Fetal Magnetic Resonance Imaging Research Articles

Frequency of MRI Low Signal Intensity in the Buccal Fat of Fetuses and Speculation as to What It May Reflect

Purpose: We aimed to characterize the fetal buccal fat pad (BFP) on magnetic resonance imaging (MRI) to determine the frequency and types of sequences on which the BFP demonstrates low signal intensity and determine any possible correlation with timing of the MRI during fetal development. Materials and Methods: A retrospective review of all fetal MR studies was performed, and a pediatric radiologist blinded to the referring and final fetal diagnosis as well as outcome evaluated the included cases. A positive buccal fat pad sign (BFS) was recorded as present if a round, symmetric, and bilateral area was seen in the submalar region of the face with the following signal characteristics: T1 hyperintensity, low signal on echo planar imaging (EPI), low signal on true fast imaging with steady-state free precession (TRUFI), and with restriction on diffusion-weighted imaging (DWI). Results: A total of one hundred sixty-seven (167) fetal MRI studies: one hundred fourteen (114) body (68%) and fifty-three (53) neuro (32%) scans were reviewed during the study period. The BFS was most commonly seen on EPI (63%) and TRUFI (49%) sequences. Substantial agreement between TRUFI and EPI (κ = 0.68; p < 0.01); moderate agreement between TRUFI and T1 (κ = 0.53; p < 0.01) as well as T1 and EPI (κ = 0.53; p < 0.01), and fair agreement between EPI and Diffusion (κ = 0.28; p < 0.01) was observed. The median gestational age (GA) was 24 weeks (IQR 22–30 weeks). The fetuses with a positive BFS were significantly older (mean GA of 27 weeks or higher) than those without, for each sequence. Conclusions: The focal low signal in the fetal buccal fat pad, termed the fetal BFS, is a commonly encountered normal finding in the majority of fetal MRI scans on TRUFI and EPI sequences. This finding may be related to the presence and development of brown adipose tissue in the buccal fat pad resulting in T2* effects, but further studies are needed in order to confirm this. Further work can incorporate any of the sensitive sequences demonstrating low signal in brown adipose tissue to map its distribution and development in the fetus and beyond.

The influence of antenatal imaging on prenatal bonding in uncomplicated pregnancies: a mixed methods analysis

BackgroundPrenatal bonding describes the emotional connection expectant parents form to their unborn child. Research acknowledges the association between antenatal imaging and enhanced bonding, but the influencing factors are not well understood, particularly for fathers or when using advanced techniques like fetal magnetic resonance imaging (MRI). This study aimed to identify variables which may predict increased bonding after imaging.MethodsFirst-time expectant parents (mothers = 58, fathers = 18) completed a two-part questionnaire (QualtricsXM™) about their expectations and experiences of ultrasound (n = 64) or fetal MRI (n = 12) scans in uncomplicated pregnancies. A modified version of the Prenatal Attachment Inventory (PAI) was used to measure bonding. Qualitative data were collected through open-ended questions. Multivariate linear regression models were used to identify significant parent and imaging predictors for bonding. Qualitative content analysis of free-text responses was conducted to further understand the predictors’ influences.ResultsBonding scores were significantly increased after imaging for mothers and fathers (p < 0.05). MRI-parents reported significantly higher bonding than ultrasound-parents (p = 0.02). In the first regression model of parent factors (adjusted R2 = 0.17, F = 2.88, p < 0.01), employment status (β = -0.38, p < 0.05) was a significant predictor for bonding post-imaging. The second model of imaging factors (adjusted R2 = 0.19, F = 3.85, p < 0.01) showed imaging modality (β = -0.53), imaging experience (β = 0.42) and parental excitement after the scan (β = 0.29) were significantly (p < 0.05) associated with increased bonding. Seventeen coded themes were generated from the qualitative content analysis, describing how scans offered reassurance about fetal wellbeing and the opportunity to connect with the baby through quality interactions with imaging professionals. A positive scan experience helped parents to feel excited about parenthood. Fetal MRI was considered a superior modality to ultrasound.ConclusionsAntenatal imaging provides reassurance of fetal development which affirms parents’ emotional investment in the pregnancy and supports the growing connection. Imaging professionals are uniquely positioned to provide parent-centred experiences which may enhance parental excitement and facilitate bonding.

