Parenchymal architecture and morphology of the pelvis

Radiological anatomy of the kidney revisited

In recent years some structures or features such as the "inter-renuncular septum", the "echogenic triangle" and the "echogenic line" have been described to support the concept of a kidney resulting from the fusion of two masses or renunculi. To clarify this concept and to understand the meaning of the above echographic features better, the authors have examined prospectively by sonography the kidneys of 50 children, 200 adults with a single collecting system, 25 adults with a duplicated collecting system and 32 cadavers. Furthermore, to help explain the sonographic features, we have examined 32 cadaver kidneys with sonography and 10 cadaver kidneys with magnetic resonance imaging (MRI). The sonographic, MRI and anatomical correlations have shown that the "echogenic triangle" and the "echogenic line" are not renuncular residuals, but simply an extension of the hilar fat visible when the renal sinus is rather deep. The intermediate cortical mass is not a septum dividing the kidney into an upper and lower renunculus, but a column of parenchymal tissue crossing the renal sinus, which, from an anatomical point of view, is an accessory renal lobe. The presence of two renunculi, suggested in a previous study with cortical nephrotomography, has not been confirmed.

The renal parenchymal junctional line in children: ultrasonic frequency and appearances

The kidneys of 72 children were examined ultrasonically to determine the frequency of visualisation of the parenchymal junctional line (PJL), its variation with age and its ultrasonic appearances. The PJL was seen in 47 cases, usually on the right side. No statistical variation in the frequency of visualisation with age has been established. The usual appearance is of a thin, echogenic, linear structure running from the renal sinus to the cortex in an antero-superior direction. It is believed to originate from a layer of connective tissue which is trapped when a proportion of kidneys form from the fusion of two metanephric elements. The PJL is a common ultrasonic finding in a normal child's kidney and should never be confused with a pyelonephritic scar.