Absence of harmful effects of magnetic resonance exposure at 1.5 T in utero during the third trimester of pregnancy: a follow-up study

Fetal Safety in MRI During Pregnancy: A Comprehensive Review

As medical imaging continues to expand, concerns about the potential risks of ionizing radiation to the developing fetus have led to a preference for non-radiation-based alternatives such as ultrasonography and fetal MRI. This review examines the current evidence on the safety of MRI during pregnancy, with a focus on 3 T MRI and contrast agents, aiming to provide a comprehensive synthesis that informs clinical decision-making, ensures fetal safety and supports the safe use of all available modalities that could impact management. We conducted a comprehensive review of studies from 2000 to 2024 on MRI safety during pregnancy, focusing on 3 T MRI and gadolinium use. The review included peer-reviewed articles and large database studies, summarizing key findings and identifying areas for further research. Fetal MRI, used alongside ultrasound, enhances diagnostic accuracy for fetal anomalies, particularly in the brain, thorax, gastrointestinal and genitourinary systems, with no conclusive evidence of adverse effects on fetal development. While theoretical risks such as tissue heating and acoustic damage exist, studies show no significant harm at 1.5 T or 3 T, though caution is still advised in the first trimester. Regarding gadolinium-based contrast agents, the evidence is conflicting: while some studies suggest risks such as stillbirth and rheumatological conditions, animal studies show minimal fetal retention and no significant toxicity, and later clinical research has not substantiated these risks. The existing literature on fetal MRI is encouraging, suggesting minimal risks; however, further investigation through larger, prospective and long-term follow-up studies is essential to comprehensively determine its safety and late effects.

3 Tesla Fetal MR Imaging Quality and Safety Considerations

Medical imaging, particularly fetal MR imaging, has undergone a transformative shift with the introduction of 3 Tesla (3T) clinical MR imaging systems. The utilization of higher static magnetic fields in these systems has resulted in remarkable advancements, including superior soft tissue contrast, improved spatial and temporal resolution, and reduced image acquisition time. Despite these notable benefits, safety concerns have emerged, stemming from the elevated static magnetic field strength, amplified acoustic noise, and increased radiofrequency power deposition. This article provides an overview of fetal MR imaging at 3T, its benefits and drawbacks, and the potential safety issues.

How to Perform Fetal MR Imaging

This article provides the readers with practical guidance on how to perform fetal MR imaging, including technical considerations such as scanner field strength and use of appropriate radiofrequency receive coils, and summarizes the role, strengths, and limitations of the various MR imaging sequences. The authors review the various factors to consider in scan preparation, including study indication, timing, maternal preparation, and the creation of an institutional fetal imaging protocol. Additional factors that go into scan optimization during acquisition including prioritizing maternal comfort and ways to troubleshoot various artifacts that maybe encountered in fetal imaging are discussed.

Whole cervix imaging of collagen, muscle, and cellularity in term and preterm pregnancy

Cervical softening and dilation are critical for the successful term delivery of a fetus, with premature changes associated with preterm birth. Traditional clinical measures like transvaginal ultrasound and Bishop scores fall short in predicting preterm births and elucidating the cervix's complex microstructural changes. Here, we introduce a magnetic resonance diffusion basis spectrum imaging (DBSI) technique for non-invasive, comprehensive imaging of cervical cellularity, collagen, and muscle fibers. This method is validated through ex vivo DBSI and histological analyses of specimens from total hysterectomies. Subsequently, retrospective in vivo DBSI analysis at 32 weeks of gestation in ten term deliveries and seven preterm deliveries with inflammation-related conditions shows distinct microstructural differences between the groups, alongside significant correlations with delivery timing. These results highlight DBSI's potential to improve understanding of premature cervical remodeling and aid in the evaluation of therapeutic interventions for at-risk pregnancies. Future studies will further assess DBSI's clinical applicability.

Initial Imaging of Pregnant Patients in the Trauma Bay-Discussion and Review of Presentations at a Level-1 Trauma Centre

Trauma is the leading non-obstetric cause of maternal and fetal mortality and affects an estimated 5-7% of all pregnancies. Pregnant women, thankfully, are a small subset of patients presenting in the trauma bay, but they do have distinctive physiologic and anatomic changes. These increase the risk of certain traumatic injuries, and the gravid uterus can both be the primary site of injury and mask other injuries. The primary focus of the initial management of the pregnant trauma patient should be that of maternal stabilization and treatment since it directly affects the fetal outcome. Diagnostic imaging plays a pivotal role in initial traumatic injury assessment and should not deviate from normal routine in the pregnant patient. Radiographs and focused assessment with sonography in the trauma bay will direct the use of contrast-enhanced computed tomography (CT), which remains the cornerstone to evaluate the potential presence of further management-altering injuries. A thorough understanding of its risks and benefits is paramount, especially in the pregnant patient. However, like any other trauma patient, if evaluation for injury with CT is indicated, it should not be denied to a pregnant trauma patient due to fear of radiation exposure.

Safety of Magnetic Resonance Imaging in Pregnancy

Magnetic resonance imaging is being increasingly used to diagnose and follow up a variety of medical conditions in pregnancy, both for maternal and fetal indications. However, limited data regarding its safe use in pregnancy may be a source of anxiety and avoidance for both patients and their healthcare providers. In this review, we critically discuss the main safety concerns of Magnetic Resonance Imaging (MRI) in pregnancy including energy deposition, acoustic noise, and use of contrast agents, supported by data from animal and human studies. Use of maternal sedatives and concerns related to occupational exposure in pregnant personnel are also addressed. Exposure to gadolinium-based contrast agents and sedation for MRI during pregnancy should be avoided whenever feasible.

No Meta-analytic Evidence for Risks due to Prenatal Magnetic Resonance Imaging in Animal Models

BACKGROUND

Magnetic resonance imaging (MRI) is a powerful, noninvasive tool for both clinical practice and research. Though the safety of MRI has been endorsed by many professional societies and government bodies, some concerns have remained about potential risk from prenatal MRI. Case-control animal studies of MRI scanning during gestation and effects on offspring are the most direct test available for potential risks. We performed a meta-analysis of extant animal studies of prenatal MRI examining reproductive and offspring outcomes.

METHODS

Relevant articles were identified through PubMed search and citation searching of known articles and review papers. Eighteen relevant studies were identified with case-control designs of prenatal scanning conducted in vivo with mammalian species using MRI-relevant field strength. Standardized mean difference effect sizes were analyzed across k = 81 outcomes assessed across 649 unexposed dams, 622 exposed dams, 3024 unexposed offspring, and 3328 exposed offspring using a multilevel meta-analytic approach that clustered effect sizes within publications.

