Prenatal Diagnosis Of Urinary Anomaly By Magnetic Resonance Imaging

ObjectiveTo explore the value of MRI in the diagnosis of fetal urinary abnormalities.Materials and MethodsMR scanning was performed in alive fetus which were diagnosed by US with the gestational age ranged from27～38w. Single shot (SSh) FSE T2WI and fast field echo (FFE) T1WI sequences with Philips Achieva1.5T MR scanner were used to obtain abdominal images on coronal and axial planes. Conventional ultrasonography and color Doppler flow imaging were obtained using GE730or PHILIPS IU22color Doppler flow imaging scanner with probe frequency ranging from3.5to5.0MHz. The results of prenatal MRI and US on33cases were compared with postnatal US or autopsy after abortion and the accuracy of MRI and US was acquired. Statistical analysis was performed with Chi Square Test. P<0.05was considered significant.ResultsMRI can show clearly the kidney, dilatant renal pelvis and ureter, urinary bladder in fetus. Of the33cases with urinary abnormalities diagnosed by MRI, there were4cases of multicystic renal dysplasia,5cases of polycystic kidney disease,3cases of renal dysplasia,4cases of ectopic kidney and agenesis of kidney respective,2cases of horseshoe kidney and double kidney,4cases of ureteropelvic junction anomaly,5cases of ureterovesical junction anomaly. Compared with the results of postnatal US and autopsy, the accuracy of MRI was90.9%(30/33),while the accuracy of conventional ultrasound combined with color Doppler ultrasound was87.9%(29/33).There was not statistically significant within the two imaging methods via Chi Square Test (X2=0.064, P>0.05) ConclusionMR imaging has many advantages such as safety, noninvasive, multi-direction and multiparameter. MRI could diagnose a wide variety of fetal urinary abnormalities accurately, shows higher value in the diagnosis of fetal urinary abnormalities. MRI could be used as an important complementary modality to prenatal ultrasonography.