Assessment of Amniotic Fluid Volume in Pregnancy.

Amniotic fluid (AF) is an integral part of the fetal environment and is essential for fetal growth and development. Pathways of AF recirculation include the fetal lungs, swallowing, absorption through the fetal gastrointestinal tract, excretion through fetal urine production, and movement. In addition to being a marker for fetal health, adequate AF is necessary for fetal lung development, growth, and movement. The role of diagnostic imaging is to provide a detailed fetal survey, placental evaluation, and clinical correlation with maternal conditions to help identify causes of AF abnormalities and thereby enable specific therapy. Oligohydramnios prompts evaluation for fetal growth restriction as well as genitourinary issues, including renal agenesis, multicystic dysplastic kidneys, ureteropelvic junction obstruction, and bladder outlet obstruction. Premature preterm rupture of membranes should also be clinically excluded as a cause of oligohydramnios. Clinical trials evaluating amnioinfusion are underway as a potential intervention for renal causes of oligohydramnios. Most cases of polyhydramnios are idiopathic, with maternal diabetes being a common cause. Polyhydramnios prompts evaluation for fetal gastrointestinal obstruction and oropharyngeal or thoracic masses, as well as neurologic or musculoskeletal anomalies. Amnioreduction is performed only for maternal indications such as symptomatic polyhydramnios causing maternal respiratory distress. Polyhydramnios with fetal growth restriction is paradoxical and can occur with maternal diabetes and hypertension. When these maternal conditions are absent, this raises concern for aneuploidy. The authors describe the pathways of AF production and circulation, US and MRI assessment of AF, disease-specific disruption of AF pathways, and an algorithmic approach to AF abnormalities. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

The natural history of fetal gallstones: a case series and updated literature review.

INTRODUCTION: The incidence of fetal gallstones is estimated at 0.45% and its clinical relevance after birth remains unknown. This study aimed to describe the natural history of fetal gallstones and their clinical sequelae after birth. METHODS: We queried a database of fetuses referred for second and third trimester sonograms performed for high-risk pregnancies, and identified cases with fetal gallstones (1996-2019). Demographics, prenatal/postnatal imaging findings, and clinical sequelae were collected. A literature review was performed according to PRISMA guidelines. RESULTS: We screened approximately 200,000 obstetric sonograms; 34 fetuses were found to have cholelithiasis. The median gestational age at the time of sonogram was 35 weeks (range 22-38). Fifty-six percent were female and 11.8% were twin pregnancies with one affected fetus. Median maternal age was 28 years (range 17-42). Eight fetuses underwent postnatal imaging and 4 had persistent cholelithiasis. There was one case of in utero demise. Two patients had structural anomalies (renal and cardiac) by sonogram. A subset of 17 patients was followed long-term (range 3-20 years), and none developed clinical sequelae from cholelithiasis. DISCUSSION/CONCLUSIONS: No child developed postnatal clinical sequelae related to cholelithiasis identified in utero. Fetal cholelithiasis can be managed expectantly without follow-up imaging in asymptomatic patients.

US-guided Interventions to Diagnose and Treat Gynecologic and First-Trimester Disease.

US-guided procedures have an essential role in the diagnosis and treatment of multiple obstetric and gynecologic conditions, can be performed with either transvaginal or transabdominal approaches, and include biopsy of masses, aspiration of fluid collections, injection of therapeutic materials, and saline-infused sonohysterography and hysterosalpingo contrast-enhanced sonography. The full digital presentation is available online. ©RSNA, 2021.

Role of Imaging in Obstetric Interventions: Criteria, Considerations, and Complications.

US has an established role in the prenatal detection of congenital and developmental disorders. Many pregnant women undergo US at 18-20 weeks of gestation for assessment of fetal anatomy and detection of structural anomalies. With advances in fetoscopy and minimally invasive procedures, in utero fetal interventions can be offered to address some of the detected structural and physiologic fetal abnormalities. Most interventions are reserved for conditions that, if left untreated, often cause in utero death or a substantially compromised neonatal outcome. US is crucial for preprocedural evaluation and planning, real-time procedural guidance, and monitoring and assessment of postprocedural complications. Percutaneous needle-based interventions include in utero transfusion, thoracentesis and placement of a thoracoamniotic shunt, vesicocentesis and placement of a vesicoamniotic shunt, and aortic valvuloplasty. Fetoscopic interventions include myelomeningocele repair and tracheal balloon occlusion for congenital diaphragmatic hernia. In rare cases, open hysterotomy may be required for repair of a myelomeningocele or resection of a sacrococcygeal teratoma. Monochorionic twin pregnancies involve specific complications such as twin-twin transfusion syndrome, which is treated with fetoscopic laser ablation of vascular connections, and twin reversed arterial perfusion sequence, which is treated with radiofrequency ablation. Finally, when extended placental support is necessary at delivery for repair of congenital high airway obstruction or resection of lung masses, ex utero intrapartum treatment can be planned. Radiologists should be aware of the congenital anomalies that are amenable to in utero interventions and, when necessary, consider referral to centers where such treatments are offered. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. ©RSNA, 2021.

