DMSA Case 2 Answers

1) Which is the pelvic kidney?

The right kidney is situated in the pelvis.

2) Can you comment on the split function?
3) Why?

There is functioning renal tissue in the right pelvic kidney. However, precise split function in ectopic kidneys is difficult. The split function in normally sited kidneys assumes the same amount of overlying soft tissue. This is important as for 99mTc, 4.6cm of additional tissue would decrease the total counts by 50%. Pelvic kidneys have additional but unknown amounts of overlying soft tissue in relation to the normally sited kidney. This renders accurate estimation of split function impossible!

4) What processing technique not demonstrated here can help with malpositioned or fused kidneys?

Working out the geometric mean from regions of interest on anterior and posterior images can help. This is mainly of use with fusional abnormalities such as horseshoe or crossed fused ectopia due to the above reasons.

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The text is entirely the opinion of the author and does not necessarily reflect that of RUH NHS Trust or the Bristol Radiology Training Scheme. Website content devised by Paul McCoubrie.