Association between White Matter T2 Hyper-Intense Signals in Fetal Brain Magnetic Resonance Imaging and Neurodevelopment of Fetuses with Cytomegalovirus Infection

An association between subtle changes in T2 white matter hyper-intense signals (WMHSs) detected in fetal brain magnetic resonance imaging (fbMRI) and congenital cytomegalovirus (CMV) infection has been established. The research aim of this study is to compare children with congenital CMV infection with neurodevelopment outcome and hearing deficit with and without WMHSs in a historic prospective case study cohort of 58 fbMRIs. Of these, in 37 cases, fbMRI was normal (normal group) and WMHSs were detected in 21 cases (WMHS group). The median infection week of the WMHS group was earlier than the normal fbMRI group (8 and 17 weeks of gestation, respectively). The proportion of infants treated with valganciclovir in the WMHS group was distinctly higher. Hearing impairment was not significantly different between the groups. VABS scores in all four domains were within normal range in both groups. The median score of the motor skills corrected for week of infection was better in the WMHS group. A multivariate analysis using the week of infection interaction variable of WMHS and valganciclovir treatment showed better motor score outcomes in the valganciclovir treatment group despite an earlier week of infection. WMHSs were not associated with neurodevelopmental outcome and hearing deficit. In our cohort, valganciclovir treatment may have a protective effect on fetuses with WMHSs by improving neurodevelopmental outcome.

[Developmental disorders of the gastrointestinal tract].

Developmental disorders of the gastrointestinal tract comprise abroad spectrum of congenital malformations of different etiologies and locations from the mouth to the anus. The authors present the most important malformations of the gastrointestinal tract on the basis of basic and current reviews. Gastrointestinal developmental disorders occur both sporadically and in connection with malformation syndromes. Symptoms are highly variable and range from postnatal emergencies to asymptomatic abnormalities, which may be incidental radiological findings. Prenatal ultrasound examinations can often identify gastrointestinal developmental disorders at an early stage. Here, fetal magnetic resonance imaging can be auseful addition to the diagnostic process. In the first few days of life, simple X‑ray overview images, supplemented by images after the administration of contrast medium, are often sufficient. Many patients with amalformation of the gastrointestinal tract require lifelong medical care, so that not only pediatric radiologists need specific knowledge about this group of diseases.

Fetal magnetic resonance imaging, ultrasound, and echocardiography findings in twin reversed arterial perfusion sequence.

Twin reversed arterial perfusion (TRAP) sequence is a rare complication of monochorionic multiple gestation pregnancies, in which the pump twin provides hemodynamic support to a nonviable co-twin (acardius). Fetal magnetic resonance imaging (MRI) is used to detect pump twin abnormalities, particularly brain ischemia, prior to fetal intervention to interrupt umbilical blood flow to the acardius. To summarize the imaging findings of TRAP sequence pregnancies in a large series. A single-center retrospective review was performed of all TRAP sequence pregnancies referred for fetal MRI (2004-2021). Fetal MRI, ultrasound, and echocardiography data were collected. Eighty-eight TRAP sequence pregnancies with MRI were included (mean gestational age, 19.8±2.8 weeks). Demise of the pump twin was noted in two pregnancies at the time of MRI. By MRI, 12% (10/86) of live pump twins had abnormalities, including 3% (3/86) with brain abnormalities and 9% (8/86) with extra-cranial abnormalities. By echocardiography, 7% (6/86) of pump twins had structural cardiac abnormalities. Three acardius morphological subtypes were identified by MRI: acephalus (55%, 48/88), anceps (39%, 34/88), and amorphous (7%, 6/88). The mean ultrasound acardiustopump twin ratioA/Pratio, calculated for each twin pair as the ratio of the acardius trunk (and head, if present) plus limb volume to the pump twin estimated fetal weight) differed among the three acardius subtypes (P=.03). The mean A/P ratio moderately correlated with pump twin cardiothoracic ratio and combined cardiac output (Pearson's r=0.45 and 0.48, respectively, both P<.001). Fetal MRI of TRAP sequence pregnancies found anomalies in a substantial number of pump twins. The three acardius subtypes differed in A/P ratio, which moderately correlated with the pump twin cardiothoracic ratio and combined cardiac output.