ACR Appropriateness Criteria® Second and Third Trimester Screening for Fetal Anomaly.

The Appropriateness Criteria for the imaging screening of second and third trimester fetuses for anomalies are presented for fetuses that are low risk, high risk, have had soft markers detected on ultrasound, and have had major anomalies detected on ultrasound. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR appropriateness criteria second and third trimester screening for fetal anomaly

The Appropriateness Criteria for the imaging screening of second and third trimester fetuses for anomalies are presented for fetuses that are low risk, high risk, have had soft markers detected on ultrasound, and have had major anomalies detected on ultrasound. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Bilateral Choroid Plexus Papillomas Diagnosed by Prenatal Ultrasound and MRI.

We present a rare prenatal diagnosis of bilateral choroid plexus papillomas by obstetrical ultrasound and fetal MRI at 20 weeks 6 days gestation. The fetus demonstrated bilateral enlarged, echogenic choroid plexus with increased Doppler flow suggestive of vascularized choroid tissue. Same-day fetal MRI demonstrated that the choroid plexus appeared enlarged bilaterally without definite hemorrhage. The combined features on ultrasound and MRI suggested bilateral choroid plexus papillomas with increased cerebrospinal fluid production, leading to ventriculomegaly and enlarged extra-axial spaces. The diagnosis was confirmed by postnatal pathology, which demonstrated WHO grade II atypical choroid plexus papillomas.

Outcomes of Monochorionic, Diamniotic Twin Pregnancies with Prenatally Diagnosed Intertwin Weight Discordance.

OBJECTIVE: Monochorionic, diamniotic (MCDA) twin pairs are predisposed to various pregnancy complications due to the unique placental angioarchitecture of monochorionicity. Few studies have evaluated the outcomes of weight-discordant MCDA pairs without selective fetal growth restriction (SFGR) or the risk factors for development of SFGR. This study aims to describe the natural history of expectant, noninvasive management of weight-discordant MCDA twins and to evaluate risk factors associated with progression to SFGR. STUDY DESIGN: This was a retrospective cohort study at a single, tertiary care center in the United States. All MCDA twins with isolated intertwin weight discordance (ITWD) ≥ 20% diagnosed before 26 weeks' gestational age (GA) were included. The primary outcome of descriptive analyses was overall pregnancy outcome, incorporating both survival to delivery and GA at delivery, as defined by the North American Fetal Therapy Network. The secondary outcome was SFGR in one twin (defined as estimated fetal weight < 10% for GA) and factors associated with this progression. Only those with fetal ultrasound (US) within 4 weeks of delivery were included in this secondary analysis. RESULTS: Among 73 MCDA pairs with ITWD, 73% had a good pregnancy outcome, with dual live delivery at a median GA of 33 weeks. Among the 34 pairs with adequate US follow-up, 56% developed SFGR. There were no differences in GA at delivery or discordance at birth between those who did and those who did not develop SFGR. There was a nonsignificant association between increasing ITWD at diagnosis and subsequent development of SFGR. CONCLUSION: Expectant, noninvasive management can be considered in MCDA twin pregnancies with ITWD ≥ 20% diagnosed before 26 weeks. This approach is associated with a good pregnancy outcome in the majority of cases, even after the development of SFGR in the smaller twin. KEY POINTS: · Nearly 75% of weight-discordant mo/di twins have a good pregnancy outcome.. · Weight-discordant mo/di twins deliver at a mean gestational age of 33 weeks without invasive therapy.. · Noninvasive management should be considered for weight-discordant mo/di twins..

ACR Appropriateness Criteria® Nuchal Translucency Evaluation at 11 to 14 Weeks of Gestation.

