Fetal Magnetic Resonance Imaging Research Articles

Typical lesions in the fetal nervous system: correlations between fetal magnetic resonance imaging and obstetric ultrasonography findings.

Central nervous system (CNS) malformations play a role in all fetal malformations. Ultrasonography (US) is the best screening method for identifying fetal CNS malformations. A good echographic study depends on several factors, such as positioning, fetal mobility and growth, the volume of amniotic fluid, the position of the placenta, the maternal wall, the quality of the apparatus, and the sonographer’s experience. Although US is the modality of choice for routine prenatal follow-up because of its low cost, wide availability, safety, good sensitivity, and real-time capability, magnetic resonance imaging (MRI) is promising for the morphological evaluation of fetuses that otherwise would not be appropriately evaluated using US. The aim of this article is to present correlations of fetal MRI findings with US findings for the major CNS malformations.

Pathogenesis of Cleft Palate in Robin Sequence: Observations From Prenatal Magnetic Resonance Imaging

The etiology of the palatal cleft in Robin sequence (RS) is unknown. The purpose of this study was to assess the position of the fetal tongue at prenatal magnetic resonance imaging (MRI) and to suggest a potential relation between tongue position and development of the cleft palate seen in most patients with RS. This is a retrospective case-and-control study including fetuses with prenatal MRIs performed in the authors' center from 2002 to 2017. Inclusion criteria were 1) prenatal MRI of adequate quality, 2) liveborn infant, and 3) postnatal diagnosis of RS (Robin group) or cleft lip and palate (CLP group). Patients with postnatal RS without a palatal cleft were excluded. A control group with normal facial morphology was matched by gestational age. The outcome variable was tongue position at fetal MRI, described as within the cleft, along the floor of the mouth (normal), other, or indeterminate. One hundred twenty-two patients with mean gestational age at MRI of 25.8±4.9weeks were included (Robin, n=21 [17%]; CLP, n=47 [39%]; control, n=54 [44%]). The tongue was visualized within the palatal cleft in 76.2% of the Robin group and 4.3% of the CLP group. The tongue was found along the floor of the mouth (normal) in the remainder of the Robin and CLP groups and in 100% of the control group. These findings suggest a relation between in utero tongue position and the development of cleft palate in RS.

The fetal lung-to-liver signal intensity ratio on magnetic resonance imaging as a predictor of outcomes from isolated congenital diaphragmatic hernia.

We investigated the developmental changes in the unaffected contralateral lungs of patients with isolated left-sided congenital diaphragmatic hernia (CDH) using signal intensity ratios on prenatal magnetic resonance imaging (MRI) and determined whether these changes correlated with clinical outcomes. We performed 47 fetal MRI screens on 30 patients with isolated left-sided CDH. A cohort of 88 fetuses was selected as the control. We calculated the lung-to-liver signal intensity ratio (LLSIR) using region of interest analysis and compared LLSIR between the groups and between those in the CDH group with good and poor prognoses. In the control group, LLSIR increased as pregnancy progressed [regression line = 2.232 + 0.135 × (GW-23), r = 0.669]. In the CDH group, especially in the poor prognosis group, LLSIR did not significantly increase as pregnancy progressed [regression line for good prognosis = 1.827 + 0.092 × (gestational week-23), r = 0.733; regression line for poor prognosis = 1.731 + 0.025 × (gestational week-23), r = 0.634]. Fetal LLSIR on T2-weighted MRI is an accurate marker of fetal lung maturity that correlates with postnatal survival and can potentially be used as a prognostic parameter in CDH management.

Prenatal diagnosis of a large abdominal cyst – Recommendations and management

Abstract This case report describes a twin fetus diagnosed in the third trimester with an enlarging abdominal mass that was confirmed on fetal magnetic resonance imaging (MRI) to be a hepatic mesenchymal hamartoma (HMH) without involvement of the placenta. Serial ultrasonography demonstrated progressive enlargement of the mass and infant was delivered at 33 + 6 weeks gestational age following maternal complications. On the fifth day, at laparotomy, a huge mass connected to the lower portion of the liver was completely resected. Microscopic evaluation confirmed a hepatic mesenchymal hamartoma. Postoperative recovery was uneventful and the infant was discharged at 4 weeks. The antenatal diagnosis of the hepatic mesenchymal hamartoma by fetal MRI and subsequent follow-up by serial ultrasonography emphasizes the importance of combining these 2 modalities for optimal management of the pregnancy to allow a favorable outcome.

