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Objective To compare the outcomes of mini percutaneous nephrolithotomy (mPNL) and retrograde intrarenal surgery (RIRS) for the management of 2-3 cm lower pole renal calculi (LPC) in obese patients. Patients and methods 120 obese patients with 2-3 cm LPC were randomly divided into mPNL group and RIRS group. Demography, clinical characteristics, perioperative complications, and stone free rate (SFR) were recorded. Stone-free status means no stone on computed tomography 3 months after surgery, or residual fragments were less than 3 mm. Results Baseline characteristics were similar between the two groups. The mean stone burden was 585.39 ± 131.06 mm2 in the mPNL group and 548.64 ± 123.55 mm2 in the RIRS group (P = 0.125). The SFR of mPNL group was significantly better than that of RIRS group (86.2% vs 61.4%, P = 0.002). Besides, the overall complication rate was 22.4% in the mPNL group and 7% in the RIRS group (P = 0.02). Patients performed with mPNL required longer length of hospital stay than those with RIRS (P = 0.001). There were no significant differences in operative time and stone composition between the two groups. Conclusion In our study, both mPNL and RIRS are safe and effective techniques for the treatment of 2-3 cm LPC in obese patients. Compared to RIRS, mPNL has better SFR at the expense of the higher incidence of complications and prolonged length of hospital stay.

Introduction: Relative supersaturation (SS) for calcium oxalate (CaOx), calcium phosphate (CaP), and uric acid (UA) has been used for assessing urinary crystallization and estimated by programs, in...

To evaluate the distribution and dynamic trends in constituents of urinary stones in China. The composition of 23,182 stones were analyzed and then recorded between January 2011 and December 2019. The characteristics in terms of stone patient’s gender, age and calendar year were analyzed. Most stones (22,172, 95.64%) had several crystal components, among which 40.25% (8925/22,172) were mixtures with infection components. Calcium oxalate (CaOx) and uric acid (UA) stones were more commonly encountered in men, but calcium phosphate (CaP), magnesium ammonium phosphate (MAP) and carbonate apatite (CA) stones were more prevalent in women (p

Kidney stones and atherosclerotic plaques have an increasing rate worldwide. Although kidney stones are not life threatening, as atherosclerosis can be, they have the tense of reappearing after a period of time. Based on several studies it seems there is a correlation between these two diseases, as patients diagnosed with urolithiasis or nephrolithiasis appeared to have atherosclerotic plaques. Calcium oxalate and hydroxyapatite are the most frequently found minerals in stones. Calcium carbonate stones have also been present, but not in the same prevalence. Stones smaller than 5 mm are expected to pass on their own and thus no surgery is needed. However, each stone composition needs different treatment to be removed since they have different structural integrity among the same therapies. The very same minerals were found in spotty calcifications (

Urolithiasis is a common disease, and is an important health problem that is associated with a great economic burden. The nature of stone disease varies according by dietary and lifestyle factors, including, among others, climate variations. The majority of patients will suffer a new lithiasic episode at some point in their life, unless preventive measures, such as changing lifestyles and dietary habits, are put in place to avoid it. The risk factors involved in lithogenesis should be evaluated in order to reduce recurrences. In the majority of these patients, metabolic changes are observed in the urine that predispose lithogenesis. The kind of evaluation depends on stone composition and on the clinical presentation. A diagnosis of systemic and renal diseases of lithogenic nature can be diagnosed with these studies, and they also enable the adoption of precise prophylactic measures that achieve control of recurrence in a great number of patients.

Introduction: Large variations in demographic, economic and environmental factors might influence the worldwide distribution of urolithiasis, but scarce data are available concerning their associations with stone composition. We aimed to evaluate the frequency and composition of kidney stones and their associations with temperature, humidity, and human development index (HDI). Materials and Methods: A total of 1,158 stones from distinct patients (47±14 years old, male/female 2:1) were included. The mean annual temperature and relative humidity of each town were considered separately. Results: Calcium oxalate monohydrate (COM) was disclosed in 38.8% of patients, calcium oxalate dihydrate (COD) in 22.1%, mixed COD/apatite in 9.4%, pure apatite in 1.9%, brushite in 1.8%, struvite in 8.3%, pure uric acid in 11.1%, mixed uric acid/COM in 5.6%, and cystine/rare types in 0.8%. Mean HDI of all pooled cities was 0.780±0.03. However, people living in HDI0.800 (OR=2.14, 95% CI 1.11-4.11). Furthermore, a progressive increase in the struvite stones frequency from 4.5 to 22.8% was detected from HDI>0.800 through HDI 0,800 (OR = 2,14; IC 95% 1,11-4,11). Além disso, um aumento progressivo na frequência de cálculos de estruvita de 4,5 para 22,8% foi detectado em IDH> 0,800 até IDH

Objetivo: Evaluar la efectividad y las complicaciones del tratamiento con litotricia extracorpórea por ondas de choque (LEOC) en litiasis coraliformes. Diseño: Estudio observacional retrospectivo de litiasis coraliformes tratadas con LEOC en el Hospital Regional Universitario de Málaga entre los años 1990 y 2010. Resultados: Se incluyeron 157 pacientes sometidos a LEOC de litiasis coraliforme, 136 mujeres y 21 hombres. El número medio de sesiones para la fragmentación fue de 3,39± 1.94, el número de ondas de 10066.67±6182.96, la intensidad media de 16,24±12.37, la energía acumulada media de 402.69±182.07 y el tiempo de resolución de 7.59±7.97 meses. De los pacientes analizados, 106 quedaron libres de litiasis y 51 presentaron fragmentos residuales pequeños; sólo 12 tuvieron recidiva litiásica. La mortalidad fue del 0%. Las complicaciones según Clavien-Dindo fueron un 10% de tipo IIIb, 18% tipo IIIa y 3,31% tipo II. El coeficiente de efectividad de Clayman fue de 0,49 si consideramos retratamiento cuando se necesita más de una sesión y 0,71 si se consideran todas las sesiones como un único tratamiento. Limitaciones del estudio: Al tratarse de un estudio observacional retrospectivo, las conclusiones obtenidas son relativas, dado que existe heterogeneidad entre pacientes, en lo referente a morfología de la vía urinaria, tamaño y composición de las litiasis. Originalidad o valor: LEOC en pacientes con múltiples comorbilidades, es una alternativa a la cirugía. Conclusiones: Aunque la LEOC no es el tratamiento de elección para los cálculos coraliformes, es una opción válida en casos determinados, siempre en función de la disponibilidad del centro y/o experiencia del urólogo.

The incidence and prevalence of kidney stones have increased over the past four decades. However, the diagnosis of 'kidney stone' can range from an incidental asymptomatic finding of limited clinical significance to multiple painful episodes of ureteral obstruction with eventual kidney failure. Some general strategies may be useful to prevent the recurrence of kidney stones. In particular, greater attention to kidney stone classification, approaches to assessing the risk of recurrence and individualized prevention strategies may improve the clinical care of stone formers. Although there have been some advances in approaches to predicting the recurrence of kidney stones, notable challenges remain. Studies of kidney stone prevalence, incidence and recurrence have reported inconsistent findings, in part because of the lack of a standardized stone classification system. A kidney stone classification system based on practical and clinically useful measures of stone disease may help to improve both the study and clinical care of stone formers. Any future kidney stone classification system should be aimed at distinguishing asymptomatic from symptomatic stones, clinically diagnosed symptomatic stone episodes from self-reported symptomatic stone episodes, symptomatic stone episodes that are confirmed from those that are suspected, symptomatic recurrence from radiographic recurrence (that is, with radiographic evidence of a new stone, stone growth or stone disappearance from presumed passage) and determine stone composition based on mutually exclusive categories.

