Antenatal Magnetic Resonance Imaging Research Articles

The “cortical invagination sign”: a midtrimester sonographic marker of unilateral cortical focal dysgyria in fetuses with complete agenesis of the corpus callosum

Agenesis of the corpus callosum is associated with several malformations of cortical development. Recently, features of focal cortical dysgyria have been described in fetuses with agenesis of the corpus callosum. This study aimed to describe the "cortical invagination sign," a specific sonographic feature of focal cortical dysgyria, which is consistently seen at midtrimester axial brain ultrasound in fetuses with complete agenesis of the corpus callosum. This was a retrospective analysis of prospectively collected data from 2018 to 2021, including patients referred to 5 fetal medicine centers in the second trimester of pregnancy (19 0/7 to 22 0/7 weeks of gestation) with suspected complete agenesis of the corpus callosum. All cases with the diagnosis of complete agenesis of the corpus callosum were submitted to an axial sonographic assessment of the fetal brain on the transventricular plane. In this scanning section, the mesial profile of both cerebral hemispheres at the level of the frontal-parietal cortex was investigated. In this area, the operator looked for an abnormal invagination of the cortical surface along the widened interhemispheric fissure, which was referred to as the "cortical invagination sign." All fetuses were submitted to dedicated antenatal magnetic resonance imaging to reassess the ultrasound findings. Cases with additional brain anomalies, which did not involve the cortex, were excluded. The final diagnosis was confirmed at postnatal brain magnetic resonance imaging or postmortem examination, for cases undergoing termination of pregnancy. The primary outcome of this study was to evaluate the presence and laterality of the "cortical invagination sign" in fetuses with complete agenesis of the corpus callosum at antenatal ultrasound and magnetic resonance imaging. During the study period, 64 cases of complete agenesis of the corpus callosum were included; of those cases, 50 (78.1%) resulted in termination of pregnancy, and 14 (21.9%) resulted in a live birth. The "cortical invagination sign" was detected at ultrasound in 13 of 64 cases (20.3%) and at targeted brain magnetic resonance imaging in 2 additional cases (23.4%), all of which were electively terminated. Moreover, the "cortical invagination sign" was found to be exclusively unilateral and on the left cerebral hemisphere in all the cases. There was a predominant number, although nonsignificant, of male fetuses (80.0% of cases; P=.06) in the group of complete agenesis of the corpus callosum with the "cortical invagination sign." The "cortical invagination sign" is a specific marker of focal cortical dysgyria, which seems to characterize at midtrimester of pregnancy in a large group of fetuses with complete agenesis of the corpus callosum. The etiology, pathophysiology, and prognostic significance of this finding remain to be elucidated.

Case Report: An infant with agenesis of the corpus callosum (AgCC) with normal developmental milestones

Background: Agenesis of the corpus callosum (AgCC) is a unique and rare brain malformation that can have long-term effects on the cognitive and neurological development of those affected. Individuals with AgCC must undergo regular neuropsychological screening to secure conceivable problems and diagnose and tackle them at the appropriate times. Case report: This case is of a male-term infant born through vaginal delivery to a primigravida mother. Antenatal history was insignificant. Fetal Ultrasonography (USG) done at 24 weeks of gestation showed AgCC. The risk factor was explained to the parents, but they wanted to continue the pregnancy. The infant was delivered at term gestation and weighed 2500 gm. The baby was discharged from the hospital and was advised for follow-up. On follow-up, milestones were normal. Magnetic resonance imaging (MRI) of his brain at 24 months during follow-up showed total AgCC. Surprisingly, milestones were not delayed for his age, so he was advised to screen for neurocognitive in the subsequent follow-up. Discussion: AgCC is typically diagnosed through antenatal MRI or genetic testing, but it may be isolated in cases where no additional anomalies are present. It is also associated with various hereditary syndromes, and prenatal diagnosis through Ultrasonography (USG) can be performed between 18 and 22 weeks of gestation to identify features suggestive of AgCC so that early intervention can be done. Though we do not have exact treatment, supporting treatment is equally important to combat further complications. Conclusions: Despite diagnostic tools for AgCC, many physicians are not familiar with the neurological and cognitive features of AgCC, which can lead to delayed management and treatment. Therefore, medical professionals must receive education and training on this condition to manage individuals with AgCC and receive the most supportive care they need.

