Gadolinium periconceptional exposure: pregnancy and neonatal outcome

ACR Appropriateness Criteria® Acute Pelvic Pain in the Reproductive Age Group: 2023 Update

This review focuses on the initial imaging in the reproductive age adult population with acute pelvic pain, including patients with positive and negative beta-human chorionic gonadotropin (β-hCG) levels with suspected gynecological and nongynecological etiology. For all patients, a combination of transabdominal and transvaginal pelvic ultrasound with Doppler is usually appropriate as an initial imaging study. If nongynecological etiology in patients with negative β-hCG is suspected, then CT of the abdomen and pelvis with or without contrast is also usually appropriate. In patients with positive β-hCG and suspected nongynecological etiology, CT of the abdomen and pelvis with contrast and MRI of the abdomen and pelvis without contrast may be appropriate. In patients with negative β-hCG and suspected gynecological etiology, CT of the abdomen and pelvis with contrast, MRI of pelvis without contrast, or MRI of pelvis with and without contrast may be appropriate. 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 process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Associations of maternal urinary rare earth elements individually and in mixtures with neonatal size at birth

Prenatal rare earth elements (REEs) exposure is linked to unfavorable health consequences. Epidemiologic research on repeated measurements of REEs during gestation correlated with fetal growth is exiguous. Until now, few studies have characterized exposure characteristics of REEs in pregnant women. We aimed to ascertain the characteristics and predictors of REEs exposure over three trimesters among pregnant women and examine the possible effects of prenatal REEs exposure on size at birth. Urinary REEs concentrations exhibited considerable within-subject variation with intraclass correlation coefficients ranging from 0.16 to 0.58. Maternal age, household income, gestational weight gain, passive smoking during pregnancy, parity, and neonatal gender were associated with maternal urinary REEs concentrations. Elevated maternal urinary holmium and thulium concentrations in the 3rd trimester were significantly related to reductions in birth weight. Weighted quantile sum (WQS) regression model identified that urinary REEs mixture in the 3rd trimester were negatively related to birth weight (WQSREEs β = -26.22; 95% confidence interval [CI]: -47.62, -4.82), with holmium (40%) and thulium (24%) receiving the highest weights. Male infants received the most weight (>50%) related to decreased birth weight. This study revealed a significant association between individual and mixture REE exposure in late pregnancy with a reduction in birth weight.

Acute spontaneous non-hemorrhagic adrenal infarction in pregnancy: case-report and literature review

Unilateral non-hemorrhagic adrenal infarction (NHAI) is a very uncommon cause of acute abdomen in pregnancy. Diagnosis is highly challenging due to its rarity, heterogeneity of clinical presentation, and inconclusiveness of the initial workup. Timely recognition is pivotal to ensuring optimal outcomes. Here we describe a case of spontaneous unilateral NHAI diagnosed in a singleton pregnant woman at 32 weeks' gestation at our centre and provide the findings of an extensive literature review on the topic. We identified 22 articles describing 31 NHAI cases in 30 obstetric patients: NHAI occurs more frequently on the right side and in the third trimester, and diagnosis is formulated more than 24 h after clinical presentation in 50% of cases; second-level imaging is always necessary to reach a definitive diagnosis and start appropriate treatment. A high degree of clinical suspicion is needed to promptly recognize NHAI in pregnancy, thus allowing appropriate multidisciplinary management and timely treatment initiation. Promotion of knowledge and awareness of NHAI as a potential cause of acute abdomen in pregnancy is mandatory to improve clinical practice and, ultimately, perinatal outcomes.

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.

Reducing Gadolinium Contrast With Artificial Intelligence

Gadolinium contrast is an important agent in magnetic resonance imaging (MRI), particularly in neuroimaging where it can help identify blood-brain barrier breakdown from an inflammatory, infectious, or neoplastic process. However, gadolinium contrast has several drawbacks, including nephrogenic systemic fibrosis, gadolinium deposition in the brain and bones, and allergic-like reactions. As computer hardware and technology continues to evolve, machine learning has become a possible solution for eliminating or reducing the dose of gadolinium contrast. This review summarizes the clinical uses of gadolinium contrast, the risks of gadolinium contrast, and state-of-the-art machine learning methods that have been applied to reduce or eliminate gadolinium contrast administration, as well as their current limitations, with a focus on neuroimaging applications. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 1.

Gadolinium during human pregnancy following administration of gadolinium chelate before pregnancy

Gadolinium (Gd), a toxic rare earth element, has been shown to dissociate from chelating agents and bioaccumulate within tissues, raising concerns about the possibility of their remobilization during pregnancy with subsequent free Gd exposures to developing fetuses. Gd chelates are among the most commonly used magnetic resonance imaging (MRI) contrast agents. This investigation was undertaken after the detection of elevated Gd (800-1000× higher than the usual rare earth element levels) in preliminary unpublished studies from the placentae of subjects in the NIH ECHO/UPSIDE Rochester Cohort Study and unpublished studies from placentae analyzed in formalin-fixed placental specimens from Surgical Pathology at the University of Rochester. Fifteen pregnancies with elevated Gd were studied (12 first pregnancies and 3 second pregnancies). Maternal bloods were collected from all three trimesters, maternal, and cord (fetal) bloods at delivery as well as placental tissue. Breastmilk was also collected from selected mothers. It was determined that Gd was present in maternal bloods from all three trimesters, and in cord bloods and breastmilk in both first and second pregnancies. These results emphasize the need to fully appreciate the implications of pre-pregnancy exposure to Gd chelates and its potential effects on maternal and fetal health.

