Using a split bolus (cross-sectional imaging) technique for urography, researchers have shown that they can reduce the levels of radiation that patients usually experience with diagnosis of urinary tract abnormalities.
The typical method involves “scanning patients before contrast and at multiple phases after the administration of IV contrast,” says Lawrence Chow, MD, lead author of the study. Chow is a radiologist at Stanford University's School of Medicine in California. He says this typical method increases radiation exposure. “We wanted to show that a similar examination could be achieved with fewer scan acquisitions [meaning potentially less radiation and fewer images] by administering a split-bolus of IV contrast, without sacrificing sensitivity,” he says.
The study included 500 patients with possible urinary tract abnormalities. The imaging method devised by Chow and his team, which included radiologists from both Stanford University and the VA Palo Alto Health Care System, identifies all pathologies present in the patients.
“We were impressed with the wide spectrum of abnormalities that we were able to see with CT urography and with the ability of CT urography to detect even very small abnormalities such as papillary necrosis, renal tubular ectasia, and very small urothelial tumors,” Chow says.
Chow believes that his CT urography provides a simplified diagnostic evaluation for patients with painless hematuria (presence of blood in the urine). He says it has the potential to replace what previously required two studies: traditional excretory urography plus CT, MR, or sonography.
The results of this study appear in the August issue of the American Journal of Roentgenology.