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 1065 to 1327 mu m(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. Copyright (C) 2007 John Wiley & Sons, Ltd.