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Magnetic resonance imaging versus ultrasonography for the in utero evaluation of central nervous system anomalies: Clinical article
Abstract
The use of fetal MR imaging for the in utero evaluation of pathological conditions of the CNS is widely accepted as an adjunct to fetal ultrasonography studies. Magnetic resonance imaging is thought to characterize CNS anomalies better, and to provide a more exact diagnosis and accurate prognosis. The purpose of this study was to determine the role of and indications for fetal MR imaging in evaluating fetuses with different CNS abnormalities that were seen initially on prenatal sonograms.
Over a 3-year period, fetuses with prior sonographic evidence of CNS abnormalities who consequently received prenatal MR imaging at Columbus Nationwide Children's Hospital within 2 weeks of the fetal ultrasonography study were included in this study. For each patient, radiological reports from both studies were reviewed, analyzed, and compared with the findings at postnatal imaging or physical examination. Results of the 2 modalities were then compared in terms of diagnostic accuracy.
Twenty-six fetuses were included in this study on the basis of an in utero sonogram showing a CNS anomaly. Their gestational age ranged from 17 to 35 weeks, with a mean of 25 weeks at the time of fetal ultrasonography. Hydrocephalus was identified in 16 fetuses, 6 had evidence of a spinal dysraphic defect, 2 had holoprosencephaly, 1 had an encephalocele, and 1 had multiple body abnormalities requiring detailed CNS evaluation. Twenty-five of the fetuses were correctly evaluated as having abnormal CNS findings on both fetal ultrasonography and fetal MR imaging. Fetal ultrasonography provided a correct prenatal diagnosis in 20 cases, whereas fetal MR imaging was correct in 22 cases. There were 9 cumulative false-positive results for fetal ultrasonography and 7 for fetal MR imaging, whereas for false-negative results there were a total of 34 and 19, respectively.
Fetal MR imaging is more sensitive in detecting fetal CNS abnormalities, but its ability to provide a correct prenatal diagnosis is only marginally superior to fetal ultrasonography. Moreover, fetal MR imaging is not exempt from misdiagnosis, and still shows a significantly high rate of false-negative results. Particularly for spinal dysraphic defects, fetal MR imaging does not seem to add important diagnostic or prognostic details when compared with fetal ultrasonography.
... In the remaining 41 studies, 29 were subsequently excluded after reading the full texts for the reasons listed in Figure 1. Finally, 12 studies [21][22][23][24][25][26][27][28][29][30][31][32] were available for the metaanalysis. ...
... The summarized features of the included studies are displayed in Table 1. Overall, 12 studies [21][22][23][24][25][26][27][28][29][30][31][32] including 544 fetuses of suspected CNS anomalies were included into the meta-analysis. Of them, 143 were with validated diagnosis of ACC. ...
... The median GA for the prenatal ultrasonic diagnosis varied between 18 and 20 weeks. The protocol of prenatal ultrasonic examination was described as neurosonographic examination in seven studies [21,22,25,27,28,31,32], and as ultrasonic screening in five studies [23,24,26,29,30]. Postmortem diagnosis or postnatal images were used as the reference examinations for the validation of ACC. ...
Background
Prenatal ultrasound has been regularly used as the screening tool for agenesis of corpus callosum (ACC) of the fetuses, which were mainly suspected on the basis of indirect signs rather than the visualization of the CC. However, the diagnostic accuracy of prenatal ultrasound for ACC, compared to the gold standard of postmortem diagnosis or postnatal images, is still unknown. This meta-analysis was performed to comprehensively evaluate the efficacy of prenatal ultrasound for the diagnosis of ACC.
Methods
Studies evaluating the diagnostic accuracy of prenatal ultrasound for ACC compared to postmortem diagnosis or postnatal images were retrieved by searching PubMed, Embase, and Web of Science databases. Pooled sensitivity and specificity were calculated with a random-effects model. The diagnostic accuracy was measured by summarized area under the receiver operating characteristic (AUC) curve.
Results
Twelve studies involving 544 fetuses with suspected anomalies of central nervous system were included, and 143 of them were with validated diagnosis of ACC. Pooled results showed that prenatal ultrasound has satisfying diagnostic efficacy for ACC, with the pooled sensitivity, specificity, positive and negative likelihood ratios of 0.72 (95% confidence interval [CI]: 0.39–0.91), 0.98 (95% CI: 0.79–1.00), 43.73 (95% CI: 3.42–558.74, and 0.29 (95% CI: 0.11–0.74), respectively. The pooled AUC was 0.94 (95% CI: 0.92–0.96), suggesting good diagnostic performance of prenatal ultrasound. Subgroup analysis according to the prenatal ultrasound procedures showed a better diagnostic efficacy of neurosonography than that of regular ultrasound screening (sensitivity: 0.84 versus 0.57, specificity: 0.98 versus 0.89, and AUC: 0.97 versus 0.78).
Conclusions
Prenatal ultrasound, particularly for the neurosonography, confers satisfying efficacy for the diagnosis of ACC.
... The 34 studies, listed in Table 1, were published over a 20-year period (1994-2014). Nineteen were prospective [3,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], 12 retrospective [36][37][38][39][40][41][42][43][44][45][46][47] and three unspecified [48][49][50]. All studies selected a consecutive cohort of patients with either a remit to investigate all foetal brain abnormalities (24 studies [3, 18-23, 29-32, 35, 39-41, 44-49]) or to investigate a more specific brain abnormality e.g. ...
... USS was performed in a tertiary centre and/or conducted by foetal medicine experts in 21/34 studies [3, 18-21, 26-29, 31, 32, 35-38, 40-43, 47], in 12/34 it was either unclear or not specified [22-24, 30, 33, 34, 39, 45, 46, 48-50], and in one study [44] USS was performed in a routine clinical setting. Clear details regarding USS technique (transabdominal or transvaginal, views obtained) and equipment (manufacturer, transducer) were provided in 21 studies [18-20, 22, 24-26, 28, 32-37, 39, 40, 42, 43, 47, 48, 50]. ...
... The methodological quality assessments using the Quadas 2 criteria are presented in Fig. 2. Risk of bias for patient selection and applicability was low in 31/34 (91 %) studies [3, 18-45, 47, 50], high in one (6 %) [46] and unclear in two [48,49] with high risk of bias due to patient selection criteria not being defined and retrospective study designs. The risk of bias due to conduct and interpretation of the index tests was low risk in 15/34 (44 %) [3, 18, 20, 21, 25, 28, 30, 32, 35-37, 40, 42, 43, 47], high risk in 4/34 (12 %) [38,[44][45][46] and unclear in 15/34 (44 %) [19, 22-24, 26, 27, 29, 31, 33, 34, 39, 41, 48-50]. Assessment of potential bias introduced by the reference standard was considered low risk in 19/34 (56 %) studies [3, 18, 19, 21, 22, 24, 28-31, 35, 36, 38, 40, 44, 47-50], high risk in nine (26 %) [20, 27, 32-34, 41, 43, 45, 46] and unclear in 6/34 (18 %) [23,25,26,37,39,42], as there were a proportion of cases within the study that did not have a confirmed outcome or it was determined by clinical examination. ...
Objectives:
This systematic review was undertaken to define the diagnostic performance of in utero MR (iuMR) imaging when attempting to confirm, exclude or provide additional information compared with the information provided by prenatal ultrasound scans (USS) when there is a suspicion of foetal brain abnormality.
Methods:
Electronic databases were searched as well as relevant journals and conference proceedings. Reference lists of applicable studies were also explored. Data extraction was conducted by two reviewers independently to identify relevant studies for inclusion in the review. Inclusion criteria were original research that reported the findings of prenatal USS and iuMR imaging and findings in terms of accuracy as judged by an outcome reference diagnosis for foetal brain abnormalities.
