Nephrology
COHORT
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Can an ultrasound scan spot hidden damage in a transplanted kidney?
Frontiers in Medicine
Published April 1, 2026
For someone with a transplanted kidney, signs of trouble are deeply worrying. Figuring out what's wrong usually means a biopsy—a procedure to take a tiny piece of tissue for analysis. It's essential, but it's also invasive. Doctors are always looking for less invasive ways to get information.
Researchers looked back at 350 kidney transplant biopsies to see if certain ultrasound measurements taken just before the biopsy could hint at the damage found inside. They found that two measurements—how much of the kidney tissue showed blood flow (called POV) and how far small blood vessels were from the kidney's edge (called PVD)—were linked to signs of chronic scarring and damage seen under the microscope. A third common measurement, the resistive index (RI), didn't show any such link.
This is a single-center, retrospective look at past data, which means it's an early observation, not proof. The study wasn't designed to test if ultrasound can diagnose problems on its own. The authors are clear: while these ultrasound signs might one day support monitoring, a biopsy remains the essential, definitive tool for diagnosing what's harming the transplant.
View Original Abstract ↓
Sonography is a key method in examining kidney transplants. Recent reports on the limited diagnostic value of an elevated resistive index (RI) in detecting rejection have cast doubt on the overall utility of color-coded duplex sonography (CCDS). This study evaluated additional CCDS parameters – percentage of vascularization (POV) and periphery vessel distance (PVD) – and investigated their association with histopathologic findings in allograft dysfunction. In a retrospective single-center study, 350 kidney transplant biopsies performed between 2013 and 2022 were analyzed. Standardized sonographic evaluation, including POV, PVD, and RI, was conducted at biopsy request. Histopathologic lesions were scored according to Banff criteria. Multivariable logistic regression identified independent predictors of abnormal CCDS parameters. Recipient age, severe tubular atrophy (ct), and arterial intimal fibrosis (cv) were independent negative predictors of POV > 50%. PVD ≥ 0.25 cm was associated with recipient age and moderate tubular atrophy (ct). RI showed no association with histopathologic lesions. These findings identify POV and PVD as non-invasive markers of chronic injury in kidney allografts, highlighting their potential adjunctive role in detecting parenchymal damage. As such, CCDS may support – but not replace – biopsy, which remains essential for establishing a definitive diagnosis in graft dysfunction.
