Sonography of the simple and complicated ipsilateral fused kidney

Anomalies of renal fusion and their sonographic findings can be straightforward or quite complex. Sonograms of eight cases of simple and complicated anomalies of renal fusion in pediatric patients are reviewed to determine characteristic sonographic findings in such cases. The correct diagnosis can be suspected by evaluation of the following parameters: (1) the echoic texture of the renal "mass"; (2) the differential orientation of the renal pelves; (3) the content of the contralateral renal fossa; (4) the size of the ipsilateral kidney; (5) extension of the isthmus medially anterior to the spine; and (6) presence of a deep anteroposterior notch. Utilizing these parameters, a rationale for diagnosis and for selecting the appropriate sequence of further studies is suggested.