Objective To evaluate the outcomes of retrograde intrarenal surgery (RIRS) treatment of calyceal diverticular calculi and identify the associated factors affecting post-operative stone-free rate. Materials and methods From August 2015 to May 2019, data of 32 patients with calyceal diverticular calculi who were treated by RIRS in a Siriraj Hospital were retrospectively studied. All operations were performed by the same surgeon using flexible ureterorenoscopy (f-URS) and holmium YAG laser lithotripsy. Calyceal diverticula were identified by our refluxing technique and from the collected demographic, diverticular and stone data. Operative outcomes were retrospectively evaluated. Data were analysed to identify the factors associated with stone-free outcomes. Stone-free was defined as no residual stones remaining after surgery. Results Mean age of the patients was 55.7 years. Stone locations were non-lower pole in 81.2% of cases and lower pole for the remaining 18.8% of cases. Median stone size was 1.2 cm with three as the median number of stones per patient. Calcium oxalate was the most common stone composition (56.3%). Positions of the diverticulum were anterior calyx (34.4%) and posterior calyx (50%), while the remainder were undetermined (incomplete data). Average length of the diverticular neck was 0.4 cm. Mean operative time was 46 minutes and mean hospital stay was 2.9 days. Complications included fever in three patients (9.3%) and sepsis in two patients (6.3%), with overall post-operative stone-free rate at 75%. Factors significantly affecting stone-free status were stone size (P=0.003) and length of diverticular neck (P=0.038). Multivariate analysis determined that only stone size had a statistically significant effect on post-operative stone-free status (P=0.015). Cut off point for stone size that increased the chances of a post-operative stone-free outcome was less than 1.5 cm, as determined by the ROC curve. Conclusion RIRS was found to be an effective and safe treatment option for the removal of calyceal diverticular calculi. Stone size of less than 1.5 cm offered a better chance of post-operative stone-free condition.

Purpose The aim of this study is to determine what factors predict spontaneous passage of ≤ 1 cm ureteral stones in children. Methods Files of the patients diagnosed with a single ureteral stone on a given side between 2008 and 2017 were retrospectively reviewed. Patients with congenital obstructive uropathy, neurogenic bladder, vesicoureteral reflux and those with a stone diameter of > 1 cm were excluded. Detection of ureteral stones was done using ultrasonography (US) primarily, and computed tomography when US findings were inconclusive. Patients were treated either conservatively or surgically. Conservative treatment included adequate hydration and pain management whereas surgical treatment included ureteroscopic intervention. Apart from those who required urgent intervention, patients were referred for surgical treatment after 2–4 weeks of follow-up with no spontaneous passage. Factors analyzed for association of spontaneous passage included age, gender, type of hematuria, stone localization, laterality, presence of concomitant kidney stone, degree of hydronephrosis, stone size and stone composition. Results A total of 70 patients (38 males, 32 females); median age 4.7 years had a ≤ 1 cm ureteral stone (median diameter 7 mm). US was able to diagnose the ureteric stone in 47 patients while computed tomography was required in 23 patients. Spontaneous passage was observed in 40 patients (57.1%). Median time for stone passage was 8 days (3–34 days). Stone size and presence of hematuria (macroscopic and microscopic combined) were factors associated with spontaneous passage and 6.7 mm was found to be the cut-off (AUC = 0.953; 95% CI 0.905–1.000; sensitivity 96.7%, specificity 82.5%, p Conclusion Patients with a ureteric stone size Type of Study Case series with no comparison group. Level of Evidence IV

Urolithiasis has become more prevalent throughout China.Knowing stone composition helps identify their possible underlying etiology of urolithiasis, provide appropriate individualized treatment and prevent stone recurrence.To explore characteristics of urinary stone composition in China, and determine the effects of gender, age, body mass index (BMI), stone localization and geographical region on stone composition.We used Fourier transform infrared spectroscopy to analyse urinary stones from consecutive patients at 46 hospitals in seven geographic areas of China between June 1, 2010 and May 31, 2015.Chi-squared tests and logistic regression analyses were performed to determine associations between stone composition and sex, age, body mass index (BMI), stone location, and geographic region.The most common stone components were calcium oxalate (CaOx; 65.9%), carbapatite (15.6%), urate (12.4%), struvite (2.7%), brushite (1.7%), and cystine (0.9%). CaOx and urate occurred more frequently in males, whereas carbapatite and struvite were more common in females (p

To assess a novel low-dose CT-protocol, combining a 150 kV spectral filtration unenhanced protocol (Sn150 kVp) and a stone-targeted dual-energy CT (DECT) in patients with urolithiasis. 232 (151 male, 49 ± 16.4 years) patients with urolithiasis received a low-dose non-contrast enhanced CT (NCCT) for suspected urinary stones either on a third-generation dual-source CT system (DSCT) using Sn150 kVp (n = 116, group 1), or on a second-generation DSCT (n = 116 group 2) using single energy (SE) 120 kVp. For group 1, a subsequent dual-energy CT (DECT) with a short stone-targeted scan range was performed. Objective and subjective image qualities were assessed. Radiation metrics were compared. 534 stones (group 1: n = 242 stones; group 2: n = 292 stones) were found. In group 1, all 215 stones within the stone-targeted DECT-scan range were identified. DE analysis was able to distinguish between UA and non-UA calculi in all collected stones. 11 calculi (5.12%) were labeled as uric acid (UA) while 204 (94.88%) were labeled as non-UA calculi. There was no significant difference in overall Signal-to-noise-ratio between group 1 and group 2 (p = 0.819). On subjective analysis both protocols achieved a median Likert rating of 2 (p = 0.171). Mean effective dose was significantly lower for combined Sn150 kVp and stone-targeted DECT (3.34 ± 1.84 mSv) compared to single energy 120 kVp NCCT (4.45 ± 2.89 mSv) (p

Urinary lithiasis has been reported as a problem that affects humankind since ancient times and has been described in several animal species. The condition is a consequence of other diseases that may be present in the urinary system or related to other body disorders. The stone composition needs to be analyzed to identify the possible causes that led to the formation and development of uroliths. For this, several techniques are currently available, some of which are promptly accessible, while others are not. Thus, this literature review aimed to perform a brief introduction on urolithiasis, present the most used techniques in the analysis of the composition of canine and feline uroliths and point out the advantages and disadvantages of each technique. RESUMO: A litíase urinária foi reportada como um problema que atinge a humanidade desde a antiguidade e já foi descrita em diversas espécies de animais. A doença é considerada consequência de outras enfermidades que podem estar presentes no sistema urinário, ou relacionados com outros distúrbios do organismo. Para identificar as possíveis causas que levaram à formação e desenvolvimento de urólitos é importante analisar a composição dos cálculos. Para isso, existem várias técnicas disponíveis atualmente, algumas de mais fácil acesso e outras, nem tanto. Dessa forma, objetiva-se com a presente revisão realizar uma breve introdução sobre a urolitíase e apresentar as técnicas mais utilizadas na análise da composição de urólitos, em caninos e felinos, bem como apontar as vantagens e desvantagens de cada uma das técnicas.

