Magnetic resonance imaging of intracranial anomalies in pregnancies complicated by twin anemia-polycythemia sequence.

PURPOSE: To describe fetal brain Magnetic Resonance Imaging (MRI) findings in a large series of monochorionic (MC) pregnancies complicated by Twin Anemia-Polycythemia Sequence (TAPS) prenatally diagnosed, so to characterize the potential intracranial complications associated with this condition, their frequency and potential treatment options. METHODS: This is a retrospective study of MC twin pregnancies complicated by TAPS and undergone fetal MRI in a single institution from 2006 to 2023. MRI control was performed and post-natal ultrasound (US) or MRI were available. RESULTS: 1250 MC pregnancies were evaluated in our institution. 50 pregnancies (4%) were diagnosed with TAPS, 29 underwent a fetal brain MRI. 13/29 pregnancies (44.8%) demonstrated brain findings at MRI in at least a twin. Neuroradiological findings were detected in 14/57 twins (24.6%). We detected four main categories of findings: hemorrhagic lesions, T2-weighted white-matter hyperintensities (WMH), brain edema-swelling and venous congestion. Nineteen findings were present in the anemic and three in the polycythemic twins, with a statistically significant ratio between the two groups (p-value = 0.01). Intrauterine MRI follow-up demonstrated the sequalae of hemorrhagic lesions. A complete regression of brain swelling, veins prominence and T2-WMHs was demonstrated after treatment. Postnatal imaging confirmed prenatal features. CONCLUSIONS: Our work demonstrates that TAPS-related MRI anomalies consisted in edematous/hemorrhagic lesions that occur mostly in anemic rather than in polycythemic twins. Fetoscopic laser surgery could have a potential decongestant role. Therefore, prenatal MRI may help in counselling and management in TAPS pregnancies, especially for the planning of therapy and the monitoring of its efficacy.

Spontaneous regression of an epidermoid cyst in a pediatric patient-Case report and review of the literature.

Epidermoid cysts are infrequent, benign, slow-growing, space-occupying lesions that account for 0.5-1.8% of primary intracranial tumors. We report the case of a 17-month-old child who presented in 2015 for one episode of pallor associated with hypotonia. Epilepsy was excluded and MRI was recommended. The MRI was performed and there were no focal parenchymal lesions, but it showed an extra-axial ovoid lesion with imaging characteristics consistent with epidermoid cyst. Follow-up MRI at one year was performed and it showed minimal increased in dimensions of the cyst, without changes into the signal of the lesion. Another MRI was performed 7 years after and it showed complete resolution of the cyst. Six months afterwards, another MRI was performed and it confirmed the complete regression of the cyst, without any extra-axial masses reported. The patient did not present any neurological anomalies. No follow-up MRI was recommended afterwards. Spontaneous regression of epidermoid cyst in pediatric population is an extremely rare event, but it should be taken into account when the patient shows no symptoms. This is the third case of spontaneous regression of an epidermoid cyst reported in pediatric patients, and the first one in the temporal region. Careful follow-up and watchful waiting could be an option to surgical treatment in epidermoid cysts.

TSEN54 Gene-Related Pontocerebellar-Hypoplasia and Role of Prenatal MR Imaging: Besides the Common Posterior Fossa Cystic Malformations.

Pontocerebellar-hypoplasia (PCH) related to TSEN54-gene mutation, a rare autosomal recessive disorder, can be associated with three different phenotypes: PCH2A, PCH4 and PCH5. Prenatal imaging features are very scant, in particular for PCH4 and PCH5. The aim of this letter is to illustrate key role of prenatal MR imaging in better evaluation of the cerebellar vermis-hemispheres and pons, which may lead to the differential diagnosis between three PCH TSEN54-related phenotypes already at mid-gestation based on the pattern of the degree of involvement of the vermis and the cerebellar cortex respectively.

Complete agenesis of corpus callosum and unilateral cortical formation anomalies detected on fetal MR imaging: a phenotype strongly associated with the male fetuses.