Results:
34 studies met the inclusion criteria which allowed diagnostic accuracy to be calculated in 959 cases, all of which had an outcome reference diagnosis determined by postnatal imaging, surgery or autopsy. iuMR imaging gave the correct diagnosis in 91 % which was an increase of 16 % above that achieved by USS alone.
Conclusion:
iuMR imaging makes a significant contribution to the diagnosis of foetal brain abnormalities, increasing the diagnostic accuracy achievable by USS alone.
Key points:
• Ultrasound is the primary modality for monitoring foetal brain development during pregnancy • iuMRI used together with ultrasound is more accurate for detecting foetal brain abnormalities • iuMR imaging is most helpful for detecting midline brain abnormalities • The moderate heterogeneity of reviewed studies may compromise findings.
... All studies were cohort studies, eight prospective [5,7,17,23,24,26,28], nine retrospective studies [2,8,9,11,13,15,19,21,29], and 10 studies [6,12,14,16,18,20,22,25,27,30] did not report on this. The articles reported on an average of 54 patients (range 21-185). ...
... The average study duration was 4 years (range 2-7), nine studies did not report on its duration [6,7,10,12,14,15,19,22,28]. Gestational age during NS was described in 16 studies [2,6,7,[10][11][12][13][14][15][17][18][19][20][21]24,27] ranging from 15 to 39 weeks. Gestational age during MRI was described in 13 studies [2,5,8,9,11,16,18,[21][22][23][27][28][29] ranging from 16 to 39 weeks. ...
... Gestational age during NS was described in 16 studies [2,6,7,[10][11][12][13][14][15][17][18][19][20][21]24,27] ranging from 15 to 39 weeks. Gestational age during MRI was described in 13 studies [2,5,8,9,11,16,18,[21][22][23][27][28][29] ranging from 16 to 39 weeks. The average time interval between NS and MRI was 5 days (range 0-29) described in 13 articles [9,11,[15][16][17][18][19][22][23][24][28][29][30]. ...
Purpose:
To evaluate the additional diagnostic value of fetal Magnetic Resonance Imaging (MRI) in fetuses with suspected brain abnormalities identified with advanced neurosonography (NS).
Methods:
A systematic literature search was performed for studies reporting on a comparison between diagnosis with NS and MRI, in fetuses suspected for brain abnormalities. Abnormalities detected on NS were compared with those detected on MRI as well as with postnatal imaging findings to assess the added value of fetal MRI.
Results:
We included 27 articles, reporting on 1184 cases in which NS and MRI diagnosis were compared. In 65% of cases [773/1184] fetal NS and fetal MRI diagnosis agreed completely. In 23% [312/1184], MRI showed additional or different pathology. In 8% [99/1184], MRI rejected the NS diagnosis with normal brain as conclusion. For 454 cases a comparison with postnatal imaging could be made. Compared to the postnatal diagnosis, fetal MRI diagnosis agreed completely in 80% [364/454] and fetal NS in 54% [243/454] (difference 27%, 95% CI 21-33%). Additional abnormalities were found on postnatal imaging in 36% [164/454] after NS and in 14% [61/454] after fetal MRI.
Conclusions:
This meta-analysis shows that fetal MRI in addition to NS improves diagnostic accuracy in detecting brain abnormalities.
... Fetal MRI is the most accurate diagnostic method for most of the central nervous system abnormalities. 4,5 In addition, MRI allows the fetal brain to be evaluated, especially when the fetus is at greater risk for neurodevelopmental disorders or when abnormalities are detected on prenatal US. 1 Most midline abnormalities of the brain in the midsagittal plane of the fetal MRI or US are as follows: Corpus Callosum; aqueductal stenosis; sellar; commissural; suprasellar and pineal; posterior fossa including the brainstem, cerebellum, and fourth ventricle. 6 For the past two decades, the use of fetal brain MRI has been accepted as a complementary method. ...
... 5,9).The positive and negative likelihood ratios for IUMRI were 23.49 (95% CI: 0.37-1507.20, ...
Objective:
The aim of this study was to compare ultrasound (US) and intra uterine MRI (IUMRI) of the brain in the diagnosis of fetal brain abnormalities.
Methods:
The present systematic review is done based on guidelines for preferred reporting items for systematic reviews and meta-analysis. All major articles comparing fetal US with IUMRI in fetuses with suspected brain abnormalities were qualified. Articles published before 2010 were excluded from the study. An I2 > 20% was considered as a sign of significant change. The statistical analysis was done using STATA -15 and Meta-Disk 1.4 applications.
Results:
Five articles were considered for meta-analysis. The sensitivity of US and IUMRI in diagnosing fetal abnormalities were 86% and 95%, respectively. The corresponding rates for specificity were 77% and 80%. IUMRI and US were concordant in 72.5% (95% CI: 68%-77%) of diagnoses. However, IUMRI added information in 21.7% of cases, while US added value was only 1.48.
Conclusion:
Our results approved the good diagnostic performance of both US and IUMRI in confirming fetal brain normal development and emphasized that US is an appropriate screening technique in pregnancy. In cases of detected abnormalities in US, IUMRI is suggested as it was the most accurate imaging method and added information about the diagnosis in 22.2% of cases.
... HPE, alobar'a göre daha seyrek görülmekte ve prognoz tipe göre değişmektedir (3,4). Alobar HPE'li yenidoğanlar birkaç hafta içinde kaybedilirken semilobar tipinde yaşam şansı mevcuttur. ...
... HPE tanısında koroid pleksuslara ait kelebek görüntüsünün izlenmemesi ve tek ventrikül görülmesi en değerli ipuçlarıdır (1, 2). MRG iyonizan radyasyon içermemesi, hastanın pozisyonunu değiştirmeden istenen her planda görüntü alabilmesi ve mükemmel yumuşak doku çözümleme gücü nedeniyle merkezi sinir sistemi incelemesinde primer görüntüleme yöntemi haline gelmiştir (3). MRG kesitlerindeki karakteristik görüntülerle klinik tablo arasında sıkı bir korelasyon mevcuttur (3). ...
Holoprosensefali (HPE), erken gestasyonel dönemde ön beynin tamamen veya yetersiz ayrılmasıyla karakterli beynin yapısal bir anomalisidir. HPE’lerin yaklaşık %80’nine, karakteristik kranyofasyal anomaliler eşlik eder. HPE, yaklaşık 16.000 canlı doğumda ve 250 embryoda bir ortaya çıkan, insanda sık görülen beyin defektidir. Sıklıkla, ilk kez gebelikteki ultrason sırasında tanımlanır. Hafif ve orta derecede beyin anomalisi olan infantlar ise yaşamın ilk yılının sonuna kadar tanı alamayabilirler. Çalışmamızın amacı kliniğimizde HPE tanısı alan olguya eşlik eden ek anomalileri incelemek ve bu bulguları literatür ile eşliğinde gözden geçirmektir. Oldukça küçük başa sahip olan fetüslerde sonografik inceleme çok zor olabilir ve HPE’ye ait bulgular kolaylıkla, ilk trimesterde gözden kaçabilir. HPE’ye ait bulguların saptanabilmesi için ilk trimesterde fetusa ait serebral yapıların çok dikkatli incelenmesi önemlidir.
... Several studies have reported a higher accuracy of MRI compared with ultrasonography for diagnosing CNS anomalies 13,20,21,34,39,47 . Others have shown that additional anomalies diagnosed by MRI may lead to a change in counseling and/or management 13,[19][20][21]33,43,48,49 . An exception to this is the study by Malinger et al. ...
... More recent studies reported additional diagnostic information by MRI in a smaller proportion of cases 33,51 . Peruzzi et al. 33 described 26 fetuses with CNS anomalies diagnosed after delivery for which MRI modified the diagnosis and changed management in two (7.7%) cases. Paladini et al. 51 reported on 126 fetuses examined by 2D-US, 3D-US and MRI. ...