A fetus with an increased nuchal translucency at 11 to 14 weeks gestation is at risk for aneuploidy, genetic syndromes, structural anomalies, and intrauterine fetal demise in both single and twin gestations. In addition to referral to genetics for counseling and consideration of diagnostic genetic testing, a detailed anatomic survey and fetal echocardiogram are indicated in the second trimester to screen for congenital malformations and major heart defects. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Second and Third Trimester Vaginal Bleeding.

Vaginal bleeding can occur throughout pregnancy with varied etiologies. Although history and physical examination can identify many etiologies, imaging, in particular ultrasound (US), is the backbone of current medical practice. US pregnant uterus transabdominal, US pregnant uterus transvaginal, and US duplex Doppler velocimetry are usually appropriate for the evaluation of women with painless vaginal bleeding, those with painful vaginal bleeding, and also for those with second or third trimester vaginal bleeding with suspicion of or known placenta previa, low-lying placenta, or vasa previa. US cervix transperineal may be appropriate for those with painless or painful vaginal bleeding but is usually not appropriate for second or third trimester vaginal bleeding with suspicion of or known placenta previa, low-lying placenta, or vasa previa. Because the outcome of pregnancies is unequivocally related to the specific etiology of the vaginal bleeding, knowledge of imaging results directly informs patient management to optimize the outcome for mother and fetus. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Placenta Accreta Spectrum Disorder.

Placenta accreta spectrum disorder (PASD) is the current terminology recommended by the International Federation of Obstetrics and Gynecology (FIGO) and should replace terms such as abnormally adherent/invasive placenta or morbidly adherent placenta. PASD refers to a variety of potential clinical complications, which may result from abnormal placental implantation. More specifically, placenta accreta refers to a defect in the decidua basalis where the chorionic villi adhere directly to the myometrium with trophoblastic invasion. Accurate antenatal diagnosis is needed to plan for an appropriate delivery strategy at an experienced center in order to reduce maternal and potential fetal morbidity and mortality. Obtaining radiologic and clinical data when PASD is first suspected can play a significant role in formulating an appropriate delivery strategy. Depending on the clinical risk factors and initial imaging findings, transabdominal ultrasound of the pregnant uterus with duplex Doppler and transvaginal ultrasound as needed are the most appropriate imaging procedures. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Assessment of Gravid Cervix.

Preterm birth remains the leading cause of perinatal morbidity and mortality. Although the greatest risk factor for preterm birth is a history of prior preterm birth, a short cervical length (≤25 mm) before 24 weeks' gestational age is also associated with increased risk of spontaneous preterm delivery. As such, cervical length assessment has become of particular interest in predicting those patients at risk for preterm birth. Other clinical scenarios (eg, preterm labor, induction of labor, and active labor) may arise, in which assessment of the cervix may be of interest. Ultrasound is the mainstay imaging modality for assessing the gravid cervix, with transvaginal ultrasound recommended in patients at high risk for preterm birth or suspected preterm labor. Transperineal ultrasound is an alternate approach in those cases where transvaginal ultrasound in contraindicated. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

An Assessment of the Clinical Accuracy of Ultrasound in Diagnosing Cirrhosis in the Absence of Portal Hypertension.

Ultrasound is an invaluable tool for the diagnosis of hepatocellular carcinoma and portal hypertension. However, the accuracy of ultrasound in diagnosing cirrhosis in the absence of portal hypertension has not been well studied. Using the specific terms cirrhosis or nodular(ity), a retrospective evaluation was conducted on abdominal ultrasounds performed between 2008 and 2013. Patients with evidence of portal hypertension were excluded from the evaluation. Charts were reviewed for evidence of cirrhosis on liver biopsy performed within 1 year of the ultrasound. Of the 69 patients whose ultrasound findings reported cirrhosis without portal hypertension who underwent liver biopsy, 47 (68%) had histologic evidence of cirrhosis. When patients with advanced fibrosis (F3 or F4) on liver biopsy were included, the sensitivity of the ultrasound improved to 80%. One in 5 biopsies showed only mild to moderate or no fibrosis (F0-F2). Sonographic assessment by experts may falsely suggest or overestimate cirrhosis. In the absence of objective evidence of portal hypertension, caution should be taken in diagnosing cirrhosis based on sonographic interpretation alone.

Stage I Twin-Twin Transfusion Syndrome: Outcomes of Expectant Management and Prognostic Features.