Fetal magnetic resonance imaging in the confirmation of congenital anomalies found on routine mid-trimester ultrasound.

To determine the added value of fetal magnetic resonance imaging (MRI) when clarifying a suspected anomaly detected by mid-trimester scan. Women attending two centers of fetal medicine between January 2017 and December 2021 were identified. The centers carried out routine mid-trimester ultrasound scans to detect fetal anomalies. Those with a suspected anomaly which required further clarification were referred for fetal magnetic resonance imaging (MRI). The medical records of all referred women were examined to determine the anomalies found at scan, MRI and termination of pregnancy or delivery. A total of 9571 women had a routine mid-trimester scan and an anomaly was either diagnosed or suspected in 449 (4.7%); an MRI examination was made in 76 cases (0.79%). MRI confirmed the presence of an abnormality in 61 referrals (80%) and failed to yield a result in one case. Outcome information was available for 69 cases: the MRI confirmation rate was 89% (48/54) in those with abnormal outcome and 40% (6/15) if the outcome was normal, P<0.0001. Among defects in the most common anatomical systems identified at ultrasound, the highest confirmation rates were for urinary tract abnormalities (94%, 15/16) and facial abnormalities (100%, 8/8). Results in other systems varied according to the specific defect but the confirmation rate was high for ventriculomegaly (86%, 6/7) and neural tube defects (83%, 5/6). We have shown that in women with suspected anomaly scan results, requiring further clarification, MRI confirmed ultrasound at a high rate, particularly for urinary tract and facial anomalies.

PETS-Nets: Joint Pose Estimation and Tissue Segmentation of Fetal Brains Using Anatomy-Guided Networks.

Fetal Magnetic Resonance Imaging (MRI) is challenged by fetal movements and maternal breathing. Although fast MRI sequences allow artifact free acquisition of individual 2D slices, motion frequently occurs in the acquisition of spatially adjacent slices. Motion correction for each slice is thus critical for the reconstruction of 3D fetal brain MRI. In this paper, we propose a novel multi-task learning framework that adopts a coarse-to-fine strategy to jointly learn the pose estimation parameters for motion correction and tissue segmentation map of each slice in fetal MRI. Particularly, we design a regression-based segmentation loss as a deep supervision to learn anatomically more meaningful features for pose estimation and segmentation. In the coarse stage, a U-Net-like network learns the features shared for both tasks. In the refinement stage, to fully utilize the anatomical information, signed distance maps constructed from the coarse segmentation are introduced to guide the feature learning for both tasks. Finally, iterative incorporation of the signed distance maps further improves the performance of both regression and segmentation progressively. Experimental results of cross-validation across two different fetal datasets acquired with different scanners and imaging protocols demonstrate the effectiveness of the proposed method in reducing the pose estimation error and obtaining superior tissue segmentation results simultaneously, compared with state-of-the-art methods.

Congenital diaphragmatic hernia: automatic lung and liver MRI segmentation with nnU-Net, reproducibility of pyradiomics features, and a machine learning application for the classification of liver herniation.