RESULTS

The meta-analysis indicated no significant evidence for a deleterious effects of prenatal MRI (standardized mean difference = 0.17, 95% CI [-0.19, 0.54], t80 = 0.94, p = .35) across outcomes. Similarly, no effects were observed when separately examining the 4 most commonly assessed outcomes: birth weight, litter size, fetal viability, and physical malformations (p > .05).

CONCLUSIONS

Case-control mammalian animal studies indicate no significant known risks of prenatal MRI to reproductive outcomes or offspring development. This finding is largely mirrored in human research, though the lack of randomized case-control designs limits direct comparison. The current findings provide additional support to the prevailing consensus that prenatal MRI poses no known risk to offspring.

Not with a “zap” but with a “beep”: measuring the origins of perinatal experience

When does the mind begin? Infant psychology is mysterious in part because we cannot remember our first months of life, nor can we directly communicate with infants. Even more speculative is the possibility of mental life prior to birth. The question of when consciousness, or subjective experience, begins in human development thus remains incompletely answered, though boundaries can be set using current knowledge from developmental neurobiology and recent investigations of the perinatal brain. Here, we offer our perspective on how the development of a sensory perturbational complexity index (sPCI) based on auditory ("beep-and-zip"), visual ("flash-and-zip"), or even olfactory ("sniff-and-zip") cortical perturbations in place of electromagnetic perturbations ("zap-and-zip") might be used to address this question. First, we discuss recent studies of perinatal cognition and consciousness using techniques such as functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and, in particular, magnetoencephalography (MEG). While newborn infants are the archetypal subjects for studying early human development, researchers may also benefit from fetal studies, as the womb is, in many respects, a more controlled environment than the cradle. The earliest possible timepoint when subjective experience might begin is likely the establishment of thalamocortical connectivity at 26 weeks gestation, as the thalamocortical system is necessary for consciousness according to most theoretical frameworks. To infer at what age and in which behavioral states consciousness might emerge following the initiation of thalamocortical pathways, we advocate for the development of the sPCI and similar techniques, based on EEG, MEG, and fMRI, to estimate the perinatal brain's state of consciousness.

Magnetic resonance imaging in late pregnancy to improve labour and delivery outcomes - a systematic literature review

BACKGROUND

Magnetic resonance imaging (MRI) provides excellent soft tissue visualisation which may be useful in late pregnancy to predict labour outcome and maternal/neonatal birth trauma.

OBJECTIVE

To study if MRI in late pregnancy can predict maternal and neonatal outcomes of labour and birth.

METHODS

Systematic review of studies that performed MRI in late pregnancy or immediately postpartum. Studies were included if they imaged maternal pelvic or neonatal structures and assessed birth outcome. Meta-analysis was not performed due to the heterogeneity of studies.

RESULTS

Eighteen studies were selected. Twelve studies explored the value of MRI pelvimetry measurement and its utility to predict cephalopelvic disproportion (CPD) and vaginal breech birth. Four explored cervical imaging in predicting time interval to birth. Two imaged women in active labour and assessed mouldability of the fetal skull. No marker of CPD had both high sensitivity and specificity for predicting labour outcome. The fetal pelvic index yielded sensitivities between 59 and 60%, and specificities between 34 to 64%. Similarly, although the sensitivity of the cephalopelvic disproportion index in predicting labour outcome was high (85%), specificity was only 56%. In women with breech presentation, MRI was demonstrated to reduce the rates of emergency caesarean section from 35 to 19%, and allowed better selection of vaginal breech birth. Live birth studies showed that the fetal head undergoes a substantial degree of moulding and deformation during cephalic vaginal birth, which is not considered during pelvimetry. There are conflicting studies on the role of MRI in cervical imaging and predicting time interval to birth.

CONCLUSION

MRI is a promising imaging modality to assess aspects of CPD, yet no current marker of CPD accurately predicts labour outcome. With advances in MRI, it is hoped that novel methods can be developed to better identify individuals at risk of obstructed or pathological labour. Its role in exploring fetal head moulding as a marker of CPD should be further explored.

Maternal Cardiac Changes in Women With Obesity and Gestational Diabetes Mellitus

OBJECTIVE

We investigated if women with gestational diabetes mellitus (GDM) in the third trimester of pregnancy exhibit adverse cardiac alterations in myocardial energetics, function, or tissue characteristics.

RESEARCH DESIGN AND METHODS

Thirty-eight healthy, pregnant women and 30 women with GDM were recruited. Participants underwent phosphorus MRS and cardiovascular magnetic resonance for assessment of myocardial energetics (phosphocreatine [PCr] to ATP ratio), tissue characteristics, biventricular volumes and ejection fractions, left ventricular (LV) mass, global longitudinal shortening (GLS), and mitral in-flow E-wave to A-wave ratio.

RESULTS

Participants were matched for age, gestational age, and ethnicity. The following data are reported as mean ± SD. The women with GDM had higher BMI (27 ± 4 vs. 33 ± 5 kg/m2; P = 0.0001) and systolic (115 ± 11 vs. 121 ± 13 mmHg; P = 0.04) and diastolic (72 ± 7 vs. 76 ± 9 mmHg; P = 0.04) blood pressures. There was no difference in N-terminal pro-brain natriuretic peptide concentrations between the groups. The women with GDM had lower myocardial PCr to ATP ratio (2.2 ± 0.3 vs. 1.9 ± 0.4; P < 0.0001), accompanied by lower LV end-diastolic volumes (76 ± 12 vs. 67 ± 11 mL/m2; P = 0.002) and higher LV mass (90 ± 13 vs. 103 ± 18 g; P = 0.001). Although ventricular ejection fractions were similar, the GLS was reduced in women with GDM (-20% ± 3% vs. -18% ± 3%; P = 0.008).

CONCLUSIONS

Despite no prior diagnosis of diabetes, women with obesity and GDM manifest impaired myocardial contractility and higher LV mass, associated with reductions in myocardial energetics in late pregnancy compared with lean women with healthy pregnancy. These findings may aid our understanding of the long-term cardiovascular risks associated with GDM.

Management of May Thurner Syndrome in Pregnant Patients

May Thurner Syndrome contributes to thromboembolic disease and can cause significant morbidity in pregnant patients secondary to exaggerated anatomic relationships and physiologic changes in the hematologic system favoring thrombogenesis. Because this condition is both underrecognized and underreported, management in pregnant and postpartum patients is based on expert opinion without any formal evidence-based guidance. Herein, we review five pregnancies in four patients with May Thurner Syndrome and general management strategies. Through collaborative and multidisciplinary care, patients with May Thurner Syndrome can be safely and successfully managed during pregnancy and the postpartum period with appropriate anticoagulation.