Venous Thromboembolism Management in Pregnant Patients

Pulmonary embolism (PE) in pregnancy accounts for 10% of maternal deaths in the United States. As maternal morbidity and mortality continue to increase, it is imperative for all specialties interfacing with pregnant patients to understand the current research and guidelines surrounding risk stratification, diagnosis, and treatments of PE in pregnancy. Given the complexity of high-risk pregnancy-associated PE (PA-PE), that is, which is associated with hemodynamic instability or collapse, and the rising popularity of new technologies to treat high-risk PA-PE in the nonpregnant population, this review aims to emphasize the differences in diagnosis, risk stratification, and management of the pregnant and nonpregnant PE patients. Furthermore, this review will cover treatment paradigms that include anticoagulation versus advanced therapies such as systemic thrombolysis, surgical embolectomy, extracorporeal membrane oxygenation, and inferior vena cava disruption as well as the more novel therapies which fall under the umbrella term of catheter-based treatments. Finally, this review will include a case-based review of 2 patients with PA-PE requiring catheter-based therapies and their ultimate clinical outcomes.

Rudimentary horn pregnancy, a differential diagnosis of an intraabdominal pregnancy: a case report

BACKGROUND

Rudimentary horn pregnancy is a rare life-threatening obstetric condition with clinical and sonographic presentation resembling that of an abdominal pregnancy. Preoperative diagnosis of advanced rudimentary horn pregnancy is difficult and cases are often identified incidentally during laparotomy for a presumed abdominal pregnancy.

CASE PRESENTATION

We report a case of a 29-year-old African woman, gravida 2 para 1 at 28 weeks of gestation complaining of epigastric pain for 7 days with no other associated gastrointestinal or genitourinary symptoms. On examination, she had normal vital signs and an enlarged abdomen sized at 33 cm with unremarkable fetal lie and presentation. She had normal laboratory blood results with an ultrasound revealing an abdominal pregnancy of 28 weeks. The informed decision for conservative management was planned after informing of the benefit and risks of early termination versus conservative management, however, with worsening symptoms an emergency laparotomy had to be performed in which a left unruptured rudimentary horn pregnancy with a viable fetus was identified incidentally and delivery of the fetus followed by surgical excision of the horn was done. The postoperative period was uneventful, and the patient was discharged home with her newborn.

CONCLUSION

Rudimentary horn pregnancy is very rare and often indistinguishable from an abdominal pregnancy in advanced gestation age. First trimester ultrasound is by far the only noninvasive sensitive diagnostic modality for rudimentary horn pregnancy. Laparotomy with horn excision remains the standard of care for advanced rudimentary horn pregnancy.

Gadolinium-Based Contrast Agents in Pregnant Women: A Literature Review of MRI Safety

Gadolinium-based contrast agents (GBCAs) are commonly used in magnetic resonance imaging (MRI) to enhance the visualisation and characterisation of the region of interest/lesion. Internal structures are well seen with MRI with good spatial resolution. Although MRI is generally considered safe during pregnancy, concerns have been raised regarding the safety of GBCAs, particularly during the first trimester. Limited studies have been conducted to assess the safety of GBCAs in pregnant women, with conflicting results. A comprehensive literature search was conducted using PubMed, SpringerLink, Medscape, ResearchGate and Wiley Online Library. The search terms included various combinations of MRI, pregnancy, first trimester, gadolinium contrast agents, foetus, risk, and toxicity. The search criteria were articles published in English in the last 20 years and indexed in the MEDLINE or Embase databases. The majority of studies found no definitive evidence that GBCAs are harmful during pregnancy, particularly during the first trimester. Some studies reported no increased risk of adverse outcomes in infants exposed to GBCAs during the first trimester. However, other studies showed inconsistent results. Retrospective cohort studies provided some reassurance regarding the safety of GBCAs when indicated in pregnant women but did not address potential long-term adverse outcomes in infants exposed to GBCAs during gestation. The literature review also highlights the importance of further evaluating the subacute and chronic effects of GBCA exposure in infants. The safety of GBCAs during pregnancy, particularly during the first trimester, remains uncertain. More large-scale, long-term studies are needed to clarify the safety of GBCAs in pregnant women and their potential effects on foetal and neonatal outcomes. Until conclusive evidence is available, healthcare providers should carefully weigh the benefits and risks of using GBCAs during pregnancy and consider alternative imaging modalities, such as non-contrast MRI or ultrasound, when necessary.

Cervical cancer in the pregnant population

Cervical cancer is the second most encountered cancer in pregnant patients. The 2018 International Federation of Gynecology and Obstetrics (FIGO) staging system for cervical cancer updated the staging of primary cervical carcinoma and disease process, with formal incorporation of imaging as a vital source of information in the management process to improve accuracy. Diagnosis and treatment of the pregnant population is a complex interplay of achieving adequate diagnostic information and optimal treatment while minimizing toxicity and risks to the mother and fetus. While novel imaging techniques and anticancer therapies are rapidly developed, much information on the safety and feasibility of different therapies is not yet available in the pregnant population. Therefore, managing pregnant patients with cervical cancer is complex and requires a multidisciplinary approach.

Australian inflammatory bowel disease consensus statements for preconception, pregnancy and breast feeding

OBJECTIVE

Because pregnancy outcomes tend to be worse in women with inflammatory bowel disease (IBD) than in those without, we aimed to update consensus statements that guide the clinical management of pregnancy in patients with IBD.

DESIGN

A multidisciplinary working group was established to formulate these consensus statements. A modified RAND/UCLA appropriateness method was used, consisting of a literature review, online voting, discussion meeting and a second round of voting. The overall agreement among the delegates and appropriateness of the statement are reported.

RESULTS

Agreement was reached for 38/39 statements which provide guidance on management of pregnancy in patients with IBD. Most medications can and should be continued throughout pregnancy, except for methotrexate, allopurinol and new small molecules, such as tofacitinib. Due to limited data, no conclusion was reached on the use of tioguanine during pregnancy. Achieving and maintaining IBD remission before conception and throughout pregnancy is crucial to optimise maternofetal outcomes. This requires a multidisciplinary approach to engage patients, allay anxieties and maximise adherence tomedication. Intestinal ultrasound can be used for disease monitoring during pregnancy, and flexible sigmoidoscopy or MRI where clinically necessary.