The aim To assess the diagnostic performance of dual-energy computed tomography (DECT) in the evaluation of the composition of urinary stones "in vivo". Materials and methods A total of 91 patients aged from 20 to 70 years old (mean 42.7) with urinary stone disease were examined at Sechenov University, including 68 men (75%) and 23 women (25%). Prior to surgery, all patients underwent DECT (Canon, Japan) in order to predict the chemical composition of urinary stones in vivo. Extracorporeal shockwave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS) was performed in 53 (58.2%), 18 (19.7%) and 20 (22.1%) patients, respectively. Postoperatively, all stones or stone fragments (n=91; 100%) were examined using a comprehensive physical and chemical analysis (X-ray phase analysis, electron microscopy, infrared spectroscopy). Results In 6 patients (6.6%) staghorn stones were diagnosed, while in 15 (16.5%), 17 (18.7%), 22 (24.2%) and 31 (34.1%) stones were located in ureteropelvic junction, pelvis and ureter, respectively, including 24 patients with lower ureteric stones (26.4%). Prediction of the stone composition in vivo was carried out on the basis of the one indicator, the dual energy ratio (DER). The threshold values of DER for different types of stones were taken from the literature. All stones were divided into 4 groups according to the DECT results: vevellite stones (n=40, 43.9%), Ca-containing stones without vevellite (n=34, 37.3%), uric acid stones (n=10, 10.9%) and struvite stones (n=7, 7.9%). Thus, when comparing the results of DECT and physical and chemical analysis, in the first group four stones were incorrectly assigned by DECT to the group of Ca-containing stones without vevellite and three stones were incorrectly assigned to the group of struvite stones; in the second group four stones were incorrectly assigned to the group of vevellite stones; in the third group one stone was incorrectly assigned to the group of struvite stones; in the fourth group one stone was incorrectly assigned to the group of vevellite stones and one stone in the group of uric acid stones. In order to increase the diagnostic efficiency of DECT, we performed a comprehensive analysis of five specific DECT indicators (stone density at 135 kV, Z eff of the stone, DER, DEI, DED) using discriminant analysis. Thus, the sensitivity, specificity and overall accuracy of DECT with the use of just one indicator (DER) were 83.3%, 89.8%, 86.8% for vevellite, 88.2%, 92.9%, 91.2% for Ca-containing stones without vevellite, 90%, 98.8%, 97.8% for uric acid stones and 60%, 95.3%, 93.4% for struvite stones, respectively. When using discriminant analysis with five specific DECT indicators, higher values of sensitivity, specificity and overall accuracy were seen: 95.2%, 89.8%, 92.3% for a vevellite, 85,3%, 96,4%, 92,3% for Ca-containing stones without a vevellite and 100%, 100% and 100% for both uric acid and struvite stones, respectively. Conclusions Dual-energy computed tomography is a highly informative method which allows to perform preoperatively the reliable assessment of the chemical composition. DECT in patients with urinary stone disease allows to optimize the treatment strategy and carry out preventive measures on individual basis, taking into account the stone type.

To determine whether functionally relevant questions associated with the urinary or gut microbiome and urinary stone disease (USD) can be answered from metagenome-wide association studies (MWAS), we performed the most comprehensive meta-analysis of published clinical MWAS in USD to date, using publicly available data published prior to April 2021. Six relevant studies met inclusion criteria. For alpha-diversity, significant differences were noted between USD status, stone composition, sample type, study location, age, diet, and sex. For beta-diversity, significant differences were noted by USD status, stone composition, sample type, study location, antibiotic use (30 days and 12 months before sampling), sex, hypertension, water intake, body habitus, and age. Prevotella and Lactobacillus in the gut and urinary tract, respectively, were associated with healthy individuals, while Enterobacteriaceae was associated with USD in the urine and stones. Paradoxically, other Prevotella strains were also strongly associated with USD in the gut microbiome. When data were analyzed together, USD status, stone composition, age group, and study location were the predominant factors associated with microbiome composition. Meta-analysis showed significant microbiome differences based on USD status, stone composition, age group or study location. However, analyses were limited by a lack of public data from published studies, metadata collected, and differing study protocols. Results highlight the need for field-specific standardization of experimental protocols in terms of sample collection procedures and the anatomical niches to assess, as well as in defining clinically relevant metadata and subphenotypes such as stone composition. IMPORTANCE Studies focused on the microbiome broadly support the hypothesis that the microbiome influences the onset of chronic diseases such as urinary stone disease. However, it is unclear what environmental factors shape the microbiome in ways that increase the risk for chronic disease. In addition, it is unclear how differences in study methodology can impact the results of clinical metagenome-wide association studies. In the current meta-analysis, we show that age, stone composition, and study location are the predominant factors that associate with the microbiome and USD status. Furthermore, we reveal differences in results based on specific analytical protocols, which impacts the interpretation of any microbiome study.

Objective: To study urinary stone composition patterns in different populations around the world. Materials and methods: Data were collected by reviewing charts of 1204 adult patients of 10 countries with renal or ureteral stones (> 18 years) in whom a stone analysis was done and available. Any method of stone analysis was accepted, but the methodology had to be registered. Results: In total, we observed 710 (59%) patients with calcium oxalate, 31 (1%) with calcium phosphate, 161 (13%) with mixed calcium oxalate/calcium phosphate, 15 (1%) with carbapatite, 110 (9%) with uric acid, 7 (< 1%) with urate (ammonium or sodium), 100 (9%) with mixed with uric acid/ calcium oxalate, 56 (5%) with struvite and 14 (1%) with cystine stones. Calciumcontaining stones were the most common in all countries ranging from 43 to 91%. Oxalate stones were more common than phosphate or mixed phosphate/oxalate stones in most countries except Egypt and India. The rate of uric acid containing stones ranged from 4 to 34%, being higher in Egypt, India, Pakistan, Iraq, Poland and Bulgaria. Struvite stones occurred in less than 5% in all countries except India (23%) and Pakistan (16%). Cystine stones occurred in 1% of cases. Conclusions: The frequency of different types of urinary stones varies from country to country. Calcium-containing stones are prevalent in all countries. The frequency of uric acid containing stones seems to depend mainly on climatic factors, being higher in countries with desert or tropical climates. Dietary patterns can also lead to an increase in the frequency of uric acid containing stones in association with high obesity rates. Struvite stones are decreasing in most countries due to improved health conditions.

