P. Sonigo

MR imaging of fetal cerebral anomalies

Background. Prenatal diagnosis of fetal brain anomalies relies mainly upon ultrasonography. However, even in the most experienced hands, the technique has limitations for some difficult diagnoses. MRI is an excellent imaging modality for the paediatric and adult brain. Objective. To assess the value of prenatal MRI when a cerebral anomaly was detected by US and where the prognosis depended on the identification of other anomalies undetectable by US, or where fetuses were at risk for a CNS lesion even when the US was normal. Materials and methods. Four hundred prenatal MRI examinations were performed since 1988, and confirmed by postnatal follow-up or pathological examination. Two-thirds of the examinations were performed after 25 weeks of gestation, one-third between 21 and 26 weeks. Fetal immobilisation was obtained by maternal premedication with flunitrazepam, administered orally 1 h before the examination. The examinations were performed on 1.5 T scanners using one or two surface coils. Results. Prenatal MRI allowed the diagnosis of serious unsuspected lesions such as neuronal migration disorders, ischaemic and haemorrhagic lesions and the abnormalities observed in tuberous sclerosis. It helped to characterise ventricular dilatation and anomalies of the corpus callosum and of the posterior fossa. Conclusions. MRI is a valuable complementary tool when prenatal US is incomplete, doubtful or limited. Prenatal MRI is particularly useful for the detection of ischaemic and haemorrhagic lesions, neuronal migration disorders and tuberous sclerosis lesions. Detection of these associated anomalies worsens the fetal prognosis, has medico-legal implications and modifies obstetric management. Normal prenatal MRI does not exclude an anomaly.

Prenatal prognosis of congenital diaphragmatic hernia using magnetic resonance imaging measurement of fetal lung volume

To investigate the correlation between fetal lung volume (FLV), measured with magnetic resonance imaging (MRI), and postnatal mortality in newborns with prenatally diagnosed isolated congenital diaphragmatic hernia (CDH).

A primal sketch of the cortex mean curvature: a morphogenesis based approach to study the variability of the folding patterns

In this paper, we propose a new representation of the cortical surface that may be used to study the cortex folding process and to recover some putative stable anatomical landmarks called sulcal roots usually buried in the depth of adult brains. This representation is a primal sketch derived from a scale space computed for the mean curvature of the cortical surface. This scale-space stems from a diffusion equation geodesic to the cortical surface. The primal sketch is made up of objects defined from mean curvature minima and saddle points. The resulting sketch aims first at highlighting significant elementary cortical folds, second at representing the fold merging process during brain growth. The relevance of the framework is illustrated by the study of central sulcus sulcal roots from antenatal to adult age. Some results are proposed for ten different brains. Some preliminary results are also provided for superior temporal sulcus.

Comparison between ultrasound and magnetic resonance imaging in assessment of fetal cytomegalovirus infection

To evaluate whether fetal brain magnetic resonance imaging (MRI) adds useful information to the one obtained by ultrasound in fetuses with cytomegalovirus (CMV) infection.

Fetal Lung Volume Estimated by 3-Dimensional Ultrasonography and Magnetic Resonance Imaging in Cases With Isolated Congenital Diaphragmatic Hernia

Objective. To assess the agreement of 3‐dimensional ultrasonography and magnetic resonance imaging in estimating fetal lung volume in cases with isolated congenital diaphragmatic hernia. Methods. Fetal lung volume was measured in 11 cases of congenital diaphragmatic hernia (10 left and 1 right) by 3‐dimensional ultrasonography and magnetic resonance imaging. These examinations were performed during the same week. The operators were blinded to each others results. Intraclass correlation was used to evaluate the agreement between 3‐dimensional ultrasonography and magnetic resonance imaging estimations of the ipsilateral, contralateral, and total fetal lung volume. A Bland‐Altman graph was plotted to detect possible discordant observations. Results. The global intraclass correlation coefficient between magnetic resonance imaging and 3‐dimensional ultrasonographic measurement of fetal lung volume was 0.94 (95% confidence interval, 0.78–0.98) with no outliers observed on the Bland‐Altman plot. Conclusions. There is a good agreement between 3‐dimensional ultrasonography and magnetic resonance imaging for fetal lung volume estimation in cases with congenital diaphragmatic hernia.

Prenatal MRI diagnosis of fetal cerebral tuberous sclerosis

Tuberous sclerosis (TS) is an autosomal dominant phakomatosis. A high percentage of spontaneous mutations leads to the diagnosis of new cases in normal families. This diagnosis is suspected at antenatal ultrasound on the discovery of multiple cardiac tumors. Antenatal cerebral ultrasound shows a normal appearance in affected fetuses. Eight fetuses with multiple cardiac tumors were studied with antenatal MRI with, in five cases, an abnormal appearance showing hyperintense subependymal and cortical nodules on TI-weighted images. Among the three remaining patients MRI was non-contributive in one due to movement artefact, one had abnormal postnatal MRI consistent with TS and one had a normal postnatal and clinical examination. We conclude that MRI is a valuable tool in making the diagnosis of TS in fetuses with multiple cardiac tumors.

