Predicting the mineral composition of ureteral stone using non-contrast computed tomography

Kawahara, Takashi; Miyamoto, Hiroshi; Ito, Hiroki; Terao, Hideyuki; Kakizoe, Manabu; Kato, Yoshitake; Ishiguro, Hitoshi; Uemura, Hiroji; Yao, Masahiro; Matsuzaki, Junichi

doi:10.1007/s00240-015-0823-z

Cited by 21 publications

(19 citation statements)

References 23 publications

(44 reference statements)

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“…This is because HUs predict the stone hardness and fragility. In our previous study, we also proved that HUs could predict stone composition through a multivariate analysis [ 28 ]. Considering clinical use, it is easy to measure HUs using NCCT; however, it is usually difficult to predict the stone composition preoperatively.…”

Section: Discussionmentioning

confidence: 81%

A new prediction model for operative time of flexible ureteroscopy with lithotripsy for the treatment of renal stones

et al. 2018

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This study aimed to develop a prediction model for the operative time of flexible ureteroscopy (fURS) for renal stones. We retrospectively evaluated patients with renal stones who had been treated successfully and had stone-free status determined by non-contrast computed tomography (NCCT) 3 months after fURS and holmium laser lithotripsy between December 2009 and September 2014 at a single institute. Correlations between possible factors and the operative time were analyzed using Spearman’s correlation coefficients and a multivariate linear regression model. The P value < 0.1 was used for entry of variables into the model and for keeping the variables in the model. Internal validation was performed using 10,000 bootstrap resamples. Flexible URS was performed in 472 patients, and 316 patients were considered to have stone-free status and were enrolled in this study. Spearman’s correlation coefficients showed a significant positive relationship between the operation time and stone volume (ρ = 0.417, p < 0.001), and between the operation time and maximum Hounsfield units (ρ = 0.323, p < 0.001). A multivariate assessment with forced entry and stepwise selection revealed six factors to predict the operative time of fURS: preoperative stenting, stone volume, maximum Hounsfield unit, surgeon experience, sex, and sheath diameter. Based on this finding, we developed a model to predict operative time of fURS. The coefficient of determination (R2) in this model was 0.319; the mean R2 value for the prediction model was 0.320 ± 0.049. To our knowledge, this is the first report of a model for predicting the operative time of fURS treatment of renal stones. The model may be used to reliably predict operative time preoperatively based on patient characteristics and the surgeons’ experience, plan staged URS, and avoid surgical complications.

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Section: Discussionmentioning

confidence: 81%

A new prediction model for operative time of flexible ureteroscopy with lithotripsy for the treatment of renal stones

et al. 2018

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“…In a study by Deveci et al, pure uric acid stones were shown to be mean 311 HU (range, 112-436 HU) and mixed uric acid stones were mean 331 HU (range, 110-427 HU) [7]. In another study, the mean density of uric acid stones was reported as mean 541.5 ± 161.1 HU [11]. Although there is no standard value for standard density of uric acid stones on non-contrast CT, in the light of the previous research it seems to be <700 HU.…”

Section: Medical Dissolution Therapy For Kidney Stone With Low Densitmentioning

confidence: 95%

“…The mean of the 3 measurements was accepted as the absolute CT value for a particular stone ( Figure 3). The densities of the uric acid stones were found to be 311 HU (range 112-436 HU), 587 ± 329 HU, and 541.5 ± 161.1 HU in three different studies [7,10,11]. Stones with density <800 HU were accepted as low density stones with a uric acid component and treatment was planned accordingly.…”

Section: Ct Protocolmentioning

confidence: 99%

Medical dissolution therapy for kidney stone with low density on non-contrast computed tomography

Hasırcı¹,

Tekin²,

Dirim³

et al. 2018

biomedicalresearch

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Objective: To review the outcome of dissolution therapy in low-density urinary stones defined by nonenhanced computed tomography. Materials and methods: The outcome of dissolution therapy in patients treated between May 2011 and July 2016 was retrospectively reviewed. Potassium sodium hydrogen citrate was used in cases with syone of <800 Hounsfield units determined by non-enhanced computed tomography. A decrease of 50% in the long axis of the stone was defined as partial dissolution. Cases with complete and partial stone dissolution were taken as the treatment success group whereas those who could not tolerate the treatment and who has less than 50% decrease in stone size were noted as treatment failure. The patients were compared with respect to age, body mass index, stone size, stone density, duration of treatment and follow-up, urine pH and serum uric acid levels. Results: Of 46 patients 31 completed the treatment course. A full response was obtained in 22 (71%) and a partial response in 4 (12.9%) cases. The basic factors found to affect the success of treatment were stone surface area, pre-treatment urine pH and serum uric acid levels. Conclusion: Low-density urinary stones can be successfully treated with dissolution therapy. In patients with radiolucent stones, the stone density should be measured by using non-enhanced computed tomograms. In cases examined with suitable stone density, dissolution treatment can be started without determining the exact type of the stone.

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“…With CT imaging, Hounsfield unit density can be used to characterize differences in radiodensities among urinary stones and can be helpful in planning alternative treatment for patients with a likelihood of a poor outcome from shock wave lithotripsy [39][40][41][42]. Dual-energy CT is able to differentiate uric acid, cystine, struvite and mixed stones from other types of stones [43,44].…”

Section: Key Pointsmentioning

confidence: 99%

Metabolic evaluation

Coninck¹,

Keller

Traxer³

2019

Current Opinion in Urology

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PURPOSE OF REVIEW To summarize recommendations of the guidelines of the American Urological Association and European Association of Urology, and our opinion on which urinary tract stone disease patients should be metabolically evaluated at which moment and how often. RECENT FINDINGS A standard metabolic evaluation should be performed in all stone formers to prevent recurrent disease. This includes a medical and lifestyle history, physical examination, basic urine and blood analysis, radiological examination and stone analysis. The latter should already be performed during surgery, especially when only a couple of fragments are sent for analysis. Supplementary, performing a 24-h urine analysis should be supported in all patients to understand the lithogenic process that will guide the according follow-up. When risk factors are found, an extended individualized metabolic evaluation should be performed to exclude underlying metabolic diseases and to start stone-specific recurrence prevention. SUMMARY Urologists should be trained in perioperative stone characterization, because it contains information of urinary environment at the times of stone formation and growth. The extensiveness and frequency of metabolic work-up and follow-up of stone formers should be tailored to the type of stone, severity of the disease, patient's comorbidities and medications.

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Predicting the mineral composition of ureteral stone using non-contrast computed tomography

Cited by 21 publications

References 23 publications

A new prediction model for operative time of flexible ureteroscopy with lithotripsy for the treatment of renal stones

A new prediction model for operative time of flexible ureteroscopy with lithotripsy for the treatment of renal stones

Medical dissolution therapy for kidney stone with low density on non-contrast computed tomography

Metabolic evaluation

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