Asymptomatic kidney stones are patients who are asymptomatic but have stones found on imaging. These patients are at high risk for symptomatic kidney stone attacks. Some of them can spontaneously expel stones, while others often require surgery because of frequent stone symptoms. Therefore, it is important to predict whether asymptomatic kidney stones will attack. Selby et al. of the Mayo Clinic conducted a prospective cohort study to determine the best stone load characteristics on CT to predict the onset of stone symptoms. The study found that total stone volume was the best predictor of future symptomatic kidney stones, and the article was recently published in the journal Urology. The study included 550 patients with asymptomatic kidney stones who underwent CT scans at the Mayo Clinic between October 2005 and December 2009, and researchers quantified stone load using the number of stones, diameter of the largest stone, total stone volume, and stones bilaterally. The results found that 230 patients (43%) had a single kidney stone episode within a median of 4.7 years after the CT scan during the follow-up period. The stone load was quadratically divided into 0-1, 2-3, 4-6, and ≥7 based on the number of stones, 0-1, 2-3, 4-6, and ≥8 mm based on the maximum stone diameter, and 0-8, 9-78, 79-280, and 281 mm3 based on the total stone volume, with 48% of patients having bilateral stones. On univariate analysis, the risk ratios (HR) for the number of stones, diameter of the largest stone, total stone volume, and bilateral stones per quartile of symptomatic stones were 1.30, 1.26, 1.38, and 1.80, respectively, all of which were statistically significant. In contrast, only the total stone volume was statistically significant on multivariate analysis (HR: 1.35), which independently predicted the occurrence of symptomatic stones. It was also found that patients with intermittent stone episodes between CT scans had a faster increase in total stone volume (>570 mm3 per year), and most of these patients developed symptomatic kidney stones. These results show that total stone volume is the best imaging feature to quantify stone load compared to the number of stones, diameter of the largest stone, and the presence of bilateral stones, and that total stone volume measured by CT can predict the future occurrence of symptomatic kidney stones. Selby et al. showed that patients with asymptomatic kidney stones can be prevented from developing symptomatic kidney stones by measuring the total stone volume on CT scan and taking therapeutic measures based on the total stone volume. Regular CT scan follow-up in patients who have had stones can predict the risk of future stone development. Of particular note, patients with an annual increase in total stone volume of >570 mm3 and <570 mm3 have an 84% and 46% risk of developing symptomatic stones over the next 3 years. However, it remains unclear whether such a prediction is reasonable because it increases the cost of additional radiation exposure and CT follow-up.