Prenatal assessment of lung size and liver position is essential to stratify congenital diaphragmatic hernia (CDH) fetuses in risk categories, guiding counseling, and patient management. Manual segmentation on fetal MRI provides a quantitative estimation of total lung volume and liver herniation. However, it is time-consuming and operator-dependent. In this study, we utilized a publicly available deep learning (DL) segmentation system (nnU-Net) to automatically contour CDH-affected fetal lungs and liver on MRI sections. Concordance between automatic and manual segmentation was assessed by calculating the Jaccard coefficient. Pyradiomics standard features were then extracted from both manually and automatically segmented regions. The reproducibility of features between the two groups was evaluated through the Wilcoxon rank-sum test and intraclass correlation coefficients (ICCs). We finally tested the reliability of the automatic-segmentation approach by building a ML classifier system for the prediction of liver herniation based on support vector machines (SVM) and trained on shape features computed both in the manual and nnU-Net-segmented organs. We compared the area under the classifier receiver operating characteristic curve (AUC) in the two cases. Pyradiomics features calculated in the manual ROIs were partly reproducible by the same features calculated in nnU-Net segmented ROIs and, when used in the ML procedure, to predict liver herniation (both AUC around 0.85). Conclusion: Our results suggest that automatic MRI segmentation is feasible, with good reproducibility of pyradiomics features, and that a ML system for liver herniation prediction offers good reliability. Trial registration: https://clinicaltrials.gov/ct2/show/NCT04609163?term=NCT04609163&draw=2&rank=1 ; Clinical Trial Identification no. NCT04609163. What is Known: •Magnetic resonance imaging (MRI) is crucial for prenatal congenital diaphragmatic hernia (CDH) assessment. It enables the quantification of the total lung volume and the extent of liver herniation, which are essential for stratifying the severity of CDH, guiding counseling, and patient management. •The manual segmentation of MRI scans is a time-consuming process that is heavily reliant upon the skill set of the operator. What is New: •MRI lung and liver automatic segmentation using the deep learning nnU-Net system is feasible, with good Jaccard coefficient values and satisfactory reproducibility of pyradiomics features compared to manual results. •A feasible ML system for predicting liver herniation could improve prenatal assessments and CDH patient management.

Agreement between Fetal Brain Ultrasonography and Magnetic Resonance Imaging in the Measurements of the Corpus Callosum and Transverse Cerebellar Diameter.

As the use of magnetic resonance imaging of the fetal brain has evolved, the need to understand its efficiency in the biometry of the fetal brain has broadened. This study aimed to assess the level of agreement and correlation between the two cardinal imaging methods of fetal neuroimaging, ultrasonography (US) and magnetic resonance imaging (MRI), by measuring the corpus callosum (CC) and transverse cerebellar diameter (TCD) in terms of length and percentile. Measurements of CC and TCD length and percentile were documented over a 7-year span in a tertiary referral medical center. All US and MRI examinations were performed in the customary planes and subcategorized by valid reference charts. Exclusion and inclusion criteria were set before the collection and processing of the data. A total of 156 fetuses out of 483 were included in the study. A positive, strong correlation and agreement were found (r = 0.78; ICC = 0.76) between US and MRI in TCD measurements. For CC length measurement, a moderate correlation and moderate agreement (r = 0.51; ICC = 0.49) between US and MRI was observed. TCD and CC percentiles had lower levels of correlation and agreement compared with the length variables. Our study indicates good agreement between MRI and US in the assessment of TCD measurement as a part of antenatal neuroimaging. Furthermore, while the two techniques are not always compatible, they are complementary methods.

Optimizing prenatal diagnosis and referral of classic bladder exstrophy: Lessons from a single-institution experience

