Fetal central nervous system malformations on MR images

The impact of cerebral anomalies on cognitive outcome in patients with spina bifida: A systematic review

BACKGROUND

Spina bifida is the most common congenital birth defect affecting the central nervous system. Given the frequent association of cerebral anomalies, spina bifida is not a single developmental abnormality of the central nervous system. Patients with spina bifida typically perform below average on cognitive tasks. It has been hypothesized that associated cerebral anomalies as well negatively affect cognition in spina bifida patients.

OBJECTIVE

This study aims to review the impact of cerebral anomalies on cognitive outcome in patients with spina bifida.

METHODS

A systematic search of multiple databases, including Pubmed, Embase, Web of Science and The Cochrane Central Register of Controlled Trials, was performed. All relevant primary research articles were included. All included articles were methodologically evaluated using a critical appraisal checklist.

RESULTS

In total 27 articles were included in this systematic review. A significant impact of different cerebral anomalies on cognition was found. More specifically, hydrocephalus, Chiari malformation type II and anomalies of the corpus callosum, central executive network, default mode network, cortical thickness and gyrification, fornix, grey matter volume and total brain volume were found to have a significant impact on cognitive outcome. The presence of a CSF shunt was also negatively associated with cognition. The results on Chiari malformation type II decompression and CSF shunt complications are inconsistent.

CONCLUSION

Associated cerebral anomalies have a significant impact on cognitive outcome in patients with spina bifida. The interrelatedness of the different cerebral anomalies makes it difficult to distinguish their individual impact on cognition.

A metabolomics-based approach for non-invasive screening of fetal central nervous system anomalies

BACKGROUND

Central nervous system anomalies represent a wide range of congenital birth defects, with an incidence of approximately 1% of all births. They are currently diagnosed using ultrasound evaluation. However, there is strong need for a more accurate and less operator-dependent screening method.

OBJECTIVES

To perform a characterization of maternal serum in order to build a metabolomic fingerprint resulting from congenital anomalies of the central nervous system.

METHODS

This is a case-control pilot study. Metabolomic profiles were obtained from serum of 168 mothers (98 controls and 70 cases), using gas chromatography coupled to mass spectrometry. Nine machine learning and classification models were built and optimized. An ensemble model was built based on results from the individual models. All samples were randomly divided into two groups. One was used as training set, the other one for diagnostic performance assessment.

RESULTS

Ensemble machine learning model correctly classified all cases and controls. Propanoic, lactic, gluconic, benzoic, oxalic, 2-hydroxy-3-methylbutyric, acetic, lauric, myristic and stearic acid and myo-inositol and mannose were selected as the most relevant metabolites in class separation.

CONCLUSION

The metabolomic signature of second trimester maternal serum from pregnancies affected by a fetal central nervous system anomaly is quantifiably different from that of a normal pregnancy. Maternal serum metabolomics is therefore a promising tool for the accurate and sensitive screening of such congenital defects. Moreover, the details of the most relevant metabolites and their respective biochemical pathways allow better understanding of the overall pathophysiology of affected pregnancies.

Seventeen years of prenatal magnetic resonance imaging at the Institute of Mother and Child in Warsaw

Purpose

The purpose of this paper is to summarise and to present the experience of the main Polish centre for prenatal magnetic resonance imaging (MRI) and to discuss the place and role of MRI in antenatal diagnosis, management, and counselling.

Material and methods

Retrospective analysis of the examinations performed in the years 2001-2017.

Results

In total, 1221 medical records and/or image files were collected. The full documentation of ultrasonography and MRI referrals, reports, and images was not available in every case. During the first three years 98 pregnant women were examined (approximately 33 per year, one study per fortnight). After purchase of own MR scanner, the number of examinations grew constantly, reaching 208 in 2017, which means almost one per day, and the highest number was eight in one day. We examined 45 pairs of twins, including three pairs of conjoined twins.

Conclusions

MRI at our Institute is a practically used second-line foetal imaging tool, necessary to confirm, complete, or correct sonographic diagnoses, with important impact on clinical decisions concerning management of pregnancy and of the neonate, termination of pregnancy, choice of the time, place, and mode of delivery, and neonatal care, as well as on counselling. In experienced hands, MRI is to date the last and the best non-invasive method of diagnosis in utero. It is frequently requested by the interdisciplinary team for foetal diagnosis and therapy and routinely performed in everyday practice.

