The following is a summary of “Identification of Clinically Insignificant Renal Calculi on Sonography,” published in the JUNE 2023 issue of Urology by Taylor, et al.
For a retrospective analysis, researchers sought to determine factors that can predict if a radiologist’s report of a renal stone on ultrasound (US) is not clinically significant based on a subsequently computed tomogram (CT). The aim was to develop a decision tree and nomogram to predict when stones are unlikely to be present on subsequent CT, reducing unnecessary radiation exposure.
The study included a retrospective analysis of patients of any age who received a CT within 24 hours of a sonographic report documenting a single renal stone between 2019 and 2020 at a single institution. Novel stone-likelihood systems for US (US-SLS) and CT (CT-SLS) were devised and validated to classify stones as clinically significant or insignificant, with CT as the gold standard. Binomial logistic regression was performed to predict clinically significant stones using sonographic and patient characteristics.
A total of 820 patients underwent US followed by CT, with 228 (27.8%) having documented stones and 140 (17.1%) having a single stone. Clinically significant stones were associated with larger size (P: .002), specific location (P: .002), presence of hydronephrosis (P: .04), shadowing artifact (P: .02), depth.ßto.ßstone (P: .008), and Body Mass Index (BMI) (P: .01). US-SLS demonstrated higher sensitivity (95.4%) and negative predictive value (81.8%) compared to a multivariate model of significant variables.
The US-SLS system appears to better identify clinically irrelevant renal stones compared to established criteria, such as twinkle or shadow, as determined through the retrospective analysis. A diagnostic algorithm and nomogram were presented. US-SLS and the associated decision tree could assist healthcare providers in avoiding unnecessary radiation exposure when clinically significant stones were unlikely.
Source: goldjournal.net/article/S0090-4295(23)00276-5/fulltext