Prenatal prognosis in isolated congenital diaphragmatic hernia

OBJECTIVE A monocentric retrospective study of 79 neonates with isolated diaphragmatic hernia antenatally diagnosed was performed to identify prenatal parameters that may characterize the severity of the disease. STUDY DESIGN Postnatal treatment protocol included early high frequency ventilation, inhaled nitric oxide, and delayed surgery. Postnatal survival rate was 63.3%. RESULTS Age at diagnosis, polyhydramnios, and left ventricle/right ventricle index were not related with survival. None of the 9 left diaphragmatic hernias with intraabdominal stomach died. Neonatal mortality was significantly related with the side of the defect, intrathoracic position of the liver, the ratio of fetal lung area to head circumference value, and fetal lung volume ratio measured by resonance magnetic imaging. CONCLUSION No prenatal factor alone firmly predicts neonatal outcome. Clinicians should help stratify the severity of the disease and compare accurately different postnatal therapeutic strategies.

The contribution of prenatal diagnosis to the understanding of malformative intracranial cysts: state of the art.

Abstract This review evaluates the contribution of prenatal diagnosis to the understanding of intracranial cysts. We describe the outcome of 54 fetuses in which prenatal investigations indicated the presence of such lesions. The cysts were diagnosed between 20 and 30 weeks of gestation. Most (63%) were supratentorial and interhemispheric. There was only a single sylvian cyst. In the infratentorial compartment, median retrocerebellar cysts were predominant. Incisural cysts accounted for 14.8% of the series. Nine pregnancies were interrupted because of the presence of associated brain disorders. Forty-five children are alive. Thirty-four had neuropsychological tests. Cysts rarely progressed, most frequently stabilized and often regressed postnatally. Hydrocephalus was rare. In two cases delivery was precipitated at 36 weeks to allow urgent treatment of rapidly evolving cysts. Thirteen children (28.2%) were treated postnatally, in general for developing cysts. The median follow-up for the whole series exceeds 4 years. Behavior, neurological development, and intelligence are normal in 88% of the cases, and 91% have a normal neurological status. Prognosis at the time of the prenatal consultation was correct in 89% of the cases. We emphasize the value of prenatal magnetic resonance imaging and karyotype studies to limit risks of incorrect prognosis.

MRI and ultrasound fusion imaging for prenatal diagnosis.

OBJECTIVE A combination of magnetic resonance imaging (MRI) images with real time high-resolution ultrasound known as fusion imaging may improve prenatal examination. This study was undertaken to evaluate the feasibility of using fusion of MRI and ultrasound (US) in prenatal imaging. STUDY DESIGN This study was conducted in a tertiary referral center. All patients referred for prenatal MRI were offered to undergo fusion of MRI and US examination. All cases underwent 1.5 Tesla MRI protocol including at least 3 T2-weighted planes. The Digital Imaging and Communications in Medicine volume dataset was then loaded into the US system for manual registration of the live US image and fusion imaging examination. RESULTS Over the study period, 24 patients underwent fusion imaging at a median gestational age of 31 (range, 24-35) weeks. Data registration, matching and then volume navigation was feasible in all cases. Fusion imaging allowed superimposing MRI and US images therefore providing with real time imaging capabilities and high tissue contrast. It also allowed adding a real time Doppler signal on MRI images. Significant fetal movement required repeat-registration in 15 (60%) cases. The average duration of the overall additional scan with fusion imaging was 10 ± 5 minutes. CONCLUSION The combination of fetal real time MRI and US image fusion and navigation is feasible. Multimodality fusion imaging may enable easier and more extensive prenatal diagnosis.

Fetal magnetic resonance imaging in the antenatal diagnosis and management of hydrocolpos

Hydrocolpos should be considered systematically when an abdominopelvic cystic mass is diagnosed in a female fetus. Because the prognosis and neonatal management of isolated hydrocolpos with spontaneous resolution differs greatly from that of hydrocolpos associated with a cloacal malformation, it is important to ascertain prenatally whether there are associated anomalies. We report the prenatal characteristics of three fetuses with hydrocolpos; in two cases there was spontaneous resolution and one infant was born with digestive tract atresia. The principal ultrasound findings were an oblong anechoic pelvic mass with or without a sagittal septum, located behind a normal bladder. On magnetic resonance imaging (MRI), the cervical imprint on the vagina confirmed the diagnosis of hydrocolpos and helped to diagnose cloacal malformation by demonstrating the absence of meconium beside the bladder on T1 sequences. Our cases show that MRI is useful for differentiating isolated hydrocolpos from hydrocolpos associated with cloacal malformation. Copyright