Normal renal development investigated with fetal MRI

Abstract Objective To evaluate age-dependent changes in fetal kidney measurements with MRI. Patients and methods Fetal MRI examinations were used to study the kidney length (218 fetuses), signal intensities of renal tissue, renal pelvis, and liver tissue on T2-weighted images (223 fetuses), and the whole-kidney apparent diffusion coefficient (107 fetuses). A 1.5 T superconducting unit with a phased array coil was used in patients from 16 to 39 weeks’ gestation. The imaging protocol included T2-weighted single-shot fast spin-echo, T2-weighted balanced angiography and diffusion-weighted sequences. Slice thickness ranged from 3 to 5 mm. Results Fetal kidney length as a function of gestational age was expressed by the linear regression: kidney length (mm) = 0.190 × gestational age (d) − 8.034 ( R 2  = 0.883, p t -test analysis showed a highly statistically significant difference between the ratio of renal tissue signal intensity to renal pelvis signal intensity and the ratio of liver signal intensity to renal pelvis signal intensity on T2-weighted images ( t  = −50.963, d.f. = 162, p 2 /s) = 0.0302 × square (gestational age (d)) − 14.202 × gestational age (d) + 2728.6 ( R 2  = 0.225, p Conclusion The length, signal intensity on T2-weighted images, and apparent diffusion coefficient of the fetal kidney change significantly with gestational age. The presented data may help in the prenatal diagnosis of renal anomalies.