INTRODUCTION: In a previous study of classifying fetuses with cortical formation abnormalities (CFA) with fetal MR, we noticed a cluster of cases with unilateral CFA and complete agenesis of the corpus callosum (ACC). In this study, we provide a detailed morphological analysis of such fetuses using fetal MR to determine if there are indicators (such as the gender of the fetus) that could be used to delineate a genetic substrate of the phenotype in order to inform future studies. METHODS: We have studied 45 fetuses with the unilateral CFA/ACC phenotype and analysed through an expert consensus panel the location and fine detail of the CFA and the associated findings such as associated anomalies, head size, and sex of the fetus. RESULTS: The frontal lobe was significantly more frequently involved by CFA when compared with other lobes (p < 0.001) but no preference for the left or right hemisphere. CFA most often consisted of excessive/dysmorphic sulcation. The CFA/ACC phenotype was overwhelmingly more frequent in male fetuses (M:F 4.5:1-p < 0.0001). The most frequent associated findings were: ventriculomegaly (16/45 fetuses) and interhemispheric cysts (12/45 cases). CONCLUSIONS: This report highlights the specific phenotype of unilateral CFA/ACC that is much more common in male fetuses. This finding provides a starting point to study possible sex-linked genetic abnormalities that underpin the unilateral CFA/ACC phenotype. KEY POINTS: • We collected fetuses with unilateral cortical formation abnormality and callosal agenesis. • That distinctive neuroimaging phenotype has a strong male gender prevalence (over 80%). • This observation forms the basis of studies about outcomes and genetic substrates.

Cutting-edge applications of fetal MR neuro-imaging in clinical routine: a pictorial essay.

Over time, fetal MR neuro-imaging has undergone continuous improvement; presently, it plays a pivotal role in the diagnosis of an expanding array of complex neurological conditions. Within this pictorial essay, our focus will be exclusively directed towards those cutting-edge clinical applications, which currently yield valuable diagnostic insights on a single case basis. Specifically, the pictorial examples will center on some abnormal entities and their features at an earlier fetal stage.

Onset of Chiari type 1 malformation: insights from a small series of intrauterine MR imaging cases.

PURPOSE: Morphometric studies on idiopathic Chiari malformation type 1 (CM1) pathogenesis have been mainly based on post-natal neuroimaging. Prenatal clues related to CM1 development are lacking. We present pre- and post-natal imaging time course in idiopathic CM1 and assess fetal skull and brain biometry to establish if clues about CM1 development are present at fetal age. METHODS: Multicenter databases were screened to retrieve intrauterine magnetic resonance (iuMR) of children presenting CM1 features at post-natal scan. Syndromes interfering with skull-brain growth were excluded. Twenty-two morphometric parameters were measured at fetal (average 24.4 weeks; range 21 to 32) and post-natal (average 15.4 months; range 1 to 45) age; matched controls were included. RESULTS: Among 7000 iuMR cases, post-natal scans were available for 925, with postnatal CM1 features reported in seven. None of the fetuses presented CM1 features. Tonsillar descent was clear at a later post-natal scan in all seven cases. Six fetal parameters resulted to be statistically different between CM1 and controls: basal angle (p = 0.006), clivo-supraoccipital angle (p = 0.044), clivus' length (p = 0.043), posterior cranial fossa (PCF) width (p = 0.009), PCF height (p = 0.045), and PCFw/BPDb (p = 0.013). Postnatally, only the clivus' length was significant between CM1 cases and controls. CONCLUSION: Pre- and post-natal CM1 cases did not share striking common features, making qualitative prenatal assessment not predictive; however, our preliminary results support the view that some of the pathogenetic basis of CM1 may be embedded to some extent already in intrauterine life.

Prenatal Diagnosis and Neurodevelopmental Outcome in Isolated Cerebellar Hypoplasia of Suspected Hemorrhagic Etiology: a Retrospective Cohort Study.