The Neuroanatomy of Pregnancy and Postpartum

Pregnancy and giving birth are exceptional states in a woman's life for many reasons. While the effects of pregnancy and childbirth on the female body are obvious, less is known about their impact on the female brain, especially in humans. The scientific literature is still sparse but we have identified 12 longitudinal neuroimaging studies conducted in women whose brains were scanned before pregnancy, during pregnancy, and/or after giving birth. This review summarizes and discusses the reported neuroanatomical changes during pregnancy, postpartum, and beyond. Some studies suggest that pregnancy is mainly associated with tissue decreases, and a few studies suggest that this tissue loss is mostly permanent. In contrast, the majority of studies seems to indicate that the postpartum period is accompanied by substantial tissue increases throughout the entire brain. Future research is clearly warranted to replicate and extend the current findings, while addressing various limitations and shortcomings of existing studies.

Prospective Investigation of Glutamate Levels and Percentage Gray Matter in the Medial Prefrontal Cortex in Females at Risk for Postpartum Depression

BACKGROUND

The substantial female hormone fluctuations associated with pregnancy and postpartum have been linked to a greater risk of developing depressive symptoms, particularly in high-risk women (HRW), i.e. those with histories of mood sensitivity to female hormone fluctuations. We have shown that glutamate (Glu) levels in the medial prefrontal cortex (MPFC) decrease during perimenopause, a period of increased risk of developing a major depressive episode. Our team has also demonstrated that percentage gray matter (%GM), another neural correlate of maternal brain health, decreases in the MPFC during pregnancy.

OBJECTIVE

To investigate MPFC Glu levels and %GM from late pregnancy up to 7 weeks postpartum in HRW and healthy pregnant women (HPW).

METHODS

Single-voxel spectra were acquired from the MPFC of 41 HPW and 22 HRW using 3- Tesla in vivo proton magnetic resonance spectroscopy at five different time points.

RESULTS

We observed a statistically significant interaction between time and group for the metabolite Glu, with Glu levels being lower for HRW during pregnancy and early postpartum (p<0.05). MPFC %GM was initially lower during pregnancy and then significantly increased over time in both groups (p<0.01).

CONCLUSION

This investigation suggests that the vulnerability towards PPD is associated with unique fluctuations of MPFC Glu levels during pregnancy and early postpartum period. Our results also suggest that the decline in MPFC %GM associated with pregnancy seems to progressively recover over time. Further investigations are needed to determine the specific role that female hormones play on the physiological changes in %GM during pregnancy and postpartum.

Urolithiasis in pregnancy: Advances in imaging modalities and evaluation of current trends in endourological approaches

OBJECTIVE

Given the challenges involved in diagnosis and treatment of pregnant women with urolithiasis, we aim to review the imaging modalities and current endourological management of these patients.

MATERIALS AND METHODS

We performed a review of the available literature on urolithiasis in pregnancy. This included evaluation, diagnostic imaging, and therapeutic options. The databases we searched from included Google Scholar and PubMed. A total of 346 abstracts were screened. After our inclusion/exclusion criteria were met, we were left with 42 sources: 18 retrospective studies, 10 reviews/meta-analyses, 8 sets of guidelines, 5 randomized control trials, and 1 prospective cohort.

RESULTS

We begin our review with the literature available on the safety and efficacy of imaging modalities in the surgical planning for urolithiasis in pregnant patients. This includes renal ultrasound, abdominal x-ray, computed tomography scan, and magnetic resonance imaging. While computed tomography may result in an added radiation exposure, with possible safety concerns, magnetic resonance imaging seems to be safer, however a less sensitive test. We next describe safety, efficacy, and outcomes of various surgical interventions for urolithiasis in pregnant patients. This encompasses ureteral stenting, percutaneous nephrostomy, ureteroscopy, extracorporeal shock wave lithotripsy, and percutaneous nephrolithotomy. Ureteroscopy is a safer approach, but percutaneous nephrolithotomy offers higher stone-free rates. Using an evidence-based approach, we propose an algorithm for management of the pregnant women with renal colic.

CONCLUSION

Management of the pregnant women with suspected urolithiasis is a unique challenge for healthcare providers. A multi-disciplinary approach should be taken to optimize outcomes through an evidence-based approach.

How Could Nanomedicine Improve the Safety of Contrast Agents for MRI during Pregnancy?

Pregnancy is a delicate state, during which timely investigation of possible physiological anomalies is essential to reduce the risk of maternal and fetal complications. Medical imaging encompasses different technologies to image the human body for the diagnosis, course of treatment management, and follow-up of diseases. Ultrasound (US) is currently the imaging system of choice for pregnant patients. However, sonographic evaluations can be non-effective or give ambiguous results. Therefore, magnetic resonance imaging (MRI), due to its excellent tissue penetration, the possibility of acquisition of three-dimensional anatomical information, and its high spatial resolution, is considered a valid diagnostical alternative. Nevertheless, currently employed contrast agents to improve the MRI image quality are harmful to the fetus. Because of their ability to cross the placenta, their use on pregnant patients is avoided. This review will firstly recapitulate the most common non-obstetrical, obstetrical, and fetal indications for magnetic resonance imaging on pregnant women. Fetal safety risks, due to the use of strong magnetic fields and exogenous contrast agents, will be presented. Then, possible advantages of nanostructured contrast agents compared to current molecular ones are explored. Nanosystems’ characteristics affecting contrast efficiency, and their potential for improving contrast-enhanced MRI’s safety in pregnant women, are discussed. Lastly, promising examples of nanoparticles as safer alternatives to current MRI contrast agents in pregnancy are discussed.

MRI in Pregnancy and Precision Medicine: A Review from Literature

Magnetic resonance imaging (MRI) offers excellent spatial and contrast resolution for evaluating a wide variety of pathologies, without exposing patients to ionizing radiations. Additionally, MRI offers reproducible diagnostic imaging results that are not operator-dependent, a major advantage over ultrasound. MRI is commonly used in pregnant women to evaluate, most frequently, acute abdominal and pelvic pain or placental abnormalities, as well as neurological or fetal abnormalities, infections, or neoplasms. However, to date, our knowledge about MRI safety during pregnancy, especially about the administration of gadolinium-based contrast agents, which are able to cross the placental barrier, is still limited, raising concerns about possible negative effects on both the mother and the health of the fetus. Contrast agents that are unable to cross the placenta in a way that is safe for the fetus are desirable. In recent years, some preclinical studies, carried out in rodent models, have evaluated the role of long circulating liposomal nanoparticle-based blood-pool gadolinium contrast agents that do not penetrate the placental barrier due to their size and therefore do not expose the fetus to the contrast agent during pregnancy, preserving it from any hypothetical risks. Hence, we performed a literature review focusing on contrast and non-contrast MRI use during pregnancy.