Objectives:
To compare the accuracy of two-dimensional ultrasound (2D-US), three-dimensional ultrasound (3D-US) and magnetic resonance imaging (MRI) for the diagnosis of congenital anomalies without prior knowledge of indications and previous imaging findings.
Methods:
This was a prospective, blinded case-control study comprising women with a singleton pregnancy with fetal congenital abnormalities identified on clinical ultrasound and those with an uncomplicated pregnancy. All women volunteered to undergo 2D-US, 3D-US and MRI, which were performed at one institution. Different examiners at a collaborating institution performed image interpretation. Sensitivity and specificity of the three imaging methods were calculated for individual anomalies, based on postnatal imaging and/or autopsy as the definitive diagnosis. Diagnostic confidence was graded on a four-point Likert scale.
Results:
A total of 157 singleton pregnancies were enrolled, however nine cases were excluded owing to incomplete outcome, resulting in 148 fetuses (58 cases and 90 controls) included in the final analysis. Among cases, 13 (22.4%) had central nervous system (CNS) anomalies, 40 (69.0%) had non-CNS anomalies and five (8.6%) had both CNS and non-CNS anomalies. The main findings were: (1) MRI was more sensitive than 3D-US for diagnosing CNS anomalies (MRI, 88.9% (16/18) vs 3D-US, 66.7% (12/18) vs 2D-US, 72.2% (13/18); McNemar's test for MRI vs 3D-US: P = 0.046); (2) MRI provided additional information affecting prognosis and/or counseling in 22.2% (4/18) of fetuses with CNS anomalies; (3) 2D-US, 3D-US and MRI had similar sensitivity for diagnosing non-CNS anomalies; (4) specificity for all anomalies was highest for 3D-US (MRI, 85.6% (77/90) vs 3D-US, 94.4% (85/90) vs 2D-US, 92.2% (83/90); McNemar's test for MRI vs 3D-US: P = 0.03); and (5) the confidence of MRI for ruling out certain CNS abnormalities (usually questionable for cortical dysplasias or hemorrhage) that were not confirmed after delivery was lower than it was for 2D-US and 3D-US.
Conclusions:
MRI was more sensitive than ultrasonography and provided additional information that changed prognosis, counseling or management in 22.2% of fetuses with CNS anomalies. False-positive diagnoses for subtle CNS findings were higher with MRI than with ultrasonography. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
... In particular, there were nine cases in which MRI did not detect CNS anomalies (one of nerve cell proliferation, two of ventriculomegaly, one of hemorrhage, two of neuronal migration anomalies and three of midline anomalies), three cases in which MRI, but not ultrasound, revealed CNS anomalies that were not detected at birth (two nerve cell proliferation disorders and one hemorrhage) and two cases with discordant abnormal diagnosis (one of hemorrhage by MRI and ventriculomegaly by ultrasound and 1.00 (0.98-1.00) Salomon 17 Peruzzi 16 Whitby 21 Malinger 15 Benoist 11 Twickler 19 Simon 5 Frates 13 Wang 20 Yin 22 Sohn 18 Blaicher 12 0.50 (0.00-1.00) Salomon 17 Peruzzi 16 Whitby 21 Malinger 15 Benoist 11 Twickler 19 Simon 5 Frates 13 Wang 20 ...
... Salomon 17 Peruzzi 16 Whitby 21 Malinger 15 Benoist 11 Twickler 19 Simon 5 Frates 13 Wang 20 Yin 22 Sohn 18 Blaicher 12 0.50 (0.00-1.00) Salomon 17 Peruzzi 16 Whitby 21 Malinger 15 Benoist 11 Twickler 19 Simon 5 Frates 13 Wang 20 ...
Objectives
To analyze literature on the additional value of fetal magnetic resonance imaging (MRI) in assessing central nervous system (CNS) anomalies suspected by ultrasound.MethodsA search was performed of PubMed, EMBASE, Cochrane library and the reference lists of identified articles. Inclusion criteria were CNS anomalies suspected/diagnosed by ultrasound, MRI performed after ultrasound, and postmortem examination by autopsy or postnatal assessment. MOOSE guidelines were followed. Outcomes assessed were positive/negative agreement between ultrasound and MRI, additional information provided by MRI, and discordance between ultrasound and MRI. Pooled sensitivity and specificity of MRI were calculated using the DerSimonian-Laird method. Postnatal/postmortem examinations were used as the reference standard.ResultsWe identified thirteen articles which included 710 fetuses undergoing both ultrasound and MRI. MRI confirmed ultrasound-positive findings in 65.4% of fetuses and provided additional information in 22.1%. MRI disclosed CNS anomalies in 18.4% of fetuses. In 2.0% of cases, ultrasound was more accurate than MRI. In 30% of fetuses, MRI was so different from ultrasound that the clinical management changed. Agreement was observed mainly for ventriculomegaly (51.3%). Disagreement was noted mainly for midline anomalies (48.6%). Pooled sensitivity of MRI was 97% (95% CI, 95-98%) and pooled specificity was 70% (95% CI, 58-81%).ConclusionsMRI supplements the information provided by ultrasound. It should be considered in selected fetuses with CNS anomalies suspected on ultrasound. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
... В настоящее время в дополнение к двухмерному (2D) и 3D пренатальному УЗИ используется МРТ при условии наличия определенных показаний. Аномалии ЦНС, выявленные при проведении пренатального УЗИ, являются наиболее распространенным клиническим показанием для МРТ ЦНС плода и составляют около 80% всех МРТ-исследований плода [28][29][30]. ...
В настоящее время «золотым стандартом» диагностики аномалий плода является ультразвуковое исследование. Однако данный метод имеет ряд ограничений в диагностике аномалий центральной нервной системы плода. Это объясняется множеством факторов, включающих срок гестации, положение плода и тип порока. За последние два десятилетия методики магнитно-резонансной томографии заметно эволюционировали, предоставив новые последовательности и протоколы исследования ЦНС плода. В Республике Беларусь магнитно-резонансная томография плода применяется преимущественно в организациях IV уровня оказания медицинской помощи. Определено, что магнитно-резонансная томография используется для подтверждения или исключения выявленных при ультразвуковом исследовании патологических изменений. В статье проанализированы данные отечественной и мировой литературы о возможностях проведения магнитно-резонансной томографии плода. Кроме того, рассмотрены существующие руководства и рекомендации по использованию этого метода для оценки ЦНС плода. При магнитно-резонансной томографии плода применяются быстрые протоколы и последовательности сканирования. На сегодняшний день не существует единого протокола для обследования плода. Также не регламентированы и сами параметры применяемых импульсных последовательностей. Целью данного литературного обзора является определение места магнитно-резонансной томографии в структуре диагностических методов исследования ЦНС плода, а также выявление оптимальных последовательностей и протоколов сканирования, применяемых для диагностики аномалий ЦНС плода.
Currently, the gold standard for the diagnosis of fetal anomalies is ultrasonography. However, this method has a number of limitations in the diagnosis of fetal central nervous system anomalies. This is due to many factors including gestational age, fetal position, and type of malformation. Over the past two decades, magnetic resonance imaging techniques have evolved markedly, providing new sequences and protocols for the study of the fetal CNS. In the Republic of Belarus, fetal magnetic resonance imaging is used predominantly in level IV organizations of medical care. It is determined that magnetic resonance imaging is used to confirm or exclude pathologic changes detected by ultrasound examination. The article analyzes the data of domestic and world literature on the possibilities of fetal magnetic resonance imaging. In addition, the existing guidelines and recommendations on the use of this method for the evaluation of fetal CNS are considered. Fetal magnetic resonance imaging utilizes rapid protocols and scanning sequences. To date, there is no single protocol for fetal imaging. Nor are the parameters of the pulse sequences used regulated. The purpose of this literature review is to determine the place of magnetic resonance imaging in the structure of diagnostic methods of fetal CNS examination, as well as to identify the optimal sequences to be used for fetal CNS examination.
