Role of prenatal magnetic resonance imaging in fetuses with isolated agenesis of corpus callosum in the era of fetal neurosonography: A systematic review and meta-analysis.
Sileo Filomena Giulia,Di Mascio Daniele,Rizzo Giuseppe,Caulo Massimo,Manganaro Lucia,Bertucci Emma,Masmejan Sophie,Liberati Marco,D'Amico Alice,Nappi Luigi,Buca Danilo,Van Mieghem Tim,Khalil Asma,D'Antonio Francesco
Acta obstetricia et gynecologica Scandinavica
INTRODUCTION:Corpus callosum agenesis (ACC) is frequently diagnosed during fetal life; its prognosis depends also on additional anomalies. The additional value of fetal magnetic resonance imaging (MRI) in fetuses with "isolated" complete (cACC) and partial (pACC) agenesis of the corpus callosum on ultrasound is still debated. MATERIAL AND METHODS:We performed a systematic literature review and meta-analysis including fetuses with a prenatal diagnosis of cACC and pACC without associated structural anomalies on ultrasound, undergoing fetal MRI. The primary outcome was the rate of additional anomalies detected at fetal MRI. Further analyses assessed the effect of type of ultrasound assessment (neurosonography vs standard axial assessment), gestational age at fetal MRI and rate of postnatally detected brain anomalies. Random-effect meta-analyses of proportions were used to analyze the data. RESULTS:Fourteen studies (798 fetuses) were included. In cases with isolated cACC, 10.9% (95% CI 4.1-20.6) and 4.3% (95% CI 1.4-8.8) additional anomalies were detected by fetal MRI and postnatally, respectively. Stratifying according to the type of ultrasound assessment, the rate of associated anomalies detected only on fetal MRI was 5.7% (95% CI 0.5-16.0) with dedicated neurosonography and 18.5% (95% CI 7.8-32.4) with a standard axial assessment. In fetuses with isolated pACC, 13.4% (95% CI 4.0-27.0) and 16.2% (95% CI 5.9-30.3) additional anomalies were detected by fetal MRI or postnatally, respectively. Stratifying according to the type of ultrasound assessment, the rate of associated anomalies detected only on fetal MRI was 11.4% (95% CI 2.7-25.0) when dedicated neurosonography was performed. Cortical and posterior fossa anomalies represented the most common anomalies missed at ultrasound with both cACC and pACC. Due to the very small number of included cases, stratification according to early (<24 weeks of gestation) and late (>24 weeks) fetal MRI could not be done for either cACC or pACC. CONCLUSIONS:The rate of associated anomalies detected exclusively at fetal MRI in isolated ACC undergoing neurosonography is lower than previously reported. Cortical and posterior fossa anomalies are among the most common anomalies detected exclusively at MRI, thus confirming the crucial role of fetal MRI in determining the prognosis of these fetuses. However, some anomalies still go undetected prenatally and this should be stressed during parental counseling.
10.1111/aogs.13958
Magnetic resonance imaging of the fetal brain.
Tee L Mf,Kan E Yl,Cheung J Cy,Leung W C
Hong Kong medical journal = Xianggang yi xue za zhi
INTRODUCTION:This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. METHODS:We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. RESULTS:One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. CONCLUSIONS:Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.
10.12809/hkmj154678
A survey of pediatric diagnostic radiologists in North America: current practices in fetal magnetic resonance imaging.
Chapman Teresa,Alazraki Adina L,Eklund Meryle J
Pediatric radiology
BACKGROUND:Fetal magnetic resonance imaging (MRI) is an imaging examination in evolution. Rapid developments over recent decades have led to better image quality, an increased number of examinations and greater impact on patient care. OBJECTIVE:To gather data regarding current practices among established programs in North America and provide information to radiologists interested in implementing or growing a fetal MRI service. MATERIALS AND METHODS:An electronic survey containing 15 questions relevant to the use of fetal MRI was submitted to pediatric radiologists and neuroradiologists. Items regarded scheduling and reporting logistics, magnet strength, patient positioning and patient preparation. Answers and comments were collected, and descriptive statistics were summarized. RESULTS:One hundred and six survey responses were evaluated. Of the survey responses, 62/106 (58.5%) allow fetal MR scheduling any time during the day and 72/105 (68.6%) exclusively use 1.5-T strength platforms for fetal MRI, while only 7/105 (6.7%) use exclusively 3 T. Patient positioning is variable: supine, 40/106 (37.8%); left lateral decubitus, 22/106 (20.8%), and, patient's choice, 43/106 (40.6%). Of the centers responding, 51/104 (49.0%) require no particular fasting instructions, while 20/104 (19.2%) request the patient avoid caffeine before the scanning. CONCLUSION:Logistical trends in performing fetal MRI may supplement the American College of Radiology's published technical standards and offer guidance to radiologists new to the field.