CONCLUSION

These consensus statements provide up-to-date, comprehensive recommendations for the management of pregnancy in patients with IBD. This will enable a high standard of care for patients with IBD across all clinical settings.

Imaging of pregnant and lactating patients with suspected adrenal disorders

A high level of clinical suspicion is essential in the diagnosis and management of a suspected adrenal mass during pregnancy and the peripartum period. Timely recognition is important in order to improve fetal and maternal outcomes. Imaging is often performed to confirm a suspected adrenal lesion; however, increasing usage of diagnostic imaging during pregnancy and lactation has also increased awareness, concerns and confusion regarding the safety risks regarding fetal and maternal exposure to radiation and imaging intravenous contrast agents. This may lead to anxiety and avoidance of imaging examinations which can delay diagnosis and appropriate treatment. This article briefly reviews evidence-based recommended imaging modalities during pregnancy and the lactation period for the assessment of a suspected adrenal mass while recognizing that no examination should be withheld when the exam is necessary to confirm an important clinical suspicion. The imaging characteristics of the more common adrenal pathologies that may affect pregnant women are also discussed.

Multisystem Imaging Recommendations/Guidelines: In the Pursuit of Precision Oncology

With an increasing rate of cancers in almost all age groups and advanced screening techniques leading to an early diagnosis and longer longevity of patients with cancers, it is of utmost importance that radiologists assigned with cancer imaging should be prepared to deal with specific expected and unexpected circumstances that may arise during the lifetime of these patients. Tailored integration of preventive and curative interventions with current health plans and global escalation of efforts for timely diagnosis of cancers will pave the path for a cancer-free world. The commonly encountered circumstances in the current era, complicating cancer imaging, include coronavirus disease 2019 infection, pregnancy and lactation, immunocompromised states, bone marrow transplant, and screening of cancers in the relevant population. In this article, we discuss the imaging recommendations pertaining to cancer screening and diagnosis in the aforementioned clinical circumstances.

Contrast Agents during Pregnancy: Pros and Cons When Really Needed

Many clinical conditions require radiological diagnostic exams based on the emission of different kinds of energy and the use of contrast agents, such as computerized tomography (CT), positron emission tomography (PET), magnetic resonance (MR), ultrasound (US), and X-ray imaging. Pregnant patients who should be submitted for diagnostic examinations with contrast agents represent a group of patients with whom it is necessary to consider both maternal and fetal effects. Radiological examinations use different types of contrast media, the most used and studied are represented by iodinate contrast agents, gadolinium, fluorodeoxyglucose, gastrographin, bariumsulfate, and nanobubbles used in contrast-enhanced ultrasound (CEUS). The present paper reports the available data about each contrast agent and its effect related to the mother and fetus. This review aims to clarify the clinical practices to follow in cases where a radiodiagnostic examination with a contrast medium is indicated to be performed on a pregnant patient.

Imaging Cancer in Pregnancy

Pregnancy-associated cancer (PAC) is defined as cancer that is detected during pregnancy and up to 1 year postpartum. Although rare (~1:1000 pregnancies), PAC is increasing owing to postponed childbearing and advanced maternal age at conception. Cancer-related symptoms masked by physiologic gestational changes may delay diagnosis. Imaging, clinical management, and treatment require a carefully choreographed multidisciplinary team approach. The risk-benefit of every imaging modality, the strategies to balance the safety of mother and fetus, and the support of the patient and family at every step are crucial. US and MRI are preferred imaging modalities that lack ionizing radiation. Radiation dose concerns should be addressed, noting that most imaging examinations (including mammography, radiography, CT, and technetium 99m-labeled sulfur colloid sentinel lymph node staging) are performed at radiation levels below thresholds at which deterministic side effects are seen. Dose estimates should be provided after each examination. The use of iodinated intravenous contrast material is safe during pregnancy, but gadolinium-based contrast material should be avoided. Accurate diagnosis and staging combined with gestational age affect decisions about surgery and chemotherapy. Whole-body MRI with diffusion-weighted sequences is ideal to screen for primary and metastatic sites, determine disease stage, identify biopsy targets, and guide further cancer site-specific imaging. The authors provide an update of the imaging triage, safety considerations, cancer-specific imaging, and treatment options for cancer in pregnancy. An invited commentary by Silverstein and Van Loon is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

Gadolinium-Based Contrast Agents: Updates and Answers to Typical Questions Regarding Gadolinium Use

Gadolinium-based contrast agents have expanded the diagnostic usefulness and capability of magnetic resonance imaging. Despite their highly favorable safety profile, these agents have been associated with nephrogenic systemic fibrosis in a small number of patients who have advanced kidney disease. Recently, trace amounts of gadolinium deposition in the brain and other organs have been reported after contrast exposure, even in patients with normal renal function. In this review, we provide a brief overview of recent updates and discuss typical clinical situations related to the use of gadolinium-based contrast agents.

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.

How the Chemical Properties of GBCAs Influence Their Safety Profiles In Vivo

The extracellular class of gadolinium-based contrast agents (GBCAs) is an essential tool for clinical diagnosis and disease management. In order to better understand the issues associated with GBCA administration and gadolinium retention and deposition in the human brain, the chemical properties of GBCAs such as relative thermodynamic and kinetic stabilities and their likelihood of forming gadolinium deposits in vivo will be reviewed. The chemical form of gadolinium causing the hyperintensity is an open question. On the basis of estimates of total gadolinium concentration present, it is highly unlikely that the intact chelate is causing the T1 hyperintensities observed in the human brain. Although it is possible that there is a water-soluble form of gadolinium that has high relaxitvity present, our experience indicates that the insoluble gadolinium-based agents/salts could have high relaxivities on the surface of the solid due to higher water access. This review assesses the safety of GBCAs from a chemical point of view based on their thermodynamic and kinetic properties, discusses how these properties influence in vivo behavior, and highlights some clinical implications regarding the development of future imaging agents.