Data about the neurological prognosis of isolated cerebellar hypoplasia in utero are scant and inconsistent. In this monocentric retrospective study, we describe the neurodevelopmental outcomes in a series of children with isolated cerebellar hypoplasia of presumably hemorrhagic origin prenatally detected with fetal magnetic resonance imaging (fMRI). We retrospectively reviewed the charts of all the pregnant women who were referred for a neurological consultation, diagnosed with fetal encephalic malformation/disruption between 2010 and 2020 in the Fetal Therapy Unit of our institution. Fetal MRI (fMRI) was performed in all the pregnancies. Fetuses with cerebellar hypoplasia presumably of hemorrhagic origin were selected for the study. Fetuses exposed to alcohol or with additional malformations in other cerebral or body areas were excluded. All the infants received the postpartum follow-up care adopted in our center, including post-natal MRI, serial neurological examinations, standardized neurodevelopmental tests, and regular parental interviews. Cognitive functions were tested with GRIFFITHS II, WPPSI-III, and WISC-IV according to the child's age. A total of 14 pregnant women out of 479 fetal consultations were eligible and included in the study group. In 57% of cases, the etiology of the hemorrhage was unknown. In 21% of cases, it was attributed to a blood transfusion, while in the remaining ones, it was attributed to maternal predisposing factors. Among the survivors, two infants were excluded for prematurity, and two were lost to follow-up. Ten patients were thus included in the study. Six patients had normal neurodevelopment and cognition, and three presented mild-moderate neurological signs, i.e., mild dyspraxia and visuoperceptual impairment. Only one child had a severe outcome, i.e., autism spectrum disorder. The cerebellum is particularly vulnerable to disruptions throughout its prolonged development. Extreme caution must be used in prenatal counseling considering that in the acute phase, lesion extension and vermis involvement can be overestimated with fMRI. In cases of uncertainty, performing an additional fMRI could be advisable after 4-8 weeks. However, in our series, infants with isolated cerebellar hypoplasia tended to have a favorable prognosis. Nevertheless, a long-term follow-up is needed and should include a postnatal brain MRI, serial neurological examinations, and neurodevelopmental tests at least up to school age.

Get Your Molar Tooth Right: Joubert Syndrome Misdiagnosis Unmasked by Whole-Exome Sequencing.

Joubert syndrome (JS) is a recessively inherited ciliopathy, characterized by a specific cerebellar and brainstem malformation recognizable on brain imaging as the "molar tooth sign" (MTS). Clinical signs include hypotonia, developmental delay, breathing abnormalities, and ocular motor apraxia. Older patients develop ataxia, intellectual impairment, and variable organ involvement. JS is genetically heterogeneous, with over 40 ciliary genes overall accounting for 65-75% cases. Thus, in recent years, the genetic diagnosis of JS has been based on the analysis of next-generation sequencing targeted gene panels. Since clinical features are unspecific and undistinguishable from other neurodevelopmental syndromes, the recognition of the MTS is crucial to address the patient to the appropriate genetic testing. However, the MTS is not always properly diagnosed, resulting either in false negative diagnoses (patients with the MTS not addressed to JS genetic testing) or in false positive diagnoses (patients with a different brain malformation wrongly addressed to JS genetic testing). Here, we present six cases referred for JS genetic testing based on inappropriate recognition of MTS. While the analysis of JS-related genes was negative, whole-exome sequencing (WES) disclosed pathogenic variants in other genes causative of distinct brain malformative conditions with partial clinical and neuroradiological overlap with JS. Reassessment of brain MRIs from five patients by a panel of expert pediatric neuroradiologists blinded to the genetic diagnosis excluded the MTS in all cases but one, which raised conflicting interpretations. This study highlights that the diagnostic yield of NGS-based targeted panels is strictly related to the accuracy of the diagnostic referral based on clinical and imaging assessment and that WES has an advantage over targeted panel analysis when the diagnostic suspicion is not straightforward.

School-Age Outcome of Fetuses with Isolated Complete Septum Pellucidum Agenesis at Prenatal Magnetic Resonance Imaging.