Glutamate levels in the medial prefrontal cortex of healthy pregnant women compared to non-pregnant controls

Very little is known about maternal cerebral changes during pregnancy. Since there is an increased risk for major depression during pregnancy and postpartum, it is important to understand the structural and neurochemical changes that occur in the brain during pregnancy. Using proton magnetic resonance spectroscopy (¹H-MRS) (3 T field strength), glutamate (Glu) levels were measured in the medial prefrontal cortex (MPFC) of 21 healthy gravid subjects 2-3 weeks before their due date (6.74 ± 1.39), and in 14 non-pregnant healthy controls during their follicular phase (8.53 ± 1.55). Water quantified MPFC Glu levels were decreased in pregnant women (p < 0.01). We also observed a 13.9% decrease in percentage grey matter (%GM) (p < 0.01) in our MPFC voxel. As Glu is mostly found in GM, we repeated the statistical analysis after adjustment for %GM and found that the difference in Glu levels was no longer statistically significant when adjusted for %GM (p = 0.10). This investigation is the only systematic direct investigation of brain tissue composition and Glu levels in pregnant women. The main finding of this investigation is the decreased %GM in healthy pregnant women compared to non-pregnant women. These findings of decreased %GM in pregnancy may be responsible for the frequent complaints by pregnant women of cognitive difficulties also described as pregnesia.

Automated Bowel Polyp Detection Based on Actively Controlled Capsule Endoscopy: Feasibility Study

This paper presents an active locomotion capsule endoscope system with 5D position sensing and real-time automated polyp detection for small-bowel and colon applications. An electromagnetic actuation system (EMA) consisting of stationary electromagnets is utilized to remotely control a magnetic capsule endoscope with multi-degree-of-freedom locomotion. For position sensing, an electronic system using a magnetic sensor array is built to track the position and orientation of the magnetic capsule during movement. The system is integrated with a deep learning model, named YOLOv3, which can automatically identify colorectal polyps in real-time with an average precision of 85%. The feasibility of the proposed method concerning active locomotion and localization is validated and demonstrated through in vitro experiments in a phantom duodenum. This study provides a high-potential solution for automatic diagnostics of the bowel and colon using an active locomotion capsule endoscope, which can be applied for a clinical site in the future.

Intracerebral and subarachnoid hemorrhage in pregnancy

Maternal stroke occurs in around 34 out of every 100,000 deliveries and is responsible for around 5%-12% of all maternal deaths. It is most commonly hemorrhagic, and women are at highest risk for developing pregnancy-related hemorrhage during the early postpartum period through 6 weeks following the delivery. The most common causes of hemorrhagic stroke in pregnant patients are arteriovenous malformations and cerebral aneurysms. Management is similar to that for acute hemorrhagic stroke in the nonpregnant population with standard use of computed tomography and judicious utilization of intracranial vessel imaging and contrast. The optimal delivery method is evaluated on a case-by-case basis, and cesarean delivery is not always required. As most current studies are limited by retrospective design, relatively small sample sizes, and heterogeneous study term definitions, strong and comprehensive evidence-based guidelines on the management of acute hemorrhagic stroke in pregnant patients are still lacking. In the future, multicenter registries and prospective studies with uniform definitions will help improve management strategies in this complex patient population.

Imaging Modalities for Evaluation of Intestinal Obstruction

It is essential for the colon and rectal surgeon to understand the evaluation and management of patients with both small and large bowel obstructions. Computed tomography is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions. Additional commonly used imaging modalities include plain radiographs and contrast imaging/fluoroscopy, while less commonly utilized imaging modalities include ultrasonography and magnetic resonance imaging. Regardless of the imaging modality used, interpretation of imaging should involve a systematic, methodological approach to ensure diagnostic accuracy.

Canadian Association of Radiologists Recommendations for the Safe Use of MRI During Pregnancy

The use of magnetic resonance imaging (MRI) during pregnancy is associated with concerns among patients and health professionals with regards to fetal safety. In this work, the Canadian Association of Radiologists (CAR) Working Group on MRI in Pregnancy presents recommendations for the use of MRI in pregnancy, derived from literature review as well as expert panel opinions and discussions. The working group, which consists of academic subspecialty radiologists and obstetrician-gynaecologists, aimed to provide updated, evidence-based recommendations addressing safety domains related to energy deposition, acoustic noise, and gadolinium-based contrast agent use based on magnetic field strength (1.5T and 3T) and trimester scanned, in addition to the effects of sedative use and occupational exposure.

Silent zero TE MR neuroimaging: Current state-of-the-art and future directions

Magnetic Resonance Imaging (MRI) scanners produce loud acoustic noise originating from vibrational Lorentz forces induced by rapidly changing currents in the magnetic field gradient coils. Using zero echo time (ZTE) MRI pulse sequences, gradient switching can be reduced to a minimum, which enables near silent operation.Besides silent MRI, ZTE offers further interesting characteristics, including a nominal echo time of TE = 0 (thus capturing short-lived signals from MR tissues which are otherwise MR-invisible), 3D radial sampling (providing motion robustness), and ultra-short repetition times (providing fast and efficient scanning).In this work we describe the main concepts behind ZTE imaging with a focus on conceptual understanding of the imaging sequences, relevant acquisition parameters, commonly observed image artefacts, and image contrasts. We will further describe a range of methods for anatomical and functional neuroimaging, together with recommendations for successful implementation.

Management of brain tumors presenting in pregnancy: a case series and systematic review

Patients who present with brain tumors during pregnancy require unique imaging and neurosurgical, obstetrical, and anesthetic considerations. Here, we review the literature and discuss the management of patients who present with brain tumors during pregnancy. Between 2009 and 2019, 9 patients were diagnosed at our institution with brain tumors during pregnancy. Clinical information was extracted from the electronic medical records. The median age at presentation was 29 years (range, 25-38 years). The most common symptoms at presentation included headache (n=5), visual changes (n=4), hemiparesis (n=3), and seizures (n=3). The median gestational age at presentation was 20.5 weeks (range, 11-37 weeks). Of note, 8 patients (89%) delivered healthy newborns, and 1 patient terminated her pregnancy. In addition, 5 patients (56%) required neurosurgical procedures during pregnancy (gestational ages, 14-37 weeks) because of disease progression (n=2) or neurologic instability (n=3). There was 1 episode of postneurosurgery morbidity (pulmonary embolism [PE]) and no surgical maternal mortality. The median length of follow-up was 15 months (range, 6-45 months). In cases demonstrating unstable or progressive neurosurgical status past the point of fetal viability, neurosurgical intervention should be considered. The physiological and pharmacodynamic changes of pregnancy substantially affect anesthetic management. Pregnancy termination should be discussed and offered to the patient when aggressive disease necessitates immediate treatment and the fetal gestational age remains previable, although neurologically stable patients may be able to continue the pregnancy to term. Ultimately, pregnant patients with brain tumors require an individualized approach to their care under the guidance of a multidisciplinary team.