To predict the main component of pure and mixed kidney stones using dual-energy computed tomography and machine learning. 200 kidney stones with a known composition as determined by infrared spectroscopy were examined using a non-anthropomorphic phantom on a spectral detector computed tomography scanner. Stones were of either pure (monocrystalline, n = 116) or compound (dicrystalline, n = 84) composition. Image acquisition was repeated twice using both, normal and low-dose protocols, respectively (ND/LD). Conventional images and low and high keV virtual monoenergetic images were reconstructed. Stones were semi-automatically segmented. A shallow neural network was trained using data from ND1 acquisition split into training (70%), testing (15%) and validation-datasets (15%). Performance for ND2 and both LD acquisitions was tested. Accuracy on a per-voxel and a per-stone basis was calculated. Main components were: Whewellite (n = 80), weddellite (n = 21), Ca-phosphate (n = 39), cysteine (n = 20), struvite (n = 13), uric acid (n = 18) and xanthine stones (n = 9). Stone size ranged from 3 to 18 mm. Overall accuracy for predicting the main component on a per-voxel basis attained by ND testing dataset was 91.1%. On independently tested acquisitions, accuracy was 87.1–90.4%. Even in compound stones, the main component can be reliably determined using dual energy CT and machine learning, irrespective of dose protocol. • Spectral Detector Dual Energy CT and Machine Learning allow for an accurate prediction of stone composition. • Ex-vivo study demonstrates the dose independent assessment of pure and compound stones. • Lowest accuracy is reported for compound stones with struvite as main component.

Objectives To demonstrate the utility of a natural language processing (NLP) algorithm for mining kidney stone composition in a large-scale electronic health records (EHR) repository. Methods We developed StoneX, a pattern-matching method for extracting kidney stone composition information from clinical notes. We trained the extraction algorithm on manually annotated text mentions of calcium oxalate monohydrate, calcium oxalate dihydrate, hydroxyapatite, brushite, uric acid, and struvite stones. We employed StoneX to identify patients with kidney stone composition data and mine >125 million notes from our institutional EHR. Analyses performed on the extracted patients included stone type conversions over time, survival analysis from a second stone surgery, and disease associations by stone composition to validate the phenotyping method against known associations. Results The NLP algorithm identified 45,235 text mentions corresponding to 11,585 patients. Overall, the system achieved positive predictive value >90% for calcium oxalate monohydrate, calcium oxalate dihydrate, hydroxyapatite, brushite, and struvite; except for uric acid (positive predictive value = 87.5%). Survival analysis from a second stone surgery showed statistically significant differences among stone types (P = .03). Several phenotype associations were found: uric acid-type 2 diabetes (odds ratio, OR = 2.69, 95% confidence intervals, CI = 1.91-3.79), struvite-neurogenic bladder (OR = 12.27, 95% CI = 4.33-34.79), struvite-urinary tract infection (OR = 7.36, 95% CI = 3.01-17.99), hydroxyapatite-pulmonary collapse (OR = 3.67, 95% CI = 2.10-6.42), hydroxyapatite-neurogenic bladder (OR = 5.23, 95% CI = 2.05-13.36), brushite-calcium metabolism disorder (OR = 4.59, 95% CI = 2.14-9.81), and brushite-hypercalcemia (OR = 4.09, 95% CI = 1.90-8.80). Conclusion NLP extraction of kidney stone composition from large-scale EHRs is feasible with high precision, enabling high-throughput epidemiological studies of kidney stone disease. These tools will enable high fidelity kidney stone research from the EHR.

The present study aims to biochemically analyze the fluid samples containing stone dust taken during the perioperative period to determine the role of fluid in the prediction of stones in patients treated with ureterorenoscopic procedures. Our secondary aim is to investigate the role of both fluid analysis and stone analysis in predicting the results of the metabolic analysis. Comparative analyses were performed using fluid samples containing stone dust from 93 patients. Biochemical analysis of fluid containing stone dust was conducted; stone fragments were examined at a separate location using X-ray diffractometry(XRD). Metabolic analysis was performed to patients who provided stone-free status 1 month later. The results of chemical analysis were compared with the results of the XRD analysis. Patients’ stone type was determined with high accuracy using biochemical analysis. Differences were noted in ten patients following biochemical analysis and XRD analysis. Biochemical analysis predicted metabolic disorders in more patients than XRD analysis, particularly for those patients with multiple stone compositions. However, no significant differences between the results of biochemical and XRD analysis methods were found (κ = 0.27; p = 0.002). Moreover, biochemical analysis results revealed metabolic disorders in five patients; these findings were missed by XRD analysis. Biochemical analysis of fluid taken perioperatively during ureterorenoscopic laser lithotripsy to treat urinary system stone disease was found to determine stone composition with high accuracy. Biochemical analysis of fluid samples taken during the perioperative period is, thus, an easy, reliable and cost-effective test to assess stone composition in patients undergoing ureterorenoscopic procedures.

AIM to study the calcium level in the urine, serum and hairs and to assess the diagnostic value of the calcium level in various biosubstrates in patients with calcium and non-calcium stones. MATERIALS AND METHODS a total of 99 patients with urinary stone disease were included in the study. A diagnostic value of calcium level in biosubstrates according to the chemical analysis of stone composition performed using qualitative chemical reactions and microcrystalloscopy was evaluated. RESULTS Urinary level of calcium and oxalate is proved to have high diagnostic value in patients with calcium nephrolithiasis (specificity 93.9% and 96.9%, and positive predictive value 88.2% and 97.2%, respectively). The specificity and positive predictive value of the calcium level in the hairs was 81.2% and 87.2%, respectively. CONCLUSION A comprehensive study of the elemental spectrum in urine, hair, and serum increases the diagnostic value of the evaluation of calcium, determined by the type of studied biosubstrate and stone type in patients with nephrolithiasis.

Background: The optimal treatment for ureteral calculi must consider many factors, including stone composition, location and size, patient characteristics, technical skills of the surgeon, and instrument availability. Aim of the Work: To assess the result of ureteroscopic lithotripsy using holmium laser with laproscopic ureterolithotomy in the management of proximal ureteral stones larger than 10mm. Patients and Methods: 80 patients with unilateral upper ureteral stones were randomly divided into two groups: one group underwent ureteroscopic holmium laser lithotripsy (n=40), and another group underwent laparoscopic ureterolithotomy (n=40). Operating time, postoperative hospitalization time, stone clearance rate and perioperative complications were compared. Results: Operation was successfully performed in all 80 cases, and no open surgery was converted in any case. In the ureteroscopy and laparoscopy groups, the mean operating time was 33.83 ± 6.39 min and 107.25 ± 20.13 min, respectively, their hospitalization time was 1.65 ± 0.48 days vs. 3.90 ± 0.63days, and stone clearance rate was 880.0% (32/40) vs. 95% (38/40), and residual stones were removed by extracorporeal shock-wave lithotripsy (ESWL). All patients were followed up for more than three months, and no seriouscomplications such as ureterostenosis occurred. Conclusion: Laparoscopic ureterolithotomy and Ureteroscopy are both effective and reliable for the treatment of proximal ureteral stones. However, considering the shorter operation andhospitalization times we suggest that ureteroscopy, as a minimally invasive method, may be the first choice in the treatment of proximal ureteral stones.

