelectasis or hydronephrosis (15%) proved to be a normal variant in many infants, but had a similar appearance to those with an early obstructive cause (1%). There were 59 infants (8%) with a miscellaneous group of renal anomalies, many with a characteristic antenatal ultrasound appearance suggesting the diagnosis. Review of these 59 infants illustrates the anomalies seen and reports the associated investigations and subsequent outcome in most cases.     

节段分析法在产前超声诊断大动脉位置异常中的作用

目的探讨节段分析法在诊断胎儿大动脉位置异常中的作用。资料和方法根据节段分析法的原理将胎儿心脏分成心房、心室、大动脉三节段进行分析,在此基础上观察心房与心室、心室与大动脉的连接关系,为7例可疑大动脉位置异常的胎儿进行心脏检查。结果 7例胎儿心脏大动脉位置异常均经上级医院引产或产后超声心动图证实。结论节段分析法可提高超声诊断胎儿大动脉位置异常的准确性,对孕妇产前做出选择有重要指导意义。     

Postnatal evaluation and management of fetal pyelectasis on prenatal ultrasound

Fetal pyelectasis is the most frequently encountered anomaly on prenatal ultrasound. The ultrasound diagnostic criteria are well established: nature of dilated structures, degree of dilatation, ultrasound appearance of the kidneys, volume of amniotic fluid. Ultrasound can also determine if the anomaly is isolated or not, which is important for the management and prognosis of the pregnancy. Ultrasound is the initial postnatal study to evaluate the urinary tract. Further management will be based on suspected diagnosis. In cases of suspected vesico-ureteral reflux, VCUG is performed. In cases of obstructive uropathy or complex malformation (duplications), MRI is performed at 6 months of age to further define the anatomy of the urinary tract. Radionuclide renogram, performed in most cases, allows evaluation of split renal function. Follow-up ultrasound is important to monitor renal development, urinary tract dilatation and appearance of the renal parenchyma. Functional follow-up is assured by radionucline renography. This comprehensive follow-up is recommended to prevent complications and progressive loss of renal function.     

MRI在胎儿中枢神经系统中的临床应用

目的探讨MRI在胎儿中枢神经系统发育异常中的应用价值。方法24例孕妇，年龄25～34岁，平均28岁；孕龄20～39周，平均30周。产前例行超声检查后24h内行MR检查，T2WI采用半傅立叶单激励快速自旋回波(HASTE)快速扫描序列，T1WI采用二维快速小角度激励(FLASH)序列。将超声、MRI结果与出生后或引产后随访结果对照。结果24例孕妇共检出胎儿24个。MR T2WI可清楚、直观地显示出大脑实质、脑回、脑沟裂、胼胝体、丘脑、小脑、脑干及脊髓等解剖结构，T1WI质量差于T2WI。超声共显示病灶27个，MRI显示31个。MRI证实超声怀疑的诊断2例，进一步完善诊断10例，与超声诊断一致12例。结论MRI对胎儿中枢神经系统解剖结构的显示优于超声，而且不受孕妇体型、羊水量多少、胎儿颅骨及母体骨盆骨骼影响。在超声检查基础上进行胎儿MR检查，有助于弥补超声的不足，甚至更正超声诊断，可作为产前胎儿检查的辅助措施。     

Biological effects of long-duration, high-field (4 T) MRI on growth and development in the mouse

The effects of long-duration, high-field magnetic resonance imaging (MRI) on fetal growth and postnatal development in mice were studied. Seven experimental groups of pregnant ICR mice were exposed for 9 hours on day 9 and/or day 12 post coitus (pc) to magnetic fields (4 T static, 5 T/sec switched gradient, and 0.2 W/kg radiofrequency at 170 MHz) associated with MRI conditions. Two experimental groups (sham and exposure groups) were exposed to a combination of ultrasound (day 9 pc, 3.25 MHz, focused) and MRI-associated fields (day 12 pc). No statistically significant changes in fetal growth were observed in the animals exposed to only MRI or ultrasound fields. However, in the combined ultrasound and MRI-exposed group, the fetal weight and crown-rump length were reduced compared with the sham and cage controls. These results suggest that MRI and ultrasound exposure well in excess of current clinical conditions can exert biological effects if applied at sensitive stages of fetal development.     

The Fetal Imaging Workstation Demonstration Project

Congenital birth defects are a leading cause of infant mortality. Early detection of fetal anomalies by prenatal ultrasound may improve clinical outcome in selected cases. However, many training programs are hindered by curriculum weaknesses which include: (1) limited physician exposure to ultrasound anomalies; (2) inadequate postnatal correlation with prenatal findings; (3) constraints imposed by static images for ultrasound training; and (4) difficulty with understanding complex three-dimensional anatomy. The Fetal Imaging Workstation Demonstration Project addresses these problems by illustrating how computers can supplement traditional prenatal ultrasound training through interactive multimedia. The project uses a laserdisc library of ultrasound video images as source material for a variety of interactive software tutorials. An educational testing module has been developed that can evaluate diagnostic skills through simulated ultrasound studies provided by the laserdisc library. An interactive three-dimensional fetal heart model also provides a new way for physicians to better understand their two-dimensional ultrasound studies. A survey suggests that this prototype has been widely accepted by housestaff physicians and that there is a perceived need for this supplementary training. Future work will address the educational effectiveness of these materials and will consider cost-effective ways to disseminate the software for other institutions. However, future development must be implemented against a background of rapidly emerging technologies involving faster computers, digital video, and virtual reality applications.     