Classic bladder exstrophy (CBE) is a malformation of the genitourinary system that occurs due to failure of abdominal wall closure. Unlike other malformations of similar incidence, prenatal diagnosis of CBE relies on suggested, rather than formal, diagnostic criteria. This report describes prenatal diagnosis of CBE in the largest single-institutional cohort to date and delineates key sonographic findings and protocols for specialist referral. A single-institutional database was reviewed for CBE patients born since 2000. Data on screening ultrasound use, gestational age at ultrasound, and abnormal findings were extracted. Where possible, time of prenatal diagnosis (pre- or postnatal and gestational age), ultrasound findings and other imaging data, specialist referral, institution of birth and closure, and outcome of primary closure attempt were compared. Of 557 patients born with CBE between 2000 and 2022, 284 met inclusion criteria and complete data were available for 280 (229 born domestically and 51 born internationally) who were included for analysis. Abnormal sonography suggestive of CBE was present for 48% (n=134) of patients, for whom absent bladder was the most common abnormal finding (76% [102/134]). Of domestic patients, 46% (n=106) were diagnosed prenatally at a median gestational age of 22 weeks (inter-quartile range [IQR]: 20-24), and 14% (n=32) underwent confirmatory fetal magnetic resonance imaging. Of domestic patients with abnormal prenatal findings, 75% (n=80/106) consulted with maternal-fetal medicine and 58% (n=62/106) consulted with pediatric urology. On univariate analysis, prenatal diagnosis was positively associated with primary repair at Association for the Bladder Exstrophy Community-recognized centers of excellence (54% vs. 38%, p=0.02) and negatively associated with osteotomy at primary closure (41% vs 59%, p=0.003) but not success of primary closure (74% vs. 82%, p=0.07). Rates of prenatal diagnosis in this cohort were similar to previous reports of smaller cohorts. Diagnosis allows for comprehensive pre- and postnatal follow-up with a pediatric urologist, with implications on birth planning and decisions on termination of pregnancy. Because of the previously-reported association between exstrophy and invitro fertilization, these pregnancies should undergo detailed sonography. Any nonvisualization of the fetal bladder should prompt a detailed exam, and any finding characteristic of bladder exstrophy warrants referral to pediatric urology. Although CBE is a rare disorder, it is underdiagnosed during pregnancy. Sonographers and obstetricians should be aware of characteristic findings and best practices following diagnosis. Early referral to pediatric urology and maternal-fetal medicine is important for counseling and postnatal planning.

Assessment of mediastinal shift angles in congenital pulmonary airway malformation: a new fetal magnetic resonance imaging indicator of congenital lung disease.

The mediastinal shift angle is a new fetal magnetic resonance imaging (MRI) index that is reportedly correlated with postnatal survival in fetuses with congenital diaphragmatic hernia. However, its correlation in patients with congenital pulmonary airway malformation (CPAM) has not been assessed. This study aimed to establish a normal range for the right/left mediastinal shift angles, to evaluate the mediastinal shift angle in fetuses with CPAM, to compare the mediastinal shift angle with the CPAM volume ratio, and to evaluate the predictive value of the mediastinal shift angle measurements. To establish the normal range, we measured the mediastinal shift angle bilaterally in 124 fetuses without any lung abnormality (the control group). Subsequently, the mediastinal shift angle was measured in 32 fetuses pathologically diagnosed with CPAM. Moreover, the mediastinal shift angle and CPAM volume ratio were compared using fetal MRI. The mean values for the right/left mediastinal shift angles were 18.6°/26.3° and 39.2°/35.9° for control fetuses and fetuses with CPAM, respectively. The mediastinal shift angle and the CPAM volume ratio showed a positive statistical correlation. The area under the curve demonstrated high discriminatory accuracy for the mediastinal shift angle (0.76). The mediastinal shift angle has potential to replace the CPAM volume ratio for evaluating the severity of CPAM infetal MRI.

One model, two brains: Automatic fetal brain extraction from MR images of twins

Fetal brain extraction from magnetic resonance (MR) images is of great importance for both clinical applications and neuroscience studies. However, it is a challenging task, especially when dealing with twins, which are commonly existing in pregnancy. Currently, there is no brain extraction method dedicated to twins, raising significant demand to develop an effective twin fetal brain extraction method. To this end, we propose the first twin fetal brain extraction framework, which possesses three novel features. First, to narrow down the region of interest and preserve structural information between the two brains in twin fetal MR images, we take advantage of an advanced object detector to locate all the brains in twin fetal MR images at once. Second, we propose a Twin Fetal Brain Extraction Network (TFBE-Net) to further suppress insignificant features for segmenting brain regions. Finally, we propose a Two-step Training Strategy (TTS) to learn correlation features of the single fetal brain for further improving the performance of TFBE-Net. We validate the proposed framework on a twin fetal brain dataset. The experiments show that our framework achieves promising performance on both quantitative and qualitative evaluations, and outperforms state-of-the-art methods for fetal brain extraction.

Fetal MRI-Based Mediastinal Shift Angle (MSA) and Percentage Area of Left Ventricle (pALV) as Prognostic Parameters for Congenital Diaphragmatic Hernia.

