Quantitative fetal MRI with diffusion tensor imaging in cases with 'short' corpus callosum.

OBJECTIVES: It has been suggested previously that the presence of Probst bundles (PB) in cases with a short corpus callosum (SCC) on diffusion tensor imaging (DTI) may help to differentiate between corpus callosal (CC) dysplasia and a variant of normal CC development. The objectives of this study were to compare DTI parameters between cases of SCC vs normal CC and between cases of SCC with PB (SCC-PB+) vs SCC without PB (SCC-PB-). METHODS: This was a retrospective study of patients referred to the Necker Hospital in Paris, France, for magnetic resonance imaging (MRI) evaluation of an apparently isolated SCC detected by sonography between November 2016 and December 2022 (IRB: 00011928). MRI was performed using a 1.5-Tesla Signa system. T2-weighted axial and sagittal sequences of the fetal brain were used to measure the length and thickness of the CC. 16-direction DTI axial brain sequences were performed to identify the presence of PB and to generate quantitative imaging parameters (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)) of the entire CC, genu, body and splenium. Cases in which other associated brain abnormalities were detected on MRI were excluded. Cases were matched for fetal gender and gestational age with controls in a 1:3 ratio. Control cases were normal fetuses included in the LUMIERE on the FETUS trial (NCT04142606) that underwent the same DTI evaluation of the brain. Comparisons between SCC and normal CC cases, and between SCC-PB+ and SCC-PB- cases were performed using ANOVA and adjusted for potential confounders using ANCOVA. RESULTS: Twenty-two SCC cases were included and compared with 66 fetuses with a normal CC. In 10/22 (45.5%) cases of SCC, PB were identified. As expected, dimensions of the CC were significantly smaller in SCC compared with normal CC cases (all P < 0.01). In SCC-PB+ vs SCC-PB- cases, FA values were significantly lower in the entire CC (median, 0.21 (range, 0.19-0.24) vs 0.24 (range, 0.22-0.28); P < 0.01), genu (median, 0.21 (range, 0.15-0.29) vs 0.24 (range, 0.17-0.29); P = 0.04), body (median, 0.21 (range, 0.18-0.23) vs 0.23 (range, 0.21-0.27); P = 0.04) and splenium (median, 0.22 (range, 0.16-0.30) vs 0.25 (range, 0.20-0.29); P = 0.03). ADC values were significantly higher in the entire CC, genu and body in SCC-PB+ vs SCC-PB- cases (all P < 0.05). In SCC-PB+ cases, all FA values were significantly lower, and ADC values in the CC body were significantly higher compared with normal CC cases (all P < 0.05). In SCC-PB- cases, there was no significant difference in FA and ADC compared with normal CC cases (all P > 0.05). CONCLUSIONS: Fetal DTI evaluation of the CC showed that FA values were significantly lower and ADC values tended to be significantly higher in SCC-PB+ compared with normal CC cases. This may highlight alterations of the white matter microstructure in SCC-PB+. In contrast, isolated SCC-PB- did not demonstrate significant changes in DTI parameters, strengthening the possibility that this is a normal CC variant. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Feasibility and Added Value of Fetal DTI Tractography in the Evaluation of an Isolated Short Corpus Callosum: Preliminary Results.

BACKGROUND AND PURPOSE: Prognosis of isolated short corpus callosum is challenging. Our aim was to assess whether fetal DTI tractography can distinguish callosal dysplasia from variants of normal callosal development in fetuses with an isolated short corpus callosum. MATERIALS AND METHODS: This was a retrospective study of 37 cases referred for fetal DTI at 30.4 weeks (range, 25-34 weeks) because of an isolated short corpus callosum less than the 5th percentile by sonography at 26 weeks (range, 22-31 weeks). Tractography quality, the presence of Probst bundles, dysmorphic frontal horns, callosal length (internal cranial occipitofrontal dimension/length of the corpus callosum ratio), and callosal thickness were assessed. Cytogenetic data and neurodevelopmental follow-up were systematically reviewed. RESULTS: Thirty-three of 37 fetal DTIs distinguished the 2 groups: those with Probst bundles (Probst bundles+) in 13/33 cases (40%) and without Probst bundles (Probst bundles-) in 20/33 cases (60%). Internal cranial occipitofrontal dimension/length of the corpus callosum was significantly higher in Probst bundles+ than in Probst bundles-, with a threshold value determined at 3.75 for a sensitivity of 92% (95% CI, 77%-100%) and specificity of 85% (95% CI, 63%-100%). Callosal lipomas (4/4) were all in the Probst bundles- group. More genetic anomalies were found in the Probst bundles+ than in Probst bundles- group (23% versus 10%, P = .08). CONCLUSIONS: Fetal DTI, combined with anatomic, cytogenetic, and clinical characteristics could suggest the possibility of classifying an isolated short corpus callosum as callosal dysplasia and a variant of normal callosal development.