OBJECTIVE: To the best of our knowledge, there have not been studies to address the issue of long-term follow-up of patients with prenatal diagnosis of isolated complete septum pellucidum agenesis (SPA). The aim of this study was to acquire information about the school-age outcome of such patients as a resource for counseling parents receiving this prenatal finding. METHODS: From a large fetal magnetic resonance (MR) database, we selected only those cases with isolated complete SPA as confirmed by two senior pediatric neuroradiologists in consensus; we then gathered information from the parents of those children who had reached the school age. RESULTS: None among the 12 cases (mean age at follow-up: 8.7 years, range: 6-13 year) of the resulting final cohort presented visual or stature deficits; only one required special teaching assistance in school. All other 11 children resulted without any notable academic issue. CONCLUSION: Our report may provide information of practical value about the school-age outcome of fetuses detected by prenatal MR imaging to carry isolated complete SPA.

Diagnosis and treatment of Chiari malformation type 1 in children: the International Consensus Document.

BACKGROUND: Chiari malformation type 1 (CM1) is a rare condition where agreed classification and treatment are still missing. The goal of this study is to achieve a consensus on the diagnosis and treatment of CM1 in children. METHODS: A multidisciplinary panel formulated 57 provisional statements based on a review of the literature. Thirty-four international experts (IE) participated in a Delphi study by independently rating each statement on a 4-point Likert scale ("strongly disagree," "disagree," "agree," "strongly agree"). Statements that were endorsed ("agree" or "strongly agree") by < 75% of raters were re-formulated, or new statements were added, and another Delphi round followed (up to a maximum of three). RESULTS: Thirty-five IE were contacted and 34 agreed to participate. A consensus was reached on 30/57 statements (52.6%) after round 1. Three statements were added, and one removed. After round 2, agreement was reached on 56/59 statements (94.9%). Finally, after round 3, which took place during the 2019 Chiari Consensus Conference (Milan, Italy), agreement was reached on 58/59 statements (98.3%) about four main sections (Definition and Classification, Planning, Surgery, Isolated Syringomyelia). Only one statement did not gain a consensus, which is the "definition of radiological failure 24 month post-surgery." CONCLUSIONS: The consensus document consists of 58 statements (24 on diagnosis, 34 on treatment), serving clinicians and researchers following children with CM1. There is a clear need for establishing an international network and registry and to promote collaborative studies to increase the evidence base and optimize the long-term care of this patient population.

Cerebellar dysplasia related to PIK3CA mutation: a three-case series.

The term PROS (PIK3CA-Related Overgrowth Spectrum) indicates a wide spectrum of overgrowth disorders related to somatic mutations in PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) pathway. We present three cases with PIK3CA mutation and clinical characteristics encompassing MCAP (megalencephaly-capillary malformation) condition but lacking all criteria to a certain diagnosis, most of all showing prevalent and peculiar involvement of cerebellar structures at MRI (magnetic resonance imaging) mainly consisting in cortical rim thickening and abnormal orientation of folia axis. These cases expand the spectrum of intracranial MRI features in PIK3CA disorders.

Neuroimaging and neurodevelopmental outcome after early fetal growth restriction: NEUROPROJECT-FGR.

BACKGROUND: Adverse neurodevelopmental outcomes and MRI alterations are reported in infants born after fetal growth restriction (FGR). This study evaluates the additional role of FGR over prematurity in determining brain impairment. METHODS: Retrospective observational study comparing 48 FGR and 36 appropriate for gestational age infants born between 26 and 32 weeks' gestation who underwent a cerebral MRI at term equivalent age. Exclusion criteria were twins, congenital anomalies, and findings of overt brain lesions. Main outcomes were total maturation score (TMS) and cerebral areas independently measured by two neuro-radiologists and Griffiths or Bayley scale III scores at median age of 2 years. RESULTS: TMS was not significantly different between the groups. Inner calvarium and parenchyma's areas were significantly smaller in FGR cases. There were no significant differences in the average quotient scores. A positive correlation between parenchyma area and cognitive score was found (r = 0.372, p = 0.0078) and confirmed after adjusting for sex, gestational age, and birth weight (p = 0.0014). Among FGR, the subgroup with umbilical arterial Doppler velocimetry alterations had significantly worse gross motor scores (p = 0.005). CONCLUSIONS: FGR plays additional role over prematurity in determining brain impairment. An early structural dimensional MRI evaluation may identify infants who are at higher risk. IMPACT: Fetal growth-restricted infants showed smaller cerebral parenchymal areas than preterm controls. There is a positive correlation between the parenchyma area and the cognitive score. These results highlight the already known link between structure and function and add importance to the role of a structural dimensional MRI evaluation even in the absence of overt brain lesions.