Fetal magnetic resonance imaging (MRI) is broadly used as a method for assessing prognosis in congenital diaphragmatic hernia (CDH). In addition to the extent of lung hypoplasia, determined by measuring the lung volume, cardiac impairment due to pulmonary hypertension and left cardiac hypoplasia is decisive for the prognosis. The percentage area of left ventricle (pALV) describes the percentage of the inner area of the left ventricle in relation to the total area, whereas the mediastinal shift angle (MSA) quantifies the extent of cardiac displacement. The prognostic value of pALV and MSA should be evaluated in terms of survival, the need for extracorporeal membrane oxygenation (ECMO) therapy, and the development of chronic lung disease (CLD). In a total of 122 fetal MRIs, the MSA and pALV were measured retrospectively and complete outcome parameters were determined regarding survival for all 122 subjects, regarding ECMO therapy in 109 cases and about the development of CLD in 78 cases. The prognostic value regarding the endpoints was evaluated using logistic regression and ROC analysis. The MSA was significantly higher in children who received ECMO therapy (p = 0.0054), as well as in children who developed CLD (p = 0.0018). ROC analysis showed an AUC of 0.68 for ECMO requirement and 0.77 with respect to CLD development. The pALV showed a tendency towards higher levels in children who received ECMO therapy (p = 0.0824). The MSA and the pALV had no significant effect on survival (MSA: p = 0.4293, AUC = 0.56; pALV: p = 0.1134, AUC = 0.57). The MSA determined in fetal MRI is a suitable prognostic parameter for ECMO requirement and CLD development in CDH patients and can possibly be used as a supplement to the established parameters.

Prenatal diagnosis of pontocerebellar hypoplasia with postnatal follow-up.

To describe the MR features enabling prenatal diagnosis of pontocerebellar hypoplasia (PCH). This was a retrospective single monocentre study. The inclusion criteria were decreased cerebellar biometry on dedicated neurosonography and available fetal Magnetic Resonance Imaging (MRI) with PCH diagnosis later confirmed either genetically or clinically on post-natal MRI or by autopsy. The exclusion criteria were non-available MRI and sonographic features suggestive of a known genetic or other pathologic diagnosis. The collected data were biometric or morphological imaging parameters, clinical outcome, termination of pregnancy (TOP), pathological findings and genetic analysis (karyotyping, chromosomal microarray, DNA sequencing targeted or exome). PCH was classified as classic, non-classic, chromosomal, or unknown type. Forty-two fetuses were diagnosed with PCH, of which 27 were referred for decreased transverse cerebellar diameter at screening ultrasound. Neurosonography and fetal MRI were performed at a mean gestational age of 29+4 and 31+0weeks, respectively. Termination of pregnancy occurred. Pregnancy was terminated in 24 cases. Neuropathological examination confirmed the diagnosis in 24 cases and genetic testing identified abnormalities in 29 cases (28 families, 14 chromosomal anomaly). Classic PCH is associated with pontine atrophy and small MR measurements decreasing with advancing gestation. This is the first large series of prenatally diagnosed PCHs. Our study shows the essential contribution of fetal MRI to the prenatal diagnosis of PCH. Classic PCHs are particularly severe and are associated with certain MR features.

Cyclopia: A Rare Congenital Anomaly

Cyclopia is the most extreme form of holoprosencephaly. It is characterized by the failure of the embryonic prosencephalon to properly divide the orbits of the eye into two cavities which results in babies with a single or partially divided eye in a single orbit. We report a case of a 28 years old primigravida who came for medical termination at 25 weeks of gestation and delivered a 600 grams dead female fetus with cyclopia, fetal proboscis, and neurocutaneous marker. Its incompatibility with life makes early diagnosis using ultrasonography and fetal magnetic resonance imaging essential in early management and essential counseling to parents.

[Congenital anomalies of the kidneys and urinary tract (CAKUT) : Embryology in radiology and fetal magnetic resonance imaging].

