Using MRI-derived observed-to-expected total fetal lung volume to predict lethality in fetal skeletal dysplasia.

BACKGROUND: Pulmonary hypoplasia is the primary cause of perinatal death in lethal skeletal dysplasias. The antenatal ultrasound correlates for lethality are indirect, measuring the thorax (thoracic circumference, TC) or femur compared to the abdomen (TC/AC, FL/AC). A single study has correlated lethality with the observed-to-expected total lung volume (O/E-TFLV) on fetal MRI in 23 patients. OBJECTIVE: Our aim was to define a cutoff value to predict lethality more specifically using MRI-derived O/E-TFLV. MATERIALS AND METHODS: Two large fetal center databases were searched for fetuses with skeletal dysplasia and MRI; O/E-TFLV was calculated. Ultrasound measures were included when available. Each was evaluated as a continuous variable against lethality (stillbirth or death in the first month of life). Logistic regression and receiver operating characteristic (ROC) curve analyses evaluated the prediction ability. AUC, sensitivity, and specificity were calculated. P < 0.05 was considered statistically significant. RESULTS: A total of 80 fetuses met inclusion criteria. O/E-TFLV < 0.49 was a significant risk factor in predicting lethality, with sensitivity and specificity of 0.63 and 0.93, respectively, and an AUC of 0.81 (P < 0.001). FL/AC < 0.129 was also a strong variable with sensitivity, specificity, and AUC of 0.73, 0.88, and 0.78, respectively (P < 0.001). TC/AC and TC percentile were not significant risk factors for lethality. An O/E-TFLV of < 0.38 defines a specificity for lethality at 1.00. CONCLUSION: MRI-derived O/E-TFLV and US-derived FL/AC are significant predictors of lethality in fetuses with skeletal dysplasia. When prognosis is uncertain after ultrasound, calculation of MRI-derived O/E-TFLV may provide additional useful information for prognosis and delivery planning.

Fetoscopic Balloon Dilation and Stent Placement of Congenital High Airway Obstruction Syndrome Leading to Successful Cesarean Delivery.

INTRODUCTION: Without fetal or perinatal intervention, congenital high airway obstruction syndrome (CHAOS) is a fatal anomaly. The ex utero intrapartum treatment (EXIT) procedure has been used to secure the fetal airway and minimize neonatal hypoxia but is associated with increased maternal morbidity. CASE PRESENTATION: A 16-year-old woman (gravida 1, para 0) was referred to our hospital at 31 weeks gestation with fetal anomalies, including echogenic lungs, tracheobronchial dilation, and flattened diaphragms. At 32 weeks, fetoscopic evaluation identified laryngeal stenosis, which was subsequently treated with balloon dilation and stent placement. The patient developed symptomatic and regular preterm contractions at postoperative day 7 with persistent sonographic signs of CHAOS, which prompted a repeat fetoscopy with confirmation of a patent fetal airway followed by Cesarean delivery under neuraxial anesthesia. Attempts to intubate through the tracheal stent were limited and resulted in removal of the stent. A neonatal airway was successfully established with rigid bronchoscopy. Direct laryngoscopy and bronchoscopy confirmed laryngeal stenosis with a small tracheoesophageal fistula immediately inferior to the laryngeal stenosis and significant tracheomalacia. A tracheostomy was then immediately performed for anticipated long-term airway and pulmonary management. The procedures were well tolerated by both mom and baby. The baby demonstrated spontaneous healing of the tracheoesophageal fistula by day of life 7 with discharge home with ventilator support at 3 months of life. CONCLUSION: Use of repeated fetoscopy in order to relieve fetal upper airway obstruction offers the potential to minimize neonatal hypoxia, while concurrently decreasing maternal morbidity by avoiding an EXIT procedure. Use of the tracheal stent in CHAOS requires further investigation. The long-term reconstruction and respiratory support of children with CHAOS remain challenging.

Characterization of the Hyperintense Bronchus Sign as a Fetal MRI Marker of Airway Obstruction.