Changes in appearance of cortical formation abnormalities in the foetus detected on sequential in utero MR imaging.

OBJECTIVES: We describe 64 foetuses with cortical formation abnormalities (CFA) who had two in utero magnetic resonance (iuMR) exams, paying particular detail to those in which the original classification of CFA category changed between the two studies. The goal was to attempt to quantify the value of third-trimester follow-up studies in CFA foetuses on second-trimester iuMR imaging. METHODS: The 64 foetuses reviewed came from a CFA cohort of 374 foetuses reported in an earlier publication, which detailed a classification for foetal CFA. A consensus panel of senior paediatric neuroradiologists reviewed both studies, described any change in the category of CFA between them, and attempted to predict the possible clinical significance of any differences based on the combined clinical experience of the panel. RESULTS: In 40/64 (62%) foetuses, the CFA description was the same on both studies. In 24/64 (38%) cases, there was a category change which included three foetuses without CFA on first examination, six foetuses where the difference involved change in laterality/symmetry, and in 15 cases the re-classification involved categorical change within the same group. Brain abnormalities other than CFA were present in 30/64 (47%) foetuses on the first study and in 33/64 (52%) on the second. We predicted that prognosis would have changed on the basis of the second study in 8% of cases, all indicating worse prognosis. CONCLUSIONS: We have shown that the extra diagnostic and predicted prognostic yield justifies follow-up studies in the third trimester if a CFA is shown on the second-trimester iuMR imaging. KEY POINTS: • Sixty-four foetuses with cortical formation abnormalities had two iuMR studies, for the vast majority the baseline in the second trimester and the sequential in the third. • In three foetuses, the cortical formation abnormality (CFA) was not visible on the first study. In a further 21 foetuses, the categorical description of the CFA changed between the two studies. Prognosis changed in 8% of the cases following the second iuMR study, and in all cases, the prognosis was worse. • Multiple iuMR studies provide information about the natural history of CFA; the extra diagnostic and predicted prognostic yield justifies follow-up studies.

Fetal thick corpus callosum: new insights from neuroimaging and neuropathology in two cases and literature review.

PURPOSE: To describe the correlation between fetal imaging (in vivo and ex vivo) and neuropathology in two fetuses at early gestational age (GA) with isolated thick corpus callosum (CC), a rare finding whose pathological significance and neuropathology data are scarce. METHODS: Two fetuses at 21-week GA underwent fetal MRI (fMRI) for suspected callosal anomalies at ultrasound (US). After fMRI results, termination of pregnancy (TOP) was carried out and post-mortem MRI (pmMRI) was performed. Neuropathology correlation consisted in macro and microscopic evaluation with sections prepared for hematoxylin-eosin and immunohistochemistry staining. RESULTS: Fetal imaging confirmed in both cases the presence of a shorter and thicker CC with respect to the reference standard at the same GA, without a clear distinction between its different parts. Moreover, on pmMRI, an abnormal slightly T2-weighted hyperintense layer along the superior and inferior surface of CC was noted in both cases. At histopathology, these findings corresponded to an increased amount of white matter tracts but also to an abnormal representation of embryological structures that contribute to CC development, naming induseum griseum (IG) and the glioepithelial layer (GL) of the "callosal sling." After reviewing the literature data, we confirmed the recent embryological theory regarding the CC development and provide new insights into the pathophysiology of the abnormal cases. CONCLUSIONS: An abnormally thick CC at the early fetal period could be associated to an abnormal representation of the midline glia structures, so to result in potential disturbance of the axon guidance mechanism of callosal formation and eventually in CC dysgenesis.

