Intrarenal reflux: anatomical, dynamic and radiological studies-part I.

The radiographic appearances and dynamics of intrarenal reflux have been defined in an experimental study of the pig's kidney. Intrarenal reflux occurs only with "refluxing" papillae and is an "all-or-none" phenomenon when the threshold figure of 10-15 mm Hg is exceeded. Increasing intrapelvic pressure leads to increasing density of the radiographic shadow but new areas of intrarenal reflux are not produced.