Prenatal diagnosis of bilateral congenital microphthalmia in two fetuses from the same parents

Congenital microphthalmia (CM) is a rare anomaly of the fetal orbit, results from developmental defects of the primary optic vesicle, and is characterized by a reduced eyeball volume and axial diameter. Fetal CM cases have rarely been reported. Herein, we present a case of two fetuses with bilateral CM from the same parents, diagnosed using ultrasonography (US) and magnetic resonance imaging (MRI). We found that the antepartum US and MRI measurements were smaller than the postpartum ones. Genetic testing of the parents and fetuses revealed that GL12 gene mutation may be associated with CM.

Fetal Exposure to MR Imaging: Long-Term Neurodevelopmental Outcome

BACKGROUND AND PURPOSE

Very few studies have investigated long-term neurodevelopment of children exposed to MR imaging antenatally. Thus, the purpose of our study was to evaluate long-term neurodevelopmental outcomes of children exposed to MR imaging during pregnancy.

MATERIALS AND METHODS

We conducted a historical prospective cohort study in a single tertiary medical center. Women exposed to 1.5T noncontrast MR imaging for maternal or fetal indications were matched to unexposed controls. Long-term neurodevelopmental outcomes were evaluated of their children, 2.5 to 6 years of age, according to the Vineland-II Adaptive Behavior Scale. The Vineland-II Adaptive Behavior Scale assesses communication, daily living skills, socialization, and motor skills. A composite score summarizes these 4 domains.

RESULTS

A total of 131 exposed women matched our inclusion criteria and were included in the study group, and 771 unexposed women, in the control group. No difference was identified in the Vineland-II Adaptive Behavior Scale composite score between the children of the study and control groups (mean, 110.79 versus 108.18; P = .098). Differences were also not observed between the children of the 2 groups in 3 of the 4 questionnaire domains: communication (108.84 versus 109.10; P = .888), daily living skills (109.51 versus 108.28; P = .437), and motor skills (105.09 versus 104.42; P = .642). However, the socialization score was favorable for the study group (112.98 versus 106.47; P < .001).

CONCLUSIONS

Exposure to 1.5T noncontrast MR imaging during pregnancy had no harmful effects on long-term neurodevelopmental outcomes. This study contributes to understanding the safety of MR imaging during pregnancy.

Noninvasive high-resolution electromyometrial imaging of uterine contractions in a translational sheep model

In current clinical practice, uterine contractions are monitored via a tocodynamometer or an intrauterine pressure catheter, both of which provide crude information about contractions. Although electrohysterography/electromyography can measure uterine electrical activity, this method lacks spatial specificity and thus cannot accurately measure the exact location of electrical initiation and location-specific propagation patterns of uterine contractions. To comprehensively evaluate three-dimensional uterine electrical activation patterns, we describe here the development of electromyometrial imaging (EMMI) to display the three-dimensional uterine contractions at high spatial and temporal resolution. EMMI combines detailed body surface electrical recording with body-uterus geometry derived from magnetic resonance images. We used a sheep model to show that EMMI can reconstruct uterine electrical activation patterns from electrodes placed on the abdomen. These patterns closely match those measured with electrodes placed directly on the uterine surface. In addition, modeling experiments showed that EMMI reconstructions are minimally affected by noise and geometrical deformation. Last, we show that EMMI can be used to noninvasively measure uterine contractions in sheep in the same setup as would be used in humans. Our results indicate that EMMI can noninvasively, safely, accurately, robustly, and feasibly image three-dimensional uterine electrical activation during contractions in sheep and suggest that similar results might be obtained in clinical setting.

MRI safety considerations during pregnancy

The use of magnetic resonance imaging (MRI) during pregnancy is on the rise due its ability to provide detailed cross-sectional anatomy without ionizing radiation. Despite the favorable radiation profile, theoretically concerns regarding the safety of MRI and gadolinium-based contrast agent (GBCA) administration have been raised. Currently there are no studies that have shown any attributable harms of MRI during any trimester of pregnancy although prospective and longitudinal studies are lacking. GBCA administration may be associated with a slightly higher rate of neonatal death, although this is based on a single, large cohort study. Understanding the available evidence regarding MRI safety during pregnancy in the context of current society guidelines will help the radiologist serve as a valuable resource to patients and referring providers.

Fetal MRI for dummies: what the fetal medicine specialist should know about acquisitions and sequences

Fetal MRI is an increasingly used tool in the field of prenatal diagnosis. While US remains the first line screening tool, as an adjuvant imaging tool, MRI has been proven to increase diagnostic accuracy and change patient counseling. Further, there are instances when US may not be sufficient for diagnosis. As a multidisciplinary field, it is important that every person involved in the referral, diagnosis, counseling and treatment of the patients is familiar with the basic principles, indications and findings of fetal MRI. The purpose of the current paper is to equip radiologists and non-radiologists with basic MRI principles and essential topics in patient preparation and provide illustrative examples of when fetal MRI may be used. This aims to aid the referring clinician in better selecting and improve patient counseling prior to arrival in the radiology department and, ultimately, patient care.

Accuracy of electromyometrial imaging of uterine contractions in clinical environment

Clinically, uterine contractions are monitored with tocodynamometers or intrauterine pressure catheters. In the research setting, electromyography (EMG), which detects electrical activity of the uterus from a few electrodes on the abdomen, is feasible, can provide more accurate data than these other methods, and may be useful for predicting preterm birth. However, EMG lacks sufficient spatial resolution and coverage to reveal where uterine contractions originate, how they propagate, and whether preterm contractions differ between women who do and do not progress to preterm delivery. To address those limitations, electromyometrial imaging (EMMI) was recently developed and validated to non-invasively assess three-dimensional (3D) electrical activation patterns on the entire uterine surface in pregnant sheep. EMMI uses magnetic resonance imaging to obtain subject-specific body-uterus geometry and collects uterine EMG data from up to 256 electrodes on the body surface. EMMI software then solves an ill-posed inverse computation to combine the two datasets and generate maps of electrical activity on the entire 3D uterine surface. Here, we assessed the feasibility to clinically translate EMMI by evaluating EMMI's accuracy under the unavoidable geometrical alterations and electrical noise contamination in a clinical environment. We developed a hybrid experimental-simulation platform to model the effects of fetal kicks, contractions, fetal/maternal movements, and noise contamination caused by maternal respiration and environmental electrical activity. Our data indicate that EMMI can accurately image uterine electrical activity in the presence of geometrical deformations and electrical noise, suggesting that EMMI can be reliably translated to non-invasively image 3D uterine electrical activation in pregnant women.

Fetal Cardiac Functional Assessment by Fetal Heart Magnetic Resonance Imaging

OBJECTIVE

We attempted to evaluate fetal cardiac activity of congenital heart disease (CHD) and normal heart fetuses by magnetic resonance imaging (MRI).

