The hounsfield unit value calculated with the aid of non-contrast computed tomography and its effect on the outcome of percutaneous nephrolithotomy

Abstract

To evaluate the effect of the Hounsfield unit (HU) value, calculated with the aid of non-contrast computed tomography, on the outcome of percutaneous nephrolithotomy (PCNL). Data for 83 patients evaluated in our clinic between November 2011 and February 2014 that had similar stone sizes, localizations, and radio opacities were retrospectively reviewed. The patients were grouped according to their HU value, in a low HU group (HU a parts per thousand currency sign 1000) or a high HU group (HU > 1000). The two groups were compared based on their PCNL success rates, complications, duration of surgery, duration of fluoroscopy, and decrease in the hematocrit. There were no significant differences in terms of mean age, female-male ratio, or mean body mass index between the two groups (p > 0.05). The stone size and stone surface area did not differ significantly between the groups (p = 0.820 and p = 0.394, respectively). The unsuccessful PCNL rate and the prevalence of complications did not differ significantly between the two groups (p > 0.05). The duration of surgery, duration of fluoroscopy, and decrease in the hematocrit were significantly greater in the high HU group compared to the low HU group (p < 0.001). Calculating the HU value using this imaging method may predict cases with longer surgery durations, longer fluoroscopy durations, and greater decreases in hematocrite levels, but this value is not related to the success rate of PCNL.