The clinical relevance of fetal MRI in the diagnosis of Type IV cystic sacrococcygeal teratoma--a review

The introduction of fetal magnetic resonance imaging (MRI) has improved the prenatal evaluation of uterine, placental and fetal anatomy. However, its utilization has mostly been restricted to fetal central nervous system anomalies. We review how adjunct fetal MRI was performed and diagnosis of cystic type IV sacrococcygeal teratoma was made. We also discuss the clinical relevance of fetal MRI in differentiating this lesion from other selected abdominal/pelvic cystic malformations and lesions.

Antenatal diagnosis of agenesis of the corpus callosum

AIM

To estimate the diagnostic performance of ultrasound in detecting agenesis of the corpus callosum (ACC).

MATERIALS AND METHODS

A retrospective review was performed of 1722 in utero MRI examinations. All cases were identified in which the fetus had been referred from ultrasonography with a diagnosis of ACC and those in which ACC was given as a diagnosis on the in utero MRI study. The MRI was assumed to provide the correct diagnosis of ACC and descriptive statistics of diagnostic accuracy for ultrasound were calculated.

RESULTS

Of the 1722 ultrasound examinations performed, 121 had a diagnosis of ACC and approximately 50% were confirmed at MRI. Forty-two fetuses with ACC not suspected at ultrasonography were also identified at MRI. Ultrasonography had a positive predictive value of 47% (95% CI: 38-56%) and a negative predictive value of 97% (95% CI: 96-98%) for detecting ACC.

CONCLUSION

Ultrasound is poor in diagnosing ACC and in utero MRI should be performed if there is any suspicion on antenatal ultrasonography.

Recommendations regarding imaging of the central nervous system in fetuses and neonates

An abnormal presentation of the central nervous system in a fetus during a screening examination is an indication for extended diagnosis, the aim of which is to explain the character of such an anomaly (a congenital defect, destructive effect of intrauterine infection or abnormality with reasons that are difficult to explain). Knowledge of normal development sequence of the fetal brain, which is discussed in this paper, is the basis for correct interpretation of imaging findings. Together with the increase in survival of preterm neonates, a high risk of early brain damage is still a problem in this extremely immature population. Therefore, imaging examinations become necessary. The paper presents intrauterine and postnatal risk factors of early brain damage as well as classification of such lesions, of hemorrhagic and hypoxic-ischemic etiology. The diagnosis of the cerebellum damage, which is currently believed to be a significant cause of autism, is emphasized. The evolution of lesions over time is also presented. Moreover, the elements of diagnosis important for prognosis are stressed. The standards of imaging examinations of the central nervous system include the schedule of ultrasound examinations and provide indications for extended diagnosis with the use of magnetic resonance imaging.

Prenatal diagnosis of a vein of Galen aneurysmal malformation with MR imaging - report of two cases

BACKGROUND

Vein of Galen malformations (VGMs) are rare congenital defects of cerebral vessels. They are formed between the 6(th) and 11(th) week of gestation. The background of this defect involves presence of one or more arterovenous fistulas directing bloodflow toward a persistent, dilated, proximal part of median prosencephalic vein (MProsV). Ultrasound examination is a basic test for diagnosis of VGMs. It has now become possible to acquire images of diagnostic value using magnetic resonance (MR) techniques.

CASE REPORT

This work presents two cases of vein of Galen aneurysms diagnosed prenatally with magnetic resonance imaging. In both patients fetal CNS malformations were diagnosed in ultrasound examinations. MR imaging of the fetal head was performed for further diagnostics.

CONCLUSIONS

Because of the ability to precisely determine the size of the ventricular system, presence of raised intraventricular pressure and topographic relationships between pathologically changed vessels and particular cerebral structures as well as the presence of ischemic areas MR examination is currently not only complementary to ultrasonography, but is becoming an independent examination method in the diagnostics of vein of Galen malformations.

Prenatal-postnatal correlations of brain abnormalities: how lesions and diagnoses change over time

A combination of prenatal ultrasound and MRI can be used to detect and characterize many primary and secondary CNS abnormalities in the developing fetus. While this information is useful in prenatal patient counseling, it is important to understand the factors that can influence change in diagnosis and prognosis over time. The etiology of the abnormality, the conspicuity of associated findings, the change in appearance over time, and the opinion of subspecialty experts all can influence the diagnosis. Additionally, technical factors of imaging acquisition may allow the detection of an abnormality in the postnatal period and not prenatally. Having an understanding of the normal fetal central nervous system anatomy at varying gestational ages will aid in the imaging detection and interpretation of CNS pathology. Understanding how these appearances and diagnoses can change over time will aid in the discussion of prognosis with expectant parents, which is crucial in fetal CNS abnormalities.