METHODS

We evaluated the fetal cardiac functional assessment and the blood flow of descending aorta at 34 weeks' gestation or more by MRI and compared the results with ultrasonography findings. We measured 6 normal heart fetuses and 14 CHD fetuses.

RESULTS

The ejection fraction (EF) and descending aorta blood flow in the CHD group were 76.4% ± 11.9%, 687.5 ± 303.8 mL/min by ultrasonography and 48.3% ± 7.1%, 711.4 ± 273.1 mL/min by MRI; those in the normal group were 66.9% ± 12.2%, 898.1 ± 245.9 mL/min by ultrasonography and 51.3% ± 4.2%, 911.9 ± 223.1 mL/min by MRI.

CONCLUSIONS

There was no significant difference in descending aorta blood flow measurements between ultrasonography and MRI, but the EF showed a significant between-group difference. In the normal group, the variation of EF and blood flow measured by MRI was significantly smaller compared with those of ultrasonography.

Independent validation of metric optimized gating for fetal cardiovascular phase-contrast flow imaging

PURPOSE

To validate metric optimized gating phase-contrast MR (MOG PC-MR) flow measurements for a range of fetal flow velocities in phantom experiments. 2) To investigate intra- and interobserver variability for fetal flow measurements at an imaging center other than the original site.

METHODS

MOG PC-MR was compared to timer/beaker measurements in a pulsatile flow phantom using a heart rate (∼145 bpm), nozzle diameter (∼6 mm), and flow range (∼130-700 mL/min) similar to fetal imaging. Fifteen healthy fetuses were included for intra- and interobserver variability in the fetal descending aorta and umbilical vein.

RESULTS

Phantom MOG PC-MR flow bias and variability was 2% ± 23%. Accuracy of MOG PC-MR was degraded for flow profiles with low velocity-to-noise ratio. Intra- and interobserver coefficients of variation were 6% and 19%, respectively, for fetal descending aorta; and 10% and 17%, respectively, for the umbilical vein.

CONCLUSION

Phantom validation showed good agreement between MOG and conventionally gated PC-MR, except for cases with low velocity-to-noise ratio, which resulted in MOG misgating and underestimated peak velocities and warranted optimization of sequence parameters to individual fetal vessels. Inter- and intraobserver variability for fetal MOG PC-MR imaging were comparable to previously reported values.

Fetal MRI, lower acceptance by women in research vs. clinical setting

AIM

To determine acceptance of pregnant women to undergo fetal magnetic resonance imaging (MRI) examination in research and clinical setting.

METHODS

A prospective study included a research group [part of a study comparing brain ultrasound (US) to MRI in fetuses at risk for acquired brain damage] and a clinical group [fetuses with suspected (brain) anomalies after structural US examination] from 2011 to 2014. All women were advised to use sedatives. MRI declinations, use of sedation, MRI duration and imaging quality were compared between both groups.

RESULTS

Study participation was accepted in 57/104 (55%) research cases. Fetal MRI was performed in 34/104 (33%) research and 43/44 (98%) clinical cases. Reasons to decline study participation were MRI related in 41%, and participation was too burdensome in 46%. Acceptance was highest for indication infection and lowest in alloimmune thrombocytopenia and monochorionic twin pregnancy. Sedatives were used in 14/34 research and 43/43 clinical cases. Scan duration and quality were comparable (21 and 20 min in research and clinical cases, respectively, moderate/good quality in both groups).

CONCLUSIONS

Pregnant women consider MRI more burdensome than professionals realize. Two-third of women at risk for fetal brain damage decline MRI examination. Future studies should evaluate which information about fetal MRI is supportive.

Is there a role for cardiac magnetic resonance imaging during pregnancy?

Purpose: To assess the role of cardiac magnetic resonance imaging (CMR) for the evaluation and management of women with cardiac disorders in pregnancy and postpartum.Methods: Retrospective record review of women at a university-affiliated, single institution referred for CMR without contrast due to known or suspected cardiac disorders between January 2010 and December 2015. Medical records, echocardiogram and CMR reports were reviewed. Instances where clinical management was changed based on CMR findings were identified.Results: There were 17 peripartum CMR studies performed without contrast in 17 pregnancies from 16 women. Indications for CMR included congenital heart disease (N = 8, 47.1%), Marfan syndrome or strong family history of Marfan syndrome (N = 5, 29.4%), cardiomyopathy (N = 1, 5.9%), cardiac mass (N = 1, 5.9%), persistent dyspnea with a normal echocardiogram (N = 1, 5.9%), and hypertension with suspected aortic root dilation (N = 1, 5.9%). CMR confirmed the echocardiogram diagnosis in eight (47.1%) and improved the diagnosis in five (29.4%). Availability of CMR findings changed the delivery management in 2/17 (11.8%) women. CMR was especially helpful in assessing the size of the aortic root in women at risk for dilation.Conclusions: Although echocardiogram imaging of the heart is considered the first-line method for assessing the maternal cardiac status, CMR can provide information about cardiac anatomy and function in pregnant women with complex cardiac disease or suspected aortic pathology. Management may be changed based on results.

Fetal MRI in management of complicated meconium ileus: Prenatal and surgical imaging

OBJECTIVE

To review fetal MRI cases surgically proven to have meconium ileus (MI) and obstruction, describe the common fetal MRI findings that distinguish cases of complicated MI, and to compare these findings with surgical images and perinatal outcomes.

METHOD

We performed a retrospective review of all fetal MRI examinations and the corresponding medical record from our tertiary care children's hospital over an 18-month period. Postnatal management and outcomes were reviewed for these patients, and those patients with surgical or postmortem diagnosis of complicated MI were included in the study.

RESULTS

Our analysis revealed 7 cases. In this cohort, 3 imaging features of the fetal bowel were repeatedly seen: gradient appearance of intraluminal bowel contents, abnormally localized meconium signal, and collapsed appearance of the colon on MRI. Surgical diagnoses confirmed MI. All live-born infants underwent surgical repair.

CONCLUSION

Fetal MRI should be included in the diagnostic algorithm of any pregnancy where fetal bowel obstruction is suspected to better risk stratify patients.

Contemporary best practice urolithiasis in pregnancy

Urolithiasis is the most common nonobstetric complication in the gravid patient. The experience can provoke undue stress for the mother, fetus, and management team. The physiologic changes of pregnancy render the physical exam and imaging studies less reliable than in the typical patient. Diagnosis is further complicated by the need for careful selection of imaging modality in order to maximize diagnostic utility and minimize obstetric risk to the mother and ionizing radiation exposure to the fetus. Ultrasound remains the first-line diagnostic imaging modality in this group, but other options are available if results are inconclusive. A trial of conservative management is uniformly recommended. In patients who fail spontaneous stone passage, treatment may be temporizing or definitive. While temporizing treatments have classically been deemed the gold standard, ureteroscopic stone removal is now acknowledged as a safe and highly effective definitive treatment approach. Ultimately, a multidisciplinary, team-based approach involving the patient, her obstetrician, urologist, radiologist, and anesthesiologist is needed to devise a maximally beneficial management plan.