We aim to describe factors that are associated with kidney stones 20 mm or larger. This information would potentially guide research regarding factors of kidney stone growth. We retrospectively reviewed a patient cohort who underwent surgical treatment for kidney stones. Patients with detailed demographics, 24-h urine testing, and kidney stone profiling were included. Large stone was defined as measuring 20 mm or more. Univariate analysis was conducted to assess variables associated with kidney stones larger than 20 mm. Multivariate logistic regression and statistical machine learning methods were used to infer prediction models. The specific composition of kidney stones, laboratory testing results, and detailed demographics of 277 patients were included in our analysis. Multiple variables were significantly associated with large stones in univariate analysis. The final model that predicts large stone size includes several variables from different domains: hypertension (OR = 1.91; 95% CI 1.06, 3.43), older age (60+ vs 20–40) (OR = 2.46; 95% CI 1.07, 5.63), decreased calcium oxalate supersaturation (OR = 0.92; 95% CI 0.85, 0.99), and higher percentage of protein in stone composition (OR = 5.64; 95% CI 2.04, 15.58). This model yields a sensitivity 83% and specificity of 56%. Models using machine learning algorithms identified similar predictors, but the performance varies. Our model yielded good performance, and it could potentially be used as a clinical tool for predicting large stones and identifying factors affecting kidney stone growth. Similar analysis in other cohorts should be pursued to externally validate findings.

Kidney and uteric stones are a common cause of pain and disturbance in numerous people worldwide, as they tend to reappear. There are several studies investigating the association of urolithiasis and nephrolithiasis with atherosclerosis, as patients suffering from the former diseases were found to have been diagnosed with atherosclerotic plaques. Hydroxyapatite and calcium oxalate are the most common mineral crystals found in both kidney/uteric stones and atherosclerotic plaques’ calcifications. Even though for stones smaller than 5 mm surgery is not recommended, the knowledge of the stone composition is an important tool for the physician in order to provide better treatment for the patient. The mineral crystal characterization of atherosclerotic plaques’ calcifications smaller than 3 mm (spotty calcifications) will assist the physician to limit the possibility of myocardial infraction and stroke, as the presence of hydroxyapatite indicates possible plaque rapture. To this aim, a dual energy (DE) X-ray method was developed in this work. The calcium/phosphorus mass ratio (mCa/mP) was determined through analytical simulations and the results were verified experimentally. Both monoenergetic and polyenergetic simulation studies were implemented for hydroxyapatite, calcium carbonate and calcium oxalate with thicknesses ranging from 0.50 to 3.00 mm, at 100 μm increments, to obtain the optimized irradiation conditions. The experimental verification of the proposed method was performed using an X-ray tube combined with a high resolution complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) detector. The Mann–Whitney U test indicated that statistically significant differences were found between the different types of minerals examined for thicknesses of 0.70 mm or higher.

Background Urolithiasis is a global disease with a high incidence and recurrence rate, and stone composition is closely related to the choice of treatment and preventive measures. Calcium oxalate monohydrate (COM) is the most common in clinical practice, which is hard and difficult to fragment. Preoperative identification of its components and selection of effective surgical methods can reduce the risk of patients having a second operation. Methods that can be used for stone composition analysis include infrared spectroscopy, X-ray diffraction, and polarized light microscopy, but they are all performed on stone specimens in vitro after surgery. This study aimed to design and develop an artificial intelligence (AI) model based on unenhanced computed tomography (CT) images of the urinary tract, and to investigate the predictive ability of the model for COM stones in vivo preoperatively, so as to provide surgeons with more accurate diagnostic information. Methods Preoperative unenhanced CT images of patients with urinary calculi whose components were determined by infrared spectroscopy in a single center were retrospectively analyzed, including 337 cases of COM stones and 170 of non-COM stones. All images were manually segmented and the image features were extracted, and randomly divided into the training and testing sets in a ratio of 7:3. The least absolute shrinkage and selection operation algorithm (LASSO) was used to construct the AI model, and classification of the training and testing sets was carried out. Results A total of 1,218 radiomics imaging features were extracted, and 8 features with non-zero coefficients were finally obtained. The sensitivity, specificity and accuracy of the AI model were 90.5%, 84.3% and 88.5% for the training set, and 90.1%, 84.3% and 88.3% for the testing set. The area under the curve was 0.935 for the training set and 0.933 for the testing set. Conclusions The AI model based on unenhanced CT images of the urinary tract can predict COM and non-COM stones in vivo preoperatively, and the model has high sensitivity, specificity and accuracy.

The accurate diagnosis of urinary calculi is essential for treatment planning. Non-contrast-enhanced computed tomography (NCCT) is considered the gold standard for adults to diagnose urolithiasis in acute flank pain. Generally, CT has also overtaken the role of intravenous urography in stone diagnosis and treatment planning. Lower dose CT seems to be as accurate as NCCT for the same purpose. Ultrasonography (US) is considered first-line imaging for urolithiasis in paediatric and pregnancy groups of patients. Various iterations of US, especially with the Doppler setting, can improve diagnostic accuracy, whereas magnetic resonance imaging may be an alternative investigation tool for pregnant women. Plain radiographs and US scans can be combined for stone surveillance purposes. The study of stone composition can be inferred from double-energy CT scans. Differential kidney function is conventionally derived from nuclear renogram, but recently, CT-derived parameters have been shown to be a promising alternative.

Background The stone composition has a great influence on the outcome of its treatment. There are several tests to predict the composition of stones preoperatively and stone analysis postoperatively. Herein, we want to evaluate if the stone composition could be predicted from plain X-ray KUB (PKUB) and/or non-contrast CT (NCCT) validated by in vitro X-ray powder diffraction analysis (XRD). Methods Between April 2014 and March 2016, 100 cases with urinary tract stones were included in the study. The radio-opacity of the stones in PKUB, stone density by NCCT, and after stone extraction, XRD were performed. Statistical analysis for the results was performed using Chi-square and Fisher exact tests for categorical variables and Mann–Whitney U and Kruskal–Wallis H for the nonparametric variables. The receiver operating characteristic curve was constructed to determine the best cutoff value. Results This study included 74 males and 26 females with a median age of 32 years (range 2–70). Regarding the radio-opacity by PKUB, there were 30 stones dense opaque, 44 opaque, 21 faint opaque, and 5 radiolucent. XRD revealed 97 mixed and 3 pure stones. The calcium oxalate monohydrate (COM) stone composition could be predicted in dense opaque stone by PKUB in 75.9% and urate composition in the radiolucent stone by 40%. The cutoff value of HU density by NCCT to the dense opaque stones in the PKUB was > 1020 and for radiolucent stones was Conclusion Stone radio-opacity by PKUB and its attenuation value by NCCT could successfully predict its calcium oxalate monohydrate, struvite, and urate composition. However, the chemical stone analysis is still required as most stones are mixed.

Conventional CT imaging is an excellent tool for the diagnosis of nephrolithiasis however is limited in its ability to detect stone composition. Dual-energy CT (DECT) scans have demonstrated promise in overcoming this limitation. We review the current utility of DECT in nephrolithiasis. DECT is superior to conventional CT in differentiating uric acid stones from non-uric acid stones, with numerous studies reporting sensitivities and specificities approaching > 95%. Dose reduction protocols incorporating low-dose CT scans are commonly used, providing significantly lower effective radiation doses compared to conventional CT. DECT remains an effective diagnostic tool in patients with large body habitus. DECT can accurately detect uric acid stones, which can help guide which stones may be suitable to medical dissolution. Further studies evaluating the effectiveness of DECT in guiding management of patients with nephrolithiasis can help to promote its widespread use.