Background Fetal MRI-based differential diagnosis of congenital lung malformations is difficult because of the paucity of well-described imaging markers. Purpose To characterize the hyperintense bronchus sign (HBS) in in vivo fetal MRI of congenital lung malformation cases. Materials and Methods In this retrospective two-center study, fetal MRI scans obtained in fetuses with congenital lung malformations at US (January 2002 to September 2018) were reviewed for the HBS, a tubular or branching hyperintense structure within a lung lesion on T2-weighted images. The frequency of the HBS and respective gestational ages in weeks and days were analyzed. Areas under the curve (AUCs), 95% CIs, and P values of the HBS regarding airway obstruction, as found in histopathologic and postnatal CT findings as the reference standards, were calculated for different gestational ages. Results A total of 177 fetuses with congenital lung malformations (95 male fetuses) and 248 fetal MRI scans obtained at a median gestational age of 25.6 weeks (interquartile range, 8.9 weeks) were included. The HBS was found in 79% (53 of 67) of fetuses with bronchial atresia, 71% (39 of 55) with bronchopulmonary sequestration (BPS), 43% (three of seven) with hybrid lesion, 15% (six of 40) with congenital cystic adenomatoid malformation, and 13% (one of eight) with bronchogenic cyst at a median gestational age of 24.9 weeks (interquartile range, 9.7 weeks). HBS on MRI scans at any gestational age had an AUC of 0.76 (95% CI: 0.70, 0.83; P = .04) for the presence of isolated or BPS-associated airway obstruction at histopathologic analysis and postnatal CT. The AUC of HBS on fetal MRI scans obtained until gestational age of 26 weeks (AUC, 0.83; 95% CI: 0.75, 0.91; P < .001) was significantly higher (P = .045) than that for fetal MRI scans obtained after gestational age 26 weeks (AUC, 0.69; 95% CI: 0.57, 0.80; P = .004). Conclusion The hyperintense bronchus sign is a frequently detectable feature at fetal MRI and is associated with airway obstruction particularly before gestational age 26 weeks. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Dubinsky in this issue.

Prenatal Imaging to Predict Need for Urgent Perinatal Surgery in Congenital Lung Lesions.

BACKGROUND: Congenital lung malformations (CLMs) have a variable natural history: some patients require urgent perinatal surgical intervention (UPSI) and others remain asymptomatic. These lesions have potential growth until 26-28 wk gestation. CLM volume ratio (CVR) has been shown to predict the risk of hydrops in CLMs. However, no criteria exist to delineate lesions requiring urgent surgical intervention in the perinatal period. Our goal was to determine prenatal diagnostic features that predict the need for UPSI in patients diagnosed with CLM. METHODS: Records and imaging features of all fetuses evaluated by our fetal center between May 2015 and December 2018 were retrospectively reviewed. Data included demographics, fetal ultrasound and magnetic resonance imaging, CVR, surgical treatment, and outcome. Features were analyzed for their ability to predict the need for UPSI. RESULTS: Sixty-four patients were referred for CLM, with 48 patients serially followed. Nine (18.8%) patients were followed nonoperatively, 35 (72.9%) underwent resection, and four (8.3%) were lost to follow-up. Of the patients who underwent resection, 24 (68.5%) were electively resected and 11 were urgently resected. Five (14.3%) patients underwent ex utero intrapartum treatment resection, and six (17.1%) were urgently resected for symptomatic CLM. There were no cases of UPSI with final CVR <1.1. Of the patients with final CVR 1.1-1.7, 43% required urgent resection. CVR ≥1.1 has 100% sensitivity and 87.8% specificity to predict patients requiring UPSI (area under the curve of 0.98). CONCLUSIONS: A final CVR ≥1.1 is highly predictive for UPSI. Patients with a final CVR ≥1.1 should be referred for delivery at centers with pediatric surgeons equipped for potential UPSI for CLM.

Postoperative imaging following fetal open myelomeningocele repair: The clinical utility of magnetic resonance imaging and sonographic amniotic fluid volumes in detecting suspected hysterotomy scar dehiscence.

