Male urethral diverticulum squamous cell carcinoma containing a calculus: a rare entity.

Male urethral diverticula with calculi have a low incidence. It is extremely rare when the diverticulum accompanied with carcinoma. We report a case of diverticulum of the male urethra containing giant calculi which developed into squamous cell carcinoma. The patient initially presented with lower urinary tract symptoms and a hard, painless perineal mass. We believe that the process of diagnosis and treatment is of great significance in clinical practice.

Analysis of 7866 feline and canine uroliths submitted between 2014 and 2020 in the Netherlands.

Analysis of large datasets of uroliths is necessary to illustrate the prevalence and risk factors of urolithiasis. Furthermore, it may help to improve treatment and prevention of urolithiasis. In this study, 7866 uroliths (44.5% feline and 55.5% canine) from veterinary practitioners in the Netherlands between 2014 and 2020 were analysed. Between 2014 and 2020 the distribution over the different types of uroliths remained similar over time. Female cats, obese cats, Domestic Shorthair cats, female dogs, and large breed dogs had an increased risk for struvite. Neutered cats, all cat breeds except Domestic Shorthair, neutered dogs, male dogs, intact male dogs, and small breed dogs had an increased risk for calcium oxalate urolithiasis. Cystine and urate were found predominantly in male dogs. Dalmatians were at highest risk for urate urolithiasis. The findings of this study in the Netherlands were similar to findings in previous studies from different countries. However, urate urolithiasis in the English Cocker Spaniel and cystine urolithiasis in the Yorkshire Terrier were new associations. Body condition score, information about recurrence of urolithiasis, medical history, and diet history should be included in submission sheets in the future to explore other possible associations.

Urinary stone composition analysis and clinical characterization of 1520 patients in central China.

A total of 1520 patients with urinary stones from central China were collected and analysed by Fourier transform infrared spectroscopy between October 1, 2016 and December 31, 2019. For all patients, age, sex, comorbidities, stone location, laboratory examination and geographic region were collected. The most common stone component was calcium oxalate (77.5%), followed by calcium phosphate (8.7%), infection stone (7.6%), uric acid (UA) stone (5.3%)and cystine (0.9%). The males had more calcium oxalate stones (p < 0.001), while infection stone and cystine stones occurred more frequently in females (p < 0.001). The prevalence peak occurred at 41-60 years in both men and women. UA stones occurred frequently in patients with lower urinary pH (p < 0.001), while neutral urine or alkaline urine (p < 0.001) and urinary infection (p < 0.001) were more likely to be associated with infection stone stones. Patients with high levels of serum creatinine were more likely to develop UA stones (p < 0.001). The proportion of UA stones in diabetics was higher (p < 0.001), and the incidence of hypertension was higher in patients with UA stones (p < 0.001). Compared to the other types, more calcium oxalate stones were detected in the kidneys and ureters (p < 0.001), whereas struvite stones were more frequently observed in the lower urinary tract (p = 0.001). There was no significant difference in stone composition across the Qinling-Huaihe line in central China except UA stones, which were more frequently observed in patients south of the line (p < 0.001).

Stone size on endoscopic view as a predictor of successful stone retrieval during flexible ureteroscopy: an in vitro analysis.

PURPOSE: Basketing plays an important role during flexible ureteroscopy, but it can be time-consuming, especially when fragments are too large to pass through the ureteral access sheath. We aim to present the optimal on-screen, endoscopic stone size that predicts successful basketing through various access sheaths. METHODS: A tipless basket, individually extended to 5 mm from multiple ureteroscopes: (Flex-Xc, Karl Storz; Flex-X2s, Karl Storz; LithoVue, Boston Scientific; or URF-P6R, Olympus) and via differently sized access sheaths (10-12 Fr through 13-15 Fr), was used in retrieval attempts of various artificial stone sizes (2 mm through 5 mm). A relative endoscopic stone size was recorded as the stone's maximum diameter on endoscopic view compared to the total image diameter. RESULTS: Basketing of stones up to 2.5 mm, yielding relative endoscopic stone sizes of 0.38 (Flex-Xc), 0.30 (Flex-X2s), 0.32 (LithoVue), and 0.34 (URF-P6R), was successful using all access sheaths. Only the 12-14 Fr and greater sheaths allowed for successful basketing of 3 mm stones. Larger stones did not successfully pass through any of the access sheaths. CONCLUSION: Successful stone retrieval can be predicted by estimating the stone's size on screen, which is influenced by the type of flexible ureteroscope and access sheath. In our testing, stones of approximately one-third of the screen size passed successfully in all cases.