Cortical formation abnormalities on foetal MR imaging: a proposed classification system trialled on 356 cases from Italian and UK centres.

OBJECTIVE: To formulate a classification system for foetal cortical formation abnormalities (CFAs) based on in utero magnetic resonance (iuMR) appearances and trial it in 356 cases. METHODS: This retrospective study included all cases of foetal CFA diagnosed between 2000 and 2017 from seven centres in Italy and UK. All of the studies were reviewed by a panel of paediatric neuroradiologists experienced in iuMR with the aid of an algorithm designed to categorise the abnormalities. RESULTS: Consensus expert review confirmed 356 foetuses with CFA and the first level of classification distinguished bilateral CFA (229/356-64%) from unilateral CFA (127/356-36%) cases with sub-classification of the bilateral cases into asymmetric (65/356-18%) and symmetric (164/356-46%) involvement. There was a statistically significant excess of foetuses with small head size, e.g. 17% of the cohort had a bi-parietal diameter < 3rd centile. There was a small but statistically significant excess of males in the cohort. Further categorisation was made on fine anatomical structure. CONCLUSIONS: It is often not possible to classify foetal CFA using the principles and nomenclature used in paediatric neuroradiology. We have created a classification system for foetal CFA based on the analysis of 356 cases and believe that this will assist future research designed to correlate ante-natal and post-natal imaging features and understand the clinical sequelae of CFA described in utero. KEY POINTS: • We describe a morphological classification system of foetal brain cortical formation abnormalities that can be used in clinical practice. • This classification system can be used in future research studies to evaluate the long-term imaging and clinical outcomes of foetal brain cortical formation abnormalities in 17- to 38-week gestational age range. • The practical value of the work is in providing a framework and language to look for imaging clues that may differentiate between different CFA in further studies.

Prenatal magnetic resonance imaging within the 26th week of gestation may predict the fate of isolated upward rotation of the cerebellar vermis: insights from a multicentre study.

OBJECTIVES: We investigated whether prenatal magnetic resonance imaging (MRI) within 26 weeks of gestation (GW) may predict the fate of isolated upward rotation of the cerebellar vermis (URCV). METHODS: This retrospective multicentre observational study included foetuses diagnosed with isolated URCV in prenatal MRI performed within 26 GW. Isolated URCV was defined by a brainstem-vermis angle (BVA) ≥ 12° in the MR midline sagittal view without abnormalities of the supratentorial structures, brainstem, or cerebellum hemispheres. The assessments included the BVA, clival-supraoccipital angle, transverse diameter of the posterior cranial fossa, tentorial angle, width of the cisterna magna (WCM), ventricular width, vermian diameters, hypointense stripes, and cerebellar tail sign. Late prenatal or postnatal MRI was used as a reference standard to assess the final vermian fate (rotated/de-rotated). RESULTS: Forty-five foetuses (mean GW at prenatal MRI = 21.5 ± 1.4 weeks) were included. In the reference standard, the vermis was de-rotated in 26 cases (57.7%). At least two of the following criteria were used to predict the persistence of URCV at imaging follow-up: BVA ≥ 23°, WCM ≥ 9 mm, and the cerebellar tail sign. The results were a sensitivity of 84.21% (95% CI, 60.4-96.6%), specificity of 80.8% (95% CI, 60.6-93.4%), positive predictive value of 76% (95% CI, 58.7-87.8%), and negative predictive value of 87.5% (95% CI, 70.9-95.2%). CONCLUSIONS: MRI within 26 GW on foetuses diagnosed with isolated URCV may predict delayed cerebellar vermis de-rotation, which is associated with good neurodevelopmental outcome in most cases. KEY POINTS: • Foetal MRI is a valuable tool in predicting the fate of isolated upward-rotated cerebellar vermis. • A wider angle between the brainstem and vermis is associated with higher risk of persistence of vermian rotation. • The presence of ≥ 2 factors among a brainstem-to-vermis angle ≥ 23°, width of the cisterna magna ≥ 9 mm, and the presence of the "cerebellar tail sign" has a sensitivity of 84.21% (95% CI, 60.4-96.6%) and specificity of 80.8% (95% CI, 60.6-93.4%) in predicting the persistence of the vermian rotation at imaging follow-up.