OBJECTIVES: Hysterotomy scar disruption, ranging from myometrial thinning to complete dehiscence, is a well-established complication of open-hysterotomy fetal myelomeningocele (MMC) repair. This study sought to (a) determine the feasibility of postoperative magnetic resonance imaging (MRI) in detecting signs of hysterotomy scar disruption and (b) identify the sonographic and clinical signs suggestive of subacute scar dehiscence, including decreasing amniotic fluid index (AFI) and uterine contractions, respectively. METHOS: A unique index case of suspected hysterotomy dehiscence following MMC repair prompted a retrospective review of 31 total open-hysterotomy fetal MMC repairs performed at our center, including 21 cases found to have intact hysterotomy scarring and 10 cases of non intact scarring detected at subsequent cesarean delivery. In each case, routine post operative MRI, performed 6 weeks after the MMC repair, was reviewed to evaluate the thickness of the hysterotomy site. Cases were also reviewed for sonographic and clinical patterns preceding delivery, including changes in AFI and the presence or absence of uterine contractions. RESULTS: Of the 31 total reviewed cases, 21 cases were found to have intact hysterotomy scar sites at the time of cesarean delivery. Among the intact cases, the net change in AFI from the time of MRI to delivery ranged from -45% to 47%, with a mean increase in fluid levels of 8% over an average of 5.6 weeks. The other 11 cases, including the index case, were found to have signs of scar disruption at delivery, including seven with thinned scar sites and four with grossly dehiscent sites. Amongst non-intact cases, AFI predominately decreased, with a net change ranging from -56% to 9% for a mean change of -24% over an average of 5.4 weeks. Regular uterine contractions close to the time of delivery occurred in 82% of the non intact cases. CONCLUSION: Hysterotomy scar disruption can rarely be detected by MRI following MMC repair. Decreasing AFI and contractions may serve as early warning signs of scar dehiscence and should be taken into consideration for obstetric management.

Cervical lymphatic malformations: Prenatal characteristics and ex utero intrapartum treatment.

BACKGROUND: The ex utero intrapartum treatment (EXIT) is utilized to transition fetuses with prenatally diagnosed airway obstruction to postnatal life. We describe the unique clinical course, diagnosis, treatment, and outcomes of patients with cervical lymphatic malformation (CLM) managed with EXIT. METHODS: Review of fetuses with diagnosed CLM was delivered by EXIT (2001-2018) in a tertiary referral fetal center. Outcomes included survival, tracheostomy at discharge, neonatal course after delivery, and pulmonary hypoplasia. Data are reported as median [range] and rate (%). RESULTS: Out of 45 patients delivered by EXIT, 10 were delivered for CLM: seven had polyhydramnios, one had nonimmune hydrops, five delivered preterm, and three were emergency EXITs. The EXIT time and estimated blood loss were 125 minutes (95, 158) and 900 mL (500, 1500), respectively. Airway was secured in all. There was one neonatal death (day 8) with prematurity, sepsis, and pulmonary hypoplasia. Three out of nine were discharged with a tracheostomy. CONCLUSION: In CLM, close monitoring for structural neck involvement and development of polyhydramnios are important and may be an indication for EXIT as the optimal delivery mode. An experienced multidisciplinary team is a key factor for an effective approach to the obstructed airway in CLM.

Correlation between maternal meal and fetal motion during fetal MRI.

BACKGROUND: Motion remains a major limitation of fetal magnetic resonance imaging (MRI). Some centers have required mothers to fast before MRI in an effort to reduce motion; however, there is no current literature that describes the effect of maternal diet on fetal activity. OBJECTIVE: The objective is to define associations between specific foods and beverages consumed before and the severity of fetal motion during fetal MRI. MATERIALS AND METHODS: Patients were asked to recall the specific foods or drinks consumed before their scan. An experienced technologist rated the level of fetal activity on a 3-point scale, from much less motion than normal (1) to much more (3). Two hundred twenty-eight patients were included. A non-inferiority test was used to establish statistical equivalence between the MR scores of those having a particular food item and those not. For items not shown to be equivalent, an additional superiority analysis evaluated for the presence of any significant difference. Additional data on time from meal to MRI and amniotic fluid index were also analyzed. RESULTS: Eleven of 15 comparisons were statistically significant for equivalence (P<0.05). In the remaining four categories, a superiority analysis revealed no significant differences. Analysis of meal-to-scan times showed no significant association with mean MR score (P=0.57). Amniotic fluid index correlated positively with scores, but the association was not statistically significant (P=0.39). CONCLUSION: Neither fasting nor a specific consumption was associated with a significant difference in fetal motion on MR. It is therefore likely unnecessary for mothers to alter their diets on the day of an MRI study.

