Diffusion-weighted MR imaging and apparent diffusion coefficient of the normal fetal lung: preliminary experience.

OBJECTIVE: To assess if a correlation is present between apparent diffusion coefficient (ADC) values and normal lung maturation during gestation to define potential reference values as indicators of the lung development. METHODS: Our study included 50 pregnant women (gestational age, GA: 18-36 weeks), with normal fetal development of lungs assessed by a previous obstetric ultrasound (US), and then confirmed by our magnetic resonance (MR) examination. We used T2-weighted sequences, diffusion-weighted imaging sequences (DWI) and ADC maps for studying pulmonary tissue. In all cases the resulting ADC values were related to GA using Pearson correlation. RESULTS: ADC values ranged from 1,2 microm(2)/ms at 18 weeks' gestation to 3,9 microm(2)/ms at 36 weeks' gestation with a mean value, regardless for the gestational age, of 2, 352 +/- 0,623106 microm(2)/ms. We found a significant correlation between ADC and gestational age (Pearson correlation = 0,816). CONCLUSION: The ADC values correlate with gestational age since alveolar fluid secretion and angiogenesis increase gradually. Therefore, ADC can be considered as a new parameter for studying lung maturity.

Potential role of fetal cardiac evaluation with magnetic resonance imaging: preliminary experience.

OBJECTIVE: To report our experience with magnetic resonance imaging (MRI) in fetal heart evaluation. METHOD: Two radiologists examined 31 MRI of fetuses with no ultrasound (US) evidence of cardio-thoracic anomalies. T2-weighted half-Fourier single-shot turbo spin-echo sequences were acquired for anatomic evaluation; fast imaging with steady-state free precession (TrueFISP) and cine-MR sequences with real-time steady-state free precession oriented like standard fetal echocardiographic projections were acquired for the characterization of cardiovascular morphology and function. RESULTS: In every case, MRI assessed the viscero-atrial situs. The four-chamber view and the short-axis view of the left ventricle were obtained in all fetuses, the long-axis view of the aortic arch in 28, the long-axis view of the ductus arteriosus in 17, the five-chamber view in 12, the long-axis of the left ventricle in 9, the three-vessel view in 7, the tricuspid-aortic view in 3, and the transverse view of the aortic arch and the angulated view of the arch and the ductus arteriosus simultaneously in 2 fetuses. CONCLUSION: Our preliminary experience demonstrates the feasibility to visualize the fetal heart with routine fetal MRI protocols in particular, by means of acquisition of TrueFISP imaging (morphological study) and real-time cine-MRI (dynamic study), potentially making MRI a second-level tool to add to fetal echocardiography in the prenatal study of congenital cardiac malformations.

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

OBJECTIVE: To investigate apparent diffusion coefficient (ADC) mapping with the measurement of renal tissue ADC value of normal and pathological fetal kidneys at various gestational ages (GAs). METHODS: Fifty pregnant women underwent magnetic resonance images (MRI) after ultrasound (US) for suspected fetal genitourinary disorders (16) or for suspected disorders in other organs (34). A multiplanar study of urinary system was obtained by using conventional T2-weighted sequences and echo planar imaging (EPI); Diffusion-weighted images and ADC maps were evaluated. The renal tissue ADC value was measured for all normal and abnormal fetuses and related to GA. RESULTS: MRI confirmed urinary anomalies in 15 fetuses [2 renal developmental variants, 2 nephropathies, 4 multicystic dysplastic kidneys (MCDK), 7 renal tract dilatations] and detected normal kidneys in the remaining 35 fetuses. Normal renal parenchyma showed bright signal on diffusion-weighted images with ADC values ranging from 1,065 to 1,327 microm(2)/s with a tendency to decrease over GA. A pathological ADC was detected in cases of bilateral MCDK, huge dilatations and in cases of nephropathies. CONCLUSION: Diffusion-weighted imaging (DWI) with ADC mapping can be used in the evaluation of fetal renal parenchyma and may become a tool of assessing function of the fetal kidney by means of measurement of renal tissue ADC values.

Fatty changes as a misleading factor in the evaluation with ultrasound of superficial lymph nodes.

The object of this paper was to investigate lipoplastic lymphadenopathy in superficial locations with ultrasound. We selected 110 patients with a total number of 247 nodes with a central hyperechoic area extended for more than one third of the transverse diameter. We considered gender, age, body mass index (BMI), and associated disease such as thyroid disorders and diabetes. For each lymph node, we measured the long:short axis ratio and the parenchyma:fat (P:F) ratio. Differences between mean P:F ratio in diabetic and nondiabetic patients were significant (p=0.045). Mean P:F ratio was negatively related to BMI (r=0.62, p=0.015) and age (r=0.54, p=0.024). All of the nodes examined with a mean P:F ratio