[Prognosis of ureteral dilatation during procedures using a ureteral access sheath in patients with urolithiasis].

AIM: To improve the results of treatment of patients with urolithiasis who underwent endoscopic interventions using a ureteral access sheath (UAS) by developing a predictive model of ureteral dilatation without pre-stenting. MATERIALS AND METHODS: A total of 180 patients with kidney stones up to 20 mm were included in the study. They were divided into two groups: in the group 1 (n=79) UAS of 12/14 Ch was used, while in group II (n=101) UAS of 10/12 Ch was inserted. In group I, 48 (60.8%) patients underwent micropercutaneous nephrolithotomy and in 31 (39.2%) retrograde intrarenal surgery was done, compared to 42 (41.6%) and 59 (58, 4%) of patients in group 2. A non-inclusion criterion was a history of ureteral stenting. At the stage of preoperative diagnosis, 60 minutes before the X-ray examination, the patient took a single dose of 80 mg of furosemide per os to improve visualization of the upper urinary tract. After digital processing of computed tomography data and 3D-reconstruction of the upper urinary tract using the DICOM image processing program "RadiAnt DICOM Viewer," a visual assessment of the ureter was carried out to exclude significant deviations and strictures. The ureteral width was measured at three points: pyeloureteral segment, the level of the iliac bifurcation and intramural part. The number of cases of successful insertion of UAS and the rate of damage to the ureteral wall according to the classification proposed by O. Traxer and A. Thomas (2012) were analyzed. The prediction of successful insertion of a UAS was carried out using ROC analysis. RESULTS: In group 1, successful insertion of UAS was observed in 37 (46.8%) patients compared to 84 (83.2%) patients in group 2. In the remaining 42 (53.2%) and 17 (16.8%) cases, respectively, placement of UAS was not possible due to significant tissue resistance and high risk of traumatic injury. The average ureteral diameter at the points of physiological narrowing in patients with successful insertion of 12/14 Ch UAS were 2.0+/-0.1 mm, compared to 1.2+/-0.4 mm in those with failed insertion (p<0.05). In the group 2, similar indicators were 1.6+/-0.1 mm and 1.2+/-0.5 mm, respectively (p<0.05). According to ROC analysis, the diagnostic efficiency of the predictive model when using 12/14 Ch and 10/12 Ch UAS was confirmed by high AUC values (0.925 [95% CI 0.871-0.98] and 0.944 [95% CI 0.89=0.97], respectively). The total number of patients with ureteral injuries was 35 (44.3%) and 40 (39.6%) in groups with 12/14 Ch and 10/12 Ch UAS, respectively. At the same time, complications of the I degree were observed in 24 (30.4%) patients of the group 1 and in 31 (30.7%) patients of the group 2, while injuries of II degree were detected in 10 (12.7%) and 9 (8.9%) cases, respectively (p>0.05). Only in 1 (1.3%) patient, when 12/14 Ch UAS was inserted, grade III damage to the ureteral wall was determined. CONCLUSION: The proposed technique for measuring the cross-section of the ureter allows to predict the successful insertion of UAS at the preoperative stage. The probability of successful passage of UAS of 10/12 and 12/14 Ch in patients with ureteral diameter in physiological narrowings of more than 1.6 mm and 2 mm, respectively, is 95%. An insertion of UAS is a safe procedure, and most complications are classified as grades I or II.

Efficient and Accurate Computed Tomography-Based Stone Volume Determination: Development of an Automated Artificial Intelligence Algorithm.

PURPOSE: Given the shortcomings of current stone burden characterization (maximum diameter or ellipsoid formulas), we sought to investigate the diagnostic accuracy and precision of a University of California, Irvine-developed artificial intelligence (AI) algorithm for determining stone volume determination. MATERIALS AND METHODS: A total of 322 noncontrast CT scans were retrospectively obtained from patients with a diagnosis of urolithiasis. The largest stone in each noncontrast CT scan was designated the "index stone." The 3D volume of the index stone using 3D Slicer technology was determined by a validated reviewer; this was considered the "ground truth" volume. The AI-calculated index stone volume was subsequently compared with ground truth volume as well with the scalene, prolate, and oblate ellipsoid formulas estimated volumes. RESULTS: There was a nearly perfect correlation between the AI-determined volume and the ground truth (R=0.98). While the AI algorithm was efficient for determining the stone volume for all sizes, its accuracy improved with larger stone size. Moreover, the AI stone volume produced an excellent 3D pixel overlap with the ground truth (Dice score=0.90). In comparison, the ellipsoid formula-based volumes performed less well (R range: 0.79-0.82) than the AI algorithm; for the ellipsoid formulas, the accuracy decreased as the stone size increased (mean overestimation: 27%-89%). Lastly, for all stone sizes, the maximum linear stone measurement had the poorest correlation with the ground truth (R range: 0.41-0.82). CONCLUSIONS: The University of California, Irvine AI algorithm is an accurate, precise, and time-efficient tool for determining stone volume. Expanding the clinical availability of this program could enable urologists to establish better guidelines for both the metabolic and surgical management of their urolithiasis patients.