Investigation of Effects of Gadolinium-Based Contrast Agents on Uterine Contractility Using Isolated Rat Myometrium

BACKGROUND

Despite concerns about safety, gadolinium-based contrast agents (GBCAs) are still used for abdominal and pelvic imaging during pregnancy. Researchers have mainly focused on teratogenicity, while very little is known about their possible direct effects on uterine contractility, yet free gadolinium potentially impacts contractility through interaction with calcium channels.

PURPOSE

To investigate possible effects of selected GBCAs (namely gadoteridol, gadoversetamide, gadobutrol, gadoterate meglumine, and gadoxetic acid) on the contractility of rat myometrium.

STUDY TYPE

In vitro organ bath study.

ANIMAL MODEL

Myometria were isolated from adult (10-12 weeks old) Sprague Dawley rats, both pregnant (N = 8) and nonpregnant (N = 36).

FIELD STRENGTH/SEQUENCE

NA.

ASSESSMENT

Myometrial strips were suspended in tissue bath containing physiological saline and isometric contractions were recorded. GBCAs were added to the tissue bath cumulatively, and their effects on contractility parameters (quantified by amplitude, frequency, and area under contractility curve [AUC]) were evaluated by 10-minute intervals.

STATISTICAL TESTS

Normality data, checked by Shapiro-Wilk test, were transformed by arcsine when needed. One- or two-way analysis of variance was performed, where appropriate, followed by Student-Newman-Keuls test. A P value of <0.05 was considered statistically significant.

RESULTS

All of the assayed GBCAs elicited some alterations in the myometrial contractility in a concentration-dependent manner. Gadoterate meglumine, gadoxetic acid, and gadoversetamide caused a concentration-dependent significant attenuation in AUC (oxytocin-induced, from 100% during control period to 45.1 ± 9.0% (nonpregnant) and 59.9 ± 8.5% (pregnant), for 90 μM gadoterate meglumine; respectively), and frequency of the spontaneous and oxytocin-induced contractions. Gadobutrol and gadoteridol at highest dose significantly attenuated mean AUC and frequency of oxytocin-induced contractions of nonpregnant myometrium.

DATA CONCLUSION

Results from this in vitro study indicate that GBCAs elicit modulation of myometrial contractions at clinically relevant concentrations. These effects may account, at least partially, for the known potential side effects (rare cases of miscarriages and elective abortion) of these agents.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 5.

Dynamic contrast enhanced magnetic resonance imaging: A review of its application in the assessment of placental function

It is important to develop a better understanding of placental insufficiency given its role in common maternofetal complications such as preeclampsia and fetal growth restriction. Functional magnetic resonance imaging offers unprecedented techniques for exploring the placenta under both normal and pathological physiological conditions. Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) is an established and very robust method to investigate the microcirculatory parameters of an organ and more specifically its perfusion. It is currently a gold standard in the physiological and circulatory evaluation of an organ. Its application to the human placenta could enable to access many microcirculatory parameters relevant to the placental function such as organ blood flow, fractional blood volume, and permeability surface area, by the acquisition of serial images, before, during, and after administration of an intravenous contrast agent. Widely used in animal models with gadolinium-based contrast agents, its application to the human placenta could be possible if the safety of contrast agents in pregnancy is established or they are confirmed to not cross the placenta.

MR Imaging Contrast Agents: Role in Imaging of Chronic Liver Diseases

Contrast-enhanced MR imaging plays an important role in the evaluation of patients with chronic liver disease, particularly for detection and characterization of liver lesions. The two most commonly used contrast agents for liver MR imaging are extracellular agents (ECAs) and hepatobiliary agents (HBAs). In patients with liver disease, the main advantage of ECA-enhanced MR imaging is its high specificity for the diagnosis of progressed HCCs. Conversely, HBAs have an additional contrast mechanism, which results in high liver-to-lesion contrast and highest sensitivity for lesion detection in the hepatobiliary phase. Emerging data suggest that features depicted on contrast-enhanced MR imaging scans are related to tumor biology and are predictive of patients' prognosis, likely to further expand the role of contrast-enhanced MR imaging in the clinical care of patients with chronic liver disease.

Imaging during pregnancy: What the radiologist needs to know

During the last decades, there has been a growing demand for medical imaging in gravid women. Imaging of the pregnant woman is challenging as it involves both the mother and the fetus and, consequently, several medical, ethical, or legal considerations are likely to be raised. Theoretically, all currently available imaging modalities may be used for the evaluation of the pregnant woman; however, in practice, confusion regarding the safety of the fetus often results in unnecessary avoidance of useful diagnostic tests, especially those involving ionizing radiation. This review article is focused on the current safety guidelines and considerations regarding the use of different imaging modalities in the pregnant population; also presented is an imaging work-up for the most common medical conditions of pregnant women, with emphasis on fetal and maternal safety.

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.

Magnetic Resonance Safety: Pregnancy and Lactation

MRI is a powerful diagnostic tool with excellent soft tissue contrast that uses nonionizing radiation. These advantages make MRI an appealing modality for imaging the pregnant patient; however, specific risks inherent to the magnetic resonance environment must be considered. MRI may be performed without and/or with intravenous contrast, which adds further fetal considerations. The risks of MRI with and without intravenous contrast are reviewed as they pertain to the pregnant or lactating patient and to the fetus and nursing infant. Relevant issues for gadolinium-based contrast agents and ultrasmall paramagnetic iron oxide particles are reviewed.

