Kidney Week

Abstract: TH-PO886

Automated 3D Cortical Thickness Measurements from CT Images: A Novel Predictor of Low Kidney Function in Living Kidney Donors

Session Information

• Transplantation: Donation and Access
  November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2102 Transplantation: Clinical

Authors

• Kline, Timothy L., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Timothy L. Kline,

• Gregory, Adriana, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Adriana Gregory,

• Korfiatis, Panagiotis, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Panagiotis Korfiatis,

• Rule, Andrew D., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Andrew D. Rule,

• Denic, Aleksandar, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Aleksandar Denic,

Background

The kidney cortex volume can be quantified on contrast-enhanced CT and is prognostic for chronic kidney disease (CKD) outcomes. Reduced cortical thickness is routinely reported from kidney ultrasound, however, cortical thickness is highly variable throughout the cortex and can be difficult to estimate from 2D images. Additionally, the relative contributions of cortical thickness and cortical volume to CKD risk are unclear.

Methods

This study examined a cohort of 1,132 living kidney donors with robust cortico-medullary differentiation on contrast-enhanced CT of the kidneys. AI techniques first separately segmented the cortex and medulla. Automated post-processing was employed to measure kidney length and volume of cortex. Then a distance map-based method was used to calculate average, maximal, and summed cortical thickness of the retained kidney. Cox proportional hazards models assessed the risk of measured glomerular filtration rate (mGFR)<60ml/min/1.73m² after donation with all five kidney cortex measures in analyses that were unadjusted and adjusted for cortex volume.

Results

Higher levels of all five AI-derived kidney cortex measures correlated with higher pre-donation mGFR (r_s=0.15-0.33, p<.0001). In unadjusted analyses, lower levels of all cortex measures associated with onset of a mGFR<60ml/min/1.73m² at a median 4 months post-donation. After adjusting for cortex volume, lower sum of cortex thickness and higher mean cortex thickness associated with onset of a mGFR<60ml/min/1.73m².

Conclusion

At the same level of cortex volume, a donor with lower total cortex thickness is at a higher risk for lower kidney function. Decreased total cortical thickness relative to total cortical volume may better detect loss of nephrons from nephrosclerosis than does cortical volume alone.

Funding

• NIDDK Support