Endoscopic identification of urinary stone composition: A study of South Eastern Group for Urolithiasis Research (SEGUR 2). / Identificación endoscópica de la composición de los cálculos urinarios: un estudio del Southeastern Group for Lithiasis Research (SEGUR 2).

INTRODUCTION AND OBJECTIVES: To assess the surgeon's ability to evaluate the composition of the stone by observation of endoscopic images. MATERIALS AND METHODS: A series of 20 video clips of endoscopic treatments of urinary stones of which was also available the result of infrared spectroscopy was uploaded to a YouTube site accessible only to members of the South Eastern Group for Urolithiasis Research (SEGUR) who were asked to identify the composition of the stones. RESULTS: A total of 32 clinicians from 9 different countries participated in the study. The average number of correct detections of participants was 7.81 ± 2.68 (range 1-12). Overall accuracy was 39% (250 out of 640 predictions). Calcium oxalate dihydrate stones have been correctly detected in 69.8%, calcium oxalate monohydrate in 41.8%, uric acid in 33.3%, calcium oxalate/uric acid in 34.3% and cystine in 78.1%. Precision rates for struvite (15.6%), calcium phosphate (0%) and mixed calcium oxalate/calcium phosphate (9.3%) were quite low. CONCLUSIONS: Observation of the stone during the endoscopic procedure was not reliable to identify the composition of most stones although it gave some information allowing to identify with a good sensitivity calcium oxalate dihydrate and cystine stones. Nevertheless, photo or video reporting of the intact stone and its internal structure could should be encouraged to implement results of still mandatory post-operative stone analysis. Endourologists should improve their ability of visual identification of the different types of stones.

Circadian clock gene BMAL1 reduces urinary calcium oxalate stones formation by regulating NRF2/HO-1 pathway.

Calcium oxalate stones are closely related to oxalate metabolism and oxidative stress injury. Normal metabolism homeostasis and tissue repair are often affected by the biological rhythm, which plays an indispensable role in maintaining the homeostasis of the organism. Nuclear factor erythroid 2-related factor/heme oxygenase-1 (NRF2/HO-1) is one pathway related to oxidative stress injury in human body. Normal operation of this pathway is conducive to the resistance against oxidative stress-related injury. This study was mainly aimed to explore whether the rhythm gene "brain and muscle ARNT-like 1" (BMAL1) was involved in regulating oxidative stress-related NRF2/HO-1 pathway to reduce the formation of urinary calcium oxalate stones. In vitro experiment found that the activation of NRF2/HO-1 can significantly reduce the oxalate-induced oxidative damage and urinary calcium oxalate stone formation, and the relative expression of BMAL1 was increased. Then overexpression of circadian gene BMAL1 can activate the NRF2/HO-1 pathway and reduce the oxalate-induced oxidative damage. In the hyperoxaluria animal model, the BMAL1 expression level decreased obviously, and the production of calcium oxalate stones was significantly reduced after activating NRF2/HO-1. Finally, we further verified the BMAL1 expression in blood samples from the patients, and analysis of several single nucleotide polymorphisms showed BMAL1 was related to calcium oxalate stones. Therefore, maintaining normal biorhythms and appropriately intervening related rhythm genes and their downstream antioxidant pathways may play an important role in the prevention and postoperative recurrence of urinary calcium oxalate calculi, which may open up new directions for the treatment of urinary calculi.

Single-stage Simultaneous Retrograde and Antegrade Endoscopic Treatment of Giant Prostatic and Bladder Urethral Calculi.

