TOPLINE:

Super-resolution ultrasound microvascular imaging, known as ultrasound localization microscopy, was a safe, reliable, and reproducible noninvasive imaging method that quantified intrarenal microvascular remodeling and identified abnormalities at an early stage in young individuals with autosomal dominant polycystic kidney disease (ADPKD), even when global kidney function was preserved.

METHODOLOGY:

• Histologic analyses of kidneys from individuals with ADPKD have demonstrated extensive intrarenal microvascular remodeling, but these observations have been limited to end-stage disease because current methods for assessing the intrarenal microvasculature are invasive.
• Researchers applied ultrasound localization microscopy to a prospective cohort of 17 young individuals (median age, 30 years; 76.5% women) with early-stage ADPKD (estimated glomerular filtration rate [GFR] > 90 mL/min/1.73 m²) and 17 sex- and age-matched control individuals.
• The analysis included an assessment of the intrarenal microvasculature using ultrasound localization microscopy, with the determination of inter-sonographer reliability, intra-observer repeatability, and inter-observer reproducibility.
• Day-to-day variability was assessed in the control group, and microvascular parameters were correlated with structural (total kidney volume) and functional (estimated GFR) markers in patients with ADPKD.

TAKEAWAY:

• All participants completed two short ultrasound scans without complications, and super-resolution ultrasound localization microscopy reconstructed detailed images of the intrarenal microvasculature in under 10 seconds.
• Ultrasound localization microscopy demonstrated excellent reliability (intraclass correlation coefficient [ICC], 0.96; 95% CI, 0.91-0.98), reproducibility (ICC, 0.96; 95% CI, 0.93-0.98), and repeatability (coefficient of variation, 3.6%) in quantifying intrarenal microvascular parameters; day-to-day variability in control individuals remained low for most parameters.
• Microvascular parameters differed between patients with ADPKD and control individuals despite preserved estimated GFR.
• Lastly, in patients with APKD, estimated GFR correlated positively with vessel density and perfusion and inversely with tortuosity, whereas vessel tortuosity correlated directly with height-adjusted total kidney volume.

IN PRACTICE:

“Our findings suggest that intrarenal microvascular parameters may constitute promising functional biomarkers to evaluate noncystic parenchyma,” the authors wrote.

SOURCE:

This study was led by Chengwu Huang, PhD, Department of Radiology, Mayo Clinic in Rochester. It was published online on in the Journal of the American Society of Nephrology.

LIMITATIONS:

This study was limited by its small number of patients and the lack of follow-up to assess the time course of observed microvascular alterations. Day-to-day variability was not determined in patients with ADPKD. Additionally, imaging was restricted to the left kidney, with quantifications limited to a region of the cortex, potentially not capturing the full extent of intrarenal microvasculature.

DISCLOSURES:

This study was supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases. Some authors reported being employees; receiving research funding, consultancy fees, or honoraria; participating in advisory toles; holding patents; and having other ties with various pharmaceutical companies and institutions.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.