Evolution of fetal ultrasonography

The authors wish to highlight the evolution that has occurred in fetal ultrasound in recent years. A first significant evolution lies in the increasing contribution of first trimester ultrasound for the detection of fetal anomalies. Malformations of several organs and systems have been diagnosed during the first trimester. Furthermore the systematic measurement of the fetal neck translucency has led to increasing rate of detection of aneuploidies and heart malformations. For several years now, three-dimensional (3D) and 4D ultrasound (US) have been used as a complementary tool to 2D US for the evaluation of fetal morphology. This brings an improved morphologic assessment of the fetus. Applications of the techniques are increasing, especially for the fetal face, heart and extremities. The third field where fetal US is continuously providing important information is the knowledge of the natural history of diseases. This has brought significant improvement in the postnatal management of several diseases, especially urinary tract dilatation and broncho-pulmonary malformation.     

胎儿后颅窝区畸形的MRI研究

胎儿后颅窝区结构发育情况是常规产前检查的重要内容，产前的准确诊断是产后干预及治疗的关键。MRI较超声可以更全面、直观地显示后颅窝区形态特征及细微结构，通过信号强度的差异辨别病灶的性质，并且能够进一步完善甚至更正超声的诊断。目前MRI已成为产前监测胎儿后颅窝区结构发育情况的主要手段，特别是三维MRI重组、扩散张量成像、扩散张量纤维束成像、磁共振波谱成像皆可提供更丰富的胎儿后颅窝区结构信息。就MRI对胎儿后颅窝区畸形产前诊断的应用予以综述。     

Fetal chest ultrasound and magnetic resonance imaging: recent advances and current clinical applications

Advances in high-resolution prenatal ultrasound and fetal magnetic resonance (MR) imaging have changed the practice of obstetrics by allowing better visualization of intrathoracic and neck structures and better estimation of lung volumes. More accurate prenatal diagnosis has increased options for pregnancy management and treatment, delivery planning, and postnatal care. Anyone who is interested in the fascinating field of fetology should become familiar with the current state of fetal imaging of the chest as well as potential advances in technology and research.     

A 5-year audit of 778 neonatal renal scans (Part 1): perplexing pyelectasis and suggested protocol for investigation

In this 5-year review of 778 neonatal renal scans seen in an Obstetric Hospital, most infants were referred because of antenatal ultrasound findings, 92% with fetal pyelectasis. The results were classified according to the ultrasound findings. The majority of neonates (76%) had a normal postnatal scan. A number had vesicoureteric reflux (VUR) found on a micturating cystourethrogram. Persistant mild to moderate pyelectasis or hydronephrosis (15%) proved to be a normal variant in many infants, but had a similar appearance to those with an early obstructive cause (1%). Pyelectasis has proved to be a poor predictor of VUR. A protocol outlining paediatric management for neonates with persisting pyelectasis is included. There were 59 infants (8%) with a miscellaneous group of renal anomalies, many with a characteristic antenatal ultrasound appearance suggesting the diagnosis. These infants have been separately reported and illustrated (Part 2). Overall, 13% of infants were found to have significant findings of obstruction, VUR or miscellaneous anomalies affecting management.     

Pre- to postnatal reduction in ultrasound attenuation coefficient of the liver

A recent study showed the ultrasound attenuation coefficient of fetal liver between 26 and 40 weeks of gestation to be 26% higher than after birth. To test the hypothesis that ultrasound attenuation is sensitive to fetal liver glycogen concentration, the livers of 24 fetuses were examined at 5 MHz just prior to and just after birth. The mean pre- to post-delivery reduction in attenuation coefficient was 0.08 dB cm-1 MHz-1 +/- 0.02 (SEM), or 17% of the post-delivery mean. This is consistent with the increase in attenuation measured by others in liver homogenate when glycogen was added. An increase in measurement accuracy, correlation with glycogen content, and, possibly, control for biological variability will be required to make predictions in individual cases, as opposed to these averages. A simple test of glycogen content would be of value scientifically and in prenatal and postnatal management.     

胎儿腹部MRI诊断进展

MRI技术用于腹部成像,有许多特殊序列可以帮助完善诊断,对于胃肠道梗阻、肝胆系统占位病变及泌尿系统异常的诊断均优于超声。随着胎儿腹部MRI诊断逐渐转向功能性研究,其在羊水偏少时更能发挥作用。MRI有望在未来用于评价胎儿腹部系统生理功能,对优生优育的作用更大。