Kidney cysts. Coloured coronal (frontal) abdominal magnetic resonance imaging (MRI) scan, showing a patient's polycystic left kidney (red/black, upper right). The kidney is enlarged by the presence of many cysts (black). Polycystic kidney disease is a common cause of kidney failure. It is an inherited condition, treated by dialysis and transplantation of the kidney. The normal kidney shape is shown by the right kidney (orange, upper left), which sits below the liver (green). The backbone, consisting of alternating vertebrae (blocks, brown) and inter-vertebral discs (dark blue), runs down the centre of this image. The patient's arms are also seen, either side of the body.