OBJECTIVES To assess the largest stone composition data available and to present the variations in the stone composition according to gender and different climatic environments in Turkey. METHODOLOGY Data for a total of 24 768 urinary stone patients from the Turkish Mineral Research and Exploration Institute were evaluated. X-ray diffraction crystallography was used for analysis and the Koppen-Trewartha classification was used to assess the climatic features of the cities. After the assessment, the cities were divided into two groups-those with a continental climate (Dc) were defined as inland areas and the others (Non-Dc) were defined as coastal areas. RESULTS The male-to-female ratio was 2.2:1. Amongst the patients, 53.7% had pure stones, while 46.3% had mixed-type stones. The most common type of stone was calcium oxalate in both pure and mixed stone groups. Given the climate patterns, the stone ratio between regions with a Dc climate and a Non-Dc climate was approximately 2:3. Cystine and uric acid stones were observed more frequently in inland regions, while calcium oxalate, whewellite, and struvite stones were observed more frequently in coastal areas (P = .005, P

Objective To identify the correlation between demographic factors and upper urinary tract stone composition in the Thai population. Method A retrospective observational study of first-time upper urinary tract stone former patients aged over 18 years who underwent stone surgery was performed in a tertiary referral university hospital from January 2013 to May 2018. Collected data included demographic information and stone composition information, which were analysed by the Fourier Transform-Infrared Spectroscopy (FTIR) method. The correlation between the demographic factors and major upper urinary tract stone composition was analysed using Fisher's exact test. Results A total of 480 patients were included in this study. The stones were 319 (66.5%) renal calculi and 161 (33.5%) ureteric calculi. There were 248 (51.7%) single composition stones and 232 (48.3%) mixed composition stones. The major stone compositions were 288 (60.0%) calcium oxalate (CaOx), 125 (26.0%) calcium phosphate (CaP), 40 (8.3%) uric acid (UA), 19 (4.0%) magnesium ammonium phosphate (MAP), five (1.0%) cystine, and three (0.6%) ammonium hydrogen urate (AHU). Gender was correlated with the major stone composition. In females, a correlation was found between the major stone composition and age, diabetes mellitus (DM), and glomerular filtration rate (GFR). The study showed no significant correlation between the major stone composition and dyslipidemia (DLP), hypertension (HT), gout, and body mass index (BMI) in both genders. Conclusion Gender, age, DM, and GFR were the factors affecting the stone composition., Renal system; Physiology; Urology; Evidence-based medicine; Internal medicine; Health informatics; Health promotion; Upper urinary tract stone; Stone composition; Stone component; Urolithiasis; Renal calculi; Ureteric calculi; Renal stone; Ureteric ston.

Objective Artificial intelligence (AI) is used in various urological conditions such as urolithiasis, pediatric urology, urogynecology, benign prostate hyperplasia (BPH), renal transplant, and uro-oncology. The various models of AI and its application in urology subspecialties are reviewed and discussed. Material and methods Search strategy was adapted to identify and review the literature pertaining to the application of AI in urology using the keywords "urology," "artificial intelligence," "machine learning," "deep learning," "artificial neural networks," "computer vision," and "natural language processing" were included and categorized. Review articles, editorial comments, and non-urologic studies were excluded. Results The article reviewed 47 articles that reported characteristics and implementation of AI in urological cancer. In all cases with benign conditions, artificial intelligence was used to predict outcomes of the surgical procedure. In urolithiasis, it was used to predict stone composition, whereas in pediatric urology and BPH, it was applied to predict the severity of condition. In cases with malignant conditions, it was applied to predict the treatment response, survival, prognosis, and recurrence on the basis of the genomic and biomarker studies. These results were also found to be statistically better than routine approaches. Application of radiomics in classification and nuclear grading of renal masses, cystoscopic diagnosis of bladder cancers, predicting Gleason score, and magnetic resonance imaging with computer-assisted diagnosis for prostate cancers are few applications of AI that have been studied extensively. Conclusions In the near future, we will see a shift in the clinical paradigm as AI applications will find their place in the guidelines and revolutionize the decision-making process.

INTRODUCTION AND OBJECTIVE:New Zealand is an ethnically diverse country with a large number of Maori and Pacific Islanders (PI). Inferior health outcomes for Maori and PI continue to persist. Our o...

To investigate the outcomes of transurethral seminal vesiculoscopy (TSV) for the treatment of seminal vesicle calculi (SVC), prostatic utricle calculi (PUC) and combination of them, a retrospective review on 27 patients with SVC and/or PUC who complained of intractable haematospermia was conducted. Patient demographics, disease duration, operation time, stone location and complications were recorded. The calculi in the seminal vesicle and/or prostatic utricle were removed by holmium laser lithotripsy and/or basket extraction. The stone composition was determined in 19 of 27 patients using Infrared spectroscopy. The average age and disease duration of patients were 39.4 years and 23.1 months respectively. The mean operative time was 78.5 min. We detected SVC, SVC and PUC, and PUC in 59.3% (16/27), 33.3% (9/27) and 7.4% (2/27) patients respectively. The stones were mainly composed of calcium oxalate dehydrate (COD), carbonate apatite (CA), COD and calcium oxalate monohydrate (COM), CA and magnesium ammonium phosphate, CA and COM, and COD and uric acid in 42.1% (8/19), 21.1% (4/19), 15.8% (3/19), 15.8% (3/19), 5.3% (1/19) and 5.3% (1/19) cases respectively. No intraoperative and post‐operative complications were noted. These results suggested that SVC and PUC can be diagnosed and treated using TSVs.

To study the impact of stone density as assessed by Hounsfield units (HU) on total laser energy (TLE) used and total laser time (TLT) spent in complete fragmentation of upper urinary tract stones. In addition, we also studied the impact of stone composition on the laser energy and time required for fragmentation. Thirty consecutive patients fulfilling inclusion and exclusion criteria were included in the study. Patients with renal or proximal ureteral stones with a size of 5–20 mm were included. Stone fragmentation was performed using Ho:YAG 100 W laser and TLT and TLE were correlated with the HU and stone composition. The mean stone diameter was 10.83 ± 3.5 mm and the mean HU was 893 ± 315. The mean TLE and TLT were 8.86 ± 3.12 kJ and 18.46 ± 6.9 min, respectively. We observed a strong positive correlation between HU and TLE (r = 0.84, p value