INTRODUCTION: Calculi encountered in the lower urinary tract typically reside within the bladder, less often in the urethra. In this video, we present a minimally invasive endoscopic approach for removal of the largest total stone volume in the lower urinary tract reported in the literature to date. METHODS: A 25-year-old male (body mass index 61 kg/m2) with neurogenic bladder presented with urosepsis and acute kidney injury secondary to obstructive uropathy. Computerized tomography (CT) of the abdomen and pelvis demonstrated bilateral severe hydroureteronephrosis, a 4.2-cm bladder stone, and 3 urethral stones, including a 7.7-cm prostatic urethral stone and 2 membranous urethral stones (Fig. 1). Urgent bilateral percutaneous nephrostomy tubes were placed. The patient elected for endoscopic management. RESULTS: The patient was placed in the supine lithotomy position. His buried penis and narrow urethra only accommodated a 16-French flexible cystoscope. Multiple stones were encountered in the membranous urethra. A 60-W SuperPulse Thulium Fiber laser at 2 J and 30 Hz was utilized to dust the urethral stones efficiently. Simultaneous ultrasound-guided percutaneous access into the bladder was obtained and ultrasonic lithotripsy via shockpulse was used to clear the bladder stone and prostatic stone from above. Total stone treatment time was 240 minutes. Suprapubic and urethral catheters were placed at the conclusion. Postoperative day 1 CT scan confirmed stone-free status and he was discharged postoperative day 2. Outpatient nephrostogram demonstrated patency of bilateral ureters and nephrostomy tubes were removed. CONCLUSION: Higher morbidity procedures including open or laparoscopic approaches have been described for management of large lower urinary tract stones. In this video, we demonstrate a minimally invasive approach of combined simultaneous antegrade and retrograde lithotripsy to achieve a stone-free status in this morbidly obese and complicated patient.

Deciphering genetic signatures by whole exome sequencing in a case of co-prevalence of severe renal hypouricemia and diabetes with impaired insulin secretion.

BACKGROUND: Renal hypouricemia (RHUC) is a hereditary disorder where mutations in SLC22A12 gene and SLC2A9 gene cause RHUC type 1 (RHUC1) and RHUC type 2 (RHUC2), respectively. These genes regulate renal tubular reabsorption of urates while there exist other genes counterbalancing the net excretion of urates including ABCG2 and SLC17A1. Urate metabolism is tightly interconnected with glucose metabolism, and SLC2A9 gene may be involved in insulin secretion from pancreatic ß-cells. On the other hand, a myriad of genes are responsible for the impaired insulin secretion independently of urate metabolism. CASE PRESENTATION: We describe a 67 year-old Japanese man who manifested severe hypouricemia (0.7 mg/dl (3.8-7.0 mg/dl), 41.6 µmol/l (226-416 µmol/l)) and diabetes with impaired insulin secretion. His high urinary fractional excretion of urate (65.5%) and low urinary C-peptide excretion (25.7 µg/day) were compatible with the diagnosis of RHUC and impaired insulin secretion, respectively. Considering the fact that metabolic pathways regulating urates and glucose are closely interconnected, we attempted to delineate the genetic basis of the hypouricemia and the insulin secretion defect observed in this patient using whole exome sequencing. Intriguingly, we found homozygous Trp258* mutations in SLC22A12 gene causing RHUC1 while concurrent mutations reported to be associated with hyperuricemia were also discovered including ABCG2 (Gln141Lys) and SLC17A1 (Thr269Ile). SLC2A9, that also facilitates glucose transport, has been implicated to enhance insulin secretion, however, the non-synonymous mutations found in SLC2A9 gene of this patient were not dysfunctional variants. Therefore, we embarked on a search for causal mutations for his impaired insulin secretion, resulting in identification of multiple mutations in HNF1A gene (MODY3) as well as other genes that play roles in pancreatic ß-cells. Among them, the Leu80fs in the homeobox gene NKX6.1 was an unreported mutation. CONCLUSION: We found a case of RHUC1 carrying mutations in SLC22A12 gene accompanied with compensatory mutations associated with hyperuricemia, representing the first report showing coexistence of the mutations with opposed potential to regulate urate concentrations. On the other hand, independent gene mutations may be responsible for his impaired insulin secretion, which contains novel mutations in key genes in the pancreatic ß-cell functions that deserve further scrutiny.