Congenital anomalies of the kidney and urinary tract (CAKUT) are very common findings in fetal diagnostics. Their effects range from variants without pathological significance to pronounced functional impairment with the need for renal replacement therapy in childhood. Sometimes the genital organs are also affected. The aim of the article is to provide an overview of embryology and examples of key findings. In the fetal period, magnetic resonance imaging (MRI) is used, while postnatally, sonography with the option of contrast-enhanced micturition urosonography (MUS, ceVUS) dominates imaging in pediatric radiology, supplemented in individual cases by fluoroscopy (micturition cysturethrography) and MRI. Quantitative methods for assessing kidney function and excretion (MAG3 scintigraphy, functional MR urography) are essential when planning further therapeutic procedures, especially in obstructive uropathies. Imaging plays an essential role in the assessment of abnormalities of the kidneys and urinary tract both pre- and postnatally. Knowledge of embryology facilitates anatomical understanding and assessment of pathologies.

Creating the freedom to thrive: Honoring the legacy of RSNA gold medalist, Deborah Levine, MD

Awarded the Radiological Society of North America (RSNA) Gold Medal in 2018, Dr. Deborah Levine's research, journalism, and mentorship have left an indelible mark on the radiology field. Her work in ultrasound led to its use as the standard for monitoring benign adnexal cysts. She helped popularize obstetric magnetic resonance imaging (MRI) through her research on its use in placental accreta and fetal abnormalities, which led to the development of the ‘Compendium of Fetal MRI’ website. This work in research led naturally to a career in journalism, where she eventually became Senior Deputy Editor of Radiology and founded Radiology Select. Concurrently with her personal achievements, Dr. Levine has dedicated herself to the mentorship of her female trainees. She sought various leadership positions to learn more about and advocate for the promotion and support of female leadership in radiology departments. In many ways, Dr. Levine's career and work have transformed radiology as we know it today for both patients and physicians.

PDFF-CNN: An attention-guided dynamic multi-orientation feature fusion method for gestational age prediction on imbalanced fetal brain MRI dataset.

Fetal brain magnetic resonance imaging (MRI)-based gestational age prediction has been widely used to characterize normal fetal brain development and diagnose congenital brainmalformations. The uncertainty of fetal position and external interference leads to variable localization and direction of the fetal brain. In addition, pregnant women typically concentrate on receiving MRI scans during the fetal anomaly scanning week, leading to an imbalanced distribution of fetal brain MRI data. The above-mentioned problems pose great challenges for deep learning-based fetal brain MRI gestational ageprediction. In this study, a pyramid squeeze attention (PSA)-guided dynamic feature fusion CNN (PDFF-CNN) is proposed to robustly predict gestational ages from fetal brain MRI images on an imbalanced dataset. PDFF-CNN contains four components: transformation module, feature extraction module, dynamic feature fusion module, and balanced mean square error (MSE) loss. The transformation and feature extraction modules are employed by using the PSA to learn multiscale and multi-orientation feature representations in a parallel weight-sharing Siamese network. The dynamic feature fusion module automatically learns the weights of feature vectors generated in the feature extraction module to dynamically fuse multiscale and multi-orientation brain sulci and gyri features. Considering the fact of the imbalanced dataset, the balanced MSE loss is used to mitigate the negative impact of imbalanced data distribution on gestational age predictionperformance. Evaluated on an imbalanced fetal brain MRI dataset of 1327 routine clinical T2-weighted MRI images from 157 subjects, PDFF-CNN achieved promising gestational age prediction performance with an overall mean absolute error of 0.848 weeks and an R2 of 0.904. Furthermore, the attention activation maps of PDFF-CNN were derived, which revealed regional features that contributed to gestational age prediction at each gestationalstage. These results suggest that the proposed PDFF-CNN might have broad clinical applicability in guiding treatment interventions and delivery planning, which has the potential to be helpful with prenatal diagnosis.

Fetal cardiac magnetic resonance imaging of the descending aorta in suspected left-sided cardiac obstructions.

