Incidence of New, Nonphysiologic Maternal Findings on Fetal Magnetic Resonance Imaging

Abstract

Objective

Fetal magnetic resonance imaging (MRI) is increasingly used for evaluation of fetal anomalies, and rates of incidental maternal findings are not well characterized. Our objective was to evaluate the rate of incidental maternal findings at the time of antenatal MRI performed for fetal indications.

Study Design

This was a retrospective cohort study that included all fetal MRIs performed between 2018 and 2023 at a single tertiary care institution with a multidisciplinary fetal diagnosis and treatment center. The electronic medical record was reviewed to identify all documented maternal findings and any new, nonphysiologic maternal findings. The latter was defined as previously unknown abnormalities of maternal structures unrelated to normal physiology.

Results

Our study included 834 imaging events, performed at an average gestational age of 23 weeks. The most common indication for imaging was fetal anomaly (81.1%). The most common imaging type was fetal brain MRI (81.4%). Overall, 16.2% reported a maternal finding and 7% reported a new, nonphysiologic finding. The most common new, nonphysiologic findings were renal cysts (n = 11), liver cysts (n = 6), and gallstones or gallbladder sludge (n = 5). Compared with imaging events that included a fetal brain MRI, imaging events that included a fetal body MRI had a significantly higher rate of any maternal findings (53.0 vs. 10.4%, p < 0.001) and new, nonphysiologic maternal findings (26.9 vs. 3.7%, p < 0.001).

Conclusion

Our results suggest that the risk of identifying new, nonphysiologic maternal findings on fetal MRI is low. The rate of any maternal and new, nonphysiologic maternal findings may differ by fetal MRI type due to differences in imaging depth and extent of radiology subspecialist review. These data should be incorporated into pretest counseling for patients planning to have fetal MRI.

Key Points

• The rate of incidental maternal findings on fetal MRI was 7%—lower than previously reported.

• Incidental maternal findings were more common on fetal body versus brain MRI.

• Maternal BMI did not impact incidence of new, nonphysiologic maternal findings.

• Our results could inform pretest counseling and consent discussions around fetal MRI.

Keywords

fetal imaging - incidental finding - incidentaloma - obstetrics

Publikationsverlauf

Eingereicht: 12. Oktober 2024

Angenommen: 11. November 2024

Accepted Manuscript online:
12. November 2024

Artikel online veröffentlicht:
17. Dezember 2024

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