Prenatal diagnosis and outcome of fetuses with isolated agenesis of septum pellucidum: cohort study and meta-analysis.

OBJECTIVE: To evaluate the postnatal outcome of children with a prenatal diagnosis of apparently isolated agenesis of the septum pellucidum (ASP). METHODS: A retrospective cohort study of cases of prenatally diagnosed ASP followed in two tertiary centers and a meta-analysis combining data from the cohort study with data from published studies identified in a systematic review were carried out. Only cases with apparently isolated ASP on antenatal ultrasound and/or magnetic resonance imaging and with available postnatal follow-up data were considered eligible for inclusion. The following outcomes were analyzed: incidence of chromosomal anomalies, agreement between antenatal and postnatal findings, overall incidence of septo-optic dysplasia (SOD) and incidence of major neurological disability (motor, language, coordination or behavioral disorder or epilepsy) in non-SOD children. The incidence of SOD in infants with apparently normal optic pathways on antenatal imaging was also evaluated. RESULTS: Fifteen cases of isolated ASP, with median postnatal follow-up of 36 months (range, 12-60 months), were selected from the two centers. Six previously published studies met the inclusion criteria for the systematic review and a total of 78 cases were eligible for the analysis, including the 15 cases from our series. Genetic tests were carried out antenatally in 30 fetuses, of which two had an abnormal result (pooled proportion, 9.0% (95% CI, 1.8-20.7%); I2 = 0%). Additional or discordant imaging findings were noted postnatally in 9/70 (pooled proportion, 13.7% (95% CI, 3.5-29.0%); I2 = 63.9%) cases. Of all 78 neonates with available follow-up, SOD was diagnosed postnatally in 14 (pooled proportion, 19.4% (95% CI, 8.6-33.2%); I2 = 51.2%). In 60 cases, the optic pathways were considered to be normal on antenatal imaging, and six of these (pooled proportion, 9.1% (95% CI, 1.1-24.0%); I2 = 62.0%) were diagnosed postnatally with SOD. Of the 46 infants with available neurological follow-up who were not affected by SOD, a major neurological disability was diagnosed in three (pooled proportion, 6.5% (95% CI, 0.5-18.6%); I2 = 40.1%). CONCLUSIONS: In the vast majority of cases with a prenatal diagnosis of apparently isolated ASP, the prognosis is favorable. However, an additional anomaly is detected after birth in about 14% of cases and has a negative impact on clinical outcome. Detailed antenatal assessment of the brain and optic pathways is strongly recommended in order to identify the presence of associated anomalies. Antenatal visualization of apparently normal optic pathways does not rule out SOD. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Adenomyosis of the inner and outer myometrium are associated with different clinical profiles.