Severe left-sided cardiac obstructions are associated with high morbidity and mortality if not detected in time. The correct prenatal diagnosis of coarctation of the aorta (CoA) is difficult. Fetal cardiac magnetic resonance imaging (CMR) may improve the prenatal diagnosis of complex congenital heart defects. Flow measurements in the ascending aorta could aid in predicting postnatal CoA, but its accurate visualization is challenging. To compare the flow in the descending aorta (DAo) and umbilical vein (UV) in fetuses with suspected left-sided cardiac obstructions with and without the need for postnatal intervention and healthy controls by fetal phase-contrast CMR flow. A second objective was to determine if adding fetal CMR to echocardiography (echo) improves the fetal CoA diagnosis. Prospective fetal CMR phase-contrast flow in the DAo and UV and echo studies were conducted between 2017 and 2022. A total of 46 fetuses with suspected left-sided cardiac obstructions [11 hypoplastic left heart syndrome (HLHS), five critical aortic stenosis (cAS), and 30 CoA] and five controls were included. Neonatal interventions for left-sided cardiac obstructions (n = 23) or comfort care (n = 1 with HLHS) were pursued in all 16 fetuses with suspected HLHS or cAS and in eight (27%) fetuses with true CoA. DAo or UV flow was not different in fetuses with and without need of intervention. However, DAo and UV flows were lower in fetuses with either retrograde isthmic systolic flow [DAo flow 253 (72) vs. 261 (97) ml/kg/min, p = 0.035; UV flow 113 (75) vs. 161 (81) ml/kg/min, p = 0.04] or with suspected CoA and restrictive atrial septum [DAo flow 200 (71) vs. 268 (94) ml/kg/min, p = 0.04; UV flow 89 vs. 159 (76) ml/kg/min, p = 0.04] as well as in those without these changes. Adding fetal CMR to fetal echo predictors for postnatal CoA did not improve the diagnosis of CoA. Fetal CMR-derived DAo and UV flow measurements do not improve the prenatal diagnosis of left-sided cardiac obstructions, but they could be important in identifying fetuses with a more severe decrease in blood flow across the left side of the heart. The physiological explanation may be a markedly decreased left ventricular cardiac output with subsequent retrograde systolic isthmic flow and decreased total DAo flow.

Estimate of fetal brain temperature using proton resonance frequency thermometry during 3 Tesla fetal magnetic resonance imaging.

T2-weighted Single Shot Fast Spin Echo (SSFSE) scans at 3 Tesla (3T) are increasingly used to image fetal pathology due to their excellent tissue contrast resolution and signal-to-noise ratio (SNR). Temperature changes that may occur in response to radio frequency (RF) pulses used for these sequences at 3T have not been studied in human fetal brains. To evaluate the safety of T2-weighted SSFSE for fetal brains at 3T, magnetic resonance (MR) thermometry was used to measure relative temperature changes in a typical clinical fetal brain MR exam. Relative temperature was estimated using sets of gradient recalled echo (GRE) images acquired before and after T2-weighted SSFSE images which lasted 27.47±8.19 minutes. Thirty-one fetuses with cardiac abnormalities, and 20 healthy controls were included in this study. Fetal brain temperature was estimated by proton resonance frequency (PRF) thermometry and compared to the estimated temperature in the gluteal muscle of the mother. Seven scans with excessive motion were excluded. Local outlier factor (LOF) was performed to remove 12 additional scans with spurious phase measurements due to motion degradation and potential field drift. Linear regression was performed to determine if temperature changes are dependent on the rate of energy deposition during the scan. For the 32 participants used in the analysis, 17 with cardiac abnormalities and 15 healthy controls, the average relative fetal temperate change was 0.19±0.73 ℃ higher than the mother, with no correlation between relative temperature change and the rate of images acquired during the scans (regression coefficient =-0.05, R-squared =0.05, P=0.22, F-statistic =1.60). The difference in the relative temperature changes between the fetal brain and mother's gluteal tissue in the healthy controls was on average 0.08 ℃ lower and found not to be statistically different (P=0.76) to the group with cardiac abnormalities. Our results indicate that the estimated relative temperature changes of the fetal brain compared to the mother's gluteal tissue from RF pulses during the course of the T2-weighted SSFSE fetal MR exam are minimal. The differences in acquired phase between these regions through the exam were found not to be statistically different. These findings support that fetal brain imaging at 3T is within FDA limits and safe.