Agreement between magnetic resonance imaging and computed tomography in the postnatal evaluation of congenital lung malformations: a pilot study.

OBJECTIVES: To compare postnatal magnetic resonance imaging (MRI) with the reference standard computed tomography (CT) in the identification of the key features for diagnosing different types of congenital lung malformation (CLM). METHODS: Respiratory-triggered T2-weighted single-shot turbo spin echo (ss-TSE), respiratory-triggered T1-weighted turbo field echo (TFE), balanced fast field echo (BFFE), and T2-weighted MultiVane sequences were performed at 1.5 T on 20 patients prospectively enrolled. Two independent radiologists examined the postnatal CT and MRI evaluating the presence of cysts, hyperinflation, solid component, abnormal arteries and/or venous drainage, and bronchocele. Diagnostic performance of MRI was calculated and the agreement between the findings was assessed using the McNemar-Bowker test. Interobserver agreement was measured with the kappa coefficient. RESULTS: CT reported five congenital pulmonary airway malformations (CPAMs), eight segmental bronchial atresias, five bronchopulmonary sequestrations (BPS), one congenital lobar overinflation, one bronchogenic cyst, and three hybrid lesions. MRI reported the correct diagnosis in 19/20 (95%) patients and the malformation was correctly classified in 22/23 cases (96%). MRI correctly identified all the key findings described on the CT except for the abnormal vascularization (85.7% sensitivity, 100% specificity, 100% PPV, 94.1% NPV, 95% accuracy for arterial vessels; 57.1% sensitivity, 100% specificity, 100% PPV, 84.2% NPV, 87% accuracy for venous drainage). CONCLUSIONS: MRI can represent an effective alternative to CT in the postnatal assessment of CLM. In order to further narrow the gap with CT, the use of contrast material and improvements in sequence design are needed to obtain detailed information on vascularization, which is essential for surgical planning. KEY POINTS: • Congenital lung malformations (CLMs) can be effectively studied by MRI avoiding radiation exposure. • Crucial features of CLM have similar appearance when comparing CT with MRI. • MRI performs very well in CLM except for aberrant vessel detection and characterization.

Intrauterine fetal MR versus postmortem MR imaging after therapeutic termination of pregnancy: evaluation of the concordance in the detection of brain abnormalities at early gestational stage.

BACKGROUND AND PURPOSE: Fetal postmortem MR Imaging (pmMRI) has been recently used as an adjuvant tool to conventional brain autopsy after termination of pregnancy (TOP). Our purpose was to compare the diagnostic performance of intrauterine MRI (iuMRI) and pmMRI in the detection of brain anomalies in fetuses at early gestational age (GA). MATERIAL AND METHODS: We retrospectively collected 53 fetuses who had undergone iuMRI and pmMRI for suspected brain anomalies. Two pediatric neuroradiologists reviewed iuMRI and pmMRI examinations separately and then together. We used Cohen's K to assess the agreement between pmMRI and iuMRI. Using the combined evaluation iuMRI+pMRI as the reference standard, we calculated the "correctness ratio." We used Somers' D to assess the cograduation between postmortem image quality and time elapsed after fetus expulsion. RESULTS: Our data showed high agreement between iuMRI and pmMRI considering all the categories together, for both observers (K1 0.84; K2 0.86). The correctness ratio of iuMRI and pmMRI was 79% and 45% respectively. The major disagreements between iuMRI and pmMRI were related to postmortem changes as the collapse of liquoral structures and distorting phenomena. We also found a significant cograduation between the time elapsed from expulsion and pmMRI contrast resolution and distortive phenomena (both p < 0.001). CONCLUSIONS: Our study demonstrates an overall high concordance between iuMRI and pmMRI in detecting fetal brain abnormalities at early GA. Nevertheless, for the correct interpretation of pmMRI, the revision of fetal examination seems to be crucial, in particular when time elapsed from expulsion is longer than 24 h. KEY POINTS: • IuMRI and pmMRI showed overall high concordance in detecting fetal brain abnormalities at early GA. • PmMRI corroborated the antemortem diagnosis and it could be a valid alternative to conventional brain autopsy, only when the latter cannot be performed. • Some caution should be taken in interpreting pmMR images when performed after 24 h from fetal death.

