Study: Abnormalities revealed by CT may not exclude kidney donors

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Routine CT scanning of the renal arteries and kidneys of middle-aged individuals can commonly present radiographic abnormalities, but the majority of the imaging findings are not perceived to be harmful enough to prevent kidney donation, according to a January study published online in Clinical Journal of the American Society of Nephrology.

Elizabeth Lorenz, MD, of the Mayo Clinic in Rochester, Minn., and colleagues conducted their study by analyzing the imaging results of potential kidney donors undergoing protocol evaluations between 2000 and 2008.

The participants included 1957 potential kidney donors from the Mayo Clinic, between the ages of 31 and 55 years, with women accounting for 58 percent of the observed cohort. All patients involved had undergone both CT angiography and urography as part of a routine kidney donor evaluation. The researchers reviewed each radiographic report in order to note the prevalence of radiographic abnormalities of the renal arteries and kidneys within the patient population.

The researchers noted that the occurrences of radiographic abnormalities were stratified by gender and age, and the study sought to determine the effect to which the imaging results had on approval for kidney donation.

The study found that 25 percent of all potential donors presented with at least one abnormality. The most commonly noted abnormalities were kidney stones, accounting for 11 percent of the patient population, focal scarring at 3.6 percent, fibromuscular dysplasia, 2.8 percent and other renal artery narrowing or atherosclerosis, with a rate of 5.3 percent, collectively.

According to Lorenz and colleagues, abnormalities such as renal artery narrowing, focal scarring and indeterminate masses increased with age. In addition, fibromuscular dysplasia, focal scarring, parenchymal atrophy and upper tract dilation were determined to be more common in women.

Despite the rate of incidental radiographic abnormalities, only 6.7 percent of the patient population were excluded from donation based on the results of their imaging evaluations, said the authors.

"These findings highlight an interesting challenge implicit with improvements in imaging technology: Physicians are now finding more subtle abnormalities in the kidneys and renal arteries, but lack clear evidence as to whether these findings are benign or harmful to the long-term health of patients," said Lorenz.

While the authors concluded that the majority of imaging findings were not necessarily perceived to be harmful enough to prevent kidney donation, the investigation highlighted the need for future studies to determine their clinical relevance.