normal images

Last reviewed 01/2018

Sequential images are obtained at 5-20 second intervals over a period of 20-30 minutes. A renogram is constructed by plotting activity of the isotope against time in selected regions. Three phases are recognised:

• vascular phase - a rapidly rising curve of activity due to arrival of isotope in the kidney from the bloodstream. It is usually of about 30 seconds duration.
• filtration phase - a more slowly rising curve denoting concentration of isotope as it passes into the collecting system
• excretory phase - a declining curve denoting that isotope is no longer being delivered to the kidney but continues to pass down the ureter