STUDY QUESTION: Do adenomyosis phenotypes such as external or internal adenomyosis, as diagnosed by MRI, have the same clinical characteristics? SUMMARY ANSWER: External adenomyosis was found more often in young and nulliparous women and was associated with deep infiltrating endometriosis, whereas, in contrast, internal adenomyosis was more often associated with heavy menstrual bleeding (HMB) but no differences were noted in terms of pain symptoms. WHAT IS KNOWN ALREADY: Adenomyosis is characterized by the presence of endometrial glands and stroma deep within the myometrium, giving rise to dysmenorrhea, pelvic pain and menorrhagia. Various forms have been described, including adenomyosis of the outer myometrium (external adenomyosis), which corresponds to lesions separated from the junctional zone (JZ), and adenomyosis of the inner myometrium (internal adenomyosis), which is mostly characterized by endometrial implants scattered throughout the myometrium and enlargement of the JZ. Although the pathogenesis of adenomyosis is not clearly understood, several lines of evidence suggest that these two phenotypes could have distinct origins. The clinical presentation of different forms of adenomyosis in patients warrants further investigation. STUDY DESIGN, SIZE, DURATION: This was an observational study that used data collected prospectively in non-pregnant patients aged between 18 and 42 years who had undergone surgical exploration for benign gynecological conditions at our institution between May 2005 and May 2018. Only women with a pelvic MRI performed by a senior radiologist during the preoperative work-up were retained for this study. For each patient, a standardized questionnaire was completed during a face-to-face interview conducted by the surgeon in the month preceding the surgery. The women's histories (notably their age, gravidity, history of surgery and associated endometriosis), as well as clinical symptoms such as the pain intensity, presence of menorrhagia and infertility, were noted. PARTICIPANTS/MATERIALS, SETTING, METHODS: A pelvic MRI was performed in 496 women operated at our center for a benign gynecological disease who had provided signed informed consent. Of these, 248 women had a radiological diagnosis of adenomyosis. Based on the MRI findings, the women were diagnosed as having external and/or internal adenomyosis. The women were allocated to two groups according to the adenomyosis phenotype (only external adenomyosis vs only internal adenomyosis). Women exhibiting an association of both adenomyosis forms were analyzed separately. MAIN RESULTS AND THE ROLE OF CHANCE: In all, following the MRI findings, 109 women (44.0%) exhibited only external adenomyosis, while 78 (31.5%) had only internal adenomyosis. The women with external adenomyosis were significantly younger (mean ± SD; 31.9 ± 4.6 vs 33.8 ± 5.2 years; P = 0.006), more often nulligravid (P ≤ 0.001) and more likely to exhibit an associated endometriosis (P < 0.001) compared to the women in the internal adenomyosis group. Moreover, the women exhibiting internal adenomyosis significantly more often had a history of previous uterine surgery (P = 0.002) and HMB (62 (80%) vs 58 (53.2%), P < 0.001) compared to the women with external adenomyosis. No differences in the pain scores (i.e. dysmenorrhea, non-cyclic pelvic pain and dyspareunia) were observed between the two groups. LIMITATIONS, REASONS FOR CAUTION: The exclusive inclusion of surgical patients could constitute a possible selection bias, as the women referred to our center may have suffered from particularly severe clinical symptoms. WIDER IMPLICATIONS OF THE FINDINGS: Further studies are needed to explore the pathogenesis by which these types of adenomyosis occur. This could help with the development of new treatment strategies specific for each entity. STUDY FUNDING/COMPETING INTEREST(S): none. TRIAL REGISTRATION NUMBER: N/A.

Heterogeneity in defining fetal corpus callosal pathology: systematic review.

OBJECTIVE: Fetal anomalies of the corpus callosum (CC) have been reported in the prenatal imaging literature since 1985, and, especially when isolated, pose challenges for both the patient and fetal medicine specialist. The purpose of this study was to review systematically the literature on prenatally diagnosed abnormalities of the CC, focusing on the terminology used to describe abnormalities other than complete agenesis of the CC, and to assess the heterogeneity of the nomenclature and definitions used. METHODS: This study was conducted in accordance with the PRISMA statement for reporting systematic reviews. A literature search was performed to identify prospective or retrospective case series or cohort studies, published in English, French, Italian, German or Spanish, reporting fetal imaging findings and describing anomalies of the CC. Quality and risk of bias of the studies were evaluated using the Newcastle-Ottawa scale and a modification of the scale developed by Conde-Agudelo et al. for other fetal imaging studies. The data extracted included the number of patients, the number of different anomalies identified, the descriptive names of the anomalies, and, where applicable, the definitions of the anomalies, the number of cases of each type of anomaly and the biometric charts used. Secondary tests used to confirm the diagnosis, as well as the postnatal or post-termination tests used to ascertain the diagnosis, were also recorded. RESULTS: The search identified 998 records, and, after review of titles and abstracts and full review of 45 papers, 27 studies were included initially in the review, of which 24 were included in the final analysis. These 24 studies had a broad range of quality and risk of bias and represented 1135 cases of CC anomalies, of which 49% were complete agenesis and the remainder were described using the term partial agenesis or nine other terms, of which five had more than one definition. CONCLUSIONS: In comparison to the postnatal literature, in the prenatal literature there is much greater heterogeneity in the nomenclature and definition of CC anomalies other than complete agenesis. This heterogeneity and lack of standard definitions in the prenatal literature make it difficult to develop large multicenter pooled cohorts of patients who can be followed in order to develop a better understanding of the genetic associations and neurodevelopmental and psychological outcomes of patients with CC anomalies. As this information is important to improve counseling of these patients, a good first step towards this goal would be to develop a simpler categorization of prenatal CC anomalies that matches better the postnatal literature. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Accuracy of prenatal ultrasound screening to identify fetuses infected by cytomegalovirus which will develop severe long-term sequelae.