ACR Appropriateness Criteria® Acute Onset Flank Pain-Suspicion of Stone Disease (Urolithiasis).

Noncontrast CT (NCCT) is the imaging study of choice for initial evaluation of patients with acute onset of flank pain and suspicion of stone disease without known prior stone disease. NCCT can reliably characterize the location and size of an offending ureteral calculus, identify complications, and diagnose alternative etiologies of abdominal pain. Although less sensitive in the detection of stones, ultrasound may have a role in evaluating for signs of obstruction. Radiography potentially has a role, although has been shown to be less sensitive than NCCT. For patients with known disease and recurrent symptoms of urolithiasis, NCCT remains the test of choice for evaluation. In pregnancy, given radiation concerns, ultrasound is recommended as the initial modality of choice with potential role for noncontrast MRI. In scenarios where stone disease suspected and initial NCCT is inconclusive, contrast-enhanced imaging, either with MRI or CT/CT urogram may be appropriate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Ultrasound-guided extracorporeal shock wave lithotripsy with minimal x-ray exposure prevented genitourinary tract injury patients with urolithiasis in Taiwan.

BACKGROUND: This study investigated the use of ultrasound-guided extracorporeal shock wave lithotripsy (ESWL) to break stones in the genitourinary tract and prevent genitourinary injury. Our goals were to achieve accurate focusing and minimal X-ray exposure for the benefit of the patients. METHODS: The LiteMed LM-9200 lithotripter with ultrasonography and fluoroscopy was used for two different procedures: autoaimed and autoperiodical. These procedures enabled dual focusing on stone localization and tracking. RESULTS: Out of 108 patients who underwent autoperiodical procedures, 29 had no gross hematuria. Among the 335 patients who received autoaimed procedures, 194 had no gross hematuria. The average duration of X-ray exposure during autoperiodical and autoaimed procedures was 120 and 50 s, respectively. CONCLUSION: The ultrasound-guided ESWL with minimal X-ray exposure was found to be useful in treating genitourinary upper-tract urolithiasis in the autoaimed procedure. Patients who underwent the autoaimed procedure experienced less gross hematuria compared to those who underwent the autoperiodical procedure.

The prevalence of urolithiasis in subjects undergoing computer tomography in selected referral diagnostic centers in Mogadishu, Somalia.

Introduction and objectives: Somalia was predicted to be in the global stone belt with high urolithiasis prevalence. We aimed to determine the prevalence of urolithiasis and their demographic and computer tomography (CT) characteristics among subjects under CT scans in Mogadishu, Somalia. Materials and Methods: From March 2014 to November 2022, a total of 7,276 patients who underwent an abdominopelvic non-contrast CT scan for various indications were retrospectively reviewed. The mean age was 45.6 years with a standard deviation of 21.1 (range, 0.2-110 years). Patients were subdivided into two categories: adults (≥18 years) and pediatric (≤17 years). Results: Of the 7,276 patients, 1,075 (14.8%) were diagnosed with urolithiasis. Among those with urolithiasis, 702 (65.3%) were male patients, and 373 (34.7%) were female patients. Among them, adults accounted for 92.7%, while children were 7.3%. Renal stones (nephrolithiasis) were the most common, representing 57% followed by ureteric stones at 35.5%, making upper urinary stones 92.5%. Approximately 70 patients (6.5%) had bladder stones; of these, 26 of them (37%) were accompanied by benign prostatic hyperplasia (BPH). There were 10 urethral stones (0.9%) recorded in the study, all were found in male patients, 8 localized in prostatic urethra, and 2 in the bulbar urethra. The overall mean stone size was 13.2 mm, and 60% of them ranged from 5 to 22 mm. Only 24% of the patients were asymptomatic. Single stones were almost 70%, while staghorn calculi were 8.2%. More than 60% of the patients with urolithiasis showed some degree of hydronephrosis ranging between mild to severe. Conclusion: A CT scan-based urolithiasis prevalence indicates 14.8% in Mogadishu, Somalia, and these results are consistent with the probability calculation of the weights-of-evidence (WofE) methodology based on several risk factors including temperature, climate change, mineral deposit, drinking water quality, and distribution of carbonated rocks. Considering the high prevalence of the disease, Somalia needs to invest more in prevention and treatment facilities while also training urologists that are capable of utilizing minimally invasive techniques in the country.