Fetal Lung Volumes by MRI: Normal Weekly Values From 18 Through 38 Weeks' Gestation.

OBJECTIVE: The purpose of this study is to establish normal total fetal lung volume reference ranges from 18 to 38 weeks' gestation at 1-week intervals. MATERIALS AND METHODS: A retrospective analysis of 665 patients who underwent fetal MRI at two tertiary fetal centers from 2001 to 2013 was performed. Total fetal lung volume was measured in at least two planes, either manually or using a 3D workstation. The mean, median, SD, minimum, maximum, and lower and upper quartiles for total fetal lung volume were determined per gestational week. A t test was used to compare our values to previously reported values. A new formula to calculate total fetal lung volume derived from our data was created using a regression model. Comparisons between total fetal lung volume obtained by different imaging planes and manual versus semiautomatic calculation were also performed. RESULTS: The mean normal total fetal lung volume showed a weekly increase from 18 through 35 weeks' gestation. Means were compared with the expected total fetal lung volume generated by the Rypens formula, showing statistically significant lower mean total fetal lung volume from week 19 to week 22 (p < 0.05). Comparison between our data-derived total fetal lung volume formula and the Rypens formula showed very similar values at every gestational age. No difference in total fetal lung volume was seen when comparing imaging planes or manual versus semiautomatic methods. CONCLUSION: Measured mean total fetal lung volume values at 19-22 weeks are significantly lower than those predicted by the Rypens formula. Therefore, we propose preferential use of our values for prenatal counseling and delivery planning.

Correction to: Comparative safety and efficacy of balloon use in air enema reduction for pediatric intussusception.

The original version on this paper contained an error. The names of M. John Hicks and R. Paul Guillerman, though correctly appeared in the published version, are incorrectly displayed in indexing sites.

Comparative safety and efficacy of balloon use in air enema reduction for pediatric intussusception.

BACKGROUND: Intussusception, a common cause of bowel obstruction in young children, is primarily treated with air enema reduction. There is little literature comparing the safety and efficacy of air reduction without or with a rectal balloon. OBJECTIVE: To determine the safety and efficacy of a rectal balloon seal in air enema reduction. MATERIALS AND METHODS: We retrospectively reviewed the records of children who underwent air reduction for ileocolic or ileo-ileocolic intussusception over an 8-year period. We sorted data from 566 children according to whether a rectal balloon was used in the reduction, and further sorted them by type and experience level of the practitioner. Using logistic regression analyses, we identified risk factors for iatrogenic bowel perforation or failed reduction. RESULTS: Significant associations with bowel perforation included balloon use (P=0.038), age <1 year (P<0.0001), and attending physician's level of experience <5 years (P=0.043). Younger age was associated with both perforation (P<0.0001) and procedural failure (P=0.001). The risk-adjusted predicted probability of perforation decreased with age, approaching zero by 10 months regardless of balloon use. For cases without bowel resection, the risk-adjusted predicted probability of failure decreased toward zero by 30 months with balloon use, while remaining constant at 3-12% regardless of age when not using a balloon. CONCLUSION: The likelihood of a successful air reduction might be safely increased by using an inflated rectal balloon in children older than 9 months. Use of a balloon in younger infants is associated with a higher risk of iatrogenic bowel injury.

Fetal left-sided cardiac structural dimensions in left-sided congenital diaphragmatic hernia - association with severity and impact on postnatal outcomes.

