Researchers from Canada have discovered that MRI measurements of stiffness in patients who received kidney transplants can gauge damage to the organ and predict future kidney function within one year, according to a study published online August 30 in the Clinical Journal of the American Society of Nephrology.
The group from St. Michael's Hospital in Toronto used MRI elastograms to measure kidney scarring in 17 people who had kidney transplants. Healthy kidney tissue is soft, while scar tissue is stiff, and scarring is a major cause of kidney transplant failure.
By analyzing MRI elastograms, clinicians could assess the stiffness of tissue and thus determine the presence and degree of scarring. The findings could help patients avoid an invasive needle biopsy (Clin J Am Soc Nephrol, August 30, 2017).
"We needed a way to measure how soft or stiff [a] kidney is without actually going inside the body," said lead author Dr. Anish Kirpalani, a radiologist in St. Michael's Li Ka Shing Knowledge Institute, in a statement from the hospital. "Using the MRI elastogram, we were able to measure kidney stiffness, which gave us an indication of how much scarring there was."
The MRI results were comparable to the results of a kidney biopsy and also were able to detect high variability in the amount and location of scarring throughout the organ. In addition, the degree of kidney stiffness predicted how well the organ would function one year after the MRI scan. Patients with greater levels of stiffness in their kidneys lost more function than those with softer kidney tissue.
The authors cautioned that MRI should not replace biopsies, but rather serve as an additional test to provide a more comprehensive assessment of kidney health.
The MRI elastogram also could be a valuable tool to determine the efficacy of antiscarring treatments, since there currently are no drugs to prevent or treat scarring.
The void is due in part to the challenge in justifying multiple kidney biopsies on patients as part of a pharmaceutical trial, commented senior author Dr. Darren Yuen, a transplant nephrologist in St. Michael's Keenan Research Centre for Biomedical Science.