2022 Recommendations of the AFU Lithiasis Committee: Diagnosis.

The choice of imaging modality is guided by the clinical presentation and the context (acute or not). Although ultrasound is safe (no radiation) and easily available, non-contrast-enhanced CT has become the gold standard in the diagnostic strategy for patients with acute flank pain because of its sensitivity (93.1%) and specificity (96.6%). It also allows determining the stone size, volume and density, visualizing their internal structure, and assessing their distance from the skin and the adjacent anatomy. All these parameters can influence the stone management and the choice of intervention modality. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendations method (CPR) and the ADAPTE method, depending on whether the issue was considered in the EAU recommendations (https://uroweb.org/guidelines/urolithiasis [EAU Guidelines on urolithiasis. 2022]) and their adaptability to the French context.

Dose Optimization Using a Deep Learning Tool in Various CT Protocols for Urolithiasis: A Physical Human Phantom Study.

Background and Objectives: We attempted to determine the optimal radiation dose to maintain image quality using a deep learning application in a physical human phantom. Materials and Methods: Three 5 × 5 × 5 mm3 uric acid stones were placed in a physical human phantom in various locations. Three tube voltages (120, 100, and 80 kV) and four current-time products (100, 70, 30, and 15 mAs) were implemented in 12 scans. Each scan was reconstructed with filtered back projection (FBP), statistical iterative reconstruction (IR, iDose), and knowledge-based iterative model reconstruction (IMR). By applying deep learning to each image, we took 12 more scans. Objective image assessments were calculated using the standard deviation of the Hounsfield unit (HU). Subjective image assessments were performed by one radiologist and one urologist. Two radiologists assessed the subjective assessment and found the stone under the absence of information. We used this data to calculate the diagnostic accuracy. Results: Objective image noise was decreased after applying a deep learning tool in all images of FBP, iDose, and IMR. There was no statistical difference between iDose and deep learning-applied FBP images (10.1 ± 11.9, 9.5 ± 18.5 HU, p = 0.583, respectively). At a 100 kV-30 mAs setting, deep learning-applied FBP obtained a similar objective noise in approximately one third of the radiation doses compared to FBP. In radiation doses with settings lower than 100 kV-30 mAs, the subject image assessment (image quality, confidence level, and noise) showed deteriorated scores. Diagnostic accuracy was increased when the deep learning setting was lower than 100 kV-30 mAs, except for at 80 kV-15 mAs. Conclusions: At the setting of 100 kV-30 mAs or higher, deep learning-applied FBP did not differ in image quality compared to IR. At the setting of 100 kV-30 mAs, the radiation dose can decrease by about one third while maintaining objective noise.

How did COVID-19 affect acute urolithiasis? An inner Anatolian experience.

BACKGROUND: The COVID-19 pandemic has changed the number of patients seeking medical help from the emergency service (ES) with non-COVID complaints, consequencing in postponed presentations of different surgical and medical situations. Acute urinary stone disease is one of these situations and needs to be investigated in terms of the effect of COVID-19 on its presentation to the ES. METHODS: In this observational, retrospective, and single-center study, we scanned each abdominopelvic computed tomography requested in ES for possible acute urolithiasis during 1 year before and after the outbreak of COVID-19. We searched to state the number of abdominopelvic computed tomographies applied and the number of ratifying urinary stone positivity. We enrolled patients' gender, age, stone location, and stone size. We also recorded C-reactive protein, leukocyte count, and creatinine and noted how long the patients suffering from pain, the duration until the intervention, and the management option selected for each case. RESULTS: Total number of abdominopelvic computed tomographies performed was 1089. Of these, 517 were pre-pandemic and 572 were peri-pandemic. The number of pre and peri-pandemic stone-positive scans were, respectively, 363 (70.2%) and 379 (66.2%) (P=0.643). The females' percentage in the COVID-19 period (37.2%) was significantly lower than in the pre-pandemic period (54.3%) (P=0.013). The median size of ureter stones of the pre and peri-pandemic groups were, respectively, 4.8 mm and 3.9 mm depicting no significant difference (P=0.197). No significant difference was sighted between the pre and peri-pandemic groups concerning stone locations, blood parameters, painful duration, treatment options, and time to intervention. CONCLUSION: The COVID-19 pandemic resulted in neither sicker nor fewer patients suffering from acute ureteric colic in the ES.