OBJECTIVES: Fetuses with congenital diaphragmatic hernia (CDH) demonstrate varying degrees of left heart hypoplasia. Our study assesses the relationship between fetal left-sided cardiac structural dimensions, lung size, percentage liver herniation, lung-to-head ratio, postnatal left-sided cardiac structural dimensions, and postnatal outcomes. METHODS: We performed a retrospective cohort study of fetuses with left-sided CDH who had prenatal echocardiographic, ultrasound, and magnetic resonance imaging examinations at our institution between January 2007 and March 2015. Postnatal outcomes assessed include use of inhaled nitric oxide (iNO), use of extracorporeal membrane oxygenation, and death. RESULTS: Fifty-two fetuses with isolated left-sided CDH were included. Multivariate logistic regression models indicated that smaller fetal aortic valve z-score was associated with postnatal use of iNO (p = 0.03). Fetal mitral valve z-score correlated with lung-to-head ratio (p = 0.04), postnatal mitral valve z-score correlated with percent liver herniation (p = 0.03), and postnatal left ventricular end-diastolic dimension z-score correlated with liver herniation <20% (p = 0.04). CONCLUSION: We identified associations between smaller fetal left-sided cardiac structural dimensions and classic CDH indices. Smaller aortic valve z-score was associated with iNO use; however, left heart dimensions showed no association with extracorporeal membrane oxygenation or mortality. Further study into the impact of left-sided hypoplasia on outcomes in CDH is worthy of evaluation in a larger, prospective study. © 2017 John Wiley & Sons, Ltd.

Improving the Prediction of Neonatal Outcomes in Isolated Left-Sided Congenital Diaphragmatic Hernia by Direct and Indirect Sonographic Assessment of Liver Herniation.

OBJECTIVES: Liver herniation can be assessed sonographically by either a direct (liver-to-thoracic area ratio) or an indirect (stomach position) method. Our objective was to evaluate the utility of those methods to assess liver herniation for the prediction of neonatal outcomes in patients with isolated left-sided congenital diaphragmatic hernia (CDH). METHODS: We conducted a retrospective cohort study of all patients with CDH who had prenatal assessment and were delivered at Texas Children's Hospital between January 2004 and April 2014. The predictive value of sonographic parameters for mortality and the need for extracorporeal membrane oxygenation was evaluated by univariate, multivariate, and factor analysis and by receiver operating characteristics curves. RESULTS: A total of 77 fetuses with isolated left-sided CDH were analyzed. The lung-to-head ratio, liver-to-thorax ratio, and stomach position (according to the classifications of Kitano et al [Ultrasound Obstet Gynecol 2011; 37:277-282] and Cordier et al [J Matern Fetal Neonatal Med 2015; 28:190-195]) were significantly associated with both neonatal outcomes (P < .03). Significant correlations were observed between all of these sonographic parameters. A combination of the liver-to-thorax ratio and stomach position (Kitano) or stomach position (Cordier) with the lung-to-head ratio increased the area under the receiver operating characteristic curve of the lung-to-head ratio for mortality prediction (0.86 [95% confidence interval, 0.74-0.98], 0.83 [0.72-0.95], and 0.83 [0.74-0.92], respectively). CONCLUSIONS: Sonographic measurements of liver herniation (liver-to-thorax ratio and stomach position) are predictive of neonatal outcomes in isolated left-sided congenital diaphragmatic hernia. Our study shows that the combination of those sonographic measurements of liver herniation and lung size improves the accuracy of predicting mortality in those fetuses.

Prenatal Identification of Pierre Robin Sequence: A Review of the Literature and Look towards the Future.

Fetal ultrasonography is an important tool used to prenatally diagnose many craniofacial conditions. Pierre Robin sequence (PRS) is a rare congenital deformation characterized by micrognathia, glossoptosis, and airway obstruction. PRS can present as a perinatal emergency when the retropositioned tongue obstructs the airway leading to respiratory compromise. More predictable and reliable diagnostic studies could help the treating medical team as well as families prepare for these early airway emergencies. The medical literature was reviewed for different techniques used to prenatally diagnose PRS radiologically. We have reviewed these techniques and suggested a possible diagnostic pathway to consistently identify patients with PRS prenatally.

Maternal morbidity in patients with morbidly adherent placenta treated with and without a standardized multidisciplinary approach.