How much energy do we need to ablate 1 mm3 of stone during Ho:YAG laser lithotripsy? An in vitro study.

INTRODUCTION: Holmium:yttrium-aluminium-garnet (Ho:YAG) is currently the gold standard for lithotripsy for the treatment of all known urinary stone types. Stone composition and volume are major determinants of the lithotripsy. This in vitro study evaluated the required energy to ablate 1 mm3 of various stone types with different laser settings using Ho:YAG. METHODS: 272 µm core-diameter laser fibers (Boston Scientific©) were connected to a 30 Watt MH1 Ho:YAG generator (Rocamed®). An experimental setup consisting of immerged human stones of calcium oxalate monohydrate (COM), uric acid (UA) or cystine (Cys) was used with a single pulse lasing emission (0.6/0.8/1 J), in contact mode. Stones were dried out before three-dimensional scanning to measure ablation volume per pulse (AVP) and required energy to treat 1 mm3 (RE). RESULTS: All settings considered, ablation volumes per pulse (AVP) for COM were significantly lower than those for UA and Cys (p = 0.002 and p = 0.03, respectively), whereas AVP for Cys was significantly lower than those for UA (p = 0.03). The mean REs at 0.6 J pulse energy (PE) for COM, Cys and UA were 34, 8.5 and 3.2 J, respectively The mean REs at 1 J PE for COM, Cys and UA were 14.7, 6.4 and 2 J, respectively. At 0.6 J PE, RE for COM was more than tenfold and fivefold higher than those for UA and Cys, respectively. CONCLUSION: This in vitro study shows for the first time a volumetric evaluation of Ho:YAG efficiency by the ablation volume per pulse on human stone samples, according to various pulse energies. The REs for COM, UA and Cys should be considered in clinical practice.

Materialise's interactive medical image control system (MIMICS) is feasible for volumetric measurement of urinary calculus.

In this study, we aimed to investigate the feasibility of using Materialise's interactive medical image control system (MIMICS) to measure urinary calculi volume. We used a cylinder measuring to measure the same polymer clay volume in different groups. Polymer clay was made into an oval shape, an antler type, and a multiple irregular shapes by hand. They are divided into three groups, that is, A, B, and C, each of which has seven polymer clays. The computer tomography (CT) 3D images of each sample were obtained by 256iCT scanning. The CT 3D image was imported into MIMICS to measure the theoretical volume and average CT value of polymer clay. The differences between the volume and CT values measured by MIMICS and 256iCT were evaluated. The volume of each polymer clay that was measured by a measuring cylinder was 34.7 ml. The average CT values of groups A, B, and C measured by 256iCT were 1121.3 ± 35.8, 1071.3 ± 22.2, and 1083.9 ± 6.3 Hu, respectively. The theoretical volume and CT values of the ceramics measured by MIMICS were as follows: the averaged volume of group A was 35.1 ± 0.4 ml, and the average CT value was 1065.7 ± 5.3 Hu. The average volume of group B was 34.5 ± 0.2 ml, and the average CT value was 1008.9 ± 7.7 Hu. The average volume of group C was 34.4 ± 0.5 ml, and the average CT value was 980.9 ± 6.1 Hu. MIMICS was reliable in measuring urinary stone volume. The difference between the CT values measured by MIMICS and 256iCT was statistically significant. MIMICS had a slightly lower CT value than that of 256iCT. However, from the data point of view, the difference between the two methods was small.

The Impact of Glycosylation of Osteopontin on Urinary Stone Formation.

