Study of non-contrast helical computed tomography in evaluating holmium laser lithotripsy for urinary calculus

The present study aimed to investigate the correlation between the parameters of non-contrast helical computed tomography (NCHCT) and the total energy of holmium laser lithotripsy, and establish a correlative mathematical model. From March 2016 to February 2017, 120 patients with a single urinary calculus were examined by NCHCT prior to holmium laser lithotripsy. The calculus location was confirmed, the CT value was measured and the volume of the calculus in the established three-dimensional reconstruction model was calculated. The total energy of lithotripsy (TEL) was recorded post-operatively. A significant difference in the TEL between renal calculi and ureteral calculi was identified (P<0.001) and a high and significant correlation between the volume of the calculus and the TEL was determined (Spearman r=0.827, P<0.001). A moderate correlation was identified between the CT value of the calculus and the TEL (Spearman r=0.468, P<0.001). Multivariate linear regression analysis revealed that the location, the volume and the CT value of the calculus were independently associated with the TEL (F=288.858, adjusted R(2)=0.879, P<0.01). A mathematical model correlating the parameters of NCHCT with the TEL was established, which may provide a foundation to guide the use of energy in holmium laser lithotripsy, and it was possible to estimate the TEL by the location, the volume and the CT value of the calculus.