OBJECTIVE: This article describes the natural history of stage I twin-twin transfusion syndrome (TTTS) including risk of progression to higher stage TTTS and pregnancy outcomes, and to identify risk factors for progression. STUDY DESIGN: Retrospective cohort study of monochorionic diamniotic (MCDA) twin pregnancies from 2006 to 2016 with expectantly managed Quintero stage I TTTS. RESULTS: A total of 30 MCDA twin pregnancies with expectantly managed stage I TTTS were identified. Of these, eight (26.7%) progressed to higher stage TTTS. Median gestational age (GA) at diagnosis for those that progressed was 18.9 ± 2.9 weeks versus 21.4 ± 3.4 weeks in those that remained stable (p = 0.06). Presence of an arterioarterial (A-A) anastomosis was assessed for 20/30 patients, and eight A-A were identified. Of those, 7/8 (87.5%) remained stable. In the complete cohort, a tiny or transiently visible bladder was noted in seven donor twins. Of these, 4/7 (57.1%) progressed. Excluding one termination, 47/58 (81.0%) fetuses survived. CONCLUSION: With expectant management of stage I TTTS, nearly three-fourths of pregnancies remain stable and most have survival of ≥ 1 twin. A-A anastomoses were not associated with progression to higher stage TTTS, whereas earlier GA at diagnosis or a small or intermittently visible donor bladder may herald greater risk of progression.

Polyhydramnios Affecting a Recipient-like Twin: Risk of Progression to Twin-Twin Transfusion Syndrome and Outcomes.

OBJECTIVE: The significance of polyhydramnios of one twin in the absence of oligohydramnios of the cotwin in monochorionic diamniotic (MCDA) twin pregnancies (polyhydramnios affecting a recipient-like twin [PART]) is unknown. Our aim is to assess the risk of progression to twin-twin transfusion syndrome (TTTS) with PART, progression to ≥ stage II TTTS, and neonatal survival. STUDY DESIGN: This study was a retrospective cohort study of MCDA twin pregnancies with PART evaluated at a referral center from 2008 to 2015. RESULTS: Sixty-four MCDA twin pregnancies with PART were identified. Fifteen (23.4%) progressed to TTTS, including 10 (15.6%) who progressed to ≥ stage II TTTS. Three pregnancies were terminated and one underwent selective reduction by radiofrequency ablation. Overall survival was 113 out of 128 (88.3%). Of those who remained stable, 91.8% (N = 45) had survival of both neonates. In multivariate analysis, the presence of arterioarterial (A-A) anastomosis by in utero Doppler ultrasound was associated with decreased risk of progression to TTTS (odds ratio: 0.12, p = 0.03, 95% confidence interval: 0.02-0.78). CONCLUSION: Most MCDA twin pregnancies with PART do not progress to TTTS and have a favorable prognosis. Progression rates are higher than observed in uncomplicated MCDA twins; however, so close surveillance is warranted. The presence of an A-A anastomosis appears to confer decreased risk of progression to TTTS.

Subclinical Atherosclerosis in Pediatric Liver Transplant Recipients: Carotid and Aorta Intima-Media Thickness and Their Predictors.

OBJECTIVE: To investigate prevalence and predictors of cardiovascular risk in pediatric liver transplant recipients using noninvasive markers of subclinical atherosclerosis: carotid intima-media thickness (cIMT) and aorta intima-media thickness (aIMT). STUDY DESIGN: Cross-sectional study of 88 pediatric liver transplant recipients. The cIMT and aIMT were measured by ultrasound imaging using standardized protocol. RESULTS: Participants were 15.4 ± 4.8 years of age, and 11.2 ± 5.6 years post-transplantation. The cIMT and aIMT were both higher in males than females. In analyses adjusted for sex, age, and height, the cIMT was higher in subjects transplanted for chronic/cirrhotic liver disease and lower in subjects on cyclosporine (n = 9) than tacrolimus (n = 71). The cIMT was not associated with rejection history or current corticosteroid use. The cIMT increased with increasing diastolic blood pressure and triglycerides. The aIMT (n = 83) also increased with age, and its rate of increase post-transplant varied by age at transplantation. In adjusted analyses, aIMT was higher in subjects with glucose intolerance. In analysis of patients ≤20 years of age for whom blood pressure percentiles could be calculated (n = 66), aIMT increased with increasing diastolic blood pressure percentile (0.010 mm per 5-percentile; 95% CI, 0.000-0.021; P = 0.05). Neither the cIMT nor the aIMT was associated with obesity, systolic hypertension, or other dyslipidemia at study visit. CONCLUSION: Measures of long-term cardiovascular risk were associated with conditions that are more common in pediatric liver transplant recipients than nontransplanted peers, namely, diastolic hypertension and glucose intolerance. Larger, longitudinal studies are warranted to investigate whether cIMT could be useful for stratifying these patients' cardiovascular risk-and potential need for proactive intervention-during long-term follow-up.