Osteopontin (OPN) is a matrix glycoprotein of urinary calculi. This study aims to identify the role of aberrant glycosylation of OPN in urolithiasis. We retrospectively measured urinary glycosylated OPN normalized by urinary full-length-OPN levels in 110 urolithiasis patients and 157 healthy volunteers and 21 patients were prospectively longitudinal follow-up during stone treatment. The urinary full-length-OPN levels were measured using enzyme-linked immunosorbent assay and glycosylated OPN was measured using a lectin array and lectin blotting. The assays were evaluated using the area under the receiver operating characteristics curve to discriminate stone forming urolithiasis patients. In the retrospective cohort, urinary Gal3C-S lectin reactive- (Gal3C-S-) OPN/full-length-OPN, was significantly higher in the stone forming urolithiasis patients than in the healthy volunteers (p < 0.0001), with good discrimination (AUC, 0.953), 90% sensitivity, and 92% specificity. The Lycopersicon esculentum lectin analysis of urinary full-length-OPN showed that urinary full-length-OPN in stone forming urolithiasis patients had a polyLacNAc structure that was not observed in healthy volunteers. In the prospective longitudinal follow-up study, 92.8% of the stone-free urolithiasis group had Gal3C-S-OPN/full-length-OPN levels below the cutoff value after ureteroscopic lithotripsy (URS), whereas 71.4% of the residual-stone urolithiasis group did not show decreased levels after URS. Therefore, Gal3C-S-OPN/full-length-OPN levels could be used as a urolithiasis biomarker.

Contribution of SLC22A12 on hypouricemia and its clinical significance for screening purposes.

Differentiating between inherited renal hypouricemia and transient hypouricemic status is challenging. Here, we aimed to describe the genetic background of hypouricemia patients using whole-exome sequencing (WES) and assess the feasibility for genetic diagnosis using two founder variants in primary screening. We selected all cases (N = 31) with extreme hypouricemia (<1.3 mg/dl) from a Korean urban cohort of 179,381 subjects without underlying conditions. WES and corresponding downstream analyses were performed for the discovery of rare causal variants for hypouricemia. Two known recessive variants within SLC22A12 (p.Trp258*, pArg90His) were identified in 24 out of 31 subjects (77.4%). In an independent cohort, we identified 50 individuals with hypouricemia and genotyped the p.Trp258* and p.Arg90His variants; 47 of the 50 (94%) hypouricemia cases were explained by only two mutations. Four novel coding variants in SLC22A12, p.Asn136Lys, p.Thr225Lys, p.Arg284Gln, and p.Glu429Lys, were additionally identified. In silico studies predict these as pathogenic variants. This is the first study to show the value of genetic diagnostic screening for hypouricemia in the clinical setting. Screening of just two ethnic-specific variants (p.Trp258* and p.Arg90His) identified 87.7% (71/81) of Korean patients with monogenic hypouricemia. Early genetic identification of constitutive hypouricemia may prevent acute kidney injury by avoidance of dehydration and excessive exercise.

[Congenital mega urethra complicated by stones: about a case]. / Méga-urètre congénital compliqué de calculs: à propos d'un cas.

Congenital mega-urethra is a rare malformation causing micturition disturbance sometimes associated with upper urinary tract impairment. Despite the frequent association with other urinary and non-urinary abnormalities in children, stone-related complication has been reported only once in the literature. We report a case of congenital mega urethra complicated by stasis and stone formation in a 3 year old child successfully treated in the Department of Paediatric Surgery at the Mother-Child Hospital in Nouakchott. This study highlights the epidemiological clinical and therapeutic features of this association between congenital mega-urethra and urinary stones.

[The basis of endoscopic stones recognition, a prospective monocentric study]. / Base pédagogique de la reconnaissance endoscopique des calculs, étude prospective monocentrique.

INTRODUCTION: To evaluate by junior urologists the morphology of urinary stone using visual endoscopic recognition after expert teaching. Material From December 2017 to May 2018, surface and section stone pictures extracted from digital ureteroscopy had been submitted to description and recognition. Participants could take benefit from an expert coaching. Each stone was evaluated by a different coherence questionnaire (score 1-5). RESULTS: Nine stones had been analyzed by 15 junior urologists. Mean score was initially 1.94/4 and then from 2.07 to 4.07/5 during the study. A perfect stone recognition and a matching etiological lithiasis research had been observed in 40.7% and 55.6% of cases respectively. CONCLUSION: This first teaching experience of the urinary stone morphological endoscopic typing confirms the possibility to train urologists to gain this specific initial skill. Thereby, they could play a more important role in the etiological and diagnostic lithiasis research.

