Abnormal renal morphology Decreased renal parenchymal thickness 2017-02-11T10:48:34Z The thickness of the renal parenchyma decreases with age. The thickness of the renal parenchyma is correlated with renal function. Reduced dimension of the solid part of the kidney (parenchyma, the renal cortex and medulla) as measured from the collecting system (renal calyces and pelvis) to the border of the kidney. This measurement can be performed by measuring the thickness of the parenchyma in computed tomography scans.