Consensus Guidelines of the French Society of Neuroradiology (SFNR) on the use of Gadolinium-Based Contrast agents (GBCAs) and related MRI protocols in Neuroradiology

Gadolinium-based contrast agents (GBCAs) are used in up to 35% of magnetic resonance imaging (MRI) examinations and are associated with an excellent safety profile. Nevertheless, two main issues have arisen in the last two decades: the risk of nephrogenic systemic fibrosis and the risk of gadolinium deposition and retention. As a first step, this article reviews the different categories of GBCAs available in neuroradiology, their issues, and provides updates regarding the use of these agents in routine daily practice. Recent advances in MRI technology, as well as the development of new MRI sequences, have made GBCA injection avoidable in many indications, especially in patients with chronic diseases when iterative MRIs are required and when essential diagnostic information can be obtained without contrast enhancement. These recent advances also lead to changes in recommended MRI protocols. Thus, in a second step, this review focuses on consensus concerning brain MRI protocols in 10 common situations (acute ischemic stroke, intracerebral hemorrhage, cerebral venous thrombosis, multiple sclerosis, chronic headache, intracranial infection, intra- and extra-axial brain tumors, vestibular schwannoma and pituitary adenoma). The latter allowing the standardization of practices in neuroradiology. Recommendations were also made concerning the use of GBCAs in neuroradiology, based on evidence in the literature and/or by consensus between the different coauthors.

IBD in pregnancy: recent advances, practical management

Inflammatory bowel disease (IBD) poses complex issues in pregnancy, but with high-quality care excellent pregnancy outcomes are achievable. In this article, we review the current evidence and recommendations for pregnant women with IBD and aim to provide guidance for clinicians involved in their care. Many women with IBD have poor knowledge about pregnancy-related issues and a substantial minority remains voluntarily childless. Active IBD is associated with an increased risk of preterm birth, low for gestation weight and fetal loss. With the exception of methotrexate and tofacitinib the risk of a flare outweighs the risk of IBD medication and maintenance of remission from IBD should be the main of care. Most women with IBD will experience a normal pregnancy and can have a vaginal delivery. Active perianal Crohn's disease is an absolute and ileal pouch surgery a relative indication for a caesarean section. Breast feeding is beneficial to the infant and the risk from most IBD medications is negligible.

Prognosis and Management of BRAF V600E-Mutated Pregnancy-Associated Melanoma

BACKGROUND

Approximately one third of women who develop melanoma at childbearing age are diagnosed during gestation or the postpartum period, facing pregnancy-associated melanoma (PAM). However, only some retrospective studies with heterogeneous data have analyzed the impact of pregnancy on melanoma development, and no evidence exists about the behavior and the management of BRAF-mutated disease.

SUBJECTS, MATERIALS, AND METHODS

In order to better describe the evolution of BRAF V600E-mutated PAM, we present here all consecutive cases diagnosed in our site during the last 7 years, recording oncological, obstetrical, and perinatal parameters, as well as the therapeutic decisions for both melanoma and gestation. Based on our institutional experience, we weigh the current published evidence and discuss upcoming clinical considerations about the prognosis of PAM, the role of BRAF status, and the possible treatment options during pregnancy in localized or advanced/metastatic disease. Five women were diagnosed with newly metastatic or relapsed BRAF V600E-mutated PAM (four during gestation and one in the 1st year postpartum) between 2012 and 2019. All of them developed extensive metastatic disease with multiple organ involvement, and four developed brain metastases. All cases experienced melanoma progression in less than 6 months under targeted therapy and died soon independently of the followed sequence of treatments. All the neonates were delivered alive and healthy, but one developed melanoma earlier than the second year of life.

RESULTS

Reviewing the literature to confirm our unfavorable outcomes, no specific data on BRAF-mutated PAM were retrieved and current evidence still supports that the prognosis of PAM should be guided by the established risk factors, whereas the management of advanced/metastatic PAM should be evaluated on a case-by-case basis.

CONCLUSION

More data are required to ascertain whether BRAF-mutated profile adversely affects PAM outcome, although the clinicians should be aware to detect any potential melanoma lesion during pregnancy as soon as possible, treating it locally, regardless of its BRAF status.

IMPLICATIONS FOR PRACTICE

The prognosis and management of pregnancy-associated melanoma whether BRAF-mutated or wild type, is currently guided by the same parameters as in the nonpregnant condition. In this special nontrial subpopulation, BRAF-mutated status seems to have a detrimental effect on disease outcome, independently of the following treatments. In early stage melanoma, wide local excision with or without sentinel lymph node dissection may be curative at any trimester of gestation, while in advanced/metastatic setting, therapeutic strategy including immune-checkpoint or BRAF/MEK inhibitors, is more challenging, regardless of BRAF status, and should be based on an individualized decision in each case at a multidisciplinary level.

Emergency Imaging in Pregnancy and Lactation [Formula: see text]

The use of diagnostic imaging studies in the emergency setting has increased dramatically over the past couple of decades. The emergency imaging of pregnant and lactating patients poses unique challenges and calls upon the crucial role of radiologists as consultants to the referring physician to guide appropriate use of imaging tests, minimize risk, ensure timely management, and occasionally alleviate unwarranted trepidation. A clear understanding of the risks and benefits involved with various imaging tests in this patient population is vital to achieve this. This review discusses the different safety and appropriateness issues that could arise with the use of ionizing radiation, iodinated-, and gadolinium-based contrast media and radiopharmaceuticals in pregnant and lactating patients. Special considerations such as trauma imaging, safety concerns with magnetic resonance imaging and ultrasound, management of claustrophobia, contrast extravasation, and allergic reactions are also reviewed. The consent process for these examinations has also been described.

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.

MRI of Acute Gynecologic Conditions

Although usually not a first-line imaging modality in the setting of acute pelvic pain, magnetic resonance imaging (MRI) is able to depict and characterize a wide range gynecologic diagnoses with high accuracy. Lack of ionizing radiation renders MRI particularly useful for assessment of pregnant women and children. Furthermore, inherent high soft-tissue resolution of MRI allows accurate diagnosis without intravenous contrast use, which is advantageous for patients with renal insufficiency and pregnant patients. Familiarity with the typical MRI appearance of various acute gynecologic conditions helps establish the correct diagnosis. This article reviews the common MRI findings of acute gynecologic processes, in both pregnant and nonpregnant patients. Level of Evidence: 3 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:1291-1309.