The burden of radiation exposure in children requiring percutaneous nephrolithotomy.

BACKGROUND: Children undergoing investigation and management for complex upper tract urolithiasis often require multimodal imaging. The significance of related radiation exposure in stone care pathways has received little attention in the published literature. STUDY DESIGN: Medical records of paediatric patients undergoing percutaneous nephrolithotomy were retrospectively analysed to ascertain the modalities used and determine extent of radiation exposure occurring during each care pathway. Radiation dose simulation and calculation was performed a priori. The cumulative effective dose (mSv) and cumulative organ dose (mGy) for radiosensitive organs was calculated. RESULTS: A total of 140 imaging studies were included from the care pathways of 15 children with complex upper tract urolithiasis. Median follow-up was 9.6 years (range: 6.7-16.8 years). The average number of imaging studies with ionising radiation per patient was nine, with a cumulative effective dose of 18.3 mSv across all modalities. The most common modalities were: mobile fluoroscopy (43%), x-ray (24%), and computed tomography (18%). The cumulative effective dose per study type was greatest for CT (4.09 mSv), followed by fixed and mobile fluoroscopy (2.79 mSv and 1.82 mSv, respectively). CONCLUSION: There is high general awareness of radiation exposure involved in CT scanning with resultant caution in employing this modality in paediatric patients. However, the significant radiation exposure relating to fluoroscopy (whether fixed or mobile) is less well documented in children. We recommend implementing steps to minimise radiation exposure by optimisation and avoidance of certain modalities where possible. Paediatrics urologists must employ strategies to minimise radiation exposure in children with urolithiasis, given the significant exposures encountered.

Contemporary Use of Computed Tomography (CT) Imaging in Suspected Urolithiasis in Pregnancy.

PURPOSE OF REVIEW: We aimed to examine the role of low-dose CT (LDCT) in the diagnostic work-up for suspected urolithiasis in pregnancy. We reviewed contemporary urologic recommendations for CT in pregnancy, its utilization for suspected urolithiasis, and explored barriers to its use. RECENT FINDINGS: National urologic guidelines and the American College of Obstetricians and Gynecologists recommend the judicious use of LDCT imaging in pregnancy when necessary. We noted inconsistencies in review article management pathways and recommendations for CT imaging for suspected urolithiasis in pregnancy. Overall CT utilization in pregnancy for suspected urolithiasis is low. Proposed barriers to LDCT use in pregnancy include fears of litigation and misperceptions of the harm of diagnostic radiation. Recent advancements in imaging technologies for urolithiasis in pregnancy are limited. More specific diagnostic pathway recommendations from national urologic guideline bodies for when to use LDCT to investigate renal colic in pregnancy may reduce diagnostic and intervention delays.

Effect of surface-partial-volume correction and adaptive threshold on segmentation of uroliths in computed tomography.

Computed tomography (CT) is used to diagnose urolithiasis, a prevalent condition. In order to establish the strongest foundation for the quantifiability of urolithiasis, this study aims to develop semi-automated urolithiasis segmentation methods for CT images that differ in terms of surface-partial-volume correction and adaptive thresholding. It also examines the diagnostic accuracy of these methods in terms of volume and maximum stone diameter. One hundred and one uroliths were positioned in an anthropomorphic phantom and prospectively examined in CT. Four different segmentation methods were developed and used to segment the uroliths semi-automatically based on CT images. Volume and maximum diameter were calculated from the segmentations. Volume and maximum diameter of the uroliths were measured independently by three urologists by means of electronic calipers. The average value of the urologists´ measurements was used as a reference standard. Statistical analysis was performed with multivariate Bartlett's test. Volume and maximum diameter were in very good agreement with the reference measurements (r>0.99) and the diagnostic accuracy of all segmentation methods used was very high. Regarding the diagnostic accuracy no difference could be detected between the different segmentation methods tested (p>0.55). All four segmentation methods allow for accurate characterization of urolithiasis in CT with respect to volume and maximum diameter of uroliths. Thus, a simple thresholding approach with an absolute value may suffice for robust determination of volume and maximum diameter in urolithiasis.

Deep-Learning Segmentation of Urinary Stones in Noncontrast Computed Tomography.

