Delayed scanning with DMSA: a simple index of relative renal plasma flow.

Relative renal uptake of 99mTc-dimercaptosuccinic acid (DMSA) was compared with the relative effective renal plasma flow (ERPF) to each kidney. In 25 patients with serum creatinine less than or equal to 2.0 mg/dl, there was excellent agreement when the regions of interest were assigned by a computer. In 10 patients with serum creatinine greater than 2.0 mg/dl, agreement was poor. A 24-hour image is sufficient to obtain such data. In patients with renal failure, this technique may give inaccurate results due to high tissue background activity; moreover, since it reflects the current functioning status of the kidney, it should not be used to predict recoverable function in patients with acute or unstable renal disease.