Purpose To investigate the accuracy of rapid kV-switching single-source dual-energy computed tomography (rsDECT) for prediction of classes of non-uric-acid stones. Materials and methods Non-uric-acid renal stones retrieved via percutaneous nephrolithotomy were prospectively collected between January 2017 and February 2018 in a single institution. Only stones >= 5 mm and with pure composition (i.e., >= 80% composed of one component) were included. Stone composition was determined using Fourier Transform Infrared Spectroscopy. The stones were scanned in 32-cm-wide anthropomorphic whole-body phantom using rsDECT. The effective atomic number (Zeff), the attenuation at 40 keV (HU40), 70 keV (HU70), and 140 keV (HU140) virtual monochromatic sets of images as well as the ratios between the attenuations were calculated. Values of stone classes were compared using ANOVA and Mann-Whitney U test. Receiver operating curves and area under curve (AUC) were calculated. A p value < 0.05 was considered statistically significant. Results The final study sample included 31 stones from 31 patients consisting of 25 (81%) calcium-based, 4 (13%) cystine, and 2 (6%) struvite pure stones. The mean size of the stones was 9.9 +/- 2.4 mm. The mean Zeff of the stones was 12.01 +/- 0.54 for calcium-based, 11.10 +/- 0.68 for struvite, and 10.23 +/- 0.75 for cystine stones (p < 0.001). Zeff had the best efficacy to separate different classes of stones. The calculated AUC was 0.947 for Zeff; 0.833 for HU40; 0.880 for HU70; and 0.893 for HU140. Conclusion Zeff derived from rsDECT has superior performance to HU and attenuation ratios for separation of different classes of non-uric-acid stones.

Careful phenotyping of patients to classify those with kidney stones has a long and important history in revealing the chemical basis for stone formation. Advances in our genetic understanding of kidney stones will lead to incredible insights regarding the pathophysiology of this common disorder. At this time, both evaluation of urine chemistry and genotyping of patients are extremely useful in the setting of a university and research-based kidney stone clinic. For much of the world, in a more clinically focused setting, these techniques are neither available nor absolutely necessary. Careful implementation of an empiric prescription based on stone composition would have an important effect to reduce stone recurrence in the world’s many stone formers. Increased fluid intake, generic dietary manipulations, and prescription of potassium citrate and thiazides are all appropriate empiric therapies for people with calcium and uric acid kidney stones.

To evaluate the feasibility of using single-source dual-energy CT (SS DECT) to quantify and differentiate calcium carbonate (CA) and non-calcium carbonate (NCA) components of pancreatic duct stones (PDS) with mixed composition. A total of 12 PDS harvested from general surgery department in our hospital were analyzed with micro-CT as a reference standard for CA and NCA composition. These stones were placed in a TOS water phantom of 35 cm diameter to simulate standard adult body size. High- and low-energy image sets were acquired from SS DECT scans with high/low tube potential pairs of 80 kVp/140 kVp. All the image sets were imported into an in-house software for further post-processing. CT number ratio (CTR), defined as the ratio of the CT number at 80 kVp to 140 kVp was calculated for each pixel of the images. Threshold was preset between 1.00 and 1.25 to classify CA and NCA components. Pixels in PDS with CTR higher than the threshold were classified as CA, and those with CTR lower than the threshold were classified as NCA. The percentages of CA and NCA for each stone were determined by calculating the number of CA and NCA pixels. Finally, the minimal, maximal and root-mean-square errors (RMSE) of composition measured by SS DECT under each threshold were calculated by referring to the composition data from micro-CT. The optimal threshold was determined with the minimal RMSE. A paired t test was used to compare the stone composition determined by DECT with micro-CT. The optimal CTR threshold was 1.16, with RMSE of 6.0%. The minimum and maximum absolute errors were 0.22% and 11.35%, respectively. Paired t test showed no significant difference between DECT and micro-CT for characterizing CA and NCA composition (p = 0.414). SS DECT is a potential approach for quantifying and differentiating CA and NCA components in PDS with mixed composition.

The purpose of this study was to investigate the image quality (IQ) considerations of rapid kVp switching dual-energy CT (rsDECT) in the assessment of urolithiasis in patients with large body habitus and to evaluate whether it allows stone characterization. In this IRB-approved, HIPAA compliant retrospective study, 93 consecutive patients (M/F = 72/21, mean age 56.9 years, range 23–83 years) with large body habitus (> 90 kg/198 lbs) who underwent dual-energy (DE) stone protocol CT on a rapid kVp switching DECT scanner between January 2013 and December 2016 were included. Scan acquisition protocol included an initial unenhanced single-energy CT (SECT) scan of KUB followed by targeted DECT in the region of stones. Two readers evaluated both CT data sets (axial 5 mm 120 kVp/140 kVp QC/70 keV monoenergetic, material density water/iodine images and coronal/sagittal 3 mm images) for the assessment of image quality (Scores: 1–4) and characterization of stone composition (reference standard: crystallography). One hundred and five CT examinations were performed in 93 patients (mean body weight 105.12 ± 13.53 kg, range 91–154 kg), and a total of 321 urinary tract calculi (mean size-4.8 ± 3.2 mm, range 1.2–22 mm) were detected. Both SECT and targeted monoenergetic images were of acceptable image quality (mean IQ: 3.77 and 3.83, kappa 0.79 and 0.87 respectively). Material density water and iodine images had lower IQ scores (mean IQ: 2.97 and 3.09 respectively) with image quality deterioration due to severe photon starvation/streak artifacts in 20% (21/105) and 17% (18/105) scans, respectively. Characterization of stone composition into uric acid/non-uric acid stones was achieved in 93.14% (299/321) of calculi (mean size: 4.99 ± 3.3 mm, range 1.2–22 mm), while 7% (22/321) stones could not be characterized (mean size 3.03 ± 1.16 mm, range 1.6–6.4 mm) (p

Background: To retrospectively compare the composition of urinary tract stones formed by Uyghur children from the southern (Kashgar) and northern (Urumchi) parts of the Xinjiang region. Methods: The chemical composition of urinary tract calculi formed by 855 Uyghur children from the two regions in Xinjiang (366 Kashgar and 489 Urumchi) was compared retrospectively. Stone composition was determined by infrared spectroscopy. Factors that might have been of relevance for the findings such as age, gender, stone location and geographic region were also considered. Results: Kashgar children were younger than Urumchi children (2.8 ± 2.7 vs. 4.3 ± 3.7 years, p

Kidney stone incidence has been known to vary with temperature and climate. However, little is known about any variation in the composition of kidney stones across different regions of the United States. We attempted to evaluate whether stone composition changes depending on region.We were given access to de-identified data from LABCORPs database of kidney stone composition from August 1, 2016, to October 24, 2016, for states in seven representative areas of the country: Virginia, Minnesota, Florida, Arizona, Colorado, California, and Texas. We analyzed each component of kidney stones with optical microscopy supplemented with Fourier-transform infrared spectroscopy (FT-IR) spectrometry using both the percentage of the stone that was composed of that component as well as a binary variable coded none vs any. Univariate associations between component and state were examined using chi-square or Fisher's exact test for the binary indicator, and analysis of variance for the continuous percentage. The same set of analyses was used for decade of age vs each component. The association between age and state was examined using analysis of variance.Data were available for 4335 kidney stones, from patients in the 7 states mentioned. The most common components across all stones were calcium oxalate monohydrate and calcium phosphate (both present in 93% of stones), calcium oxalate dihydrate (in 57% of stones), and uric acid (in 12% of stones). Stone composition did not vary widely across regions, except for uric acid stones, which were more prevalent in Florida compared to other states, with an odds ratio of 1.43 (95% confidence interval 1.12, 1.83).Kidney stone composition does not vary widely by region within the United States. Although temperature and humidity play a role in stone incidence, there does not appear to be a large variation between different climates, with the exception of uric acid stone formation in Florida.

