Prenatal assessment of congenital diaphragmatic hernia at north american fetal therapy network centers: A continued plea for standardization

Abstract

Introduction Prenatal work‐up for congenital diaphragmatic hernia (CDH) is important for risk stratification, standardization, counseling, and optimal therapeutic choice. To determine current practice patterns regarding prenatal CDH work‐up, including prenatal ultrasound and magnetic resonance imaging (MRI) use, and to identify areas for standardization of such evaluation between fetal centers. Methods A survey regarding prenatal CDH work‐up was sent to each member center of the North American Fetal Therapy Network (NAFTNet) (n = 36). Results All responded. Sonographic measurement of lung‐to‐head ratio (LHR) was determined by all, 89% (32/36) of which routinely calculate observed‐to‐expected LHR. The method for measuring LHR varied: 58% (21/36) used a “trace” method, 25% (9/36) used “longest axis,” and 17% (6/36) used an “antero‐posterior” method. Fetal MRI was routinely used in 78% (28/36) of centers, but there was significant variability in fetal lung volume measurement. Whereas all generated a total fetal lung volume, the planes, methodology and references values varied significantly. All evaluated liver position, 71% (20/28) evaluated stomach position and 54% (15/28) quantified the degree of liver herniation. More consistency in workup was seen between centers offering fetal intervention. Conclusion Prenatal CDH work‐up and management differs considerably among North American fetal diagnostic centers, highlighting a need for its standardization.

Motion corrected fetal body magnetic resonance imaging provides reliable 3D lung volumes in normal and abnormal fetuses

“…Furthermore, the ability to outline lesion volumes in cases of CLL will likely produce a prognostic marker more faithful to true lesion size than the currently utilised CVR where cross sectional areas are utilised to estimate lesion volume relative to fetal size. The consistency of such a method will certainly deliver on the recent plea for consistency in prognostication of these cases 9 . It should be noted that although we have provided lesion volume proportionate to TLV, it would be possible to segment any aspect of the fetus and derive a corresponding volume ratio proportional to this as well as the relative position of the organs (e.g., the degree of liver herniation or position of the stomach in CDH cases).…”

“…While US‐based measurements are undoubtedly the bedrock upon which assessment of fetal lung anomalies should be based, high volume fetal medicine centres have suggested that MRI‐calculated lung volumes may be a more accurate predictor of survival 8 . This has not been formally proven and there is no standardised methodology for the use of MRI in these cases which limits the compilation of large datasets necessary for further study 9 …”

“…8 This has not been formally proven and there is no standardised methodology for the use of MRI in these cases which limits the compilation of large datasets necessary for further study. 9 Modern clinical fetal MRI protocols (primarily based on single shot turbo spin echo [ssTSE] sequence) allow fast acquisition of individual 2D slices that "freeze" fetal position in time. These slices have sufficiently high image and contrast resolution for diagnostic purposes in cases where fetal motion may previously have limited the information available.…”

Is fetal MRI ready for neuroimaging prime time? An examination of progress and remaining areas for development

“…More precise classification of neural atypicalities, again, better prepared patient families and providers as they develop long-term care plans. Within the realm of clinical care, the adoption of fetal MRI has been variable across fetal diagnostic centers and diagnoses ( Perrone et al, 2021 ). Some of this variation is driven by access to an MR scanner and availability of fetal imaging expertise.…”

Motion corrected fetal body MRI provides reliable 3D lung volumes in normal and abnormal fetuses

“…3D ultrasound lung volume measurements have been shown to be more difficult than by MRI, mainly because the most hypoplastic lung cannot be properly visualized 7 . High volume fetal medicine centres have suggested that MRI-calculated lung volumes may be a more accurate predictor of survival but that has not been formally proven 8 , however there is no standardised methodology for the use of MRI in these cases which limits the compilation of large datasets necessary for further study 9 .…”