The impact of Hounsfield unit-related variables on percutaneous nephrolithotomy outcomes

Area of Science:

• Urology
• Nephrolithiasis Management
• Medical Imaging

Background:

• Percutaneous nephrolithotomy (PCNL) is a key treatment for kidney stones.
• Predicting PCNL outcomes is crucial for patient management.
• Hounsfield Units (HU) from CT scans are used to characterize stones, but their direct association with PCNL outcomes requires further investigation.

Purpose of the Study:

• To investigate the association between Hounsfield Unit (HU)-related variables and percutaneous nephrolithotomy (PCNL) outcomes.
• To determine if specific CT-derived stone characteristics can predict stone-free status after PCNL.

Main Methods:

• Retrospective review of 188 patients with single renal stones (1-3 cm) undergoing single-tract PCNL.
• Analysis of preoperative and follow-up CT scans to assess stone-free status (residual stone ≤ 2 mm within 3 months).
• Measurement of stone Hounsfield Units (HU) and Cross-sectional Area (CSA); logistic regression analysis of HU-related variables.

Main Results:

• The overall stone-free rate (SFR) was 79.2%.
• No significant differences were found in age, sex, BMI, stone size, or HU between stone-free and remnant groups.
• The HU/CSA ratio was significantly different between the stone-free (10.1 ± 5.6) and remnant (7.3 ± 3.4) groups (p=0.001), while CSA differed significantly (p=0.043).

Conclusions:

• The HU/CSA ratio, not HU alone, is an independent predictor of stone-free status after PCNL.
• Pelvic and ureteropelvic junction stones were also identified as predictors of SFR.
• The HU/CSA ratio shows potential for guiding kidney stone treatment decisions and predicting PCNL outcomes.