Prenatal MRI of neck masses with special focus on the evaluation of foetal airway.

BACKGROUND: Prenatal magnetic resonance imaging is the best tool to visualize foetal airway. OBJECTIVE: To evaluate the performance of MRI in the assessment of foetal airway status in the presence of a neck mass. MATERIALS AND METHODS: Two paediatric radiologists with 12- and 2-year experience in foetal imaging retrospectively analysed 23 foetal MRI examinations, performed between 2001 and 2016, after a second-level ultrasound suspicious for presence of a neck mass. Postnatal imaging, postoperative report, histology, autopsy, and clinical outcomes were the reference standard to calculate sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of prenatal MRI in detecting airway patency. We used the Cohen к statistics to estimate the interobserver agreement. We also assessed MRI performance in the diagnosis of the mass nature. RESULTS: We obtained data about postnatal airway status in 19 of 23 patients; prenatal MRI demonstrated a sensitivity of 9/9 [100%, 95% confidence interval (CI) 66-100%], specificity 8/10 (80%, 44-98%), accuracy 17/19 (89%, 67-99%), PPV 9/11 (82%, 48-98%), and NPV 8/8 (100%, 63-100%); the interobserver agreement was perfect. Prenatal MRI correctly identified 21 of 23 masses (к = 0.858); the interobserver agreement was almost perfect (к = 0.851). CONCLUSION: Prenatal MRI demonstrated high accuracy in assessing foetal airway status and diagnosing mass nature, allowing proper delivery planning.

Brain-injured Survivors of Monochorionic Twin Pregnancies Complicated by Single Intrauterine Death: MR Findings in a Multicenter Study.

Purpose To describe and classify the range of brain injuries present at prenatal, in-utero magnetic resonance (MR) imaging in co-twin survivors of monochorionic (MC) twin pregnancies complicated by single intrauterine death (SIUD). Materials and Methods This retrospective, observational study from six tertiary fetal medicine centers that perform tertiary-level prenatal in-utero MR studies reviewed cases in which prenatal in-utero MR imaging had shown a brain injury in a surviving co-twin of a twin pregnancy with a MC component complicated by SIUD. Results Forty-two surviving MC twins were described. The primary distinction of brain abnormalities was into nonfocal and focal lesions. The nonfocal lesions included periventricular leukomalacia (group 1; two fetuses), generalized encephalomalacia (group 2; nine fetuses), posterior encephalomalacia (group 3; seven fetuses), and bilateral parasagittal and perisylvian injury (group 4; three fetuses). The focal lesions included nonhemorrhagic lesions (group 5; 14 fetuses) and hemorrhagic lesions (group 6; seven fetuses). Focal brain lesions were more likely to be found in the surviving MC pregnancies complicated by twin-twin transfusion syndrome (TTTS) (odds ratio, 2.4; 95% confidence interval: 1.3, 18.5; P = .01) and in fetuses that underwent an obstetric intervention (odds ratio, 2.8; 95% confidence interval: 1.8, 23.6; P = .006). Conclusion Brain injury of the surviving co-twin after SIUD in MC pregnancies is usually of ischemic origin and spares the brainstem and cerebellum. Focal brain lesions are more frequent in pregnancies complicated by TTTS or in those where an intervention has been performed.