In utero MRI diagnosis of fetal malformations in oligohydramnios pregnancies

Added value of fetal MRI as a complementary method to antenatal ultrasound in the assessment of non-CNS fetal congenital anomalies

Background

Birth defects and congenital anomalies are different words used to describe developmental abnormalities that occur at birth. Congenital anomalies diagnosis during pregnancy is a difficult topic to which ultrasonography has made significant contributions. The availability of a generally safe, independent technique in the evaluation of prenatal anomalies would be a welcomed clinical and scientific alternative. Ultrasound (US) is the predominant modality for evaluating disorders related to fetus and pregnancy. In most situations, this examination by a professional operator offers sufficient information about fetal morphology, surroundings, and well-being. The abnormalities revealed by ultrasound can be subtle or inconclusive at times. MRI has been demonstrated to be useful in such circumstances in various studies. So the effective use of fetal MRI in the evaluation of non-CNS abnormalities of the body is a reason for adopting fetal MRI as an adjunct to US in obstetric imaging. This study aimed to examine the role of fetal MRI as a complementary method to the antenatal US in assessing non-CNS anomalies and how it changed or modified the diagnosis of anomalies.

Results

By analyzing the data of 30 pregnant females with fetal non-CNS congenital anomalies, the diagnostic accuracy of prenatal ultrasound alone in the detection of congenital anomalies was 76%, with a sensitivity of about 76%. And diagnostic accuracy of MRI alone was 96.6%, with a sensitivity of approximately 96.6%. Moreover, the diagnostic accuracy of combined prenatal US and prenatal MRI in the detection of congenital anomalies was 100%, with sensitivity about 100% and PPV about 100%.

Conclusion

Fetal MRI raises confidence in non-CNS malformation assessment. Compared to US, MRI overcomes many of the obstacles faced by the antenatal US. MRI is superior to the US in refining, changing, or adding more diagnostic information about the disease.

Cross Attention Squeeze Excitation Network (CASE-Net) for Whole Body Fetal MRI Segmentation

Segmentation of the fetus from 2-dimensional (2D) magnetic resonance imaging (MRI) can aid radiologists with clinical decision making for disease diagnosis. Machine learning can facilitate this process of automatic segmentation, making diagnosis more accurate and user independent. We propose a deep learning (DL) framework for 2D fetal MRI segmentation using a Cross Attention Squeeze Excitation Network (CASE-Net) for research and clinical applications. CASE-Net is an end-to-end segmentation architecture with relevant modules that are evidence based. The goal of CASE-Net is to emphasize localization of contextual information that is relevant in biomedical segmentation, by combining attention mechanisms with squeeze-and-excitation (SE) blocks. This is a retrospective study with 34 patients. Our experiments have shown that our proposed CASE-Net achieved the highest segmentation Dice score of 87.36%, outperforming other competitive segmentation architectures.

Update on the Prenatal Diagnosis and Outcomes of Fetal Bilateral Renal Agenesis

Importance

Bilateral renal agenesis is a rare congenital anomaly associated with poor prognosis.

Objective

The aims of this article are to review and summarize evidence on prenatal diagnosis and outcomes of bilateral renal agenesis.

Evidence Acquisition

A search was undertaken using PubMed and ClinicalTrials.gov databases from January 1, 1998, to September 1, 2018. Search terms include "prenatal diagnosis" OR "outcomes" AND "bilateral renal agenesis." Search was limited to English language.

Results

Fetal ultrasonography is the primary imaging modality for prenatal diagnosis of fetal urogenital tract abnormalities. However, ultrasonography is limited by several factors; it is operator dependent and associated with small field of view, has limited soft-tissue acoustic contrast, and is also influenced by patient habitus and fetal position. Color Doppler ultrasonography can be used as an adjunct to exclude bilateral renal agenesis by visualizing renal arteries. In the literature, prenatal magnetic resonance imaging has been reported to be equal to or superior to prenatal ultrasonography. Bilateral renal agenesis with oligohydramnios/anhydramnios is associated with a poor prognosis; perinatal death occurs secondary to pulmonary hypoplasia in the majority of cases.

Conclusions

Ultrasonography in combination with color Doppler ultrasonography permits the fetal urinary tract to be assessed in the first and early second trimester of gestation. The magnetic resonance imaging can be used as a complementary adjunctive modality in equivocal or inconclusive ultrasonographic findings.