First-Trimester Exposure to Gadolinium-based Contrast Agents: A Utilization Study of 4.6 Million U.S. Pregnancies

BackgroundThe safety of gadolinium-based contrast agent (GBCA) exposure during pregnancy has not been established, and the use of GBCAs during pregnancy is not recommended unless it is essential to the health of the woman or fetus.PurposeTo examine the prevalence of GBCA exposure in a large sample of pregnancies resulting in a live birth.Materials and MethodsThe Sentinel Distributed Database was used to retrospectively identify U.S. pregnancies that resulted in live births between 2006 and 2017 from 16 data partners. The main outcome was the prevalence of MRI procedures with and without GBCAs, sorted by anatomic location and trimester, among pregnant and matched comparator women.ResultsAmong 4 692 744 pregnancies resulting in a live birth, we identified 6879 exposures to GBCAs in 5457 pregnancies, representing one contrast-enhanced MRI examination per 860 pregnancies (0.12% of all pregnancies). Most contrast-enhanced MRI examinations were performed in the head (n = 3499), although pelvic and abdominal MRI constituted 22.3% (n = 1536) of all contrast-enhanced MRI examinations during pregnancy. The majority (70.2%) of GBCA exposures occurred during the first trimester, with a 4.3-fold greater prevalence compared with that in the second trimester and a 5.1-fold greater prevalence compared with that in the third trimester.ConclusionThis study identified higher rates of gadolinium-based contrast agent (GBCA) exposure during the first few weeks of pregnancy compared with the later weeks of pregnancy, suggesting inadvertent exposure to GBCAs might occur before pregnancy is recognized.© RSNA, 2019Online supplemental material is available for this article.See also the editorial by Kallmes and Watson in this issue.

Pregnancy-associated breast cancer: A review of 47 women

PURPOSE

Pregnancy-associated breast cancer (PABC) is a rare disease. However, its expected incidence tends to be increased because of delayed maternal age. The purpose of this study was to describe the clinical, radiological, and histopathological characteristics of PABC cases diagnosed in our center.

METHODS

The clinical-radiological findings and histopathological characteristics of patients diagnosed and treated with PABC at our institution between January 2011 and January 2017 were retrospectively evaluated.

RESULTS

Mammography and ultrasonography were performed in all patients. MRI examination was performed in 18 patients. Nine (19.1%) out of 47 patients were diagnosed with breast cancer during pregnancy, and 38 (80.9%) were in their first year after delivery. The most frequent finding (95.7%) during imaging was one or more masses. Mammography-detected pure or accompanying microcalcifications were found in 12 (25.5%) patients. MRI detected additional multifocal and multicentric disease in 14 (29.8%) patients and contralateral cancer in one (2.1%) patient.

CONCLUSIONS

Pregnancy-related breast cancer tends to be diagnosed in an advanced stage with poor prognosis. Any breast abnormalities observed in this period should alert clinicians, and a meticulous radiological evaluation is mandatory. The early diagnosis of this disease would increase the chances of successful treatment.

Breast Cancer During Pregnancy

Breast cancer remains the most common cancer in women. A diagnosis of cancer during pregnancy is uncommon. In recent decades, obstetricians are seeing an increasing number of women who become pregnant or desire to become pregnant after breast cancer treatment because of a delay in childbearing for a variety of reasons, including cultural, educational, and professional. Consequently, breast cancer in young women often occurs before the completion of reproductive plans. A discussion among the patient, the oncologist, and the obstetrician on the relative benefits of early delivery followed by treatment versus commencement of therapy while continuing the pregnancy is of utmost importance in order to reach a consensual decision. The best available evidence suggests that pregnancy after breast cancer increases the risk of recurrence. The birth outcome in women with a history of breast cancer is no different from that in the normal female population; however, increased risks of delivery complications have been reported in the literature. As concurrent pregnancy and breast cancer are uncommon, there are no data from large randomized trials; hence, recommendations are mainly based on retrospective studies.

Causes and Treatment of Acute Ischemic Stroke During Pregnancy

PURPOSE OF REVIEW

Treatment recommendations for pregnancy associated ischemic stroke are scarce. This may be due to the fact that, in general, obstetricians tend not to make recommendations for stroke patients and neurologists are not commonly involved in the care of pregnant women. Herein, we review the multiple etiologies of ischemic stroke during pregnancy, considerations for diagnostic testing, and acute treatment and prevention options, including associated risks specific to the pregnant and puerperal state.

RECENT FINDINGS

Intravenous tissue plasminogen activator (tPA) and endovascular thrombectomy have been used successfully to treat pregnant women with acute ischemic stroke. Recent national guidelines recommend considering tPA use during pregnancy for moderate and severe strokes if the potential benefits offset the risks of uterine hemorrhage. Pregnancy-associated ischemic stroke is rare, but can be devastating, and recanalization therapy should not be systematically withheld. Women who are at risk for stroke should be followed carefully, and providers caring for pregnant women should be educated regarding stroke signs and symptoms. Many of the standard post stroke diagnostic modalities may be used safely in pregnancy, and primary and secondary stroke prevention therapy must be tailored to avoid fetal toxicity.

Monitoring inflammatory bowel disease during pregnancy: Current literature and future challenges

Inflammatory bowel disease has a high prevalence in women of childbearing age and can have a significant impact on pregnancy, from conceiving to carrying the pregnancy. Active disease during pregnancy is known to have negative effects on pregnancy outcomes; therefore, careful monitoring during this period is an important but challenging aspect of care and is crucial as it affects important management decisions. Recent data seems to suggest that endoscopy is a relatively safe procedure during all trimesters of pregnancy. Serum biomarkers such as C-reactive protein and fecal calprotectin are helpful non-invasive markers, but have shown conflicting results for correlation with disease activity in some initial studies. Further work is necessary to establish standard of care monitoring during pregnancy.