Texture analysis of the developing human brain using customization of a knowledge-based system

Background:Pattern recognition software originally designed for geospatial and other technical applications could be trained by physicians and used as texture analysis tools for evidence-based practice, in order to improve diagnostic imaging examination during pregnancy.Methods:Various machine-learning techniques and customized datasets were assessed for training of an integrable knowledge-based system (KBS) to determine a hypothetical methodology for texture classification of closely related anatomical structures in fetal brain magnetic resonance (MR) images. Samples were manually categorized according to the magnetic field of the MRI scanner (i.e., 1.5-tesla [1.5T], 3-tesla [3T]), rotational planes (i.e., coronal, sagittal, and axial), and signal weighting (i.e., spin-lattice, spin-spin, relaxation, and proton density). In the machine-learning sessions, the operator manually selected relevant regions of interest (ROI) in 1.5/3T MR images. Semi-automatic procedures in MaZda/B11 were performed to determine optimal parameter sets for ROI classification. Four classes were defined: ventricles, thalamus, gray matter, and white matter. Various texture analysis methods were tested. The KBS performed automatic data preprocessing and semi-automatic classification of ROI.Results:After testing 3456 ROI, statistical binary classification revealed that the combination of reduction techniques with linear discriminant algorithms (LDA) or nonlinear discriminant algorithms (NDA) yielded the best scoring in terms of sensitivity (both 100%, 95% CI: 99.79–100), specificity (both 100%, 95% CI: 99.79–100), and Fisher coefficient (≈E+4 and ≈E+5, respectively).Conclusions:LDA and NDA in MaZda can be useful data mining tools for screening a population of interest subjected to a clinical test.

Prenatal brain MRI samples for development of automatic segmentation, target-recognition, and machine-learning algorithms to detect anatomical structures

In this data note, we present a sorted pool of fetal magnetic resonance imaging (MRI) specimens. These were selected for a project seeking to further develop computer vision software called MaZda, which was originally created for magnetic resonance (MR) image analysis. A link to download the samples is provided in the manuscript herein. This data descriptor further explains how and why these fetal MRI samples were selected. Firstly, thousands of cross-sectional images obtained from fetal MRI scans were processed and sorted semi-manually with other software. We did so because a built-in “samplesort” (sorting algorithm) is missing in MaZda version 5. Additionally, the software is unfortunately lacking effective and efficient algorithms to allow automatic identification and segmentation of anatomical structures in fetal MRI samples. Hence, the final sorting steps were carried out manually via time-consuming methods (i.e., human visual detection and classifications by the gestational age of pregnancy and the rotational plane of the MR scanner). Thus, the latter correlates with the anatomical plane of the mother, rather than the hypothetical plane used to transect the fetus. In brief, we collated these fetal MRI samples in an effort to facilitate future research and discovery, especially to aid the improvement of MaZda.

EP22.18: Factors affecting the condition of the fetal brain on postmortem MRI

Fetal postmortem magnetic resonance imaging (MRI) of the brain may result in images of varying quality, which may limit the assessment of the fetal brain. Aim of the present study was to identify factors which may have an effect on the condition of the fetal brain at postmortem MRI. Retrospective analysis of 118 fetal postmortem MRI examinations performed on a 3 Tesla unit for clinical purposes. The fetuses (13-42 gestational weeks) were divided into three groups: (1) preterm delivery and induction of labour, (2) feticide and (3) intrauterine fetal death (IUFD). The condition of the fetal brain was visually assessed with respect to soft tissue decomposition and correlated with the way the fetus died and the time elapsed between fetal death and MRI. Different degrees of postmortem changes were found in each of the three groups. Excellent quality was found in group 1, good results in group 2, and poor quality was observed in group 3. The mean time between fetal death and postmortem MRI was 14.7 hours in group 1 (median 12.2 h), 157.1 h in group 2 (median: 58.7h), and 76.8 h in group 3 (median: 68.1), respectively. The quality of fetal postmortem MRI highly depends on the fetus' condition. The time elapsed between fetal demise and MRI and the way of death have a significant impact on the state of preservation of the fetal brain, and thus on image quality. The shorter the time between death and MRI is, the better the resulting image quality.

EP22.21: Magnetic resonance in fetal cerebral lesions

To report the outcome in a series of cases of fetal cerebral lesions where FMRI changed the perinatal management. Retrospective study that covered a period of 4 years, from 2012 to 2016. During this period of time we detected 9 cases with fetal cerebral lesions which underwent Fetal Magnetic Resonance Imaging (FMRI). We found four cases of fetal cerebral hemorrhage, one of them within a fetal intracranial tumour, two cases of thrombosis of the torcular Herofili, one case of Galeno AV malformation, one case of acute toxoplasmosis and one with ventriculomegaly. Gradient-echo T2-weighted images (T2*) and T1 images where accurate in the detection of chronic hemorrhagic lesions. We demonstrate the value of FMRI of a highly targeted examination in a very selected population of fetuses.

