Investigating the newborn kidney: update on imaging techniques.

Advances in imaging have resulted in higher-quality resolution. Techniques formerly considered to give pure anatomic information are now providing functional data, but the functions provided are not those typically measured in pathophysiologic terms. Instead, the data provided demand that we incorporate this new information into the understanding of the pathologic processes that confront us in clinical practice. Ultrasound provides information about kidney volume, blood flow velocity and blood flow volume. Radioisotopes can show the ability of the proximal tubules to extract the tracer from the blood as well as the ability of the kidney to clear the tracer into the bladder. Magnetic resonance imaging provides information about water content of the kidney.