Role of fetal MRI in the diagnosis of cerebral ventriculomegaly assessed by ultrasonography.

PURPOSE: To evaluate the additional diagnostic value of fetal MRI to evaluate cerebral ventriculomegaly assessed by ultrasonography (US) for the possibility to change the diagnosis, the counseling and the management of pregnancy. MATERIALS AND METHODS: From february 2006 to october 2008, we studied 55 pregnant women by fetal MRI (mean age 28 years), 4 with twin pregnancy, for a total of 59 fetuses with mean gestational age of 27 weeks. The number of fetuses affected by ventriculomegaly assessed by US was 55. All fetuses had a US diagnosis of ventriculomegaly: 29 fetuses with isolated ventriculomegaly and 26 fetuses with ventriculomegaly associated with CNS (central nervous system) abnormalities (18) and with no CNS abnormalities (8). RESULTS: The findings showed that the two techniques are substantially in agreement in defining the degree of VM, with the exception of some cases in which the disagreement could be attributed to the possible progression of the dilatation between the US and MRI examinations, which sway between two days and two weeks. We proved a low correlation between US and MRI in the evaluation of ventriculomegaly associated either with CNS or non-CNS anomalies: in fact while fetal MRI detected 26/55 (47,3%) VM associated with CNS anomalies, US demonstrated only 18/55(32,7%). Referring to VM associated with non-CNS anomalies, MRI diagnosed 10/55 cases (18,2%) compared to 8/55 fetuses (14,5%) showed by US. CONCLUSIONS: Our experience demonstrated that fetal MRI has an important role as adjunctive tool to sonography in the evaluation of cerebral ventriculomegaly for the additional informations given to parents and for the possibility to change the diagnosis, the counseling and the management of pregnancy.

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.

Fetal MRI with diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) assessment in the evaluation of renal development: preliminary experience in normal kidneys.

PURPOSE: The study aimed to investigate the correlation between apparent diffusion coefficient (ADC) and gestational age by applying diffusion-weighted imaging (DWI) in the study of normal fetal kidneys. MATERIALS AND METHODS: We performed magnetic resonance (MR) imaging on 88 fetuses (gestational age range 17-40 weeks) after ultrasound had ruled out urinary system malformations. A multiplanar study of the urinary system was obtained by using conventional T2-weighted sequences and echoplanar imaging (EPI). DW sequences with ADC maps were subsequently acquired, and kidney ADC values were correlated with gestational age by diving the fetuses into six groups according to age. RESULTS: We found a correlation between ADC values and gestational age. The ADC values, ranging from 0.99 to 1.62x10(-3) mm(2)/s [mean 1.22; 95% confidence interval (CI) 1.19-1.25, standard deviation (SD) 0.147], showed a tendency to decrease with increasing gestational age. The relationship between ADC values and gestational age was expressed by a linear regression equation: ADC (mm(2)/s)=1.69-0.0169 (GA) (R(2)=37.7%, R(2) ADJ=37.0%, p<0.005, Pearson correlation=-0.614). CONCLUSIONS: DWI with ADC mapping provides functional information on fetal renal parenchyma development and may thus become a useful tool in the management of pregnancy and treatment of the newborn child.

Assessment of congenital heart disease (CHD): is there a role for fetal magnetic resonance imaging (MRI)?

PURPOSE: To review our experience with fetal magnetic resonance imaging (MRI) to evaluate congenital heart disease (CHD). METHODS: We performed fetal MRI in 32 fetuses with an echocardiographically assessed CHD. Both direct and indirect signs of CHD were investigated. Direct signs considered were: morpho-volumetric abnormalities of the heart; malrotations; ventricular and atrial septal defects; anomalies of the origin, size and course of the great arteries. Indirect signs considered were: difficulty to recognize a "normal" anatomical structures in the reference projections; increase of the vascular size before a stenosis; hypertrophy of the papillary muscles; cardiomegaly and pericardial effusion. All MRI findings were compared with postnatal or autoptic findings. RESULTS: MRI allowed the CHD to be visualised by direct signs in 17 fetuses, indirect signs in 5 and both direct and indirect signs in 9 fetuses, excluding the prenatal echocardiographic suspect of hypoplastic left heart syndrome in 1 fetus. Postnatal echocardiograms or autoptic findings confirmed a normal heart in 1 fetus and CHD in 31 fetuses including a single cardiac anomaly or syndrome in 19 fetuses, 2 associated cardiac abnormalities in 11 and 3 cardiac anomalies in 1 fetus. However, in 2 fetuses MRI detected a ventricular septal defect successively disclosed by gold standard. CONCLUSIONS: MRI is a promising method for further assessment of the cardiovascular pathologies diagnosed by echocardiography, and may be a valuable tool in assessing associated extracardiac anomalies.