Feasibility of whole-body diffusion-weighted MRI for detection of primary tumour, nodal and distant metastases in women with cancer during pregnancy: a pilot study

OBJECTIVES

To evaluate the feasibility of whole-body diffusion-weighted MRI (WB-DWI/MRI) for detecting primary tumour, nodal and distant metastases in pregnant women with cancer.

METHODS

Twenty pregnant patients underwent WB-DWI/MRI in additional to conventional imaging. Reproducibility of WB-DWI/MRI between two readers was evaluated using Cohen's κ statistics and accuracy was compared to conventional imaging for assessing primary tumour site, nodal and visceral metastases.

RESULTS

Both WB-DWI/MRI readers showed good-very good agreement for lesion detection (primary lesions: κ=1; lymph nodes: κ=0.89; distant metastases: κ=0.61). Eight (40 %) patients were upstaged after WB-DWI/MRI. For nodal metastases, WB-DWI/MRI showed 100 % (95 % CI: 83.2-100) sensitivity for both readers with specificity of 99.4 % (96.9-100) and 100 % (80.5-100) for readers 1 and 2, respectively. For distant metastases, WB-DWI/MRI showed 66.7 % (9.4-99.2) and 100 % (29.2-100) sensitivity and specificity of 94.1 % (71.3-99.9) and 100 % (80.5-100) for readers 1 and 2, respectively. Conventional imaging showed sensitivity of 50 % (27.2-72.8) and 33.3 % (0.8-90.6); specificity of 100 % (98-100) and 100 % (80.5-100), for nodal and distant metastases respectively.

CONCLUSIONS

WB-DWI/MRI is feasible for single-step non-invasive staging of cancer during pregnancy with additional value for conventional imaging procedures.

KEY POINTS

• In our study, WB-DWI/MRI was more accurate than conventional imaging during pregnancy. • WB-DWI/MRI improves diagnostic assessment of patients with cancer during pregnancy. • Accurate imaging and oncologic staging improves treatment and outcome.

Imaging of Cardiovascular Disease in Pregnancy and the Peripartum Period

OPINION STATEMENT

Cardiovascular disease is an important cause of morbidity and mortality during pregnancy and the postpartum period. During pregnancy, the cardiovascular system undergoes extensive hemodynamic, hormonal, and microstructural changes which may exacerbate a preexisting underlying cardiovascular condition or predispose to cardiovascular complications not typically seen in young healthy women. Such conditions include spontaneous coronary artery dissection, atherosclerotic coronary artery disease, and peripartum cardiomyopathy. When evaluating this patient population, the diagnostic strategy should be tailored to specifically assess this distinct disease spectrum. The choice of imaging techniques must also consider potential risks to both the mother and child; a unique challenge of diagnostic imaging during pregnancy. The risk of radiation from radiography, computed tomography, and nuclear medicine imaging; iodinated and gadolinium-based contrast media for computed tomography and magnetic resonance imaging respectively; and heat deposition from sonography are of special importance during pregnancy. A thorough understanding of pregnancy-specific cardiovascular complications and the capabilities and risks of available diagnostic imaging modalities is crucial to appropriately manage the pregnant patient.

Fetal MR Imaging of Gastrointestinal Abnormalities

Fetal magnetic resonance (MR) imaging plays an increasing and valuable role in antenatal diagnosis and perinatal management of fetal gastrointestinal (GI) abnormalities. Advances in MR imaging data acquisition and use of motion-insensitive techniques have established MR imaging as an important adjunct to obstetric ultrasonography (US) for fetal diagnosis. In this regard, MR imaging provides high diagnostic accuracy for antenatal diagnosis of common and uncommon GI pathologic conditions. In the setting of fetal GI disease, T1-weighted images demonstrate the amount and distribution of meconium, which is crucial to the diagnostic capability of fetal MR imaging. Specifically, knowledge of the T1 signal intensity characteristics of fetal meconium, the normal pattern of meconium with advancing gestational age, and the expected caliber of small and large bowel in the fetus is key to diagnosis of abnormalities of the GI tract. Use of ultrafast T2-weighted sequences for evaluation of the expected location and morphology of fluid-containing structures, including the stomach and small bowel, in the fetal abdomen further aids in diagnostic confidence. Uncommonly encountered fetal GI pathologic conditions, especially cloacal dysmorphology, may demonstrate characteristic MR imaging patterns, which may add additional information to that from fetal US, allowing improved fetal and neonatal management. This article discusses common indications for fetal MR imaging of the GI tract, imaging protocols for fetal GI MR imaging, the normal appearance of the fetal GI tract with advancing gestational age, and the imaging appearances of common fetal GI abnormalities, as well as uncommon fetal GI conditions with characteristic appearances. (©)RSNA, 2016.

Use of MRI in the diagnosis of fetal brain abnormalities in utero (MERIDIAN): a multicentre, prospective cohort study

BACKGROUND

In-utero MRI (iuMRI) has shown promise as an adjunct to ultrasound but the comparative diagnostic performance has been poorly defined. We aimed to assess whether the diagnostic accuracy and confidence of the prenatal diagnosis of fetal brain abnormalities is improved with iuMRI and assess the clinical impact and patient acceptability of iuMRI.

METHODS

We did a multicentre, prospective, cohort study in the UK, at 16 fetal medicine centres, of pregnant women aged 16 years or older whose fetus had a brain abnormality detected by ultrasound at a gestational age of 18 weeks or more, had no contraindications to iuMRI, and consented to enter the study. Women carrying a fetus suspected of having a brain anomaly on ultrasound had iuMRI done within 14 days of ultrasound. The findings were reviewed by two independent panels and used to estimate diagnostic accuracy and confidence by comparison with outcome diagnoses. Changes in diagnosis, prognosis, and clinical management brought about by iuMRI and patient acceptability were assessed.

FINDINGS

Participants were recruited between July 29, 2011, and Aug 31, 2014. The cohort was subdivided by gestation into the 18 weeks to less than 24 weeks fetus cohort (n=369) and into the 24 weeks or older fetus cohort (n=201). Diagnostic accuracy was improved by 23% (95% CI 18-27) in the 18 weeks to less than 24 weeks group and 29% (23-36) in the 24 weeks and older group (p<0·0001 for both groups). The overall diagnostic accuracy was 68% for ultrasound and 93% for iuMRI (difference 25%, 95% CI 21-29). Dominant diagnoses were reported with high confidence on ultrasound in 465 (82%) of 570 cases compared with 544 (95%) of 570 cases on iuMRI. IuMRI provided additional diagnostic information in 387 (49%) of 783 cases, changed prognostic information in at least 157 (20%), and led to changes in clinical management in more than one in three cases. IuMRI also had high patient acceptability with at least 95% of women saying they would have an iuMRI study if a future pregnancy were complicated by a fetal brain abnormality.

