Diagnostic accuracy of ultrasonography and magnetic resonance imaging for the detection of fetal anomalies: a blinded case-control study

Abstract

Objectives To compare the accuracy of two-dimensional ultrasound (2D-US), three-dimensional ultrasound (3D-US) and magnetic resonance imaging (MRI) for the diagnosis of congenital anomalies without prior knowledge of indications and previous imaging findings. Methods This was a prospective, blinded case–control study comprising women with a singleton pregnancy with fetal congenital abnormalities identified on clinical ultrasound and those with an uncomplicated pregnancy. All women volunteered to undergo 2D-US, 3D-US and MRI, which were performed at one institution. Different examiners at a collaborating institution performed image interpretation. Sensitivity and specificity of the three imaging methods were calculated for individual anomalies, based on postnatal imaging and/or autopsy as the definitive diagnosis. Diagnostic confidence was graded on a four-point Likert scale. Results A total of 157 singleton pregnancies were enrolled, however nine cases were excluded owing to incomplete outcome, resulting in 148 fetuses (58 cases and 90 controls) included in the final analysis. Among cases, 13 (22.4%) had central nervous system (CNS) anomalies, 40 (69.0%) had non-CNS anomalies and five (8.6%) had both CNS and non-CNS anomalies. The main findings were: (1) MRI was more sensitive than 3D-US for diagnosing CNS anomalies (MRI, 88.9% (16/18) vs 3D-US, 66.7% (12/18) vs 2D-US, 72.2% (13/18); McNemar’s test for MRI vs 3D-US: P=0.046); (2) MRI provided additional information affecting prognosis and/or counseling in 22.2% (4/18) of fetuses with CNS anomalies; (3) 2D-US, 3D-US and MRI had similar sensitivity for diagnosing non-CNS anomalies; (4) specificity for all anomalies was highest for 3D-US (MRI, 85.6% (77/90) vs 3D-US, 94.4% (85/90) vs 2D-US, 92.2% (83/90); McNemar’s test for MRI vs 3D-US: P=0.03); and (5) the confidence of MRI for ruling out certain CNS abnormalities (usually questionable for cortical dysplasias or hemorrhage) that were not confirmed after delivery was lower than it was for 2D-US and 3D-US. Conclusions MRI was more sensitive than ultrasonography and provided additional information that changed prognosis, counseling or management in 22.2% of fetuses with CNS anomalies. False-positive diagnoses for subtle CNS findings were higher with MRI than with ultrasonography.

Placental histopathology associated with pre‐eclampsia: systematic review and meta‐analysis

“…A closer assessment of the origins of this change demonstrates that operator blinding does not significantly influence the detection of lesions in PE pregnancy, but that, in unblinded studies, the operator was much less likely to formally document histological lesions in pregnancies classified as normal. These findings stress the importance of operator blinding, both in a research and clinical context, to get impartial and unbiased reporting of placental pathology, as in other fields 21,22 .…”

A system‐based approach to the genetic etiologies of non‐immune hydrops fetalis

“…[142][143][144] Additional imaging modalities such as three-and four-dimensional ultrasound, as well as magnetic resonance imagining (MRI), have been investigated as potential ways to improve prenatal diagnosis of concurrent structural anomalies. 16,145,146 While the situations in which these modalities are most useful have not been defined, fetal MRI does appear promising in cases where intracranial anomalies are suspected and may provide additional information about cortical sulcation, gyration, leukomalacia, vascular defects, and other differences. 145,146 Prenatal phenotyping is key in the evaluation, meaning the identification of prenatal features unique to each case that allows providers to narrow the differential diagnosis and target further testing.…”

“…16,145,146 While the situations in which these modalities are most useful have not been defined, fetal MRI does appear promising in cases where intracranial anomalies are suspected and may provide additional information about cortical sulcation, gyration, leukomalacia, vascular defects, and other differences. 145,146 Prenatal phenotyping is key in the evaluation, meaning the identification of prenatal features unique to each case that allows providers to narrow the differential diagnosis and target further testing. In addition to information gained from imaging, prenatal phenotyping may include maternal serum screening results that suggest a specific disorder or range of disorders, such as elevated MSAFP with congenital nephrosis or ichthyoses, or low maternal serum unconjugated estriol with metabolic disorders.…”

Zika Virus Infection and Implications for Reproduction

“…In pregnancies where maternal Zika infection has been confirmed, serial ultrasounds are recommended, however the optimal timing of surveillance is not known (Oduyebo et al, 2017). MRI may be more sensitive at detecting structural brain changes (Goncalves et al, 2016), but again the optimal timing for MRI has not been established. In the absence of a confirmed diagnosis of viral RNA from amniotic fluid, the presence of one or more of the fetal features described above, in combination with maternal potential for exposure and supporting laboratory evidence of Zika infection, along with the exclusion of other causes should lead to a presumptive diagnosis of CZS.…”