OBJECTIVES: To compare the ability of detailed routine ultrasound examination, performed without knowledge of maternal serology and fetal status, with that of targeted prenatal imaging performed in prenatal diagnostic units in cases of known fetal infection to identify cytomegalovirus (CMV)-infected fetuses that will develop long-term sequelae. METHODS: All prenatal imaging reports were collected for 255 children with congenital CMV in a registered cohort between 2013 and 2017 (NCT01923636). All women had undergone detailed routine fetal ultrasound examination at 20-24 and 30-34 weeks as part of routine antenatal care. All cases of known fetal CMV infection had also undergone targeted prenatal ultrasound examination. Postnatal structured follow-up for up to 48 months of age involved clinical, audiological and neurological assessment, including Brunet-Lezine scoring. Long-term sequelae (> 12 months) were considered to be mild in cases with isolated unilateral hearing loss and/or vestibular disorders, and severe in cases with bilateral hearing loss and/or neurological sequelae. All imaging reports were analyzed retrospectively with the knowledge of congenital CMV infection, searching for reference to findings that were, or could have been, related to fetal infection. Findings were analyzed in relation to whether the cases were diagnosed with CMV in utero or only postnatally. RESULTS: There were 237 children with complete follow-up data (> 12 months), for a median of 24 (range, 12-48) months. Of these, 30% (71/237) were diagnosed with CMV prenatally and 70% (166/237) were diagnosed within 3 weeks after birth. 72.5% (29/40) of children with long-term sequelae, including 74% (14/19) with severe long-term sequelae, were not identified in the prenatal period. Among those diagnosed prenatally, the sensitivity of prenatal imaging for predicting long-term sequelae and severe long-term sequelae was 91% and 100%, respectively, while, in the group diagnosed only postnatally, non-specific infection-related ultrasound findings had been reported without raising suspicion in 48% of cases with long-term sequelae and 64% of those with severe long-term sequelae. CONCLUSIONS: Routine detailed ultrasound examination in pregnancy is not an appropriate screening tool for congenital CMV infection that leads to long-term sequelae, in contrast with the high performance of targeted prenatal imaging in known cases of fetal infection. The non-specific nature of ultrasound features of CMV and their evolution, and a lack of awareness of caregivers about congenital CMV, are likely explanations. Awareness of the sonologist regarding congenital CMV and knowledge of the maternal serological status in the first trimester seem key to the performance of prenatal ultrasound. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Fetal brain imaging following laser surgery in twin-to-twin surgery.

OBJECTIVE: To describe the incidence and nature of prenatal brain damage following fetoscopic laser selective coagulation (FLSC) of placental vessels for twin-to-twin transfusion syndrome (TTTS). DESIGN: Retrospective observational study. SETTING: Single center cohort. POPULATION: All consecutive cases referred for TTTS treated by FLSC between 2003 and 2015. METHODS: After the FLSC, patients were followed weekly by ultrasound. Fetal magnetic resonance imaging (MRI) scans were systematically planned at 30-32 weeks of gestation. MAIN OUTCOME MEASURES: Brain damage diagnosed prenatally by ultrasound or MRI. RESULTS: In total, 1023 cases were reviewed. Brain damage was diagnosed prenatally in 22/1023 (2.1%) cases. Diagnosis was performed by ultrasound prior to MRI in 18 (82%) cases. All lesions were within the spectrum of ischaemic haemorrhagic lesions. Postoperative twin anaemia polycythaemia sequence and recurrence of TTTS were significantly associated with brain damage. CONCLUSION: The incidence of prenatal brain damage is low following FSLC, and is strongly associated with incomplete surgery. TWEETABLE ABSTRACT: Following FSLC for TTTS, prenatal brain damage occurs in 2% of cases and is associated with incomplete surgery.

[Prenatal discovery of Joubert syndrome associated with small bowel volvulus]. / Découverte anténatale d'un syndrome de Joubert associé à un volvulus du grêle.

Joubert syndrome and prenatal volvulus are difficult to diagnose during pregnancy. Joubert syndrome and related diseases should be considered in case of prenatal abnormal features of the fourth ventricle. Small bowel volvulus is also a surgical emergency because of the risk of intestinal necrosis before or after delivery. This type of condition justifies the transfer of pregnant women to a specialized hospital where the newborn may receive appropriate care. We report the case of a 31-week and 4-day gestational-age fetus in whom intrauterine growth retardation and small-bowel volvulus were diagnosed. Additional imaging revealed associated Joubert syndrome. This highlights the need for regular ultrasound monitoring during pregnancy and the comanagement of obstetricians and pediatricians to provide appropriate care before and after delivery.

Urinary endometriosis: MR imaging appearance with surgical and histological correlations.