... MRI is often necessary for postnatal follow-up, especially in cases with other associated anomalies. 8 Based on the appearance of intracranial cystic lesions on ultrasound, there are a wide variety of subgroups: (a) normal variants, (b) developmental cystic lesions, (c) cysts due to perinatal injury, (d) vascular cystic structures, (e) infectious cysts, and (f) tumoral types. 9 Moreover, due to the anatomical origin, fetal brain cysts can be classified into two subgroups: extra-axial and intra-axial which are further divided into supratentorial and infratentorial. ...
This pictorial essay focuses on ultrasound (US) and magnetic resonance imaging (MRI) features of fetal intracranial cysts. Intracranial cysts are common findings in prenatal imaging, and if great attention is paid to their size, location, and imaging features, they can be diagnosed accurately. They are usually detected by fetal ultrasound exams. However, when ultrasound data on cystic lesion characteristics is insufficient, MRI and fetal neurosonogram are the best options for detecting other associated anomalies. The prognosis is highly dependent on their location and whether they are associated with other fetal anomalies. Cysts are common findings in fetal brain imaging and they are usually diagnosed by a prenatal ultrasound scan. They are fluid‐filled spaces and sometimes have a mass effect on the ventricles or on the brain parenchyma. The prognosis is highly dependent on whether they are associated with other fetal anomalies and where they are located.
... In recent studies, for the in utero evaluation of CNS pathological conditions, the use of foetal MR imaging has become widely accepted as an adjunct to foetal ultrasonography. Foetal MRI provides an accurate in utero diagnosis of most CNS anomalies [4,5]. Moreover, MRI allows evaluation of the foetal brain, particularly when a foetus is at increased risk for neurodevelopmental disabilities or documentation when an abnormality has been detected in the prenatal US [1]. ...
Background
Foetal MR imaging is widely accepted as an adjunct to foetal ultrasonography; however, there are many controversies regarding its importance and indications. Therefore, this study aimed to evaluate foetuses with different midline cerebral abnormalities, to determine the prevalence of these anomalies, to define the role of foetal MRI, and to compare MRI and ultrasound (US) result with postnatal MRI findings. Seventy-eight pregnant women who had foetuses with CNS abnormalities detected by sonogram were included. Foetuses with midline anomalies were selected and evaluated by anomaly scan foetal US, pre- and postnatal MRI.
Results
Midline brain anomalies were found in 47.4% of foetuses with brain anomalies. Holoprosencephaly was found in 24.3% of midline anomaly foetuses, corpus callosum abnormalities (ACC) were detected in 40.5%, midline intracranial mass lesions in 2.7%, and midline posterior fossa anomalies in 32.4%. An agreement between MRI and US in the main diagnosis was in 56.76% of cases; MRI added information to US findings in 43.2% of cases, and US added information to MRI findings in 8.1% of cases.
Conclusion
In evaluating midline cerebral anomalies, US and MRI are complementary techniques. US is the primary survey, and MRI can add additional information and/or change the main diagnosis.
... Furthermore, gestational week at diagnosis of CNS abnormalities may also delay due to the ongoing development of CNS throughout the pregnancy (Kline-Fath & Calvo-Garcia, 2011). However, new imaging modalities including 3D sonography or Magnetic Resonance Imaging (MRI) may provide a chance for earlier and proper diagnosis (Peruzzi, Corbitt, & Raffel, 2010;Rizzo et al., 2011). There are also 8 cases (8/199, 4.02%) that ended up with stillbirth in our series. ...
Objective:
To demonstrate major congenital abnormalities delivered or terminated at our institution between 2014 and 2018.
Materials and methods:
Necessary information was retrieved from the registries of the delivery room and electronic database of Hacettepe University Hospital, Ankara.
Results:
This study was consisted of 307 major congenital anomalies. The incidence of major congenital anomalies was 2.9 per 1,000 live births, while the majority of the cases were related to cardiovascular, central nervous system, and diaphragmatic hernia with 97, 87, and 25 cases at each group, respectively. Rate of termination of pregnancy (TOP) and live birth were 35.1 and 59.2%, respectively. The overall infant mortality rate was 28.9% in cases with live birth, while this rate was highest in cardiovascular system abnormalities and diaphragmatic hernia. Out of 182 newborns, 92.8% admitted to the neonatal intensive care unit after the delivery. Median gestational week at TOP was 21(20).
Conclusion:
We have shown that TOP and infant mortality rates were 35.1 and 28.9%, respectively in pregnancies with fetal malformations. Detailed multidisciplinary counseling must be provided for parents in pregnancies with major congenital abnormalities.
... In case of doubts in diagnosis or need of detailed assessment of the brain including the structures of the posterior cerebral fissure, fetal MRI examination can be performed. However, screening of the neural tube caudal defects by fetal MRI is not more effective than prenatal ultrasonography [365]. Ventriculomegaly is the most common developmental anomaly of the brain, which can occur during fetal period, approximately in 1 case per 1000 live-born children [366,367]. ...
... There are indisputable indications for prenatal MRI, among them: suspicion of central nervous system (CNS) pathologies, differentiation of pulmonary pathologies and those resulting from the dislocation of abdominal organs to the chest, searching for a missing kidney and many more. This gives rise to a question, whether prenatal MRI can replace postnatal diagnostics [1,2]. ...
Objectives:
The role of magnetic resonance imaging, similarly to ultrasound, in the evaluation of foetal anomalies is in-disputable. This gives rise to a question, whether prenatal diagnostics can replace postnatal one. To assess the diagnostic accuracy of foetal MRI in children with congenital anomalies by using postnatal MRI, X-ray/US and surgery (histopathol-ogy/autopsy) results as a reference standard.
Material and methods:
110 children were included in the analysis. All of them underwent foetal MRI, and the diagnoses were verified after birth. All the results were analysed both by: 1. evaluation of correctness of the prenatal diagnosis with the reference standard diagnosis of each patient, and 2. statistical evaluation of prenatal diagnosis using standard measures of binary diagnostic tests' abilities.
Results:
The accordance of prenatal and final diagnoses was 70%. Only 3.64% of patients were misdiagnosed. Most of the prenatal diagnoses that were incomplete (23.64%), concerned children who underwent surgery, and among them patients with abdominal cystic laesions of undetermined origin on foetal MRI constituted the majority. In 2.73% of cases prenatal diagnoses remained inconclusive.
Conclusions:
High correlation of prenatal and postnatal tests' results in the study material confirms the high value of foetal MRI in perinatal diagnostics. Comprehensive assessment of the foetus in prenatal MRI is very effective and facilitates impor-tant therapeutic decisions in the prenatal period (in utero treatment) and in perinatal care (application or withdrawal from the EXIT procedure, surgery or backtracking from neonatal resuscitation if it should bear the hallmarks of persistent therapy).
... du! SNC! [29]! [30].! Dans! une! autre! série,! ...
