Hounsfield Units On CT Predict Stone-free Rates Of Upper Urinary Positive Calculi After ESWL

ObjectiveTo study whether the HUs of upper urinary stones could be used to predict the stone-free rates after ESWL.MethodsWe analyzed 52 patients who underwent ESWL for 0.5cm to 1.5cm upper urinary tract solitary stones. HU calculations were performed for each stone and posttreatment KUB or US assessment categorized patients into a stone-free or a residual stone group. Patients with residual fragments less than 3mm were arbitrarily placed in the stone-free group. Statistical analysis was performed to compare patient characteristics.ResultsOf the patients 36(69.2%) were stone-free and 16(30.8%) had residual stones. HU values for the stone-free and residual stone groups were significantly different (579.65±194.65HU versus 1032.18 ±270.49HU, t=6.842, P<0.01). Numbers of shock waves for the stone-free and residual stone groups were significantly different (1526.67 ± 723.01 versus 2612.50 + 518.81, t=5.407, P<0.01). OR was 0.993 (95%C.I.:0.988-0.998), 0.998 (95%C.I.:0.997 -1.000) respectively on HU values and Numbers of shock waves.ConclusionsThe HUs of upper urinary stones on pretreatment NCHCT may predict the stone-free rates after ESWL. Ureteroscopy, percutaneous nephrolithotomy or open surgery were preferred treatments for patients of upper urinary calculi with high CT values.