Hepatic steatosis after pediatric liver transplant.

Hepatic steatosis develops after liver transplantation (LT) in 30% of adults, and nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in nontransplanted children. However, posttransplant steatosis has been minimally studied in pediatric LT recipients. We explored the prevalence, persistence, and association with chronic liver damage of hepatic steatosis in these children. In this single-center study of pediatric patients transplanted 1988-2015 (n = 318), 31% of those with any posttransplant biopsy (n = 271) had ≥ 1 biopsy with steatosis. Median time from transplant to first biopsy with steatosis was 0.8 months (interquartile range [IQR], 0.3-6.5 months) and to last biopsy with steatosis was 5.5 months (IQR, 1.0-24.5 months); 85% of patients with steatosis also had for-cause biopsies without steatosis. All available for-cause biopsies were re-evaluated (n = 104). Of 9 biopsies that could be interpreted as nonalcoholic steatohepatitis (NASH)/borderline NASH, with steatosis plus inflammation or ballooning, 8 also had features of cholestasis or rejection. Among 70 patients with surveillance biopsies 3.6-20.0 years after transplant, only 1 overweight adolescent had a biopsy with NAFLD (grade 1 steatosis, mild inflammation, no ballooning or fibrosis)-despite a 30% prevalence of overweight/obesity in the cohort and 27% with steatosis on previous for-cause biopsy. Steatosis on preceding for-cause biopsy was not associated with portal (P = 0.49) or perivenular fibrosis (P = 0.85) on surveillance biopsy. Hepatic steatosis commonly develops early after transplant in children and adolescents, but it rarely persists. Biopsies that did have steatosis with NASH characteristics were all for-cause, mostly in patients with NAFLD risk factors and/or confounding causes of liver damage. Prospective studies that follow children into adulthood will be needed to evaluate if and when hepatic steatosis presents a longterm risk for pediatric LT recipients. Liver Transplantation 23 957-967 2017 AASLD.

Sonography Predicts Liver Steatosis in Patients With Chronic Hepatitis B.

OBJECTIVES: Liver inflammation and fibrosis may impair the ability of sonography to identify steatosis. We determined the accuracy of sonography in grading steatosis in patients with chronic hepatitis B compared to liver biopsy. METHODS: We conducted was a single-center retrospective study of all nontransplanted patients with chronic hepatitis B undergoing sonography and liver biopsy between 2004 and 2014 (n = 109). Steatosis was graded by sonography as none, mild, moderate, or severe. Liver histologic analysis graded steatosis (0, <5%; 1, <33%; 2, <66%; or 3, ≥66%) and staged fibrosis (F0-F4). Severe steatosis was defined as grade 2 or 3. Clinical variables within 6 months of liver biopsy were collected, and the association with steatosis was analyzed by univariate logistic regression. RESULTS: Patients were predominantly Asian (83%), male (62%), and hepatitis B e antigen negative (62%). Twenty-nine percent of patients were obese; 9% had diabetes mellitus; 23% had hypertension; and 31% had dyslipidemia. Forty-four percent of patients had steatosis on liver biopsy; 8% had severe steatosis. The presence of any steatosis on sonography correctly identified any steatosis on liver biopsy in 29 of 48 patients (60%). The absence of steatosis on sonography ruled out severe steatosis on biopsy (specificity, 100%). Severe steatosis on sonography correctly predicted the presence of severe steatosis on liver biopsy (89%; P < .001); however, it was not accurate at distinguishing between steatosis grades. Predictors of biopsy-proven steatosis on univariate analysis included diabetes (P < .001), hypertension (P = .03), hypercholesterolemia (P = .02), and body mass index (P < .001). CONCLUSIONS: Sonography had excellent accuracy in identifying patients with steatosis on biopsy. Abdominal sonography can be used to predict clinically important steatosis in patients with chronic hepatitis B.

Radiologic assessment of fetal tracheal balloon occlusion.

Fetal endoscopic tracheal occlusion (FETO) is a novel technique to treat cases of isolated severe congenital diaphragmatic hernia (CDH). Although there are benefits of MRI over ultrasound in assessing lung volumes, it is unknown whether there are benefits of MRI for localizing the tracheal balloon. This is a retrospective study reviewing the imaging characteristics of FETO in patients who underwent both MRI and ultrasound exams done to localize tracheal balloons.