Objectif : évaluer l'application des recommandations HAS sur la prise en charge des ventriculomégalies (VMG) cérébrales foetales 10 ans après leur parution Matériels et Méthodes : étude rétrospective de 2005 à 2012 sur 2 centres pluridisciplinaires de diagnostic prénatal de France avec relevé des informations sur les VMG, les investigations réalisées, leurs résultats et les issues de grossesse. Résultats : 319 cas de VMG foetale ont été inclus, dont 74% concernaient des VMG associées. Les VMG dites graves étaient plus fréquentes en cas de VMG associées bilatérales. L'échographie a été répétée dans 41% des cas, une sérologie toxoplasmose était renseignée pour 72% des cas, une sérologie CMV était renseignée pour 28% des cas (4 séroconversions CMV), le caryotype est renseigné pour 66% des cas (anormal dans 21 cas), une consultation auprès d'un neuropédiatre a eu lieu dans 43% des cas, une IRM cérébrale foetale a été faite pour 122 cas (73% des VMG isolées modérées ou sévères) et a modifié la prise en charge pour 15 cas. L'issue de grossesse a été une interruption médicale de grossesse pour 54% des patientes, un accouchement pour 36%. Conclusion : Les recommandations HAS ne sont pas respectées. Cependant, le taux et le type d'anomalies dépistées en antenatal sont comparables aux autres séries publiées portant sur la prise en charge des VMG. La prise en charge des couples a été donc adaptée à chaque cas
... CNS abnormalities are the most common clinical indication for fetal MRI representing about 80% of all examinations requested. [25][26][27]. ...
Prenatal ultrasonographic (US) examination is considered as the first tool in the assessment of fetal abnormalities. However, several large-scale studies point out that some malformations, in particular central nervous system (CNS) anomalies, are not well characterized through US. Therefore, the actual malformation severity is not always related to prenatal ultrasound (US) findings.
Over the past 20 years, ultrafast Magnetic Resonance Imaging (MRI) has progressively increased as a prenatal 3rd level diagnostic technique with a good sensitivity, particularly for the study of fetal CNS malformations. In fact, CNS anomalies are the most common clinical indications for fetal MRI, representing about 80% of the total examinations.
This review covers the recent literature on fetal brain MRI, with emphasis on techniques, safety and indications.
... [13][14][15] Some studies have questioned this indication and demonstrated no added advantage in using MRI for detecting fetal anomalies. [16] However, MRI possibly could have a role in parent counseling. [17] Craniospinal rachischisis totalis being a lethal congenital malformation necessitates early termination of the pregnancy. ...
Craniospinal rachischisis is a rare and severe form of neural tube defects (NTDs), which is always fatal. It is characterized by anencephaly accompanied by a bony defect of the spine and exposure of neural tissue. We describe the two patients with ultrasonographic and magnetic resonance imaging appearance of craniospinal rachischisis totalis, detected antenatally at 22 and 25 weeks of gestation, and confirmed after termination of pregnancy. The multifactorial etiology of NTDs, with specific reference to folate deficiency, is discussed with possible role of folate fortification in the Indian context.
... Although postnatal MRI features of meningoencephaloceles have been systematically analyzed [12] , prenatal MRI data of these defects are limited to rare case reports [13][14][15][16][17][18][19][20][21][22] . Due to the absence of systematically assessed imaging data, our confidence in predicting the neurological outcome in these cases is generally low. ...
Introduction:
This retrospective study aims to describe systematically the fetal cerebral MR morphology in cases with occipital meningoencephaloceles using standard and advanced fetal MRI techniques.
Material and methods:
The 1.5-tesla MR examinations (T1- and T2-weighted imaging, echo planar imaging, EPI, diffusion-weighted imaging, DWI) of 14 fetuses with occipital/parietal meningoencephaloceles were retrospectively analyzed for the classification of anatomic characteristics. A diffusion tensor sequence was performed in 5 cases.
Results:
In 9/14 cases the occipital lobes were entirely or partially included in the encephalocele sac. Typical features of Chiari III malformation were seen in 6/14 cases. The displaced brain appeared grossly disorganized in 6/14. The brainstem displayed abnormal 'kinking'/rotation (3/14), a z-shape (1/14) and/or a molar tooth-like configuration of the midbrain (3/14). Tractography revealed the presence and position of sensorimotor tracts in 5/5 and the corpus callosum in 3/5. DWI was helpful in the identification of a displaced brain (in 8/9). EPI visualized the anatomy of draining cerebral veins in 7/9 cases. Clinical (9/14) and MRI (7/14) follow-up data are presented.
Discussion:
Encephaloceles show a wide range of morphological heterogeneity. Fetal MRI serves as an accurate tool in the visualization of brainstem, white matter pathway and cerebral venous involvement and facilitates the detection of specific underlying syndromes such as ciliopathies.
... Além disso, atualmente a RM tem sido bastante empregada para o diagnóstico intraútero de anomalias do sistema nervoso central, sendo, nesse caso, um exame mais sensível do que a ultrassonografia (7,8) . ...
Association of basal sphenoethmoidal encephalocele with midline cleft lip and palate is extremely rare. The authors report the case of a nine-year-old girl presenting a midline facial cleft with meningocele that was noticeable through the palatine defect as a medial intranasal pulsatile mass. An analysis of clinical and radiological findings of the present case of cranial dysraphism is carried out.
... The clinical impact of prenatal MRI has not yet been evaluated in large prospective, longitudinal studies. Analysis of its utility as an adjunct to prenatal US in spinal dysraphic defects appear to be negligible, available only in small case series studies [27]. Other studies have shown that prenatal US may be more accurate in determining the level of the defect and termination of the neural placode [6,28]. ...
Since intrauterine repair of open spinal dysraphism have demonstrated promising results, it has become crucial to accurately define the various prenatal pathologies. The embryogenesis of spinal dysraphism according to a clinical neuroradiological classification is reviewed, with special emphasis on the recent advances in prenatal ultrasound (US), such as high-frequency linear transducers and three-dimensional imaging.
The role of magnetic resonance imaging (MRI) of the fetus as a complementary tool for delineating complex fetal spinal anomalies and further defining associated central nervous system (CNS) anomalies is explored. Differentiation between normal appearance of the fetal spine and the wide range of congenital neural tube defects are demonstrated in both modalities with special emphasis on their complementary role in the accurate diagnosis of neural tube defects.
OBJETIVO:
Conocer los aportes de la resonancia magnética, como estudio complementario al ultrasonido, en el diagnóstico de malformaciones fetales en el sistema nervioso central, musculoesquelético y tórax en dos unidades de Medicina Materno Fetal.
MATERIALES Y MÉTODOS:
Estudio retrospectivo, observacional y comparativo, de corte transversal, efectuado con base en la revisión de las historias clínicas registradas durante tres años de pacientes con más de 18 semanas de embarazo remitidas a la Unidad de Medicina Materno Fetal del Hospital San José y la Clínica Colsubsidio por alguna malformación estructural fetal identificada en el sistema nervioso central, musculoesquelético y tórax diagnosticada con base en la ultrasonografía.
RESULTADOS:
Se revisaron 109 historias clínicas de pacientes embarazadas con fetos con diagnóstico de malformación congénita por ultrasonido. Las indicaciones más frecuentes fueron: anormalidades en el sistema nervioso central en 61.5%; hidrocefalia no comunicante en 36.6% por ultrasonido y 21% por resonancia magnética, seguida de las del tórax con 40.4% por ultrasonido y 36.7% por resonancia magnética y malformaciones del sistema musculoesquelético con 20.1% por ultrasonido y 2.8% por resonancia magnética. La concordancia diagnóstica entre el ultrasonido y el diagnóstico posnatal fue del 66% y el de la resonancia magnética de 76%. En comparación con el ultrasonido inicial la resonancia magnética aumentó la frecuencia de diagnóstico de malformación fetal.
CONCLUSIÓN:
La resonancia magnética, complementaria al diagnóstico por ultrasonido de malformaciones congénitas, fue más notable en los sistemas nervioso central y musculoesquelético donde permitió mejorar la caracterización de las alteraciones detectadas en el ultrasonido.
Background
Ultrasonography has been the mainstay of antenatal screening programmes in the UK for many years. Technical factors and physical limitations may result in suboptimal images that can lead to incorrect diagnoses and inaccurate counselling and prognostic information being given to parents. Previous studies suggest that the addition of in utero magnetic resonance imaging (iuMRI) may improve diagnostic accuracy for fetal brain abnormalities. These studies have limitations, including a lack of an outcome reference diagnosis (ORD), which means that improvements could not be assessed accurately.