Multiple stones in neobladder: Case report and literature review.

INTRODUCTION: Neobladder urolithiasis is a rare but important long-term complication of orthotopic urinary diversion. It may be asymptomatic and can be discovered as an incidental finding on a radiological investigation. However, when symptoms occur, they may include lower abdominal pain, dysuria, hematuria, and lower urinary tract symptoms. CASE DESCRIPTION: We report the case of a 63-year-old male patient with irritative lower urinary tract symptoms, lower abdominal fullness, urinary incontinence, fecaluria, and urinary loss from the left inguinal fold 12 years after a radical cystoprostatectomy with a orthotopic neobladder. Computed tomography scan and urethrocystography showed a distended pouch with multiple large stones, an enterovesical fistula, and neovesicocutaneous fistula. The fistulae were successfully managed conservatively with the placement of a Foley catheter. After 3 months, open cystolithotomy was performed and approximately 50 stones with dimensions varying from 5 mm to 5 cm, with a total weight of 890 g, were removed. After a 1-year follow-up, the patient did not report pain, urinary tract infections, or symptoms suggestive of fistula and imaging evaluation confirmed no recurrence of neobladder stones. CONCLUSION: Neobladder stones may present with various symptoms. Our patient had irritative lower urinary tract symptoms, lower abdominal fullness, urinary incontinence, fecaluria, and urinary loss from the left inguinal fold 12 years after a radical cystoprostatectomy with a orthotopic neobladder. Our experience demonstrates that open cystolithotomy is an effective intervention for the removal of large stones in neobladder.

Amplicon targeted resequencing for SLC2A9 and SLC22A12 identified novel mutations in hypouricemia subjects.

BACKGROUND: To identify potential causative mutations in SLC2A9 and SLC22A12 that lead to hypouricemia or hyperuricemia (HUA). METHODS: Targeted resequencing of whole exon regions of SLC2A9 and SLC22A12 was performed in three cohorts of 31 hypouricemia, 288 HUA and 280 normal controls. RESULTS: A total of 84 high-quality variants were identified in these three cohorts. Eighteen variants were nonsynonymous or in splicing region, and then included in the following association analysis. For common variants, no significant effects on hypouricemia or HUA were identified. For rare variants, six single nucleotide variations (SNVs) p.T21I and p.G13D in SLC2A9, p.W50fs, p.Q382L, p.V547L and p.E458K in SLC22A12, occurred in totally six hypouricemia subjects and were absent in HUA and normal controls. Allelic and genotypic frequency distributions of the six SNVs differed significantly between the hypouricemia and normal controls even after multiple testing correction, and p.G13D in SLC2A9 and p.V547L in SLC22A12 were newly reported. All these mutations had no significant effects on HUA susceptibility, while the gene-based analyses substantiated the significant results on hypouricemia. CONCLUSION: Our study first presents a comprehensive mutation spectrum of hypouricemia in a large Chinese cohort.

The Analysis of Risk Factors for Hemorrhage Associated with Minimally Invasive Percutaneous Nephrolithotomy.

