Role of volume and attenuation value histogram of urinary stone on noncontrast helical computed tomography as predictor of fragility by extracorporeal shock wave lithotripsy

Yoshida, Soichiro; Hayashi, Tetsuo; Ikeda, Jun; Yoshinaga, Atsushi; Ohno, Rena; Ishii, Nobuyuki; Okada, Takemichi; Osada, Hiroyuki; Honda, N.; Yamada, Terumasa

doi:10.1016/j.urology.2006.01.052

Cited by 51 publications

(34 citation statements)

References 8 publications

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“…This result differs from several published studies [9][10][11]13,14]. The likely explanation for this discrepancy is that the fragility data in the present study were normalized to stone size, a procedure that was not done in any of the previous studies.…”

Section: Discussioncontrasting

confidence: 99%

“…Helical computed tomography (CT) has been proposed as a means to predict the success or failure of lithotripsy [6,8], and a number of studies have attempted to utilize CT numbers (in Hounsfield units, which are related to x-ray attenuation values) as a predictor of stone fragility [9][10][11][12][13][14]. However, given the resolution of clinical CT and the effects of volume averaging, the simple measure of Hounsfield units in stones is most likely to correlate with stone size [15,16], and stone size correlates with the number of SW's required for comminution [5].…”

Section: Introductionmentioning

confidence: 99%

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CT visible internal stone structure, but not Hounsfield unit value, of calcium oxalate monohydrate (COM) calculi predicts lithotripsy fragility in vitro

et al. 2007

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COM stones are often resistant to breakage using shock wave (SW) lithotripsy. It would be useful to identify by computed tomography (CT) those COM stones that are susceptible to SW's. For this study, 47 COM stones (4-10 mm in diameter) were scanned with micro CT to verify composition and also for assessment of heterogeneity (presence of pronounced lobulation, voids, or apatite inclusions) by blinded observers. Stones were then placed in water and scanned using 64-channel helical CT. As with micro CT, heterogeneity was assessed by blinded observers, using high-bone viewing windows. Then stones were broken in a lithotripter (Dornier Doli-50) over 2 mm mesh, and SW's counted. Results showed that classification of stones using micro CT was highly repeatable among observers (κ=0.81), and also predictive of stone fragility. Stones graded as homogeneous required 1874±821 SW/g for comminution, while stones with visible structure required half as many SW/g, 912±678. Similarly, when stones were graded by appearance on helical CT, classification was repeatable (κ=0.40), and homogeneous stones required more SW's for comminution than did heterogeneous stones (1702±993 SW/g, compared to 907±773). Stone fragility normalized to stone size did not correlate with Hounsfield units (p=0.85). In conclusion, COM stones of homogeneous structure require almost twice as many SW's to comminute than stones of similar mineral composition that exhibit internal structural features that are visible by CT. This suggests that stone fragility in patients could be predicted using pre-treatment CT imaging. The findings also show that Hounsfield unit values of COM stones did not correlate with stone fragility. Thus, it is stone

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Section: Discussioncontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

CT visible internal stone structure, but not Hounsfield unit value, of calcium oxalate monohydrate (COM) calculi predicts lithotripsy fragility in vitro

et al. 2007

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“…We hypothesise that stone volume measured by 3D reconstruction of NCCT is an accurate measurement of stone burden and strongly predicts the outcome of ESWL. Our results concur with a recent study in which stone volume was significantly different between the SF and RS groups [8]. Our results indicate that stone volume is a reliable predictor of SF status after ESWL.…”

Section: Discussionsupporting

confidence: 93%

“…Recently, many studies have attempted to correlate the radiographic findings on NCCT with treatment success of ESWL [1][2][3][4][5][6][7][8]. Specifically, studies show that the size, location, attenuation value of urinary calculi measured in Hounsfield unit (HU) density, body mass index (BMI) and skinto-stone distance (SSD) might be predictors of the success of ESWL, as determined by the stone-free (SF) rate [1][2][3][4][5][6][7][8]. A recent study investigated the value of stone volume measured on NCCT as an independent predictor of the outcome of ESWL [8].…”

Section: Introductionmentioning

confidence: 99%

“…Specifically, studies show that the size, location, attenuation value of urinary calculi measured in Hounsfield unit (HU) density, body mass index (BMI) and skinto-stone distance (SSD) might be predictors of the success of ESWL, as determined by the stone-free (SF) rate [1][2][3][4][5][6][7][8]. A recent study investigated the value of stone volume measured on NCCT as an independent predictor of the outcome of ESWL [8]. In an effort to better characterize the predictability of SF rates after ESWL, we analysed the effect of stone volume on the success of ESWL and compared it with other available variables.…”

Section: Introductionmentioning

confidence: 99%

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Stone measurement by volumetric three‐dimensional computed tomography for predicting the outcome after extracorporeal shock wave lithotripsy

Bandi¹,

et al. 2009

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(HU) density and axial stone diameter. Stone volume was calculated on a volumerendered 3D image for each stone. Maximum stone length was determined by comparative measurements of each stone in coronal, sagittal and axial planes, and was also measured on a plain abdominal film before ESWL. For ESWL we used the DoliS lithotripter (Dornier Medical Systems, Marrietta, GA, USA). A plain film at 6 weeks was used to categorize patients as stonefree (SF) or with residual stone. RESULTSIn all, 58 (62%) patients were SF and 36 (38%) had RS; the mean stone volume was significantly different between these groups (274 vs 464 µ L, P = 0.002). Logistic regression analysis showed that stone volume was the strongest predictor of SF status ( P < 0.001), compared to peak HU ( P = 0.015), mean HU ( P = 0.04) and axial stone diameter ( P = 0.006). The body mass index, SSD and maximum stone length on NCCT or a plain film did not predict success. A stone volume of < 500 µ L best predicted treatment success ( P < 0.001) with 72% of patients with a stone volume of < 500 µ L having a successful outcome, vs only 27% with a stone volume of > 500 µ L. CONCLUSIONOur study suggests that stone volume is an optimal predictor of SF status after ESWL of solitary upper urinary tract calculi. KEYWORDSurinary calculi, stone volume, success, shock wave lithotripsy Study Type -Diagnostic (exploratory cohort study) Level of Evidence 2b OBJECTIVETo evaluate the efficacy of stone volume measured using a three-dimensional (3D) reconstruction of preoperative non-contrast computed tomography (NCCT) as an independent predictor of success after extracorporeal shock wave lithotripsy (ESWL) of upper urinary tract calculi. PATIENTS AND METHODSWe evaluated preoperative NCCT in 94 patients who had ESWL for solitary upper urinary tract calculi of 4-20 mm in diameter. Axial images were used to measure the skinto-stone distance (SSD), Hounsfield Unit

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Improving Shockwave Lithotripsy Outcomes

Pearle

Antonelli

Babbar

2013

Surgical Management of Urolithiasis

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Role of volume and attenuation value histogram of urinary stone on noncontrast helical computed tomography as predictor of fragility by extracorporeal shock wave lithotripsy

Cited by 51 publications

References 8 publications

CT visible internal stone structure, but not Hounsfield unit value, of calcium oxalate monohydrate (COM) calculi predicts lithotripsy fragility in vitro

CT visible internal stone structure, but not Hounsfield unit value, of calcium oxalate monohydrate (COM) calculi predicts lithotripsy fragility in vitro

Stone measurement by volumetric three‐dimensional computed tomography for predicting the outcome after extracorporeal shock wave lithotripsy

Improving Shockwave Lithotripsy Outcomes

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