Objectives
To assess the diagnostic impact, acceptability and cost consequence of iuMRI among fetuses with a suspected fetal brain abnormality.
Design
A pragmatic, prospective, multicentre, cohort study with a health economics analysis and a sociological substudy.
Setting
Sixteen UK fetal medicine centres.
Participants
Pregnant women aged ≥ 16 years carrying a fetus (at least 18 weeks’ gestation) with a suspected brain abnormality detected on ultrasonography.
Interventions
Participants underwent iuMRI and the findings were reported to their referring fetal medicine clinician.
Main outcome measures
Pregnancy outcome was followed up and an ORD from postnatal imaging or postmortem autopsy/imaging collected when available. Developmental data from the Bayley Scales of Infant Development and questionnaires were collected from the surviving infants aged 2–3 years. Data on the management of the pregnancy before and after the iuMRI were collected to inform the economic evaluation. Two surveys collected data on patient acceptability of iuMRI and qualitative interviews with participants and health professionals were undertaken.
Results
The primary analysis consisted of 570 fetuses. The absolute diagnostic accuracies of ultrasonography and iuMRI were 68% and 93%, respectively [a difference of 25%, 95% confidence interval (CI) 21% to 29%]. The difference between ultrasonography and iuMRI increased with gestational age. In the 18–23 weeks group, the figures were 70% for ultrasonography and 92% for iuMRI (difference of 23%, 95% CI 18% to 27%); in the ≥ 24 weeks group, the figures were 65% for ultrasonography and 94% for iuMRI (difference of 29%, 95% CI 23% to 36%). Patient acceptability was high, with at least 95% of respondents stating that they would have iuMRI again in a similar situation. Health professional interviews suggested that iuMRI was acceptable to clinicians and that iuMRI was useful as an adjunct to ultrasonography, but not as a replacement. Across a range of scenarios, iuMRI resulted in additional costs compared with ultrasonography alone. The additional cost was consistently < £600 per patient and the cost per management decision appropriately changed was always < £3000. There is potential for reporting bias from the referring clinicians on the diagnostic and prognostic outcomes. Lower than anticipated follow-up rates at 3 years of age were observed.
Conclusions
iuMRI as an adjunct to ultrasonography significantly improves the diagnostic accuracy and confidence for the detection of fetal brain abnormalities. An evaluation of the use of iuMRI for cases of isolated microcephaly and the diagnosis of fetal spine abnormalities is recommended. Longer-term follow-up studies of children diagnosed with fetal brain abnormalities are required to fully assess the functional significance of the diagnoses.
Trial registration
Current Controlled Trials ISRCTN27626961.
Funding
This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment ; Vol. 23, No. 49. See the NIHR Journals Library website for further project information.
Fetal and placental magnetic resonance imaging (MRI) has grown from a tool for highly targeted examination in selected cases to a feasible and reproducible modality for a number of applications. However, MRI is not yet a standard screening tool and should be used only to answer specific questions raised by targeted ultrasound (US) or help refine prognosis in certain high-risk situations. Compared with US, MRI can provide important anatomic information; it is less limited by fetal lie, oligohydramnios, multiple pregnancy, or obesity and offers high-contrast images that can be acquired in true anatomic planes. MRI can also provide functional information, which may become a common tool for assessment of fetal cerebral or placental physiology. Importantly, the clinician performing and interpreting the MRI should have a clear understanding of previous US findings and of the relevant fetal anatomy and pathophysiology. This chapter summarizes the principles, benefits, limitations, and main indications for fetal or placental MRI.
Neural tube defects (NTDs) and hemivertebra represent major congenital abnormalities of the cranial vault and the fetal spine.NTDs are the consequence of a failed closure of the cranial and/or the caudal neural tube. Their pathogenesis is unknown; however, an association with folic acid deficiency and a variable incidence of structural abnormalities and karyotype/genetic defects have been reported. NTDs include the spectrum of acrania-exencephaly-anencephaly, encephaloceles, spinal defects ("spina bifida" or myelomeningocele), and combined cranial and spinal defects such as craniorachischisis. Prognosis is strongly dependent on the type of the NTD and the presence or absence of additional structural or genetic findings. Spina bifida, either open or covered by skin, represents a common malformation of the central nervous system. Closed defects generally have a good prognosis, whereas open defects are associated with high rates of mortality and handicap. Acrania-exencephaly-anencephaly sequence and craniorachischisis represent invariably lethal defects. On the other hand, treatment options do exist for encephaloceles and spina bifida. In these latter, prognosis is dependent on the extent of the defect, its location in the skull or in the spine, and the amount of herniated neural tissue. Among NTDs, encephalocele carries the higher chance of associated extracranial abnormalities and chromosomal or genetic defects.Hemivertebra is among the causes of congenital scoliosis and is caused by the failed development of one half of the vertebral body. Hemivertebra is commonly associated with other skeletal, cardiac, and genitourinary tract anomalies; however, when isolated, it usually carries a good prognosis.
If ultrasonography is the first intention exam in the evaluation of fetal cerebral structures, MR is the second intention exam the indications of which are well defined. Both techniques are complementary but still independent and the retrospective synthesis of these exams allows optimal analysis of fetal cerebral anomalies. Real time virtual sonography can synchronize a sonographic image and MRI multiplanar image of the same section in real time. This technique can be performed in the evaluation of fetal cerebral structures and synchronous recognition of anatomic structures and has many advantages especially on the pedagogic plan. However, this technique is currently limited to the research area.
Copyright © 2014. Published by Elsevier SAS.
Objective
To determine whether a standard complete fetal anatomical survey, as recommended for ultrasound examination guidelines, is feasible using a standardized magnetic resonance imaging (MRI) protocol. Methods
Based on guidelines for ultrasound examination, we created a specific MRI protocol for fetal anatomical survey. This protocol was then tested prospectively in 100 women undergoing fetal MRI examination for various specific indications at a median gestational age of 30 weeks. The feasibility of using MRI to perform the fetal anatomical survey was analyzed by two reviewers (A and B) based on 26 predefined anatomical criteria, yielding a score ranging from 0 to 26 (26 meaning successful complete anatomical study). Reproducibility was analyzed using percentage agreement and modified kappa statistics. ResultsThe mean score for the standardized MRI anatomical survey was 24.6 (SD, 1.4; range, 15–26) for Reviewer A and 24.2 (SD, 1.7; range, 15–26) for Reviewer B (P = 0.1). Twenty-two, two and two criteria could be assessed in > 95%, 80–95% and 95%, 80–95% and
Objective
To assess the accuracy of expert neurosonography (two- and three-dimensional NSG) in the characterization of major fetal central nervous system (CNS) anomalies seen at a tertiary referral center and to report the differential clinical usefulness of magnetic resonance imaging (MRI) used as a second-line diagnostic procedure in the same cohort.
Methods
This was a retrospective analysis of all 773 fetuses with confirmed CNS abnormalities referred to our center between 2005 and 2012. The following variables were analyzed: gestational age at NSG and MRI, NSG and MRI diagnoses, indication forMRI (confirmation of NSG findings; diagnostic doubt; search for possible additional brain anomalies), association with other malformations, diagnostic accuracy of NSG vs MRI (no additional clinical value for either MRI or NSG; additional information with clinical/prognostic significance on MRI relative to NSG; additional information with clinical/prognostic significance on NSG relative to MRI, NSG and MRI concordant but incorrect) and final diagnosis, which was made at autopsy or postnatal MRI/surgery.
Results
CNS malformations were associated with other anomalies in 372/773 (48.1%) cases and were isolated in the remaining 401 (51.9%) cases. NSG alone was able to establish the diagnosis in 647/773 (83.7%) cases. MRI was performed in 126 (16.3%) cases. The indication for MRI was: confirmation of NSG diagnosis in 59 (46.8%) cases; diagnostic query (in the case of inconclusive or uncertain finding on NSG) in 20 (15.9%) cases; search for possible additional brain anomalies in 47 (37.3%) cases.