INTERPRETATION

iuMRI improves diagnostic accuracy and confidence for fetal brain anomalies and leads to management changes in a high proportion of cases. This finding, along with the high patient acceptability, leads us to propose that any fetus with a suspected brain abnormality on ultrasound should have iuMRI to better inform counselling and management decisions.

FUNDING

National Institute for Health Research Health Technology Assessment programme.

Parameter set for computer-assisted texture analysis of fetal brain

BACKGROUND

Magnetic resonance data were collected from a diverse population of gravid women to objectively compare the quality of 1.5-tesla (1.5 T) versus 3-T magnetic resonance imaging of the developing human brain. MaZda and B11 computational-visual cognition tools were used to process 2D images. We proposed a wavelet-based parameter and two novel histogram-based parameters for Fisher texture analysis in three-dimensional space.

RESULTS

Wavenhl, focus index, and dispersion index revealed better quality for 3 T. Though both 1.5 and 3 T images were 16-bit DICOM encoded, nearly 16 and 12 usable bits were measured in 3 and 1.5 T images, respectively. The four-bit padding observed in 1.5 T K-space encoding mimics noise by adding illusionistic details, which are not really part of the image. In contrast, zero-bit padding in 3 T provides space for storing more details and increases the likelihood of noise but as well as edges, which in turn are very crucial for differentiation of closely related anatomical structures.

CONCLUSIONS

Both encoding modes are possible with both units, but higher 3 T resolution is the main difference. It contributes to higher perceived and available dynamic range. Apart from surprisingly larger Fisher coefficient, no significant difference was observed when testing was conducted with down-converted 8-bit BMP images.

Functional Connectivity of the Human Brain in Utero

The brain is subject to dramatic developmental processes during the prenatal period. Nevertheless, information about the development of functional brain networks during gestation is scarce. Until recently it has not been possible to probe function in the living human fetal brain. Advances in functional MRI have changed the paradigm, making it possible to measure spontaneous activity in the fetal brain and to cross-correlate functional signals to attain information about neural connectional architecture across human gestation. We summarize the earliest MRI studies of fetal neural functional connectivity and highlight unique challenges and limitations inherent in the technique. In addition, we discuss future directions to unlock the potential of fetal brain functional MRI research.

Magnetic Resonance Imaging of Abdominal and Pelvic Pain in the Pregnant Patient

The utility of MR imaging in evaluating abdominal and pelvic pain in the pregnant patient is discussed. Details regarding the indications, technical aspects, and imaging findings of various common abdominal and pelvic abnormalities in pregnancy are reviewed.

Fetal magnetic resonance imaging: exposure times and functional outcomes at preschool age

BACKGROUND

Fetal magnetic resonance imaging (MRI) has been routinely used as a noninvasive diagnostic tool for more than a decade; however, there is a paucity of follow-up studies examining the effects of prenatal exposure to 1.5-T MRI on developmental outcome.

OBJECTIVE

The objective of this study was to assess the safety of 1.5-T fetal MRI by evaluating functional outcomes of preschool children who were exposed in utero.

MATERIALS AND METHODS

In the context of a prospective observational study, healthy pregnant women underwent a 1.5-T MRI study using single-shot fast spin echo (SSFSE) sequences during the second or third trimester of pregnancy. The study was approved by the institutional review board at our institution, and written informed consent was obtained from all study participants. MRI scanning times were recorded, and prenatal/postnatal clinical data were collected prospectively. Functional outcomes were assessed using the Vineland Adaptive Behavior Scale (VABS), a widely used, norm-referenced and psychometrically sound functional assessment.

RESULTS

We studied 72 healthy pregnant women, who underwent fetal MRI at a mean gestational age of 30.5 ± 3.1 weeks. The cohort of fetuses was composed of 43% females, and 18 fetuses were scanned during the second trimester. All fetuses were born at term with appropriate birth weights (3.54 ± 0.5 kg) for gestational age. Mean age at follow-up testing was 24.5 ± 6.7 months. All children had age-appropriate scores in the communication, daily living, socialization and motor skills subdomains of the VABS (z-scores, P > 0.05). Furthermore, all children passed their newborn otoacoustic emission test and had normal hearing at preschool age. MRI study duration and exposure time to radio frequency waves and SSFSE sequences were not associated with adverse functional outcomes or hearing impairment.

CONCLUSION

Prenatal exposure to 1.5-T MRI during the second or third trimester of pregnancy in a cohort of healthy fetuses is not associated with disturbances in functional outcomes or hearing impairment at preschool age.

Computer-assisted surgical planning and intraoperative guidance in fetal surgery: a systematic review

Fetal surgery has become a clinical reality, with interventions for twin‐to‐twin transfusion syndrome (TTTS) and spina bifida demonstrated to improve outcome. Fetal imaging is evolving, with the use of 3D ultrasound and fetal MRI becoming more common in clinical practise. Medical imaging analysis is also changing, with technology being developed to assist surgeons by creating 3D virtual models that improve understanding of complex anatomy, and prove powerful tools in surgical planning and intraoperative guidance.

We introduce the concept of computer‐assisted surgical planning, and present the results of a systematic review of image reconstruction for fetal surgical planning that identified six articles using such technology.

Indications from other specialities suggest a benefit of surgical planning and guidance to improve outcomes. There is therefore an urgent need to develop fetal‐specific technology in order to improve fetal surgical outcome. © 2015 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd.

What's already known about this topic?

Fetal surgery has now become a clinical reality, with interventions such as laser treatment for twin‐to‐twin transfusion syndrome (TTTS) and open fetal surgery for spina bifida demonstrated in randomised control trials to improve neonatal outcome

Other specialities are increasingly utilising computer‐assisted surgical planning software, with evidence that this can improve outcome

What does this study add?

We feel that there is an urgent need to develop fetal‐specific technology for surgical planning as it is likely to play an important role in improving outcomes from fetal surgery

Challenges in magnetic resonance imaging for suspected acute appendicitis in pregnant patients

The assessment of a gravid patient with abdominal pain is a clinical challenge, as one must consider not only the common etiologies for abdominal pain but also etiologies resulting from the pregnancy. Further complicating the assessment is the altered anatomy and physiology that result from the enlarged uterus displacing and compressing normal anatomical structures. This alteration of anatomy makes the symptoms of appendicitis more variable and thus the diagnosis more difficult. Appropriate and timely imaging can result in better patient outcomes, and when appendicitis is suspected, imaging investigation should not be delayed. This article reviews some of the challenges of magnetic resonance imaging in gravid patients with suspected appendicitis and presents strategies for imaging this population.