Preoperative Computed Tomography Aortic Calcification and Attenuation of the Vertebral Body Predict Fractures...

Area of Science:

• Nephrology
• Radiology
• Orthopedics

Background:

• Post-transplant fractures are a significant complication in kidney transplant recipients (KTRs), impacting mortality and graft survival.
• Computed tomography (CT) metrics like vertebral trabecular bone attenuation and aortic calcification are known osteoporosis indicators but their predictive value for fractures in KTRs is unexplored.

Purpose of the Study:

• To investigate pre-transplant CT imaging parameters for predicting post-transplant fractures in KTRs.
• To identify key CT-derived factors associated with fracture risk using machine learning.

Main Methods:

• Retrospective analysis of 111 primary living-donor KTRs with preoperative CT scans.
• Quantification of aorto-iliac calcification using Agatston score and vertebral trabecular bone CT attenuation (Hounsfield units) at T12-L5.
• Application of machine learning with SHapley Additive exPlanations (SHAP) to determine fracture predictors.

Main Results:

• The L1 vertebral CT attenuation value and aortic segment calcification score were top predictors of post-transplant fractures.
• Fracture risk was significantly elevated in groups with high L1 CT attenuation/high calcification (SHR 3.06) and low L1 CT attenuation/high calcification (SHR 11.66) compared to low calcification/high L1 CT.

Conclusions:

• Pre-transplant CT assessment of vertebral bone attenuation and aortic calcification can identify KTRs at high risk for post-transplant fractures.
• These imaging biomarkers offer valuable insights for pre-transplant risk stratification and management strategies.