10.1007/s00247-018-4236-3
Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation.
Goolaub Datta Singh,Marini Davide,Seed Mike,Macgowan Christopher K
Journal of visualized experiments : JoVE
Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the recognized standard-of-care for blood flow quantification based on phase contrast MRI. While such measurement of blood flow has been possible in adults for decades, methods to extend this capability to fetal blood flow have only recently been developed. Fetal blood flow quantification in major vessels is important for monitoring fetal pathologies such as congenital heart disease (CHD) and fetal growth restriction (FGR). CHD causes alterations in the cardiac structure and vasculature that change the course of blood in the fetus. In FGR, the path of blood flow is altered through the dilation of shunts such that the oxygenated blood supply to the brain is increased. Blood flow quantification enables assessment of the severity of the fetal pathology, which in turn allows for suitable in utero patient management and planning for postnatal care. The primary challenges of applying phase contrast MRI to the human fetus include small blood vessel size, high fetal heart rate, potential MRI data corruption due to maternal respiration, unpredictable fetal movements, and lack of conventional cardiac gating methods to synchronize data acquisition. Here, we describe recent technical developments from our lab that have enabled the quantification of fetal blood flow using phase contrast MRI, including advances in accelerated imaging, motion compensation, and cardiac gating.
10.3791/61953
Three-dimensional reconstruction of fetal abnormalities using ultrasonography and magnetic resonance imaging.
Werner Heron,Marcondes Maene,Daltro Pedro,Fazecas Tatiana,Ribeiro Bianca Guedes,Nogueira Renata,Araujo Júnior Edward
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians
We aimed to compare three-dimensional (3D) fetal malformation images obtained using ultrasonography (US) and magnetic resonance imaging (MRI) on the same day during the third trimester of pregnancy. Total 33 fetuses were selected from cases evaluated for malformations. Morphological abnormalities were first scanned using 3DUS. MRI was used to confirm the previous preliminary 3DUS findings, and diagnoses were confirmed postnatally. 3DUS scans were performed transabdominally using an Rab (4-8 L) probe, Voluson 730 Pro/Expert and E8 (General Electric, Healthcare, Zipf, Austria). MRI was performed using a 1.5-T scanner (Magneton Avanto, Siemens, Erlangen, Germany) with a body coil. The 3D reconstruction of the structure of interest was manually performed from a True FISP sequence using an interactive pen tablet (Syngo multimodality 2009B, Siemens, Erlangen, Germany). Despite recent advancements in 3DUS, the quality of 3D images obtained from MRI was superior during the third trimester. 3DUS had certain limitations, such as being influenced by the fetal position, the volume of amniotic fluid, and maternal obesity. Fetal movements during image acquisition were one of the main challenges for MRI. The quality of the 3D images obtained using MRI was superior to that of images obtained using US during the third trimester of pregnancy.
10.1080/14767058.2018.1465558
Fetal brain morphometry on prenatal magnetic resonance imaging in congenital diaphragmatic hernia.