OBJECTIVE: The purpose of this study was to test the hypothesis that a standardized multidisciplinary treatment approach in patients with morbidly adherent placenta, which includes accreta, increta, and percreta, is associated with less maternal morbidity than when such an approach is not used (nonmultidisciplinary approach). STUDY DESIGN: A retrospective cohort study was conducted with patients from 3 tertiary care hospitals from July 2000 to September 2013. Patients with histologically confirmed placenta accreta, increta, and percreta were included in this study. A formal program that used a standardized multidisciplinary management approach was introduced in 2011. Before 2011, patients were treated on a case-by-case basis by individual physicians without a specific protocol (nonmultidisciplinary group). Estimated blood loss, transfusion of packed red blood cells, intraoperative complications (eg, vascular, bladder, ureteral, and bowel injury), neonatal outcome, and maternal postoperative length of hospital stay were compared between the 2 groups. RESULTS: Of 90 patients with placenta accreta, 57 women (63%) were in the multidisciplinary group, and 33 women (37%) were in the nonmultidisciplinary group. The multidisciplinary group had more cases with percreta (P = .008) but experienced less estimated blood loss (P = .025), with a trend to fewer blood transfusions (P = .06), and were less likely to be delivered emergently (P = .001) compared with the nonmultidisciplinary group. Despite an approach of indicated preterm delivery at 34-35 weeks of gestation, neonatal outcomes were similar between the 2 groups. CONCLUSION: The institution of a standardized approach for patients with morbidly adherent placentation by a specific multidisciplinary team was associated with improved maternal outcomes, particularly in cases with more aggressive placental invasion (increta or percreta), compared with a historic nonmultidisciplinary approach. Our standardized approach was associated with fewer emergency deliveries.

5, 4, 3, 2, 1: embryologic variants of pentalogy of Cantrell.

BACKGROUND: The purpose of this study was to evaluate our experience with pentalogy of Cantrell and the various embryologic variants. MATERIALS AND METHODS: Patient charts and diagnostic imaging studies of all fetuses evaluated at Texas Children's Fetal Center for pentalogy of Cantrell between April 2004 and June 2014 were reviewed retrospectively. Data collected from patient charts included demographic information, clinical presentation, fetal and postnatal imaging findings, operative treatment, pathologic evaluation, and outcomes. RESULTS: There were 10 patients who presented with embryologic variants of pentalogy of Cantrell over a 6-y period. Two cases displayed the full range of embryologic defects observed, and eight cases exhibited variants of the classic pentalogy. Sternal and pericardial defects were each present in 40% of patients. Additional anomalies present included pulmonary hypoplasia, pulmonary artery stenosis, and chromosomal abnormalities. Four patients presented with diaphragmatic defects but no defect in the pericardium, and one patient presented with a defective pericardium but no associated diaphragmatic defect, suggesting highly specific losses of somatic mesoderm during embryologic development. One patient was lost to follow-up, and a second patient underwent termination of pregnancy. Five of the remaining eight patients survived, one of which had the full range of embryologic defects and now attends preschool but requires speech and occupational therapy. The remaining surviving patients have developed without serious sequelae. CONCLUSIONS: This report highlights the spectrum of anomalies observed in the pentalogy of Cantrell and demonstrates that these fetuses can survive but with substantial morbidity.

Revisiting outcomes of right congenital diaphragmatic hernia.