NSG and MRI were concordant and correct in 109/126 (86.5%) cases.
Clinically relevant findings were evident on MRI alone in 10/126 (7.9%) cases (1.3% of the whole population) and on NSG alone in 6/126 (4.8%) cases; in all six of these cases, MRI had been performed at<24 weeks of gestation. In one case, both NSG and MRI diagnoses were incorrect. The main type of malformation in which MRI played an important diagnostic role was space-occupying lesions, MRI identifying clinically relevant findings in 42.9% (3/7) of these cases.
Conclusions
(1) In a tertiary referral center with good NSG expertise in the assessment of fetal CNS malformations, MRI is likely to be of help in a limited proportion of cases;
(2) MRI is more useful after 24 weeks of gestation;
(3) the lesions whose diagnosis is most likely to benefit from MRI are gross space-occupying lesions.
La diastématomyélie est une malformation rachidienne rare caractérisée par la présence d’un éperon médian fibreux ou osseux
séparant la moelle en deux hémimoelles. Nous rapportons le cas d’une diastématomyélie diagnostiquée à l’échographie anténatale
morphologique. Le diagnostic a été confirmé par l’imagerie par résonance magnétique (IRM) postnatale, alors que l’IRM anténatale
évoquait le diagnostic de myélolipome lombosacré. Le diagnostic anténatal repose sur des signes échographiques spécifiques.
Nous discutons de l’intérêt de l’IRM fœtale, faite en seconde intention, dans l’évaluation du diagnostic et du pronostic de
cette malformation.
Diastematomyelia is a rare spinal malformation characterized by a cleft in the spinal cord caused by a sagittal osseous or
fibrocartilaginous spur. We report a case of prenatal diagnosis of diastematomyelia on a routine second-trimester sonography.
Postnatal MRI confirmed the diagnosis, whereas fetal MRI detected a lumbosacral lipoma. Diastematomyelia can be diagnosed
antenatally with highly specific sonographic signs. We discuss the interest of antenatal MRI, made in second intention, to
specify the diagnosis and the prognosis of this malformation.
Mots clésDiastématomyélie–Diagnostic anténatal–IRM fœtale–Dysraphisme spinal
KeywordsDiastematomyelia–Prenatal diagnosis–MRI fetal–Spinal dysraphism
Hydrocephalus is the most frequent and devastating illness affecting a fetus. The development of both ultrasonography and magnetic resonance, associated with laboratorial tests, has greatly facilitated its diagnosis.
In the Fetal Medicine Service of the Federal University of São Paulo and in the Santa Joana/Pro-Matre Paulista Hospital Complex, in São Paulo, SP, Brazil, repeated cephalocenteses, ventricular-amniotic shunting, and neuroendoscopy were used to treat 57 fetuses with hydrocephalus, all of them at a gestational age under 32 weeks. Another eight fetuses had myelomeningocele and underwent correctional open surgery to prevent hydrocephalus.
Thirty-nine patients were followed up for a period longer than 3 years and had their intelligence coefficient assessed: 26 of them were considered normal (IQ above 70); six had mild or moderate handicaps (IQ from 35 to 70), and seven were severely handicapped (IQ below 35). Out of the eight patients operated for correction of myelomeningocele, only two came to require shunting. There were no cases of maternal morbidity, and no infectious condition was observed in any of the patients subjected to intrauterine treatment.
Selected cases of isolated, evolutive, non-destructive hydrocephaly diagnosed before 32 gestational weeks may benefit from fetal neurosurgical procedures. With the accuracy improvement of diagnoses, the number of patients fitting into that group has become very small.
This paper describes our experience with magnetic resonance imaging (MRI) in the assessment of fetal anatomical structures and major fetal pathologies.
The retrospective study included 128 pregnant women between the 22nd and 38th week of gestation. We used the following imaging protocol: T2-weighted single-shot fast spin-echo sequences for all foetuses and, in selected cases, gradient echo with steady-state free precession (SSFP), T1-weighted spoiled gradient echo [fast low-angle shot (FLASH)] with and without fat saturation, and T2 thick-slab sequences with multiplanar technique. In 32 cases, we performed diffusion-weighted sequences with apparent diffusion coefficient (ACD) maps on the brain, the kidneys and the lungs.
We achieved diagnostic-quality images in 125 of 128 patients; MR image quality was unsatisfactory in three cases only. In 16 cases with previous negative ultrasound (US) findings, MRI confirmed the US diagnosis. MRI confirmed the positive US diagnosis in 67 of 109 cases (61.5%); in 11 cases it changed the US diagnosis, and in 31/109 the examination was negative. In addition, MRI identified other anomalies not recognised during US examination.
With its ultrafast sequences, fetal MRI provides good detail of normal fetal anatomy and allows characterisation of suspected anomalies.
Fetal magnetic resonance imaging (MRI) is a well-established second line imaging modality in identifying complex pathologies of the central nervous system (CNS), especially when ultrasound (US) findings are equivocal. It may enable an early and precise diagnosis, which is essential in terms of management of pregnancy and pre-, peri- and postnatal care. We present three cases with rare complex midline malformations of the CNS, diagnosed prenatally by fetal MRI. Two cases revealed holoprosencephaly; one case demonstrated rhombencephalosynapsis. In addition, we reviewed the literature and provide a summary of recent findings regarding cerebral midline development and discuss the advantages of fetal MRI.
The neonatal, pathologic outcome and karyotypic abnormalities are reported for 44 fetuses with mild ventriculomegaly diagnosed antenatally. Seventeen of these 44 fetuses (39%) had other ultrasonographic defects, and five (12%) had abnormal karyotypes. Five pregnancies were electively aborted and three other fetuses died in the neonatal period. Twenty-six (72%) of the remaining 36 live-born neonates are developmentally and clinically normal at 3 to 18 months of age. Twenty-one of these 26 had isolated mild ventriculomegaly as the only ultrasonographic finding. The other 10 live-born infants are developmentally impaired, and five of these 10 had mild ventriculomegaly as the only prenatal ultrasonographic abnormality. In conclusion, these data show that fetuses with mild ventriculomegaly have a lower incidence of associated anomalies and a better outcome than fetuses with more severe ventricular dilatation, as reported in the literature. The majority of fetuses with mild ventriculomegaly as an isolated finding and a normal karyotype are developing normally.
New hardware and software allow for increased magnetic resonance imaging (MRI) speed. This speed is crucial for MRI of the fetus, where motion degrades image quality. Single-shot sequences such as echo-planar and single-shot fast spin echo now are practical with most clinical scanners. This article reviews and illustrates the physics of fast magnetic resonance sequences.
To elucidate further the magnetic resonance (MR) imaging appearance of fetal cerebral ventricles by comparing ultrasonographic (US) and MR images.
A retrospective review of MR and US images was performed for 110 normal fetuses and 94 fetuses with central nervous system abnormalities to assess lateral ventricular morphology as having (a) a normal appearance, (b) mild, disproportionate dilatation of the occipital horns with overall preservation of ventricular morphology, (c) colpocephaly with or without normal orientation of the frontal horns, (d) abnormal orientation of the frontal horns without colpocephaly, (e) an angular appearance, (f) fused frontal horns, (g) global dilation, or (h) a distorted appearance. Ventricular morphology on US and MR images was compared and correlated with reference standard diagnoses.