PVR: Patch-to-Volume Reconstruction for Large Area Motion Correction of Fetal MRI.

In this paper, we present a novel method for the correction of motion artifacts that are present in fetal magnetic resonance imaging (MRI) scans of the whole uterus. Contrary to current slice-to-volume registration (SVR) methods, requiring an inflexible anatomical enclosure of a single investigated organ, the proposed patch-to-volume reconstruction (PVR) approach is able to reconstruct a large field of view of non-rigidly deforming structures. It relaxes rigid motion assumptions by introducing a specific amount of redundant information that is exploited with parallelized patchwise optimization, super-resolution, and automatic outlier rejection. We further describe and provide an efficient parallel implementation of PVR allowing its execution within reasonable time on commercially available graphics processing units, enabling its use in the clinical practice. We evaluate PVR’s computational overhead compared with standard methods and observe improved reconstruction accuracy in the presence of affine motion artifacts compared with conventional SVR in synthetic experiments. Furthermore, we have evaluated our method qualitatively and quantitatively on real fetal MRI data subject to maternal breathing and sudden fetal movements. We evaluate peak-signal-to-noise ratio, structural similarity index, and cross correlation with respect to the originally acquired data and provide a method for visual inspection of reconstruction uncertainty. We further evaluate the distance error for selected anatomical landmarks in the fetal head, as well as calculating the mean and maximum displacements resulting from automatic non-rigid registration to a motion-free ground truth image. These experiments demonstrate a successful application of PVR motion compensation to the whole fetal body, uterus, and placenta.

OP18.06: Comparison of fetal brain weight determined by fetal magnetic resonance imaging with autopsy brain weight

OP18.06: Comparison of fetal brain weight determined by fetal magnetic resonance imaging with autopsy brain weight

OP05.10: Fetal magnetic resonance imaging (MRI) versus 3D ultrasonography (3D‐US) in assessment of fetal lung volumes in cases at risk of pulmonary hypoplasia

To analyse the correlation and agreement between 3D-US & MRI in measuring fetal lung volumes in cases at risk of developing pulmonary hypoplasia. 38 fetuses at high risk of developing lung hypoplasia either due to extrathoracic causes like renal anomalies causing oligohydraminos and skeletal dysplasias with narrow chest (22cases) or due to intrathoracic causes like congenital cystic adenomatoid malformation (CCAM) and congenital diaphragmatic hernia (CDH) (16 cases) were involved in a cross sectional study. 3D volume data sets of the fetal lungs were acquired were using a commercially available ultrasound system & total lung volumes were calculated using the virtual organ computer-aided analysis (VOCAL) method. MRI obtained fast T2 weighted images of fetal chest in axial, coronal and sagittal planes with assessment of signal intensity & lung volumetry. Comparison between mean lung volumes was performed using unpaired t test. Agreement between the 3D-US and MRI methods was done using Cohen Kappa test. Finally sensitivity, specificity, positive predictive value, negative predictive value & diagnostic accuracy were calculated for 3D-US and for MRI. Good agreement was detected between the two methods(Kappa = 0.715, p = 0.001). The measured lung volumes by 3D-US were smaller than those measured by MRI (p >0.05, non-significant). MRI showed greater specificity, positive predictive value and diagnostic accuracy (100%each) than 3D-US (68.75,78.26 &82.86%) respectively. There is good concordance between 3D-US and MRI in measuring lung volumes and in assessment of pulmonary hypoplasia. MRI can be used complementary to US in borderline cases of pulmonary hypoplasia and in difficult diagnostic situations due to complicated lesions or due to technical problems as in cases of severe oligohydraminos & improper fetal position.