Radhakrishnan Rupa,Merhar Stephanie L,Burns Patricia,Zhang Bin,Lim Foong-Yen,Kline-Fath Beth M
Pediatric radiology
BACKGROUND:Many infants with congenital diaphragmatic hernia (CDH) show brain abnormality on postnatal brain MRI related to severity of CDH, degree of lung hypoplasia, intrathoracic liver, right diaphragmatic hernia and large diaphragmatic defect. It is not known whether these factors affect brain growth in utero in CDH. OBJECTIVE:To assess prenatal brain morphometry and abnormalities on fetal MR in congenital diaphragmatic hernia. MATERIALS AND METHODS:We retrospectively reviewed 109 fetal MRIs in 63 fetuses with CDH from 2009 to 2014 (27 died before discharge, 36 survived to discharge). We compared brain injury and gestational-age-corrected z-scores of brain measurements between survivors and non-survivors. We assessed correlations between brain abnormalities and CDH severity. RESULTS:Enlarged extraaxial space was the most common abnormality, frequently seen on fetal MRI at >28 weeks of gestation, similar in survivors versus non-survivors. Anteroposterior cerebellar vermis dimension at >28 weeks of gestation was smaller in non-survivors compared to survivors (P=.02) and positively correlated with observed/expected total fetal lung volume (P=.01). Transverse cerebellar diameter at >28 weeks of gestation was also positively correlated with observed/expected total fetal lung volume (P=.04). We did not identify maturational delay, abnormal parenchymal signal or intracranial hemorrhage on fetal MRI. CONCLUSION:Enlarged extraaxial spaces in the third trimester was the most common abnormality on fetal MRI in congenital diaphragmatic hernia. Cerebellar dimensions on fetal MRI are associated with CDH severity. There was no major brain parenchymal injury on fetal MRI, even in the third trimester, in CDH survivors and non-survivors.
10.1007/s00247-018-4272-z
Measuring fetal adipose tissue using 3D water-fat magnetic resonance imaging: a feasibility study.
Giza Stephanie A,Olmstead Craig,McCooeye Daniel A,Miller Michael R,Penava Deborah A,Eastabrook Genevieve D,McKenzie Charles A,de Vrijer Barbra
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians
Analysis of fetal adipose tissue volumes may provide useful insight towards assessment of overall fetal health, especially in cases with abnormal fetal growth. Here, we assess whether fetal adipose tissue volume can be reliably measured using 3D water-fat MRI, using a quantitative assessment of the lipid content of tissues. Seventeen women with singleton pregnancies underwent a fetal MRI and water-only and fat-only images were acquired (modified 2-point Dixon technique). Water and fat images were used to generate a fat signal fraction (fat/(water + fat)) from which subcutaneous adipose tissue was segmented along the fetal trunk. Inter-rater (three readers) and intrarater reliability was assessed using intraclass-correlation coefficients (ICC) for 10 image sets. Relationships between adipose tissue measurements and gestational age and estimated fetal weight percentiles were examined. The ICC of the inter-rater reliability was 0.936 ( < .001), and the ICC of the intrarater reliability was 0.992 ( < .001). Strong positive correlations were found between adipose tissue measurements (lipid volume, lipid volume/total fetal volume, mean fat signal fraction) and gestational age. 3D water-fat MRI can reliably measure volume and quantify lipid content of fetal subcutaneous adipose tissues.
10.1080/14767058.2018.1506438
Understanding Fetal Hemodynamics Using Cardiovascular Magnetic Resonance Imaging.
Sun Liqun,Marini Davide,Saini Brahmdeep,Schrauben Eric,Macgowan Christopher K,Seed Mike
Fetal diagnosis and therapy
Human fetal circulatory physiology has been investigated extensively using grey-scale ultrasound, which provides excellent visualization of cardiac anatomy and function, while velocity profiles in the heart and vessels can be interrogated using Doppler. Measures of cerebral and placental vascular resistance, as well as indirect measures of intracardiac pressure obtained from the velocity waveform in the ductus venosus are routinely used to guide the management of fetal cardiovascular and placental disease. However, the characterization of some key elements of cardiovascular physiology such as vessel blood flow and the oxygen content of blood in the arteries and veins, as well as fetal oxygen delivery and consumption are not readily measured using ultrasound. To study these parameters, we have historically relied on data obtained using invasive measurements made in animal models, which are not equivalent to the human in every respect. Over recent years, a number of technical advances have been made that have allowed us to examine the human fetal circulatory system using cardiovascular magnetic resonance (CMR). The combination of vessel blood flow measurements made using cine phase contrast magnetic resonance imaging and vessel blood oxygen saturation and hematocrit measurements made using T1 and T2 mapping have enabled us to emulate those classic fetal sheep experiments defining the distribution of blood flow and oxygen transport across the fetal circulation in the human fetus. In addition, we have applied these techniques to study the relationship between abnormal fetal cardiovascular physiology and fetal development in the setting of congenital heart disease and placental insufficiency. CMR has become an important diagnostic tool in the assessment of cardiovascular physiology in the setting of postnatal cardiovascular disease, and is now being applied to the fetus to enhance our understanding of normal and abnormal fetal circulatory physiology and its impact on fetal well-being.
