A renal scan is a simple way to evaluate the split renal function. Split renal function is the relative function of each of the kidneys. This scan can show that one of the kidney is contributing 60% and the other is contributing 40% to the overall renal function.

For a normal renal scan, the patient should be well hydrated (at least 2 glasses of water one hour prior to the exam). The patient should not have a solid meal for at least 4 hours prior to the exam.

For the scan the patient will be on a table with the camera under their back. The patient is injected with a radiopharmaceutical in a vein in the arm. The radiopharmaceutical will not change the way the patient feels or make the patient sick. The camera takes a series of pictures over a thirty minute period. During that time, the patient needs only to remain still.

Once the scan is over, it will take time for the technologist to process the scan information. The scan will be read by a radiologist, and the patient's doctor should have the results by the following day.

Hypertensive Renal Scan

A hypertensive renal scan is the same as the regular renal scan with the exception that, for a hypertensive renal scan, the patient is asked to come back later in the day. Later in the day the patient is given a medication called captopril. Captopril is a type of blood pressure medication called an ACE inhibitor. The patient's blood pressure is monitored for one hour and then a second renal scan is performed, identical to the first scan. When the radiologist reads the hypertensive renal scan, they want to see if there are any differences between the first scan and the second scan after the captopril.