OP27.07: Does imaging correlate with clinical findings for morbidly adherent placenta? An audit from University Hospitals Coventry and Warwickshire

The incidence of morbidly adherent placenta is rising secondary to the increasing Caesarean rate and advancing maternal age. The Royal College of Obstetricians and Gynecologists (RCOG) recommends that women with an anterior low placenta and a Caesarean section scar at 32 completed weeks gestation undergo further imaging with either ultrasonography and/or magnetic resonance imaging (MRI) to distinguish if there is likely placenta accreta. The aim of this audit was to determine if imaging correlated with clinical findings in our unit. Patients were identified from the fetal medicine department and MRI log from January 2015 until March 2017. Images, reports and clinical notes were reviewed to determine if morbidly adherent placenta was suspected on imaging and found at the time of Caesarean section. Six patients were identified. The number of previous Caesarean sections ranged from 1 to 5. 5 patients underwent colour Doppler ultrasonography all of which were suspicious for placenta accreta. 6 patients underwent MRI of which 5 were suspicious for at least accreta. For the patient with an MRI showing previa only, clinical findings correlated with this scan. One patient is awaiting surgery. For the other four patients there were three placental accreta and one percreta. Blood loss ranged from 1.4 - 10.5 litres. Two patients had a hysterectomy. From this study the fetal medicine Colour Doppler ultrasonography sensitivity was 100%, with a 100% positive predicative value. For MRI there was 100% sensitivity, specificity and positive and negative predictive values. Morbidly adherent placenta is uncommon but is increasing in incidence. RCOG states that colour Doppler has a sensitivity of 92% in detecting invasive placental disorders, which is similar to the sensitivity in our department. MRI has been shown to have a sensitivity of 93% and specificity of 71%. The sensitivity from this cohort was higher, which we have attributed to small sample size.

OP07.01: Fetal neurosonography versus magnetic resonance imaging: comparing their accuracy in diagnosing brain anomalies with respect to neuropsychiatric outcome

OP07.01: Fetal neurosonography versus magnetic resonance imaging: comparing their accuracy in diagnosing brain anomalies with respect to neuropsychiatric outcome

Contemporary Modalities to Image the Fetal Brain.

Fetal brain ultrasound remains as the mainstay for screening fetal intracranial anatomy. One of its main advantages is the availability of 3 dimensional and other ultrasound modalities for a better understanding of fetal neurodevelopment. Neurosonography is performed when findings, suggestive of an abnormality, are present on a screening ultrasound or if a high-risk situation of brain injury is present. This technique offers the use of complementary imaging planes, axial, coronal and sagittal, and the ability to image intracranial anatomy from the transabdominal and transvaginal approaches. Fetal brain magnetic resonance imaging is more sensitive than ultrasound. As an adjunctive imaging modality, magnetic resonance imaging offers additional sequences to complete the information on neurodevelopment from different perspectives, such as brain metabolism, microstructure, and connectivity.

OP05.05: New advances in fetal cardiovascular magnetic resonance imaging

OP05.05: New advances in fetal cardiovascular magnetic resonance imaging

EP21.02: Intrauterine open fetal surgery for cervical spina bifida correction: case report

Spina bifida is characterised by the incomplete formation of structures that protect the spinal cord and the inappropriate closure of the spinal bones. It presented a high rate of associated comorbidities (hydrocephalus, neurological deficits, motor deficiency in the lower limbs, vesical e and intestinal dysfunctions) secondary to the herniation of the structures of the posterior fossa by the foramen magno (Arnold-Chiari II malformation) and spinal cord injury and anchorage. Currently, there is the possibility of intrauterine open fetal surgery for correction of spina bifida lumbosacral which showed benefits in relation to the postnatal treatment according to MOMS clinical trial. Spina bifida in cervical topography is rare (3.5% of cases) and may be associated with Chiari II, hydrocephalus and cognitive deficits. Although it does not meet the criteria for intrauterine correction, we present a case with an isolated diagnosis of cervical myelomeningocele submitted to open fetal surgery for correction of spinal dysraphism. Pregnant LMOC, 37 years old, primigravida, no comordidades, ultrasound showing cervical myelomeningocele (C5-C7), no ventriculomegaly, chiari II (with anchoring of the cervical spine), no other malformations in the central nervous system. Fetal magnetic resonance imaging confirming findings of the ultrasound. Normal fetal karyotype. After clarification and consent of the couple and approval of our institution's ethics committee, patient underwent open fetal surgery at 26 weeks. Post-surgical ultrasound showed complete reversal of cerebellar herniation and absence of ventriculomegaly. Caesarean delivery at 37 weeks, newborn weight 3035g, female, apgar 9/10. Postnatal exams normal. Immediate postnatal follow-up adequate for the age. Cervical spina bifida is rare, but may present sequelae such as hydrocephalus and cognitive deficits. In carefully-selected cases, intrauterine surgery may be considered as therapeutic option.

EP03.02: Impact of fetal magnetic resonance imaging of the brain in assessment of fetal CNS anomalies

EP03.02: Impact of fetal magnetic resonance imaging of the brain in assessment of fetal CNS anomalies

In vivo assessment of placental and brain volumes in growth-restricted fetuses with and without fetal Doppler changes using quantitative 3D MRI.