Placenta accreta spectrum in major placenta previa diagnosed only by MRI: incidence, risk factors, and maternal morbidity.

Antenatal assessment of maternal risk factors and imaging evaluation can help in diagnosis and treatment of placenta accreta spectrum (PAS) in major placenta previa (PP). Recent evidence suggests that magnetic resonance imaging (MRI) could complement ultrasonography (US) in the PAS diagnosis. Evaluate the incidence, risk factors, and maternal morbidity related to the MRI diagnosis of PAS in major PP. A 10-year retrospective cohort study. Tertiary care hospital. We report on patients with major PP who had cesarean delivery in Abha Maternity and Children's Hospital (AMCH) over a 10-year period (2012-2021). They were evaluated with ultrasonography (US) and color Doppler for evidence of PAS. Antenatal MRI was ordered either to confirm the diagnosis (if equivocal US) or to assess the depth of invasion/extra-uterine extension (if definitive US). Risk factors for PAS in major PP and maternal complications. 299 patients RESULTS: Among 299 patients, MRI confirmed the PAS diagnosis in 91/299 (30.5%) patients. The independent risk factors for MRI diagnosis of PAS in major PP included only repeated cesarean sections and advanced maternal age. The commonest maternal morbidity in major PP with PAS was significantly excessive intraoperative bleeding. MRI may be a valuable adjunct in the evaluation of PAS in major PP; as a complement, but not substitute US. MRI may be suitable in major PP/PAS patients who are older and have repeated cesarean deliveries with equivocal results or deep/extra-uterine extension on US. Single center, small sample size, lack of complete histopathological diagnosis. None.

Anterior extension of the choroid plexus into the frontal horns of the fetal lateral cerebral ventricles: Prenatal findings and postnatal outcome.

To evaluate the short- and long-term outcome of fetuses with evidence of extension of the choroid plexus into the frontal horns. This is a retrospective cohort study of fetuses diagnosed with isolated choroid plexi extending into the frontal horns. Fetuses with major central nervous system anomalies were excluded. Ultrasound and fetal/postnatal magnetic resonance imaging (MRI) were evaluated. Postnatal outcomes, including developmental assessment, were obtained. Twenty nine fetuses were diagnosed with choroid plexus extension (22 unilateral and 7 bilateral). Gestational age at diagnosis was 19.3weeks. Three cases (10.3%) presented with nonspecific extra-CNS findings. At presentation, 8/29 (28%) cases had single/multiple choroid plexus cysts (CPC). Twenty-six (89.6%) cases underwent antenatal MRI. On MRI, four cases had punctate susceptibility weighted imaging (SWI) foci suggesting trace hemosiderin and two cases had ventriculomegaly. Antenatal follow-up demonstrated resolution of the choroid plexus extension in 90% (18/20). Gestational age at delivery was 39.6weeks. All had normal neurologic examinations within 24h of life. Postnatal MRI studies were notable for deep venous differences in seven cases. Long-term clinical outcome was assessed in 14 cases with a median follow-up of 1.75years, with normal neurodevelopment reported in 13/14 (92.8%). Most fetuses with an anterior extension of the choroid plexus as the sole sonographic finding had favorable outcomes.

Fetal Lung Volume Appears to Predict Respiratory Morbidity in Congenital Diaphragmatic Hernia.

