Contribution of MRI to ultrasound in the diagnosis of fetal anomalies

Abstract

Purpose: To evaluate the contribution of MRI to ultrasound (US) in the diagnosis of fetal anomalies. Materials and Methods:After informed consent and institutional review board approval, concomitant US and MR imaging were performed for 184 fetuses with suspected anomalies in university hospital. Postnatal final diagnoses were obtained for 183 anomalies in 151 fetuses either by radiological examination, surgery, autopsy, or inspection. The prenatal US and MR diagnoses were compared with respect to postnatal diagnoses. Sign test was used to determine the statistical significance.Results: Both ultrasound and MR imaging correctly diagnosed 93 (50%) cases and failed in 12 (7%) cases. Ultrasound was superior in 7 (4%) cases. MR imaging was superior in 71 (39%) cases (P < 0.001). MR contributed to the prenatal diagnosis by the confirmation of the suspected US diagnosis in 13%, by demonstration of additional findings in 31% and by changing the diagnosis in 56% of the cases. The contribution rates were 55% for the central nervous system (CNS) (P < 0.001), 44% for thorax (P ¼ 0.016), 38% for gastrointestinal system (GIS) (P ¼ 0.031) and 29% for genitourinary system (GUS) (P ¼ 0.003) anomalies. In facial, cardiac and extremity-skeletal system anomalies, there was not a significant contribution of MR imaging over US.Conclusion: MR imaging can be used as an adjunct to US in the prenatal diagnosis of fetal anomalies of not only the CNS but also the non-CNS origin especially those involving the GIS, GUS and thorax. ULTRASOUND (US) IS the standard and primary modality used for the imaging of the fetus. It is widely available, easy to apply, cost-effective, safe for the fetus and allows real-time imaging. However, it has some limitations. Especially in case of oligohydramnios, large maternal body habitus and inappropriate fetal position, its effectiveness reduces. Also in the evaluation of some body parts and complex pathologies, the results of US might be unclear (1,2). In such cases, MR imaging is being increasingly used as a complementary imaging modality.Magnetic resonance imaging has the potential to improve diagnostic accuracy of the prenatal imaging and facilitate the pregnancy management (3-5). It offers a high spatial, temporal, and contrast resolution, which makes the detailed study of fetal pathologies possible. To date, it has not been shown that MR imaging has any adverse effects on the fetal growth or development (2,6).Multiple studies have up to now been published to compare the effectiveness of the prenatal US and MR imaging. These studies showed that MR imaging provides additional information to US in 36% to 57% of the cases (3,4,7,8). Although this effect has been well-established for CNS anomalies, it has not been well-documented for non-CNS anomalies. Additionally, there were some important limitations of these previous studies. In most of these studies, the comparison of the imaging methods had been made without postnatal correlation and MR results had been accepted as the gold-standard. Secondarily, in most...

Prenatal Diagnosis of Clubfoot: A Review of Current Available Methodology

“…For these reasons, magnetic resonance imaging (MRI) examination has been proposed by some authors. 30,31 This procedure, without using ionizing radiation has been demonstrated to be safe for the foetus. Moreover it has excellent tissue contrast, exam results are not operator-dependent and it is not infl uenced by external factors such as obesity of the mother or oligohydramnios.…”

“…However, it is still unclear what effect MRI has on the developing foetus; for this reason, some authors argue that offering MRI as routine examination is not justifi ed. 13,30 Although idiopathic in the majority of cases, clubfoot could be sometimes associated with chromosomal abnormalities, genetic syndromes or other deformities. Historically, a sonographic diagnosis of clubfoot was considered an indication for amniocentesis, though recent studies have suggested karyotyping only if associated anomalies on the sonographic survey are presents.…”

Fetal magnetic resonance imaging and ultrasound

“…These studies were, however, criticized for their inherent biases, such as their retrospective nature, skill of ultrasound examiners, and time lapse between ultrasound and MRI that may allow for some in utero evolution of the lesions. Prospective studies were designed to overcome these limitations, and the results still suggested that MRI can provide additional information that lead to changes in clinical management for fetuses with either intra or extracranial anomalies [23,24]. Obstetric conditions where MRI may provide additional information of clinical significance are summarized in Table 2.…”

“…There were 44% ultrasound and 25% MRI examinations disagreement with postnatal diagnosis [27]. The MRI can either reverse the diagnosis or discover additional CNS findings in up to 55% of fetuses with borderline ventriculomegaly [24]. Figure 1 shows the difference in visual inspection of fetal brain from an ultrasound and MR image.…”

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“…Im Schädelbereich hat sich die fetale MRTDiagnostik als Ergänzung fest etabliert [3]. Bei be- ren Anomalien ist die Datenlage noch zu unsicher und kasuistisch, um über den diagnostischen Mehrgewinn des MRT eine Aussage treffen zu können [4].…”