Antenatal US diagnosis of Horseshoe kidney

Prenatal diagnosis of horseshoe kidney by measurement of the renal pelvic angle.

Cho JY, Lee Y, Toi A, Macdonald B.

Department of Radiology, Samsung Cheil Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea. radjycho@skku.edu

METHODS: We retrospectively measured the renal pelvic angle in 19 fetuses with horseshoe and 20 fetuses with normal kidneys in the second and third trimesters. Renal pelvic angle was defined as the angle between the long axis of the renal pelves on the axial view of the abdomen. We compared the renal pelvic angles of horseshoe and normal kidneys with unpaired t-test. Taking 140 degrees as a cut-off value, we calculated the sensitivity, specificity and accuracy of pelvic angle measurement for the prenatal diagnosis of horseshoe kidney.

RESULTS: The mean pelvic angles in the fetuses with horseshoe kidney were 116 degrees and 110 degrees in the second and third trimester, respectively. In the normal fetuses, the equivalent angles were 172 degrees and 161 degrees. The difference between the two groups was statistically significant.

CONCLUSION: Observation and measurement of the renal pelvic angle is a simple and useful method in the prenatal diagnosis of the horseshoe kidney.

Ultrasound Obstet Gynecol. 2005 Jun;25(6):554-8