US and MR imaging classifications were concordant in 145 of 188 (77%) examinations. Mild disproportion of occipital horns with respect to frontal horns was seen only on MR images. This ventricular configuration was present in eight of 110 normal fetuses and in 10 of 16 fetuses with isolated mild ventriculomegaly (P <.001). An angular configuration of the lateral ventricles, which is seen in fetuses with neural tube defects (NTDs), was present on review of MR images in 11 fetuses and on US images in one fetus. The ventricles of fetuses with NTDs and angular ventricles (3-12 mm) were significantly smaller than those of fetuses with NTDs and global dilatation of the ventricles (13-25 mm; P <.05).
Ventricular contours differ with differing diagnoses of central nervous system abnormalities.
To examine the ultrasonographic feasibility of imaging the fetal pons and to construct a reference chart for its normal development during gestation.
A cross-sectional, prospective study on 293 healthy fetuses of low-risk pregnancies between 19 and 34 weeks was performed. The transfontanel approach, via the abdominal or vaginal routes, was used to evaluate the fetal metencephalon (pons and cerebellum). The anteroposterior diameter of the fetal pons was measured in a mid-sagittal plane. The longitudinal diameter of the cerebellar vermis was measured at the same plane and the vermis-pons ratio (VPR) was established.
One hundred and forty-four fetuses were in vertex position. In 140 (97.2%) satisfactory visualization and measurements of the pons and cerebellar vermis were obtained. One hundred and forty-nine fetuses were breech presentations and measurements were successfully performed in 147 (98.6%). The pons anteroposterior and vermis longitudinal diameters showed a linear correlation with gestational age (GA) (r = 0.95 for both measurements; P < 0.001). The mean VPR was 1.5 (+/-0.1 SD) and did not change in the gestational interval that was considered.
By using the transfontanel approach, evaluation of the fetal pons is feasible via the mid-sagittal plane. The nomograms developed and the ratio to fetal vermis provides reference data that may be helpful when evaluating anomalies of the brainstem.
To evaluate the progression in utero of mild isolated fetal ventriculomegaly (defined as a transverse diameter of the atrium of the lateral ventricle measuring between 10 and 15 mm), and to estimate the proportion of fetuses that normalize (diameter decreasing to less than 10mm), stabilize (remaining between 10 and 15 mm), or progress to more severe ventriculomegaly (becoming greater than 15 mm).
The obstetric databases of 3 institutions were queried for any studies mentioning ventriculomegaly or hydrocephalus. Reports and original images were reviewed to verify cases of isolated mild ventriculomegaly, with no other anomalies on comprehensive ultrasonographic examination. Fetuses that had 2 or more evaluations more than 3 weeks apart were included.
A total of 63 fetuses met the criteria for isolated mild ventriculomegaly. The mean gestational age and ventricular measurements were 24.7+/-3.7 weeks and 11.8+/-1.1mm, respectively, at the initial scan and 34+/-2.9 weeks and 12.1 +/-3.8mm, respectively, at the final scan. The mean number of scans was 3.75 per fetus (range, 2-6). Amniocentesis revealed the deletion of 5p, which causes the cri du chat, in 1 of 21 fetuses; 26 fetuses (41%) showed normalization of the lateral ventricles; 10 fetuses (16%) showed progression; and 27 (43%) appeared stable. shows the statistics of the individual groups. Three of the fetuses that "stabilized" improved from 15 mm to 11, 11.5, and 11.7 mm, respectively. Two worsened from 10.2 to 14 mm and from 11.4 to 13 mm.
More than 40% of the cases of mild isolated fetal ventriculomegaly resolved in utero. The significant overlap in measurements for the different groups precludes prediction in individual cases. However, of the 13 cases where the transverse diameter measured 13 mm or more, only 1 normalized, while 9 of the remaining 12 cases stabilized and 3 progressed.
To define the contribution of prenatal investigation and evaluate the prognosis of isolated mild ventriculomegaly (IMV).
Retrospective study.
University hospital between January 1992 and December 2002.
One hundred and sixty-seven cases of prenatal unilateral or bilateral IMV without any associated anomaly at the time of initial diagnosis.
Complementary investigations were performed: amniocentesis with karyotyping, screening for viruses and acetylcholinesterase electrophoresis, magnetic resonance imaging (MRI), and ultrasonography every 3-4 weeks.
Results of prenatal investigations, pregnancy outcome, and postnatal psychomotor development.
IMV was diagnosed around 26.5 weeks. Amniocentesis revealed four chromosomal anomalies and two cytomegalovirus infections. MRI diagnosed brain-associated anomalies in 15 cases and ultrasonographic monitoring highlighted malformations not initially diagnosed in 28 cases. Termination of pregnancy (TOP) was considered in 21 pregnancies (12.6%). Indications were aneuploidy, fetal infectious disease or associated malformations. In women for whom a TOP was considered, consanguinity, fetus of female sex and frontal horn enlargement were statistically more frequent, ventriculomegaly was more often bilateral and asymmetrical, atrial width, and the rate of progressive ventricular enlargement were significantly higher. One hundred and one children with prenatal IMV were assessed between 19 and 127 months (mean age 54.68 +/- 2.87 months). Twelve children had neurological disease or psychomotor delay and 89 children had a normal psychomotor development. Poor neurological outcome was more often associated with atrial width greater than or equal to 12 mm, asymmetrical bilateral enlargement, and progression of the ventriculomegaly.
The detection of IMV raises the question of the child's psychomotor development and justifies meticulous prenatal investigation. In addition to associated anomalies, three criteria are often associated with an unfavourable outcome: atrial width greater than 12 mm, progression of the enlargement, and asymmetrical and bilateral ventriculomegaly.
Fetal MR imaging is an increasingly available technique used to evaluate the fetal brain and spine. This is made possible by recent advances in technology, such as rapid pulse sequences, parallel imaging and advances in coil design. This provides a unique opportunity to evaluate processes that cannot be approached by any other current imaging technique and affords a unique opportunity for studying in vivo brain development and early diagnosis of congenital abnormalities inadequately visualized or undetectable by prenatal sonography. This 2-part review summarizes some of the latest developments in MR imaging of the fetal brain and spine and its application to prenatal diagnosis. This first part discusses the utility, safety, and technical aspects of fetal MR imaging, the appearance of normal fetal brain development, and the role of fetal MR imaging in the evaluation of fetal ventriculomegaly. The second part focuses on additional clinical applications of fetal MR imaging, including suspected abnormalities of the corpus callosum, malformations of cortical development, and spine abnormalities.
The purpose of this study was to determine the contribution of magnetic resonance imaging (MRI) in evaluating fetuses with the sonographic diagnosis of ventriculomegaly (VM).
Over 4 years, consecutive fetuses with the sonographic diagnosis of VM at 1 facility who underwent prenatal MRI at a second facility were included. The roles of MRI and follow-up sonography were tabulated. The patients were analyzed in 2 groups based on the presence or absence of other central nervous system (CNS) abnormalities.
Twenty-six fetuses with a gestational age range of 17 to 37 weeks had sonographically detected VM (atria > or =10-29 mm), including 19 with mild VM (atria 10-12 mm). In group 1, 14 had isolated VM, 6 of which reverted to normal by the third trimester. Magnetic resonance imaging showed cerebellar hypoplasia not shown by sonography in 1 fetus and an additional finding of a mega cisterna magna in a second fetus. In group 2, 12 fetuses had VM and other CNS anomalies on sonography. Additional findings were seen with MRI in 10 of these fetuses, including migrational abnormalities (n = 4), porencephaly (n = 4), and 1 diagnosis each of abnormal myelination, hypoplasia of the corpus callosum, microcephaly, a kinked brain stem, cerebellar hypoplasia, and congenital infarction. There were significantly more fetuses with additional CNS anomalies found by MRI among those in group 2 compared with those in group 1 (Fisher exact test, P = .001).
Although sonography is an accurate diagnostic modality for the evaluation of fetuses with VM, MRI adds important additional information, particularly in fetuses in whom additional findings other than an enlarged ventricle are seen sonographically.