Congenital diaphragmatic hernia (CDH) is associated with pulmonary hypoplasia and respiratory morbidity. To assess whether respiratory morbidity during the first 2 years of life in infants with left-sided CDH is associated with fetal lung volume (FLV) evaluated by the observed-to-expected FLV ratio (o/e FLV) on antenatal magnetic resonance imaging (MRI). In this retrospective study, o/e FLV measures were collected. Respiratory morbidity in the first 2 years of life was studied according to two endpoints: treatment with inhaled corticosteroids for >3 consecutive months and hospitalization for any acute respiratory disease. The primary outcome was a favorable progression defined by the absence of either endpoint. Forty-seven patients were included. The median o/e FLV was 39% (interquartile range, 33-49). Sixteen (34%) infants were treated with inhaled corticosteroids and 13 (28%) were hospitalized. The most efficient threshold for a favorable outcome was an o/e FLV ≥ 44% with a sensitivity of 57%, specificity of 79%, negative predictive value of 56%, and positive predictive value of 80%. An o/e FLV ≥ 44% was associated with a favorable outcome in 80% of cases. These data suggest that lung volume measurement on fetal MRI may help to identify children at lower respiratory risk and improve information during pregnancy, patient characterization, decisions about treatment strategy and research, and personalized follow-up.

Advances in Maternal–Fetal Imaging

Advances in Maternal–Fetal Imaging

Prenatal imaging and whole-exome sequencing identify novel tetratricopeptide repeat domain 7A mutation in foetus with gastrointestinal atresia: a case report

BackgroundTetratricopeptide repeat domain 7A (TTC7A, chromosome 2p21) is a highly conserved structural motif essential for multiprotein scaffolding and cell survival. Fewer than 60 cases of TTC7A deficiency have been reported globally. It produces multisystemic disease phenotypes which are lethal in two-thirds of patients, with a median survival age of 12 months. It is predominantly detected postnatally, often rendering medical and surgical interventions futile.Case presentationWe report the antenatal sonographic and magnetic resonance imaging characteristics of a novel phenotype of TTC7A-deficiency presenting with gastrointestinal atresia. This has never been previously documented. The diagnosis was confirmed via whole-exome next-generation sequencing, thus facilitating prompt initiation of management and prolonging viability.ConclusionsNovel insight into the prenatal morphological characteristics of TTC7A-deficiency phenotypes expands knowledge of this rare condition. Furthermore, antenatal recognition facilitates targeted investigation, genetic counselling, and earlier multidisciplinary intervention to prolong viability of this predominantly lethal condition.

Visual assessment of the placenta in antenatal magnetic resonance imaging across gestation in normal and compromised pregnancies: Observations from a large cohort study.

Visual assessment of the placenta in antenatal magnetic resonance imaging is important to confirm healthy appearances or to identify pathology complicating fetal anomaly or maternal disease. We assessed the placenta in a large cohort of 228 women with low and high risk pregnancies across gestation. All women gave written informed consent and were imaged using either a 3T Philips Achieva or 1.5T Philips Ingenia scanner. Images were acquired with a T2-weighted single shot turbo spin echo sequence of the whole uterus (thereby including placenta) for anatomical information. A structured approach to visual assessment of the placenta on T2-weighted imaging has been provided including determination of key anatomical landmarks to aid orientation, placental shape, signal intensity, lobularity and granularity. Transient factors affecting imaging are shown including the effect of fetal movement, gross fetal motion and contractions. Placental appearances across gestation in low risk pregnancies are shown and compared to pregnancies complicated by preeclampsia and chronic hypertension. The utility of other magnetic resonance techniques (T2* mapping as an indirect marker for quantifying oxygenation) and histological assessment alongside visual assessment of placental T2-weighted imaging are demonstrated. A systematic approach with qualitative descriptors for placental visual assessment using T2-weighted imaging allows confirmation of normal placental development and can detect placental abnormalities in pregnancy complications. T2-weighted imaging can be visually assessed alongside functional imaging (such as T2* maps) in order to further probe the visual characteristics seen.

Maternal and fetal incidental findings on antenatal magnetic resonance imaging

BackgroundMagnetic resonance imaging (MRI) examinations are increasingly used in antenatal clinical practice. Incidental findings are a recognized association with imaging and although in some circumstances their identification can alter management, they are often associated with increased anxiety, for both patient and clinician, as well as increased health care costs.ObjectiveThis study aimed to evaluate the incidence of unexpected findings in both the mother and fetus during antenatal MRI examinations.Materials and methodsA retrospective study was undertaken over a five-year period at St.. Thomas’ Hospital in London. Maternal incidental findings were recorded from all clinical reports of all fetal MRIs performed (for clinical reasons and in healthy volunteers) during this period. Fetal incidental findings were recorded only in cases where women with uncomplicated pregnancies were participating as healthy volunteers.ResultsA total of 2,569 MRIs were included; 17% of women had maternal incidental findings. Of these, 1,099 were women with uncomplicated pregnancies who undertook research MRIs as healthy volunteers; fetal incidental findings were identified in 12.3%.ConclusionIncidental findings are a common occurrence in antenatal MRI. Consideration should be given to counseling women appropriately before imaging and ensuring that robust local protocols are in place for follow-up and further management of such cases.

