Stone Attenuation Value and Cross-Sectional Area on Computed Tomography Predict the Success of Shock Wave Lithotripsy

Abstract

PurposeTo identify the parameters on noncontrast computed tomography (NCCT) that best predict the success of shock wave lithotripsy (SWL).Materials and MethodsWe reviewed the records of 75 patients who underwent SWL for urinary calculi measuring 5 to 20 mm. Using NCCT images, we estimated the largest stone cross-sectional area and contoured the inner edge of the stone. Clinical outcome was classified as successful (stone-free or <4 mm in diameter) or failed (stone fragments, ≥4 mm). The impact of preoperative parameters was evaluated by univariate and multivariate analysis.ResultsThe overall success rate was 73.3%. Average stone attenuation value, stone length, and stone cross-sectional area in the success and failure groups were 627.4±166.5 HU (Hounsfield unit) vs. 788.1±233.9 HU (p=0.002), 11.7±3.8 mm vs. 14.2±3.6 mm (p=0.015), and 0.31±0.17 cm2 vs. 0.57±0.41 cm2 (p<0.001), respectively. In the multivariate analysis, stone attenuation value was the only independent predictor of SWL success (p=0.023), although stone cross-sectional area had a tendency to be associated with SWL success (p=0.053). Patients were then classified into four groups by using cutoff values of 780 HU for stone attenuation value and 0.4 cm2 for cross-sectional area. By use of these cutoff values, the group with a low stone attenuation value and a low cross-sectional area was more than 11.6 times as likely to have a successful result on SWL as were all other groups (odds ratio, 11.6; 95% confidence interval, 3.9 to 54.7; p<0.001).ConclusionsStone attenuation value and stone cross-sectional area are good predictors of extracorporeal SWL outcome.

94 Impact of colic pain as a significant factor for predicting the stone free rate of one-session shock wave lithotripsy for treating ureter stones: A Bayesian logistic regression model analysis

“…SSD as a predictor of SWL success remains controversial. Until recently, SSD was a significant factor in a half of published studies, and in the rest studies, there was no significant difference in SSD for success or stone-free rate after SWL [22][23][24][25][26][27]. In the present study, SSD was also not a significant predictor for one-session stone-free status after SWL.…”

Rückblick auf 50 Jahre Steintherapie

“…Bei HE > 1 000 sprechen die Steine meist nicht mehr auf eine extrakorporale Stoßwellenlithotripsie (ESWL) an, weshalb primär endourologische Verfahren zur Anwendung kommen sollten. Niedrige Werte von < 500, gemeinsam mit pH-Werten < 5.5, sprechen dagegen für Harnsäuresteine, bei denen eine Chemolitholyse angeboten werden kann [10,11]. Ein lange bestehender Kritikpunkt der CT-Diagnostik, die höhere Strahlenbelastung, konnte durch spezielle low-dose Protokolle entkräftet werden [12].…”

Taş Hastalarının Çağdaş Radyolojik Yöntemlerle Değerlendirilmesi ve Ufuktaki Yeni Görüntüleme Yöntemleri

“…Bir çalışmada hastalar 780 HU ve 0.4 cm² kesit alanı cut off değeri kullanılarak 4 gruba ayrıl-mıştır. Bu değerler kullanılarak düşük HU değerine ve kesit alanına sahip taşı olan grubun SWL de başarılı sonuç alma olasılığı diğer gruplardan 11.6 kat fazla bulunmuştur (22).…”