Non-Invasive characterisation of renal stones using dual energy CT: A method to differentiate calcium stones

Background: Non-invasive DECT based characterization of renal stones using their effective atomic number (Zeff) and the electron density (rho e) in patients. Aim: This paper aims to develop a method for in-vivo characterization of renal stone. Differentiation of renal stones in-vivo especially sub types of calcium stones have very important advantage for better judgement of treatment modality. Materials and Methods: 50 extracted renal stones were scanned ex-vivo using dual energy CT scanner. A method was developed to characterize these renal stones using effective atomic number and electron density obtained from dual energy CT data. The method and formulation developed in ex-vivo experiments was applied in in-vivo study of 50 randomly selected patients of renal stones who underwent dual energy CT scan. Results: The developed method was able to characterize Calcium Oxalate Monohydrate (COM) and the combi-nation of COM and Calcium Oxalate Dihydrate (COD) stones non-invasively in patients with a sensitivity of 81% and 83%respectively. The method was also capable of differentiating Uric, Cystine and mixed stones with the sensitivity of 100, 100 and 85.71% respectively. Conclusion: The developed dual energy CT based method was capable of differentiating sub types of calcium stones which is not differentiable on single energy or dual energy CT images.

Automated summary

The developed dual energy CT based method in this study can effectively characterize renal stones in patients, especially differentiating sub types of calcium stones. Through the study of 50 patients, it was found that the method could differentiate different types of stones with high sensitivity, providing important guidance for treatment decisions.