Caliceal fistula in kidney transplantation. The role of magnetic resonance imaging.

Caliceal fistula is a rare complication of renal transplantation, which often raises some diagnostic problems. We report the case of a patient in which this complication occurred and in whom the diagnosis could be clearly demonstrated by using magnetic resonance imaging (MRI). On the T1-weighted images, a perirenal collection was depicted by a low signal intensity. On T2-weighted images, the collection appeared with a high signal intensity, and a linear hyperintensity was observed on the internal graft's labium at the level of the inferior pole corresponding to a caliceal fistula arising from the lower pole of the graft. In this setting, the use of MRI is compared with the other diagnostic techniques (sonography, CT scan, nephrogram, scintigraphy). MRI constitutes a progress in imaging of the renal graft by its high definition and the lack of nephrotoxicity. Its place remains, however, to be more precisely defined in the evaluation of a renal graft's complications.