Editor's Highlight: In Utero Exposure to Gadolinium and Adverse Neonatal Outcomes in Premature Infants

Gadolinium is a toxic rare earth element that is used as a contrast enhancement agent for diagnostic medical imaging. However, because of safety concerns to the developing fetus derived from preclinical studies, gadolinium can only be used during pregnancy if the potential benefits justify the potential risks to a fetus. Because there are no previous well designed safety studies on the developing fetus, we aimed to evaluate the potential adverse effects of in utero gadolinium exposure in high-risk premature infants. We performed a prospective dose (cord blood gadolinium concentration) - response (outcomes) study involving 104, 24-33 weeks gestational age (GA) infants. The mean (range) cord blood gadolinium concentration of infants measured using Inductively Coupled Plasma Mass Spectrometry was 191 (3.4-3729.6) pg/ml. The association between cord blood gadolinium concentration and each neonatal outcome was evaluated using linear or logistic regression analysis. The GA, race, gender, and antenatal steroid exposure were considered priori confounders. Recent adult human studies have shown that gadolinium exposure may be associated with nephrotoxicity. However, we found no adverse effects on renal function or other common outcomes including degree of prematurity, small for GA, respiratory distress syndrome, hyperbilirubinemia, intraventricular hemorrhage, necrotizing enterocolitis, patent ductus arteriosus, chronic lung disease, retinopathy of prematurity, and osteopenia of prematurity during the neonatal period with an increase in cord blood gadolinium concentration. None of the infants had clinically evident congenital malformations. In conclusion, gadolinium use during pregnancy is unlikely to be associated with adverse effects in infants during the neonatal period.

Radiographic and magnetic resonances contrast agents: Essentials and tips for safe practices

With extended and continued expansion of medical imaging utilization in modern medical practice over last decade, radiologists as well as other faculty staff dealing with radiographic and magnetic resonances contrast media (CM) have to be well oriented with their potential hypersensitivity reactions and recognize high-risk groups liable to develop it and enable early recognition. Radiologists and other medical staff involved in administration and dealing with CM have to be ready to implement prompt, practical and effective management plan to deal with these scenarios should they emerge. Strategies to prevent potential contrast-induced acute and delayed renal injuries have to be routinely exercised. Paying attention to the pregnant and nursing women, pediatrics, diabetics, as well as other fragile populations is of utmost importance for patient safety during contrast administrations. Radiologists should play a pivotal role in orienting patients about necessity to use CM for their imaging studies, in case it is needed, and assure them about its safety. Moreover, they have to be oriented with the medico-legal issues related to use of CM. These will pay as improved patient safety as well as safe daily working environmentat different levels of radiology practices.

Gadolinium Chelate Safety in Pregnancy: Barely Detectable Gadolinium Levels in the Juvenile Nonhuman Primate after in Utero Exposure

Purpose To determine whether gadolinium remains in juvenile nonhuman primate tissue after maternal exposure to intravenous gadoteridol during pregnancy. Materials and Methods Gravid rhesus macaques and their offspring (n = 10) were maintained, as approved by the institutional animal care and utilization committee. They were prospectively studied as part of a pre-existing ongoing research protocol to evaluate the effects of maternal malnutrition on placental and fetal development. On gestational days 85 and 135, they underwent placental magnetic resonance imaging after intravenous gadoteridol administration. Amniocentesis was performed on day 135 prior to administration of the second dose of gadoteridol. After delivery, the offspring were followed for 7 months. Tissue samples from eight different organs and from blood were harvested from each juvenile macaque. Gadolinium levels were measured by using inductively coupled plasma mass spectrometry. Results Gadolinium concentration in the amniotic fluid was 0.028 × 10^-5 %ID/g (percentage injected dose per gram of tissue) 50 days after administration of one gadoteridol dose. Gadolinium was most consistently detected in the femur (mean, 2.5 × 10^-5 %ID/g; range, [0.81-4.1] × 10^-5 %ID/g) and liver (mean, 0.15 × 10^-5 %ID/g; range, [0-0.26] × 10^-5 %ID/g). Levels were undetectable in the remaining sampled tissues, with the exception of one juvenile skin sample (0.07 × 10^-5 %ID/g), one juvenile spleen sample (0.039 × 10^-5 %ID/g), and one juvenile brain (0.095 × 10^-5 %ID/g) and kidney (0.13 × 10^-5 %ID/g) sample. Conclusion The presence of gadoteridol in the amniotic fluid after maternal injection enables confirmation that it crosses the placenta. Extremely low levels of gadolinium are found in juvenile macaque tissues after in utero exposure to two doses of gadoteridol, indicating that a very small amount of gadolinium persists after delivery. ^© RSNA, 2017.

"Pulmonary embolism diagnostics of pregnant patients: What is the recommended clinical pathway considering the clinical value and associated radiation risks of available imaging tests?"

Pulmonary embolism (PE) during pregnancy remains the leading preventable cause of maternal morbidity and mortality in the developed countries. Diagnosis of PE in pregnant patients is a challenging clinical problem, since pregnancy-related physiologic changes can mimic signs and symptoms of PE. Patient mismanagement may result into unjustified anticoagulant treatment or unnecessary imaging tests involving contrast-related or/and radiation-related risks for both the expectant mother and embryo/fetus. On the other hand, missing or delaying diagnosis of PE could lead to life-threatening conditions for both the mother and the embryo/fetus. Thus, a timely and accurate diagnostic approach is required for the optimal management of pregnant patients with suspected PE. Aim of the current review is to discuss a pregnancy-specific clinical pathway for the early diagnosis of PE with non-ionizing radiation- and ionizing radiation-based imaging modalities taking into account previously reported data on diagnostic value of available imaging tests, and radiation related concerns.

