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Oktay C. et al., 2022: The usefulness of the Hounsfield unit and stone heterogeneity variation in predicting the shockwave lithotripsy outcome.

Oktay C, Çoraplı M, Tutuş A.
Department of Radiology, Adıyaman University Education and Research Hospital, Adıyaman, Turkey.
Department of Urology, Adıyaman University Education and Research Hospital, Adıyaman, Turkey.

Abstract

PURPOSE This study aimed to evaluate the use of stone density variation coefficient (SDVC) as an indicator of stone heterogeneity and previously reported parameters for predicting extracorporeal shock wave lithotripsy (ESWL) outcome in urinary calculi. Moreover, a new formula that could be used to predict ESWL success was suggested. METHODS A total of 850 patients, who underwent the first session of ESWL for urinary stones between 2015 and 2020, were examined, and 220 eligible patients were included in the study. Stone density variation coefficient and other parameters associated with stone attenuation values and stone size parameters were studied as potential predictors based on noncontrast com- puted tomography (NCCT). Extracorporeal shock wave lithotripsy success was considered after 3 months by radiography or NCCT. Logistic regression analysis was performed to determine the factors contributing to treatment success. RESULTS For the 220 patients, ESWL success rate was 39.5%. The receiver operating characteristic analysis showed that SDVC (AUC=0.82; 95% confidence interval [CI]: 0.76-0.87; P < .001), mean stone density (AUC=0.81; 95% CI:0.75-0.87; P < .001), maximum stone density (AUC=0.70; 95% CI: 0.63-0.78; P < .001), stone volume (AUC=0.70; 95% CI: 0.62-0.77; P < .001), and major diam- eter (AUC=0.67; 95% CI: 0.59-0.74; P < .001) had significant prediction accuracy from high to low. Additionally, SDVC was found to be successful in predicting ESWL success, especially for patients with high mean stone density (OR = 10; 95% CI: 3.55-28.57; P < .001). The logistic regres- sion model, in which the "stone disintegration probability" (SDP) formula was found, correctly predicted ESWL success with a single session by 79.1%. CONCLUSION In conclusion, size and attenuation values were predictors of treatment success, and the best predictor was SDVC. Evaluation of SDP formula prior to ESWL could predict treatment outcomes and facilitate the decisions regarding treatment strategies.
Diagn Interv Radiol. 2022 May;28(3):187-192. doi: 10.5152/dir.2022.20945. PMID: 35748199

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Comments 2

Hans-Göran Tiselius on Wednesday, 21 September 2022 10:45

It is amazing how much information that can be obtained from NCCT images of stones.
MSD mean stone density
MXSD maximum stone density
SDSD standard deviation of stone density
SV stone volume and other geometrical stone properties
SSD skin-to-stone distance

In the current report the authors introduce SDVC as the variation coefficient of the stone density. This variable might have certain clinical significance because it describes the stone heterogeneity, which repeatedly has been shown to be of importance for stones’ susceptibility to shockwave power.
A significantly higher SDVC was found in patients successfully treated with SWL. The finding is of interest despite the relatively low success rates after one SWL session of both kidney stones and ureteral stones.
A formula was presented on the probability of success. Apart from the fact that the formula is difficult to understand, I doubt that such a formula ever will be clinically useful.

Some notations on cut-off values from the study:
Maximum stone length 10.8 mm
SV 293 mm3
MSD 824 HU
MXSD 1371 HU
SDVC 43.2 % (the higher SDVD, the better)

Hans-Göran Tiselius

It is amazing how much information that can be obtained from NCCT images of stones. MSD mean stone density MXSD maximum stone density SDSD standard deviation of stone density SV stone volume and other geometrical stone properties SSD skin-to-stone distance In the current report the authors introduce SDVC as the variation coefficient of the stone density. This variable might have certain clinical significance because it describes the stone heterogeneity, which repeatedly has been shown to be of importance for stones’ susceptibility to shockwave power. A significantly higher SDVC was found in patients successfully treated with SWL. The finding is of interest despite the relatively low success rates after one SWL session of both kidney stones and ureteral stones. A formula was presented on the probability of success. Apart from the fact that the formula is difficult to understand, I doubt that such a formula ever will be clinically useful. Some notations on cut-off values from the study: Maximum stone length 10.8 mm SV 293 mm3 MSD 824 HU MXSD 1371 HU SDVC 43.2 % (the higher SDVD, the better) Hans-Göran Tiselius
Guest - Sameer Parmar on Monday, 26 September 2022 17:48

The author had an ESWL success rate was 39.5% this is a point of concern

Few pointers on the poor success rate
1) Stone up to 30 mm were included in the study.
2) Stone free was evaluated after the first session of SWL (considering the inclusion criteria of up to 30 mm of stone)

Readers of the article should read these two points before they quote the poor success rate of SWL.

The author had an ESWL success rate was 39.5% this is a point of concern Few pointers on the poor success rate 1) Stone up to 30 mm were included in the study. 2) Stone free was evaluated after the first session of SWL (considering the inclusion criteria of up to 30 mm of stone) Readers of the article should read these two points before they quote the poor success rate of SWL.
Saturday, 18 May 2024