Background: Noncontrast CT (NCCT) relies on labor-intensive examinations of CT slices to identify urolithiasis in the urinary tract, and, despite the use of deep-learning algorithms, false positives remain. Materials and Methods: A total of 410 NCCT axial scans from patients undergoing surgical treatment for urolithiasis were used for model development. The deep learning model was customized to combine a urolithiasis segmentation with per-slice classification for screening. Prediction models of the axial, coronal, and sagittal views were trained, and an additive model with an intersection of the coronal and sagittal predictions added to the axial outcome was introduced. Automated quantification of clinical metrics was evaluated in three-dimensional models of urinary stones. Results: The axial model detected 88.92% of urinary stones and produced a dice similarity coefficient of 87.56% in the urolithiasis segmentation. For urolithiasis (>5 mm), the sensitivity of the axial model reached 95.10%. False positives were reduced to 0.34 per patient using an ensemble of individual models. The additive model improved the sensitivity to 90.97% by detecting more small urolithiasis (<5 mm). All clinical metrics of size, long-axis diameter, volume, mean stone density, stone heterogeneity index, and skin-to-stone distance showed a strong correlation of R2 > 0.964. Conclusions: The proposed system could reduce the burden on the physician for imaging diagnosis and help determine treatment strategies for urinary stones through automated quantification of clinical metrics with high accuracy and reproducibility.

Rapid binary visual detection of oxalate in urine samples of urolithiasis patients via competitive recognition and distance reading test strips.

Urolithiasis is a common disease with wide ranging effects, with oxalate stones being the most prevalent type. Existing clinical diagnostic methods rely on complex instruments and professionals, are difficult to distinguish between stone types, and have insufficient sensitivity. Moreover, high-sensitivity point-of-care testing (POCT) methods remain scarce. We constructed a rapid homogeneous dual fluorescence and binary visualization analysis system to diagnose oxalate urolithiasis because oxalate can efficiently reduce Cu2+ to Cu+, which can be selectively competitively recognized by both calcein and cadmium telluride quantum dots (CdTe QDs). Under optimized conditions, the system exhibited high sensitivity to oxalate ranging from 10 pM to 10 nM within 3 min. Following that, visualized test strips of calcein and QDs were generated by inkjet printing; oxalate concentrations as low as 10 nM can be easily identified by reading the quenching distance on the strip. We then analyzed 66 clinical urine samples: 11 healthy, 10 oxalate-negative, and 45 oxalate-positive samples. The fluorescence and visual mode results were highly consistent with clinical computed tomography (CT) images and clinical diagnostics. Therefore, our analysis strategy has the potential to use POCT for the assessment of oxalate urolithiasis.

Diagnostic accuracy of Doppler twinkling artifact for identifying urolithiasis: a systematic review and meta-analysis.

OBJECTIVE: The goal of this study was to perform a comprehensive meta-analysis to assess the overall diagnostic value of Doppler twinkling for the diagnosis of urolithiasis. METHODS: We systematically searched the PubMed, EMBASE, and Cochrane Library databases from inception through May 31, 2021. Studies including patients with urolithiasis who underwent color flow Doppler sampling to highlight the twinkling artifact and computed tomography were included. Diagnostic test meta-analysis was performed with a bivariate model. We used summary receiver operating characteristic curves to summarize the overall diagnostic performance. The weighted sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were calculated. RESULTS: Sixteen studies involving 4572 patients were included in the systematic review and meta-analysis. The weighted sensitivity was 0.86 (95% confidence interval [CI] 0.72-0.94), specificity 0.92 (95% CI 0.75-0.98), positive likelihood ratio 11.3, negative likelihood ratio 0.2, and diagnostic odds ratio 75.5. CONCLUSION: The Doppler twinkling artifact has good diagnostic value for the diagnosis of urolithiasis and should be used as a complementary tool in the diagnosis of urolithiasis.

Duration of Follow-up and Timing of Discharge from Imaging Follow-up, in Adult Patients with Urolithiasis After Surgical or Medical Intervention: A Systematic Review and Meta-analysis from the European Association of Urology Guideline Panel on Urolithiasis.