Neurologic complications in critically ill pregnant patients

Neurologic complications in a critically ill pregnant woman are uncommon but some of the complications (such as eclampsia) are unique to pregnancy and the puerperal period. Other neurologic complications (such as seizures in the setting of epilepsy) may worsen during pregnancy. Clinical signs and symptoms such as seizure, headache, weakness, focal neurologic deficits, and decreased level of consciousness require careful consideration of potential causes to ensure prompt treatment measures are instituted to prevent ongoing neurologic injury. Clinicians should be familiar with syndromes such as pre-eclampsia, eclampsia, stroke, posterior reversible encephalopathy syndrome, and reversible cerebral vasoconstriction syndrome. Necessary imaging studies can usually be performed safely in pregnancy. Scoring systems for predicting maternal mortality are inadequate, as are recommendations for neurorehabilitation. Tensions can arise when there is conflict between the interests of the mother and the interests of the fetus, but in general maternal health is prioritized. The complexity of care requires a multidisciplinary and multiprofessional approach to achieve best outcome in an often unexpected situation.

Gadolinium-based contrast agents: A comprehensive risk assessment

Gadolinium-based contrast agents (GBCAs) have been used in magnetic resonance imaging (MRI) since the 1980s and are now administered in up to 35% of all MRI examinations. While GBCAs were initially felt to carry minimal risk, the subsequent identification of GBCAs as the key etiologic factor in the development of nephrogenic systemic fibrosis (NSF) has raised concerns about the broader health impacts of gadolinium exposure. Clinicians, radiologists, and patients should be aware of the most up-to-date data pertaining to the risks of GBCA administration. Specific issues covered in this review article include immediate adverse reactions; pregnancy and lactation; and gadolinium deposition and toxicity, with a special focus on NSF. Practice recommendations based on the presented data, as well as current professional society guidelines, are provided for each section.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 5 J. MAGN. RESON. IMAGING 2017;46:338-353.

Committee Opinion No. 656: Guidelines for Diagnostic Imaging During Pregnancy and Lactation

Imaging studies are important adjuncts in the diagnostic evaluation of acute and chronic conditions. However, confusion about the safety of these modalities for pregnant and lactating women and their infants often results in unnecessary avoidance of useful diagnostic tests or the unnecessary interruption of breastfeeding. Ultrasonography and magnetic resonance imaging are not associated with risk and are the imaging techniques of choice for the pregnant patient, but they should be used prudently and only when use is expected to answer a relevant clinical question or otherwise provide medical benefit to the patient. With few exceptions, radiation exposure through radiography, computed tomography scan, or nuclear medicine imaging techniques is at a dose much lower than the exposure associated with fetal harm. If these techniques are necessary in addition to ultrasonography or magnetic resonance imaging or are more readily available for the diagnosis in question, they should not be withheld from a pregnant patient. Breastfeeding should not be interrupted after gadolinium administration.

Imaging Pregnant and Lactating Patients

As use of imaging in the evaluation of pregnant and lactating patients continues to increase, misperceptions of radiation and safety risks have proliferated, which has led to often unwarranted concerns among patients and clinicians. When radiologic examinations are appropriately used, the benefits derived from the information gained usually outweigh the risks. This review describes appropriateness and safety issues, estimated doses for imaging examinations that use iodizing radiation (ie, radiography, computed tomography, nuclear scintigraphy, and fluoroscopically guided interventional radiology), radiation risks to the mother and conceptus during various stages of pregnancy, and use of iodinated or gadolinium-based contrast agents and radiotracers in pregnant and lactating women. Maternal radiation risk must be weighed with the potential consequences of missing a life-threatening diagnosis such as pulmonary embolus. Fetal risks (ie, spontaneous abortion, teratogenesis, or carcinogenesis) vary with gestational age and imaging modality and should be considered in the context of the potential benefit of medically necessary diagnostic imaging. When feasible and medically indicated, modalities that do not use ionizing radiation (eg, magnetic resonance imaging) are preferred in pregnant and lactating patients. Radiologists should strive to minimize risks of radiation to the mother and fetus, counsel patients effectively, and promote a realistic understanding of risks related to imaging during pregnancy and lactation.

A Practical Guide to MR Imaging Safety: What Radiologists Need to Know

Magnetic resonance (MR) imaging can provide critical diagnostic and anatomic information while avoiding the use of ionizing radiation, but it has a unique set of safety risks associated with its reliance on large static and changing magnetic fields, high-powered radiofrequency coil systems, and exogenous contrast agents. It is crucial for radiologists to understand these risks and how to mitigate them to protect themselves, their colleagues, and their patients from avoidable harm and to comply with safety regulations at MR imaging sites. Basic knowledge of MR imaging physics and hardware is necessary for radiologists to understand the origin of safety regulations and to avoid common misconceptions that could compromise safety. Each of the components of the MR imaging unit can be a factor in injuries to patients and personnel. Safety risks include translational force and torque, projectile injury, excessive specific absorption rate, burns, peripheral neurostimulation, interactions with active implants and devices, and acoustic injury. Standards for MR imaging device safety terminology were first issued in 2005 and are required by the U.S. Food and Drug Administration, with devices labeled as "MR safe," "MR unsafe," or "MR conditional." MR imaging contrast agent safety is also discussed. Additional technical and safety policies relate to pediatric, unconscious, incapacitated, or pregnant patients and pregnant imaging personnel. Division of the MR imaging environment into four distinct, clearly labeled zones--with progressive restriction of entry and increased supervision for higher zones--is a mandatory and key aspect in avoidance of MR imaging-related accidents. All MR imaging facilities should have a documented plan to handle emergencies within zone IV, including cardiac arrest or code, magnet quench, and fires. Policies from the authors' own practice are provided for additional reference. Online supplemental material is available for this article.