To prospectively examine the diagnostic performance of fast kilovoltage switching dual-energy computed tomography (DECT) in characterization of in vivo renal stone composition compared with postoperative stone analysis. Consecutive consenting patients scheduled for endoscopic kidney stone surgery in a tertiary referral hospital from June 2015 to January 2016 were enrolled. Patients were preoperatively scanned with single-source, fast kilovoltage switching DECT. Stone compositions were determined regarding the effective atomic number measurements. Results of the stone compositions from DECT were compared to postoperative infrared spectroscopy stone analysis as the standard reference. For the 39 patients enrolled in the study, DECT was able to detect uric acid stone with sensitivity of 88.9% and specificity of 100%. There was 100% positive predictive value, 96.8% negative predictive value, and 97.4% accuracy. For non-contrast CT scan, sensitivity was 88.9%, specificity was 96.7%, positive predictive value was 88.9%, negative predictive value was 96.7%, and accuracy was 94.8%. Of the 39 samples examined, 21 (54%) were single composition, whereas 18 (46%) were combined. Single composition stones were correctly characterized by DECT in 100% (8/8) for uric acid. Whereas the result of uric acid stone containing stone discrimination in mixed composition was not so good with Zeff alone, iodine imaging can compensated this fault. DECT provides excellent accuracy in characterizing uric acid stone compositions. With the addition of iodine image, all of uric acid-containing stones can be determined by the DECT.

Compared to adults, urolithiasis is less common in children, with a definite rise in incidence, especially among young adults (Tasian et al. in Clin J Am Soc Nephrol 11:488, 2016). In the last 25 years, the incidence in children has increased by approximately 6-10% annually, for reasons still unknown, with an associated significant increase in related health care-related expenditures (Hyams and Matlaga in Transl Androl Urol 3(3):278-83, 2014). It has been shown that there is twice as high a risk of chronic kidney disease (CKD) or end stage renal disease (ESRD) in stone formers compared to non-stone formers (Tasian et al. 2016). While calcium-containing stones are by far the most common category of stone encountered in both children and adults, non-calcium stones are more common in children than adults and have been shown in several studies to be associated with greater morbidity and lower renal function than calcium stones (Issler et al. in BMC Nephrol 18(1):136, 2017; Gambaro et al. in J Urol 198:268-273, 2017). This could be related to the challenges in the management of non-calcium-containing stones due to associated infection or metabolic derangements, further leading to recurrence and loss of renal function. There is currently a gap in our understanding of how to appropriately and effectively encounter and manage patients with non-calcium-containing stones, as such cases are encountered less frequently. Identification of stone composition and appropriate management is very important to reduce serious complications and recurrence, especially in non-calcium stones. We present a review of diagnosis and management of non-calcium-containing stones in the pediatric population, in hopes of providing more clarity to providers and promoting a consideration of non-calcium stone composition with all children presenting with urolithiasis.

Introduction Urolithiasis is a globally-distributed disease; however, its prevalence varies across countries and regions. Countries in the Middle East have been reported to have particularly high nephrolithiasis prevalence rates. To date, however, we have an incomplete understanding of the composition of stones seen in this region. Therefore, we performed a study to characterize stone composition over a 14-year period in the Eastern Province of the Kingdom of Saudi Arabia (KSA). Materials and methods A retrospective review of all adult patients who had the composition of their upper urinary tract calculi analyzed at Johns Hopkins Aramco Healthcare (JHAH) between 1999 and 2013 was performed. Patient demographics and pathology results were obtained from the electronic medical record. Results A total of 1,747 stones were analyzed in the study period. The results are presented in the Table. Male patients predominated (79%). For both men and women, the majority of stones were calcium oxalate: 85.2% male, 85.9% female. Uric acid stones were the next most common: 10.1% male; 9.0% female. Overall, there were no significant differences between gender with regards to the distribution of stone types. Conclusion This study represents one of the largest characterizations of stone composition in the Middle East. There remains a significant gender disparity in stone prevalence in the Eastern Province of KSA, with males affected to a significantly greater extent. Calcium oxalate is the most common type of stone, and this is true for both men and women. Future investigations of dietary and environmental factors can build on these initial epidemiologic findings. .

Urethral stones, or urolithiasis, is a pathologic and condition which is still a frequent problematic issue in the clinic, especially for itsrecurrence. This condition appears mostly in productive-age groups leading to affect their productivity. By stone analysis, the type andthe composition of concretes could be identified, so that the handling of patients could be arranged and its recurrence could be prevented.The study was carried to find out the distribution of urethral stone composition according to age and sex groups. A cross-sectional studyby means of medical records of 199 patients with urethral stone admitted to Dr. Wahidin Sudirohusodo Hospital was carried out duringMay 2002 to May 2004. Analysis was conducted microscopically and macroscopically by colorimetric and titrimetry. Urethral stoneswere found more in men 79.9% (159 of 199) than in women 20.1% (40 of 199). The peak prevalence of age between 31 to 45 yearswere 71.35%, the eldest being 86 years while the youngest was 2 years. The mostly found composition of calcium-oxalate was 87.4%,brushitt was 45.2%, and uric acid was 32.2%. The prevalence of urethral stones was still high, mostly found in 31 to 45 years of agegroup, affecting more men than women, and calcium oxalate showed the highest frequency.

International audience; Few studies have examined the relative risk of recurrence of different stone types. The object of the present study was to evaluate the tendency for stone recurrence as a function of major mineral composition of the stones and morphological characteristics of the stones. This study was carried out using 38,274 stones for which we had data available to specify if the stone was from the first or a subsequent urinary stone episode. Stones were analyzed for morphology by stereomicroscope and for composition by infrared spectroscopy. Overall, 42.7% of stones were from patients who had had a previous stone event, with these being more frequent in men (44.4%) than in women (38.9%, p < 0.0001). Age of first stone occurrence was lowest for dihydroxyadenine (15.7 ± 16.6 years) and highest for anhydrous uric acid (62.5 ± 14.9 years), with the average age of first stones of calcium oxalate falling in the middle (40.7 ± 14.6 years for calcium oxalate dihydrate, and 48.4 ± 15.1 years for calcium oxalate monohydrate, COM). By composition alone, COM was among the least recurrent of stones, with only 38.0% of COM stones coming from patients who had had a previous episode; however, when the different morphological types of COM were considered, type Ic—which displays a light color, budding surface and unorganized section—had a significantly greater rate of recurrence, at 82.4% (p < 0.0001), than did other morphologies of COM. Similarly, for stones composed of apatite, morphological type IVa2—a unique form with cracks visible beneath a glossy surface—had a higher rate of recurrence than other apatite morphologies (78.8 vs. 39–42%, p < 0.0001). Stone mineral type alone is insufficient for identifying the potential of recurrence of the stones. Instead, the addition of stone morphology may allow the diagnosis of highly recurrent stones, even among common mineral types (e.g., COM) that in general are less recurrent.