VP38.11: Antenatal magnetic resonance imaging of fetal skeletal system

VP38.11: Antenatal magnetic resonance imaging of fetal skeletal system

In-vitro fertilisation–embryo-transfer complicates the antenatal diagnosis of placenta accreta spectrum using MRI: a retrospective analysis

To evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) for the antenatal diagnosis of placenta accreta spectrum (PAS). Data from 95 patients with placenta previa or low-lying placenta who underwent MRI at Osaka University Hospital for the antenatal diagnosis of PAS between January 2013 and December 2018 were reviewed retrospectively. The antenatal MRI signs suggesting PAS were assessed. Patients were divided into two groups depending on whether they were diagnosed with PAS. Factors that affected PAS diagnosis were identified using multivariate analysis. The diagnostic accuracy of MRI for detecting PAS was as follows: 71.4% sensitivity, 96.4% specificity, and area under the curve (AUC) of 0.839 (95% confidence interval [CI]: 0.73-0.91). The diagnostic accuracy was lower in patients with in-vitro fertilisation with embryo transfer (IVF-ET): 22.2% sensitivity, 93.3% specificity, and AUC=0.578 (95% CI: 0.417-0.724). On multivariate analysis, only IVF-ET showed a significant association with false-positive or -negative MRI diagnosis of PAS (adjusted odds ratio: 26.5; 95% CI: 2.42-289.4; p=0.007). IVF-ET affects the antenatal diagnosis of PAS using MRI.

The comparative study of antenatal magnetic resonance imaging and ultrasound in the evaluation of fetal central nervous system abnormalities

Background: The role of fetal magnetic resonance imaging (MRI) was studied in antenatal anomalies detected by ultrasound. Materials and Methods: The study was conducted in the Department of Radiodiagnosis and Imaging, Government Medical College, Srinagar, over a period of 12 months including all pregnant women with suspected fetal anomalies on ultrasonography (US). Results: In 9/23 cases (39.1%), the US findings and MRI findings were similar. MRI changed the diagnosis in 11/23 cases (47.8%). MRI provided additional information than US in 2/23 cases (8.69%), and there was 1/23 (4.3%) cases in which US provided additional information to that provided by MRI in terms of intrauterine growth restriction. Conclusions: US and MRI are complementary to each other in reaching a diagnosis in the fetal central nervous system abnormalities, and MRI is a major problem-solving modality where the US findings are inconclusive. The major role for fetal MRI was found in confirmation of inconclusive sonographic findings and the evaluation of sonographically occult diagnoses.

Early alterations in cortical and cerebellar regional brain growth in Down Syndrome: An in vivo fetal and neonatal MRI assessment.

Down Syndrome (DS) is the most frequent genetic cause of intellectual disability with a wide spectrum of neurodevelopmental outcomes. At present, the relationship between structural brain morphology and the spectrum of cognitive phenotypes in DS, is not well understood. This study aimed to quantify the development of the fetal and neonatal brain in DS participants, with and without a congenital cardiac defect compared with a control population using dedicated, optimised and motion-corrected in vivo magnetic resonance imaging (MRI). We detected deviations in development and altered regional brain growth in the fetus with DS from 21 weeks' gestation, when compared to age-matched controls. Reduced cerebellar volume was apparent in the second trimester with significant alteration in cortical growth becoming evident during the third trimester. Developmental abnormalities in the cortex and cerebellum are likely substrates for later neurocognitive impairment, and ongoing studies will allow us to confirm the role of antenatal MRI as an early biomarker for subsequent cognitive ability in DS. In the era of rapidly developing technologies, we believe that the results of this study will assist counselling for prospective parents.