BACKGROUND: Studies comparing outcomes of right- and left-sided congenital diaphragmatic hernia (R-CDH and L-CDH) have yielded conflicting results. We hypothesized that R-CDH is associated with higher short-term pulmonary morbidity than L-CDH. METHODS: We reviewed all CDH patients at a tertiary children's hospital over 10 y. In prenatally diagnosed CDH, the observed-to-expected total fetal lung volume and percentage liver herniation (%LH) were calculated using fetal magnetic resonance imaging-based measurements. Outcomes were compared in patients with isolated CDH. Patients were subsequently matched by %LH to compare outcomes. RESULTS: Of 189 CDH patients, 37 (20.1 %) were R-CDH and 147 (79.9%) were L-CDH. Those with R-CDH were prenatally diagnosed at a significantly lower rate (40.5% versus 73.5%; P < 0.001) and later gestational age (26.5 ± 7.7 versus 22.6 ± 5.65 wk; P = 0.062). There was no difference in observed-to-expected total fetal lung volume between those with R-CDH and L-CDH (30.2 ± 11.1% versus 33.1 ± 14.2%; P = 0.471). Fetuses with R-CDH had a higher %LH than those with L-CDH (37.5 ± 14.1% versus 18.6 ± 12.2%; P < 0.001). Patients with isolated R-CDH had a higher need for extracorporeal membrane oxygenation than L-CDH (48% versus 27%; P = 0.055). There was no difference in duration of tracheal intubation, hospital stay, need for supplemental oxygen at 30-d of life or 6-mo mortality between groups. There was no difference in mortality and pulmonary morbidity when patients were matched by %LH. CONCLUSIONS: Compared to those with L-CDH, fetuses with R-CDH are less likely to be diagnosed prenatally and have a higher need for extracorporeal membrane oxygenation. The sidedness of the hernia defect was not associated with differences in short-term pulmonary morbidity in this large, contemporary single-institution experience of neonates with CDH.

Predictive Value of MRI Findings for the Identification of a Hernia Sac in Fetuses With Congenital Diaphragmatic Hernia.

OBJECTIVE: The purpose of this study was to identify MRI features of diaphragmatic hernia sac, as well as to assess the accuracy of diagnosing a sac prenatally. MATERIALS AND METHODS: All fetal MRI examinations performed for intrapleural congenital diaphragmatic hernia (CDH) from 2004 to 2013 were retrospectively reviewed by two pediatric radiologists blinded to the hernia sac status (defined intraoperatively or at autopsy). Reviewers noted whether a sac was present on the basis of identification of the following four MRI findings: 1, meniscus of lung posterior or apical to the hernia contents; 2, encapsulated appearance of hernia contents, exerting less than expected mass effect on the heart and mediastinum; 3, presence of pleural fluid outlining a sac from above; and 4, presence of ascites outlining a sac from below. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each finding and for various combinations. Contingency tables, chi-square testing, and logistic regression were applied to calculate the probability of a sac. RESULTS: Ninety patients were included: 21 with and 69 without a sac. The first three MRI findings correlated with the presence of a sac. Logistic regression yielded high predicted probability of a sac when one finding was identified (finding 1, 94.4%; finding 2, 96.2%). Adding a second and a third finding improved the probability to 99.7% and 99.9%, respectively. Sensitivity and specificity for the presence of a sac were 0.43 and 0.97, respectively. PPV and NPV were 83.8% and 80%, respectively. CONCLUSION: On fetal MRI, presence of a hernia sac in CDH can be diagnosed with high specificity when indicative findings are present.

Improving spectral quality in fetal brain magnetic resonance spectroscopy using constructive averaging.

PURPOSE: A common source of loss in signal-to-noise ratio (SNR) in fetal brain magnetic resonance spectroscopy (MRS) is from fetal movement and temporal magnetic field drift. We investigated the feasibility of using constructive averaging strategies for improving the spectral quality and recovering the SNR loss from these effects. MATERIALS AND METHODS: Eight fetuses, between 20 3/7 and 38 2/7 weeks' gestation, were scanned with MRS at 1.5 T. Single-voxel point-resolved spectroscopy of the fetal brain with TE = 144 ms (in one case additional TE = 288 ms) was performed in a dynamic mode, and individual spectra of 128 acquisitions were saved. With constructive averaging strategy individual acquisitions were corrected for phase variations and frequency drift before averaging. Constructively averaged spectra were compared to those using conventional averaging to evaluate differences in spectral quality and SNR. RESULTS: The definition of key metabolite peaks was qualitatively improved using constructive averaging, including the doublet structure of lactate in one case. Constructive averaging was associated with SNR increases, ranging from 11% to 40%, and the SNR further improved in one case when outliers from severe motion were rejected before averaging. CONCLUSION: Our results demonstrate the feasibility of using constructive averaging for improving SNR in fetal MRS, which is likely to improve the characterization of fetal brain metabolites.