T2 Hyperintensity and ADC Values in Fetal Brain MRI following Prenatal Open Neural Tube Defect Repair
Year: 2026
Type: article
Study design: Observational Study
Abstract: BACKGROUND AND PURPOSE: T2 hyperintensity on fetal brain MRI is frequently observed in fetuses with an open neural tube defect (ONTD) and may reflect edema, impaired CSF circulation, or altered brain maturation. By characterizing the diffusion of water molecules within brain tissue, DWI may help differentiate among these etiologies by assessing water diffusion as a marker of brain microstructure. Our aim was to investigate the relationship between brain T2-hyperintensity and ADC values in fetuses following prenatal ONTD repair. MATERIALS AND METHODS: We retrospectively analyzed fetal MRI scans performed 6 weeks after in utero ONTD repair at a single center. T2 hyperintensity was defined as a region with signal intensity subjectively higher than that of the surrounding brain parenchyma. ADC values were measured in the frontal, temporal, parietal, and occipital lobes on axial brain DWI sequences (b=700 s/mm2). Hindbrain herniation was evaluated, and reversal was defined when the cerebellum was seen above the foramen magnum. ADC values were compared between fetuses with and without T2 hyperintensity using the Mann-Whitney U test. A P value < .05 was considered significant. RESULTS: Forty-nine fetuses underwent repair at 25.0 [23.3–26.4] weeks. During the postoperative MRI at 31.2 [29.9–33.3] weeks, T2 hyperintensity was seen in 35/49 (71.4%) fetuses. ADC values were lower in most studied brain regions in fetuses with T2 hyperintensity compared with their counterparts without T2 hyperintensity (right parietal lobe: 2.68 [1.38–7.82] ×10−6 mm2/s versus 3.36 [2.32–7.05] ×10−6 mm2/s, P = .02; left parietal lobe: 2.80 [1.40–7.38] versus 3.45 [1.81–7.58] ×10−6 mm2/s, P = .03; right temporal lobe: 2.75 [1.41–6.63] versus 3.53 [1.87–7.58] ×10−6 mm2/s, P <.01; right occipital lobe: 3.19 [1.20–7.86] versus 4.30 [2.18–7.18], P = .04). Complete hindbrain herniation reversal was more common in those without T2 hyperintensity (100% versus 65.7%, P < .01). CONCLUSIONS: After prenatal ONTD repair, the presence of T2 hyperintensity was associated with lower ADC values in most examined brain regions, suggesting altered brain microstructure or delayed myelination.
DOI: 10.3174/ajnr.a9099
Institutions: Baylor College of Medicine, Texas Children's Hospital
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
OpenAlex ID: W7160060714