Govind Babusing Chavhan MD, Presenter: Nothing to Disclose

Alan Daneman MD, Abstract Co-Author: Nothing to Disclose

Rahim Moineddin, Abstract Co-Author: Nothing to Disclose

Ruth Lim MD, Abstract Co-Author: Nothing to Disclose

Valerie Langlouis MD, Abstract Co-Author: Nothing to Disclose

Jeffrey Traubici MD, Abstract Co-Author: Nothing to Disclose

To determine whether increased echogenicity of the medullary pyramids in ureteropelvic junction obstruction correlates with differential renal function (DRF) of the kidney as determined by MAG3 scan.

Renal sonograms in 60 children with ureteropelvic junction obstruction were retrospectively reviewed. Children were divided into three groups- 1. Normal pyramids, 2. Echogenic pyramids with maintained corticomedullary differentiation (CMD), and 3. Lost CMD. Differential function of the obstructed kidney 45% and above was considered as normal and 44% and below was considered abnormal based on a published study of correlating histological changes with DRF. Fisher Exact test was performed for assessing association between DRF and normal/abnormal pyramids.

Of 13 children in group 1, 11 had normal DRF and 2 had abnormal DRF. Of 33 in group 2, 15 had normal DRF and 18 had abnormal DRF. Of 14 children in group 3, two had normal DRF and 12 had abnormal DRF. Statistical analysis showed a strong association between abnormal pyramids and differential function (p=0.0009). The risk ratio of DRF becoming abnormal for echogenic pyramids compared to normal pyramids was RR=1.56 with 95% confidence interval (1.088-2.236). The risk ratio DRF becoming abnormal for lost CMD compared to normal pyramid was 5.571 with 95% confidence interval (1.530-20.294).

We observed that in obstructed kidneys the echogenicity of medullary pyramids (EPM) increases. The increased echogenicity of pyramids correlated weakly with abnormal DRF and does not necessarily indicate poor renal function. However, lost CMD is strongly correlated with poor renal function. It is not clear whether increased EPM indicates substantial damage to renal parenchyma & whether it can be used to predict poor function.

The clinical relevance of increased EPM in obstructed kidneys is not clear from our study, except in cases when CMD is lost. More studies are needed.

Chavhan, G, Daneman, A, Moineddin, R, Lim, R, Langlouis, V, Traubici, J, Renal Pyramid Echogenicity in Ureteropelvic Junction Obstruction: Correlation of Altered Echogenicity and Renal Function.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5009885.html