10.1159/000505091
Role of magnetic resonance imaging in fetuses with mild or moderate ventriculomegaly in the era of fetal neurosonography: systematic review and meta-analysis.
Di Mascio D,Sileo F G,Khalil A,Rizzo G,Persico N,Brunelli R,Giancotti A,Panici P B,Acharya G,D'Antonio F
Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology
OBJECTIVES:To report the rate of additional central nervous system (CNS) anomalies detected exclusively on prenatal magnetic resonance imaging (MRI) in fetuses diagnosed with isolated mild or moderate ventriculomegaly (VM) on ultrasound, according to the type of ultrasound protocol adopted (dedicated neurosonography vs standard assessment of the fetal brain), and to explore whether the diagnostic performance of fetal MRI in detecting such anomalies is affected by gestational age at examination and laterality and degree of ventricular dilatation. METHODS:MEDLINE, EMBASE, CINAHL and Clinicaltrials.gov were searched for studies reporting on the prenatal MRI assessment of fetuses diagnosed with isolated mild or moderate VM (ventricular dilatation of 10-15 mm) on ultrasound. Additional anomalies detected only on MRI were classified as callosal, septal, posterior fossa, white matter, intraventricular hemorrhage, cortical, periventricular heterotopia, periventricular cysts or complex malformations. The rate of additional anomalies was compared between fetuses diagnosed on dedicated neurosonography, defined as a detailed assessment of the fetal brain, according to the International Society of Ultrasound in Obstetrics and Gynecology guidelines, and those diagnosed on standard fetal brain assessment. The rate of additional CNS anomalies missed on prenatal MRI and detected only at birth was calculated and compared between fetuses that had early (at or before 24 weeks' gestation) and those that had late (after 24 weeks) MRI. Subanalysis was performed according to the laterality (uni- vs bilateral) and degree (mild vs moderate, defined as ventricular dilatation of 10-12 and 13-15 mm, respectively) of ventricular dilatation. Whether MRI assessment led to a significant change in prenatal management was explored. Random-effects meta-analysis of proportions was used. RESULTS:Sixteen studies (1159 fetuses) were included in the systematic review. Overall, MRI detected an anomaly not identified on ultrasound in 10.0% (95% CI, 6.2-14.5%) of fetuses. However, when stratifying the analysis according to the type of ultrasound assessment, the rate of associated anomalies detected only on MRI was 5.0% (95% CI, 3.0-7.0%) when dedicated neurosonography was performed compared with 16.8% (95% CI, 8.3-27.6%) in cases that underwent a standard assessment of the fetal brain in the axial plane. The overall rate of an additional anomaly detected only at birth and missed on prenatal MRI was 0.9% (95% CI, 0.04-1.5%) (I , 0%). There was no difference in the rate of an associated anomaly detected only after birth when fetal MRI was carried out before, compared with after, 24 weeks of gestation (P = 0.265). The risk of detecting an associated CNS abnormality on MRI was higher in fetuses with moderate than in those with mild VM (odds ratio, 8.1 (95% CI, 2.3-29.0); P = 0.001), while there was no difference in those presenting with bilateral, compared with unilateral, dilatation (P = 0.333). Finally, a significant change in perinatal management, mainly termination of pregnancy owing to parental request, following MRI detection of an associated anomaly, was observed in 2.9% (95% CI, 0.01-9.8%) of fetuses undergoing dedicated neurosonography compared with 5.1% (95% CI, 3.2-7.5%) of those having standard assessment. CONCLUSIONS:In fetuses undergoing dedicated neurosonography, the rate of a CNS anomaly detected exclusively on MRI is lower than that reported previously. Early MRI has an excellent diagnostic performance in identifying additional CNS anomalies, although the findings from this review suggest that MRI performed in the third trimester may be associated with a better detection rate for some types of anomaly, such as cortical, white matter and intracranial hemorrhagic anomalies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.
10.1002/uog.20197