Intravoxel incoherent motion MR imaging analysis for diagnosis of placenta accrete spectrum disorders: A pilot feasibility study.

BACKGROUND: Placenta accreta spectrum (PAS) disorders occur when the placenta adheres abnormally to the uterine myometrium and can have devastating effects on maternal health due to risks of massive postpartum hemorrhage and possible need for emergency hysterectomy. PAS can be difficult to diagnose using routine clinical imaging with ultrasound and structural MRI. OBJECTIVE: To determine feasibility of using intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) analysis in the diagnosis of the placenta accreta spectrum disorders in pregnant women. METHODS: A total of 49 pregnant women were recruited including 14 with pathologically confirmed cases of PAS and 35 health controls without prior cesarean delivery and no suspected PAS by ultrasound. All women underwent diffusion-weighted imaging with an 8 b-value scanning sequence. A semi-automated method for image processing was used, creating a 3D object map, which was then fit to a biexponential signal decay curve for IVIM modeling to determine slow diffusion (Ds), fast diffusion (Df), and perfusion fraction (Pf). RESULTS: Our results demonstrated a high degree of model fitting (R2 ≥ 0.98), with Pf significantly higher in those with PAS compared to healthy controls (0.451 ± 0.019 versus 0.341 ± 0.022, p = 0.002). By contrast, no statistical difference in the Df (1.70 × 10-2 ± 0.38 × 10-2 versus 1.48 × 10-2 ± 0.08 × 10-2 mm2/s, p = 0.211) or Ds (1.34 × 10-3 ± 0.10 × 10-3 versus 1.45 × 10-3 ± 0.007 × 10-3 mm2/s, p = 0.215) was found between subjects with PAS and healthy controls. CONCLUSIONS: The use of MRI, and IVIM modeling in particular, may have potential in aiding in the diagnosis of PAS when other imaging modalities are equivocal. However, the widespread use of these techniques will require generation of large normative data sets, consistent sequencing protocols, and streamlined analysis techniques.

It Is Complex: Predicting Gastroschisis Outcomes Using Prenatal Imaging.

BACKGROUND: Gastroschisis occurs in one of 2000 births with survival rates partially contingent on intestinal complications and time to establishing feeding. Enhancements in prenatal imaging have given better insight into postnatal outcomes. The goal of this study was to examine the gastroschisis patient population at a single children's hospital in the modern era and to use prenatal ultrasound (US) to develop new prenatal prognostic indicators. METHODS: We performed a retrospective review of gastroschisis patients at a quaternary-care referral children's hospital from 2010 through 2018. We recorded demographics, prenatal data and imaging, early postnatal data, operative data, and patient outcomes. We compared patients within our cohort born with complex gastroschisis (bowel atresia/perforation) to uncomplicated gastroschisis patients. Second trimester and third trimester prenatal US were evaluated for changes in amniotic fluid level, amount of external bowel, bowel dilatation, and bowel wall edema to identify prognostic indicators of the status of the bowel at birth. For categorical variables, chi-square tests were used to assess for significance. Univariate and multivariable analyses were used to assess significance between categorical and continuous variables using medians and interquartile ranges or means. RESULTS: A total of 134 patients were included in the study: complex (n = 24), uncomplicated (n = 110). Compared with uncomplicated gastroschisis, complex patients required longer median days to feeding initiation (44 versus 10; P < 0.001), full feeding (80 versus 23; P < 0.001), length of stay (83 versus 33; P < 0.001), and total parenteral nutrition at discharge (P = 0.004). Full US data were available on 81% of patients, and partial data were identified on 19%. Prenatal US analysis showed significantly more complex patients had polyhydramnios on third trimester US (23.5%-4.3%; P = 0.018). US analysis showed these additional factors to be most associated with complex gastroschisis: large amount of external bowel on third trimester US, increase in bowel edema on third trimester US, and increase in external bowel dilation on third trimester US. Multivariable logistic regression analyses revealed amniotic fluid on third trimester US to be the most significant predictor of complex gastroschisis (P = 0.01). Polyhydramnios in combination with two-thirds of the other US factors had both sensitivity and positive predictive value for predicting complex gastroschisis of 75%. Patients with two or less of these positive US factors had high specificity (96.8%) and negative predictive value (87.5%), suggesting uncomplicated disease. There were no differences in perioperative or long-term complications in the complex group when compared with the group with uncomplicated gastroschisis. CONCLUSIONS: Polyhydramnios on third trimester prenatal US on babies with gastroschisis can predict complex gastroschisis at birth, whereas the absence of markers on prenatal US can suggest uncomplicated disease. Complex gastroschisis is associated with increased time to feeds and length of stay.