ObjectiveThe relationship between placental and fetal brain growth is poorly understood, and difficult to assess. The objective of this study was to interrogate placental and fetal brain growth in healthy pregnancies and those complicated by fetal growth restriction (FGR).Study DesignIn a prospective, observational study, pregnant women with normal pregnancies or pregnancies complicated by FGR underwent fetal MR imaging. Placental, global and regional brain volumes were calculated.Results114 women (79 controls and 35 FGR) underwent MR imaging (median GA 30 weeks, range 18 –39). All measured volumes increased exponentially with advancing GA. Placental, total brain, cerebral and cerebellar volumes were smaller in FGR compared to controls (p<0.05). Increasing placental volume was associated with increasing cerebral and cerebellar volumes (p<0.05).ConclusionQuantitative fetal MRI can accurately detect decreased placental and brain volumes in pregnancies with FGR and may provide insight into the timing and mechanisms of brain injury in FGR.

Sirenomelia, the Fetal ‘Mermaid’: Ultrasound and Magnetic Resonance Features

Sirenomelia (otherwise known as Mermaid Syndrome), is a very rare congenital anomaly characterized by variable fusion of lower limbs along with thoracolumbar spinal anomalies, sacrococcygeal agenesis, genitourinary and gastrointestinal tract malformations, with an incidence of 0.8 to 1 case per 100,000 births. This anomaly has a strong association with maternal diabetes, and some researchers consider it to be a severe form of caudal regression syndrome. It is a lethal anomaly, with half of the cases being stillborn and most cases involving live births dying within a few days. We present here a radiological evaluation of a case of sirenomelia in a 28-year-old primigravida with history of occasional cocaine and alcohol use. The fetus had duodenal atrasia, bilateral renal agenesis, caudal dysgenesis, imperforate anus and absent genitalia, as determined by fetal sonogram and fetal magnetic resonance imaging (MRI), which had been carried out for better evaluation. Fetal sonogram revealed sacral dysgenesis, and double bubble sign suggestive of duodenal atresia. Fetal MRI showed bilateral renal agenesis, duodenal atresia and single hypoplastic lower limb. One of two upper limbs was also found to be hypoplastic. After delivery, the stillborn was examined externally. There were no external genitalia and the anus was imperforate. There was a single hypoplastic lower limb. One of two upper limbs was also hypoplastic. Early diagnosis of sirenomelia is necessary for safe termination of pregnancy. However, complete evaluation of a sirenomelia fetus is hindered by associated severe oligohydramnios. Fetal MRI has no such constraints and can demonstrate various anomalies in a greater detail than fetal sonogram.

Sirenomelia: A Rare Congenital Anomaly

ABSTRACTIntroductionSirenomelia is a congenital structural anomaly characterized by abnormal development of the caudal region of the body. The peculiar characteristics of sirenomelia are complete fusion of bilateral lower limbs giving the fetus an appearance of mermaid. The other anatomical defects may be renal agenesis, gastrointestinal defects, and absent external genitalia. The outcome of the condition is usually fatal for the baby despite attempts for corrective surgery. This abnormality was initially confused with caudal regression syndrome, but later was given a new name, i.e., sirenomelia mermaid syndrome.Case reportWe present a case of a 23-year-old primigravida unbooked case reported at 25 weeks 6 days period of gestation with complaint of decreased fetal movements. The ultrasound was suggestive of single live intrauterine fetus of 24 weeks with severe oligohydramnios (amniotic fluid index 1–2 cm). Based on fetal magnetic resonance imaging, which revealed multiple congenital anomalies including nonvisualization of kidneys and poorly formed lower limbs, provisional diagnosis of sirenomelia with renal aplasia incompatible with life was made. She delivered a baby 943 gm with features and appearance suggestive of mermaid syndrome (sirenomelia). Patient was discharged with advice to report early in next pregnancy.ConclusionSirenomelia is a very rare disorder, with prevalence of 1 in 100,000 live births with a total of 300 cases reported until today in which 9 are from India. The precise etiology of sirenomelia is not well understood. Many theories have been proposed, but none of these is considered definitive. It is very important to diagnose this universally fatal condition by ultrasonography in early pregnancy, so that termination of pregnancy can be carried out.How to cite this articleVerma P, Bhardwaj D, Sinha SK, Heer AK. Sirenomelia: A Rare Congenital Anomaly. J South Asian Feder Obst Gynae 2017;9(3):271-273.