Investigation and management of Toxoplasma gondii infection in pregnancy and infancy: a prospective study

AIM

Toxoplasma gondii infection during pregnancy poses a serious risk to the fetus, therefore timely and accurate diagnosis is essential. The aim of this study was to estimate the frequency of congenital infection via evaluating mother's immunological status and the possibility to improving the diagnostic and therapeutic approaches.

METHODS

Eighty five mothers with Toxoplasma seroconversion and their offspring were enrolled (among them, 2 spontaneous abortions were documented in the first trimester). Prenatal PCR diagnosis was carried out on 50 patients (60%), with 7 positive cases (14%). Morphological ultrasound scanning revealed anomalies in one fetus. Long-term follow-up included general physical examinations, serological status tested using Western blot, neuro-radiological, ophthalmologic and neurologic examinations, psychological and developmental tests, visual evoked potential tests and audiology tests, as well as anti-Toxoplasma treatment regimes.

RESULTS

Fourteen (17%) of the infants were infected at one-year serological follow-up. Chi-square for linear trend of vertical transmission from the first to the third trimester was significant (P=0.009). Western blot analysis showed IgM and IgA in half of the infected infants. In 69 uninfected infants, anti-Toxoplasma IgG immunoblot analysis excluded infection within the 3 months in 18 infants (26%) and in the others within 6 months of life. The most relevant instrumental findings are described.

CONCLUSION

Western blot analysis may help to evaluate infection within the 6 months of life. The accuracy of ultrasound imaging to determine the brain damage in the fetus and newborns is doubtful, and should be combined with MR imaging. Multistep approaches can improve the timing of postnatal follow-up.

[Significance of magnetic resonance studies in prenatal diagnosis of malformations of the fetal central nervous system]

MRI investigation, as an imaging technique, has been gaining more and more importance in prenatal diagnostics. It has become essential due to its advantages in diagnosing the malformations of the central nervous system. Similarly to ultrasonography, its reliability is greatly dependent on the knowledge of the person performing the investigation. In addition to the knowledge of the exact anatomy of central nervous system, the researcher should have a multidisciplinary approach. In the case of malformations where repeated investigations are needed to provide a diagnosis in early pregnancy (e.g. neural tube defects), ultrasonography is more effective than MRI. In case of intrauterine infections and malformations of the posterior fossa, however, the two imaging techniques are excellent supplements to each other. MRI also plays an important role in making the prognosis for fetal ventriculomegaly, as well as in the short term diagnosis of ischaemias affecting the fetal nervous system. Difficulties in evaluating ultrasonographic images (owing to maternal obesity, oligohydramnion) render MRI an important technique in making the final diagnosis. Currently, the drawbacks of MRI include reduced accessibility, poor cost-effectiveness and shortage of skilled experts in this technique.

Fetal MRI of the cardiovascular system: role of steady-state free precession sequences for the evaluation of normal and pathological appearances

PURPOSE

This study aimed to evaluate the feasibility of fetal magnetic resonance imaging (MRI) with steady-state free precession (SSFP) sequences to visualise the normal and pathological appearances of the cardiovascular system.

MATERIALS AND METHODS

This is a prospective observational study of 83 pregnant women who underwent fetal cardiac MRI: 43 patients (cases) had echocardiographic suspicion of congenital heart disease; 40 patients (controls) did not. Fetal cardiac MRI consisted of a static phase with multiplanar SSFP sequences and a dynamic phase with real-time SSFP sequences. Two radiologists evaluated the diagnostic quality of the SSFP images in both the controls and cases, the MRI morphological and functional features in the controls and the MRI signs of congenital heart disease in the cases.

RESULTS

In both groups, SSFP sequences produced goodquality MR images and good visualisation of morphological features. Functional data appeared to be unavailable due to the current small temporal resolution and the technical impossibility of fetal cardiac triggering. MRI detected direct signs of congenital heart disease in 21 fetuses, indirect signs in six and both signs in 15.

CONCLUSIONS

SSFP sequences are effective in demonstrating the morphological features of the cardiovascular system, whereas dynamic SSFP cine-MRI sequences may provide adjunctive albeit suboptimal functional information.