Neonatal central diabetes insipidus in a case of hydranencephaly

Neonatal diabetes insipidus (DI) poses both diagnostic and therapeutic challenge to the neonatologists. Neonatal central DI (CDI) is an uncommon disorder which is characterized by polyuria, hypernatremia, high plasma osmolality, and low urine osmolality. Our full-term neonate with an antenatal magnetic resonance imaging showing hydranencephaly presented to us on day 4, with persistent hypernatremic dehydration along with the polyuria which was not getting corrected by the routine management of hypernatremic dehydration. Further investigations revealed urine hypo-osmolality and high serum osmolality and a good response to oral desmopressin (DDAVP). This helped to diagnose CDI secondary to hydranencephaly. The baby was discharged on oral DDAVP, but unfortunately, the baby succumbed at 3 months of age.

Prognostic significance of an antenatal magnetic resonance imaging staging system on airway outcomes of fetal craniofacial venolymphatic malformations

BackgroundThe aim of the article was to determine if anatomical findings on fetal magnetic resonance imaging (MRI) of venolymphatic malformations of the face and neck (VLMFN) can be used to create a staging system predictive of airway outcomes. MethodsWe reviewed 13 fetuses evaluated for VLMFN. Stage was assigned based on anatomical findings on fetal MRI. Stage I: no evidence of polyhydramnios with free egress of amniotic fluid and clear visualization of the aryepiglottic folds and larynx. Stage II: lesions of the tongue or epiglottis but with normal aryepiglottic folds without polyhydramnios. Stage III: lesions of the tongue or larynx; nonvisualization of the aryepiglottic folds without free egress of amniotic fluid along with polyhydramnios. ResultsSix met stage I criteria with no airway involvement, nor any subsequent issues. Two met stage II criteria and were managed by ex-utero intrapartum therapy and intubated. One had minimal involvement of the upper airway, was extubated, and had no subsequent issues. Child two had involvement of the tongue and larynx and received a tracheostomy. Five were assigned stage III, delivered by ex-utero intrapartum therapy and intubated. Postnatal evaluation showed involvement of the upper airway by the lesion and was managed with tracheostomy. All treated by tracheostomy remain cannulated because of persistent symptomatic lesions at follow-up (relative risk 4.0; confidence interval 1.2-13.3). Median follow-up was 4 y (range 2-7 y). ConclusionsAlthough numbers are small, data suggest anatomical details obtained by antenatal fetal MRI appear to correlate with airway outcomes in children affected by a VLMFN. This information may be useful when counseling expectant families of affected fetuses.

Uterine artery embolization for management of placenta accreta, a single-center experience and literature review

“Morbidly adherent placenta” is a term that describes the continuum of placenta accreta, increta, and percreta. Placenta accreta is the least invasive form, whereas placenta percreta represents a complete penetration of the trophoblast through the uterus that reaches the serosal surface and potentially invades the bladder, rectal wall, and pelvic vessels. Leaving the placenta in situ in the setting of abnormally invasive placenta is now widely practiced. We herein present three cases of abnormal placental implantation diagnosed by antenatal ultrasound and magnetic resonance imaging, in which uterine artery embolization was performed to induce placental infarction and eventually rapid regression but most importantly to minimize peripartum and postpartum bleeding. As we do this, we sought to review the risks of placenta accreta, increta, and percreta and evaluate the role of endovascular therapy to improve maternal outcomes when abnormal placental implantation occurs.

Symptomatic Neonatal Arterial Ischemic Stroke With Prenatal and Postnatal Neuroimaging.

The authors report a girl born at term via planned cesarean delivery. Three days earlier, an antenatal magnetic resonance imaging study, showing no cerebral lesions in the fetus, was performed. Ten minutes after delivery, signs of progressive respiratory failure developed and the infant was transferred to the intensive care unit. On the next day, a computed tomography (CT) scan showed acute ischemic lesions in the areas of the left middle and posterior cerebral arteries. The exact mechanism of stroke remained unidentified. It is possible that emboli occluded the left middle cerebral artery and left posterior cerebral artery. At the age of 1 year and 4 months, the patient demonstrated a slight right-sided hemiparesis more pronounced in the hand. To our knowledge, there are no prior published case studies reporting a healthy fetal brain, which then undergoes an acute neonatal arterial infarction near or during birth following an elective cesarean delivery.