OBJECTIVE: This study investigated the risk factors for bleeding during minimally invasive percutaneous nephrolithotomy, so as to prevent the occurrence of bleeding and improve the surgical effect. PATIENTS AND METHODS: The data of 396 patients who underwent percutaneous nephrolithotomy by an experienced surgeon between May 2014 and December 2017 were retrospectively analyzed. To identify the risk factors for bleeding during percutaneous nephrolithotomy, each group was stratified according to the decrease in median hemoglobin. Age, gender, body mass index, stone size, operation time, stone type, degree of hydronephrosis, number of accesses, puncture guidance, underlying disease (diabetes; hypertension), and previous surgical history were evaluated. Univariate analysis was performed to calculate the potential factors. In order to determine the independence of each factor, we finally selected stone size, staghorn stone, degree of hydronephrosis, and operation time. Multivariate logistic regression analysis was used to identify the risk factors for bleeding during minimally invasive percutaneous nephrolithotomy. RESULTS: A total of 396 patients were successfully treated with percutaneous nephrolithotomy. The univariate analysis demonstrated that the potential risk factors for bleeding during percutaneous nephrolithotomy included stone size, type of stone, operative time, and degree of hydronephrosis. According to the previous studies, stone size, staghorn stone, degree of hydronephrosis, and operation time were ultimately selected. Multivariate logistic regression analysis was used to identify the risk factors for bleeding during percutaneous nephrolithotomy. According to the outcome of logistic regression analysis, stone size, staghorn stone, operation time, and degree of hydronephrosis were the risk factors for bleeding during minimally invasive percutaneous nephrolithotomy. CONCLUSIONS: Percutaneous nephrolithotomy is an effective method for the treatment of upper urinary calculi with few complications. According to the results achieved by an experienced surgeon, the size of stone, staghorn stone, operation time, and degree of hydronephrosis were associated with the bleeding during minimally invasive percutaneous nephrolithotomy.

In-vitro comparison of different slice thicknesses and kernel settings for measurement of urinary stone size by computed tomography.

Non-contrast enhanced computed tomography (NCCT) is widely used measuring stone size in patients with urolithiasis. We performed an evaluation of the accuracy of stone size measuring via NCCT. In an in-vitro study, we analyzed a total of 38 uric acid and 38 phantom stones. Within NCCT, we used different slice thicknesses (1.5 mm, 2.0 mm, and 3.0 mm) and kernel settings (bone and soft-tissue window). Maximal height, maximal length, and maximal width of each stone were measured on a picture archiving and communication system workstation. Blinded to these results, a second physician measured stone size in the same way using a caliper (real stone size). We used the Bland-Altman method for the analysis of agreement between the two measuring methods. The limit of agreement that was deemed clinical insignificant was ± 1.0 mm. All measurements via NCCT correlated significantly with the real stone size (p < 0.001). This was more pronounced for bone window and smaller slice thickness. Bland-Altman plots showed limits of agreement that exceeded the a priori defined level for all types of measurement with bone window and small slice thickness (1.5 mm) being better than soft-tissue window and large slice thickness (3.0 mm). We conclude that stone size measurement by NCCT with established settings is not exact. Stone size can easily be over- or underestimated by several millimeters. Using bone window and small slice thickness leads to more accurate results.

Accuracy of Ex Vivo Semiautomatic Segmentation of Urinary Stone Size in Computed Tomography Compared With Manual Size Estimation in Radiographic Correlation.

OBJECTIVE: To evaluate the accuracy of semiautomated segmentation of urinary stone size in computed tomography (CT) compared with manual measurement. MATERIALS AND METHODS: A total of 103 patients (32f, 71m ; mean age 52 years±18 that were diagnosed with urolithiasis and collected stones received standardized ex vivo CT-scans and radiography of the stones. Stone size was segmented semiautomatically using commercial software (syngo.via, Siemens, Germany) and compared with manual caliper measurement on digital radiography. RESULTS: Mean size was 4.4 mm in CT and 4.6 mm in radiography. Depending on number of stones analyzed per patient, estimation of stone size showed moderate to excellent correlation for both methods. There was no significant difference in overall size measurement. CONCLUSION: Semiautomatic segmentation of urinary stone size in CT is possible and reduces measurement errors, allowing more precise estimation especially for smaller concrements. Neighboring stones may hamper segmentation of stone size.

Giant urethral diverticulum calculus revealed by peri-urethral abscess.

Urethral diverticulum of the male is uncommon. We report a case of bulbar urethraldiverticulum with contained giant calculus presenting as left inguino-scrotal swellingsecondary to peri-urethral abscess in a 40 year-old male. In the light of this case Weemphasize the importance of investigation for the presence of urethral diverticulum in youngmale individuals presenting with voiding disturbances to preventrelated complications.