OBJECTIVES: The goals of the study were to describe the MR imaging features of endometriosis of the urinary tract and identify those that suggest intrinsic involvement of ureteric wall. MATERIALS AND METHODS: Thirty-five women with proven urinary tract endometriosis and who had preoperative MR imaging between 2001 and 2011 were included retrospectively. MR images were intrepreted by one junior and one senior radiologists. To characterize the intrinsic parietal involvement, the ureteric circumference involved by the lesion of endometriosis was noted. RESULTS: Thirty-eight ureteric and 13 bladder lesions were analyzed. They were found in association in nine women. Ureteric lesions were bilateral in seven women. Of the 38 ureteric lesions, 27 were extrinsic and 11 intrinsic at histopathological analysis. Sixteen women with extrinsic lesions and 10 with intrinsic ones were correctly identified on MR imaging. When the ureter was included less than 360° in the lesion, extrinsic involvement was confirmed in 80% of cases. CONCLUSION: MR imaging appears to be more sensitive (91%vs 82%) but less specific (59% vs 67%) than surgery for the diagnosis of intrinsic form of ureteric location.

Fusion imaging for evaluation of deep infiltrating endometriosis: feasibility and preliminary results.

OBJECTIVE: Magnetic resonance imaging (MRI) and ultrasound scanning complement each other in screening for and diagnosis of endometriosis. Fusion imaging, also known as real-time virtual sonography, is a new technique that uses magnetic navigation and computer software for the synchronized display of real-time ultrasound and multiplanar reconstructed MR images. Our aim was to evaluate the feasibility and ability of fusion imaging to assess the main anatomical sites of deep infiltrating endometriosis (DIE) in patients with suspected active endometriosis. METHODS: This prospective study was conducted over a 1-month period in patients referred to a trained radiologist for an ultrasound-based evaluation for endometriosis. Patients with a prior pelvic MRI examination within the past year were offered fusion imaging, in addition to the standard evaluation. All MRI examinations were performed on a 1.5-T MRI machine equipped with a body phased-array coil. The MRI protocol included acquisition of at least two fast spin-echo T2-weighted orthogonal planes. The Digital Imaging Communications in Medicine dataset acquired at the time of the MRI examination was loaded into the fusion system and displayed together with the ultrasound image on the same monitor. The sets of images were then synchronized manually using one plane and one anatomical reference point. The ability of this combined image to identify and assess the main anatomical sites of pelvic endometriosis (uterosacral ligaments, posterior vaginal fornix, rectum, ureters and bladder) was evaluated and compared with that of standard B-mode ultrasound and MRI. RESULTS: Over the study period, 100 patients were referred for ultrasound examination because of endometriosis. Among them were 20 patients (median age, 35 (range, 27-49) years) who had undergone MRI examination within the past year, with a median (range) time interval between MRI and ultrasound examination of 171 (1-350) days. All 20 patients consented to undergo additional evaluation by fusion imaging. However, in three (15%) cases, fusion imaging was not technically possible because of changes since the initial MRI examination resulting from either interval surgery (n = 2; 10%) or pregnancy (n = 1; 5%). Data acquisition, matching and fusion imaging were performed in under 10 min in each of the other 17 cases. The overall ability of each technique to identify and assess the main anatomical landmarks of endometriosis was as follows: uterosacral ligaments: ultrasound, 88% (30/34); MRI, 100% (34/34); fusion imaging, 100% (34/34); posterior vaginal fornix: ultrasound, 88% (30/34); MRI, 100% (34/34); fusion imaging, 100% (34/34); rectum: ultrasound, 100% (17/17); MRI, 82.3% (14/17); fusion imaging, 100% (17/17); ureters: ultrasound, 0%; MRI, 100% (34/34); fusion imaging, 100% (34/34); and bladder: ultrasound, 100%; MRI, 100%; fusion imaging, 100%. CONCLUSION: Fusion imaging is feasible for the assessment of endometriotic lesions. Because it combines information from both ultrasound and MRI techniques, fusion imaging allows better identification of the main anatomical sites of DIE and has the potential to improve the performance of ultrasound and MRI examination.

Interest of the steady state free precession (SSFP) sequence for 3D modeling of the whole fetus.

Fetal magnetic resonance imaging (MRI) has been gaining interest over the last two decades. Current fast MRI sequences provide imaging data of the whole uterus in less than 20 seconds, avoiding fetal motion related artifacts without any maternal or fetal sedation. MRI has proved to be a useful adjunct to echographic screening for prenatal diagnosis. However, MRI volumetric data is still mainly interpreted on 2D slices and 3D applications remain limited. In this paper, we discuss the qualities of the SSFP MRI sequences to provide adequate data for 3D segmentation and modeling of the fetus. Potential exploitations of 3D segmentation and derived anatomical models cover several domains: biometric and morphologic clinical studies, quantitative longitudinal studies of normal and abnormal fetus developments, direct visualization of the overall fetus body and simulations in different fields (surgery, radiation dosimetry,...).