Correlation of probability scores of placenta accreta on magnetic resonance imaging with hemorrhagic morbidity

Study Objective and DesignTo evaluate the hypothesis that assigning grades to magnetic resonance imaging (MRI) findings of suspected placenta accreta will correlate with hemorrhagic outcomes. We chose a single-center, retrospective, observational design. Setting, Patients, and MeasurementsNulliparous or multiparous women who had antenatal placental MRI performed at a tertiary level academic hospital were included. Cases with antenatal placental MRI were included and compared with cases without MRI performed. Two radiologists assigned a probability score for accreta to each study. Estimated blood loss and transfusion requirements were compared among groups by the Kruskal-Wallis H test. ResultsThirty-five cases had placental MRI performed. MRI performance was associated with higher blood loss compared with the non-MRI group (2600 [1400-4500]mL vs 900[600-1500]mL, P<.001). There was no difference in estimated blood loss (P=.31) or transfusion (P=.57) among the MRI probability groups. ConclusionsIn cases of suspected placenta accreta, probability scores for antenatal placental MRI may not be associated with increasing degrees of hemorrhage. Continued research is warranted to determine the effectiveness of assigning probability scores for antenatal accreta imaging studies, combined with clinical indices of suspicion, in assisting with antenatal multidisciplinary team planning for operative management of this morbid condition.

Fetal MRI: A Rare Case of Conjoint Twins.

The antenatal magnetic resonance imaging (MRI) of a third-trimester primipara patient showed a fetus in a vertical position with two separate heads, a common thorax, abdomen, and pelvis with a single pair of upper and lower limbs [Figure 1]. Both heads appeared equal and symmetric with normal brain development [Figure 2]. Two separate upper cervical spinal cords fused to form a single spinal cord in the mid/lower cervical spine level. There was a single heart present in the thoracic cavity. The intra-abdominal organs appeared normal in position, structure, and number [Figure 1]. The findings were confirmed at delivery [Figure 3]. Figure 1 Coronal T2-weighted turbo spin echo (TSE) showed the fetus in a vertical position with two separate heads, two cervical spinal cords fusing at the mid-cervical spine level, a common thorax, abdomen, and pelvis, and a single pair of upper and lower limbs ... Figure 2 Coronal T2-weighted turbo spin echo (TSE) the posterior half of the fetal heads showed normally and bilaterally symmetric development of the fetal brains on both sides. Normal appearing cerebral and cerebellar hemispheres, with normal sulci and gyri, ... Figure 3 Postnatal photograph of the baby delivered at 28 gestational weeks by cesarean section. (Informed consent was taken from the parents of this baby for use of this image).

Evaluation of fetal MRI in a South African referral centre.

The Department of Radiology at Groote Schuur Hospital, Cape Town, South Africa, has been performing fetal magnetic resonance imaging (MRI) since 2007. Fetal MRI findings have not previously been analysed to correlate them with antenatal and postnatal findings. To determine the most common indication for fetal MRI, and to correlate antenatal MRI with antenatal ultrasound (US), postnatal imaging and postmortem findings. This was a retrospective study of imaging carried out between January 2006 and December 2011. Seventy fetal MRI cases with complete antenatal and postnatal medical records were included. Antenatal US and antenatal MRI were compared, and also compared with the postnatal imaging findings. Stata 12 was used to analyse the data, and Spearman's test to test the agreement between the results. Intracranial pathology was the most common indication for fetal MRI, with ventriculomegaly being the commonest indication determined from prenatal US. There was 72% agreement between antenatal US and fetal MRI. Postnatal findings showed 28% agreement with antenatal US and 39% agreement with fetal MRI. Intracranial pathology was the major indication for fetal MRI. There was good agreement between prenatal US and fetal MRI but poor agreement between antenatal and postnatal findings, largely as a result of resolution of ventriculomegaly.