CONTEXT: No algorithm exists for structured follow-up of urolithiasis patients. OBJECTIVE: To provide a discharge time point during follow-up of urolithiasis patients after treatment. EVIDENCE ACQUISITION: We performed a systematic review of PubMed/Medline, EMBASE, Cochrane Library, clinicaltrials.gov, and reference lists according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. Fifty studies were eligible. EVIDENCE SYNTHESIS: From a pooled analysis of 5467 stone-free patients, we estimated that for a safety margin of 80% for remaining stone free, patients should be followed up using imaging, for at least 2 yr (radiopaque stones) or 3 yr (radiolucent stones) before being discharged. Patients should be discharged after 5 yr of no recurrence with a safety margin of 90%. Regarding residual disease, patients with fragments ≤4 mm could be offered surveillance up to 4 yr since intervention rates range between 17% and 29%, disease progression between 9% and 34%, and spontaneous passage between 21% and 34% at 49 mo. Patients with larger residual fragments should be offered further definitive intervention since intervention rates are high (24-100%). Insufficient data exist for high-risk patients, but the current literature dictates that patients who are adherent to targeted medical treatment seem to experience less stone growth or regrowth of residual fragments, and may be discharged after 36-48 mo of nonprogressive disease on imaging. CONCLUSIONS: This systematic review and meta-analysis indicates that stone-free patients with radiopaque or radiolucent stones should be followed up to 2 or 3 yr, respectively. In patients with residual fragments ≤4 mm, surveillance or intervention can be advised according to patient preferences and characteristics, while for those with larger residual fragments, reintervention should be scheduled. PATIENT SUMMARY: Here, we review the literature regarding follow-up of urolithiasis patients. Patients who have no stones after treatment should be seen up to 2-3 yr, those with large fragments should be reoperated, and those with small fragments could be offered surveillance with imaging.

Imaging urolithiasis: complications and interventions in children.

Urolithiasis affects people in all age groups, but over the last decades there has been an increasing incidence in children. Typical symptoms include abdominal or flank pain with haematuria; in acute cases dysuria, fever or vomiting also occur. Ultrasound is considered the modality of choice in paediatric urolithiasis because it can be used to identify most clinically relevant stones. Complementary imaging modalities such as conventional radiographs or non-contrast computed tomography should be limited to specific clinical situations. Management of kidney stones includes dietary, pharmacological and urological interventions, depending on stone size, location or type, and the child's condition. With a very high incidence of underlying metabolic abnormalities and significant recurrence rates in paediatric urolithiasis, thorough metabolic evaluation and follow-up examination studies are of utmost importance.

Pediatric urolithiasis: what can pediatricians expect from radiologists?

The incidence of urolithiasis in children has increased over the two last decades. Urolithiasis formation results from urine oversaturation following insufficient water intake, urinary obstruction (notably in cases of congenital uropathies), excess production of an insoluble compound, or imbalance between crystallization promoters and inhibitors. Whereas most urolithiases in adults occur secondary to environmental factors, in children, secondary causes are far more frequent, and 15% are related to genetic causes, most often monogenic. This is especially true in recurrent forms, with early and rapid progression and bilateral stones, and in cases of familial history or consanguinity. Because of differing clinical management, one should rule out cystinuria, primary hyperoxaluria and renal tubular acidosis, among other causes of urolithiasis. As such, a complete biochemical evaluation must be performed in all cases of pediatric urolithiasis, even in cases of an underlying uropathy. Ultrasound examination is the first-line modality for imaging pediatric urolithiasis, allowing both diagnosis (urolithiasis and its complications) and follow-up. US examination should also explore clues to an underlying cause of urolithiasis. This review is focused on the role of imaging in the management and etiological assessment of pediatric urolithiasis. Radiologists play an important role in pediatric urolithiasis, facilitating diagnosis, follow-up and surgical management. A trio of clinicians (pediatric nephrologist, pediatric surgeon, pediatric radiologist) is thus necessary in the care of these pediatric patients.

Three-fluorescence sensor for minute-time scale low-cost analysis of urinary oxalate in urolithiasis metabolic assessment.

Since oxalate plays an important role in the metabolic assessment of urolithiasis, there is need for convenient and efficient methods for oxalate detection. Herein, we report a three-signal fluorescence strategy for oxalate analysis based on the ability of oxalate to reduce Cu2+ to Cu+, and the ability of pyrophosphate-cerium coordination polymeric networks (PPi-Ce CPNs), cadmium telluride quantum dots (CdTe QDs), and N-Methyl Mesoporphyrin (NMM) to selectively detect Cu2+ and Cu+. The detection range was 100 nM to 1 mM, the turnaround time was 6 min, while the limits of detections for PPi-Ce CPNs, QDs and NMM as reporters were 25 nM, 10 nM and 40 nM, respectively. Visual detection of oxalate relied on color change in the solution, which could be observed using the naked eye. The fluorescent system was used for oxalate analysis in 44 urine samples (32 calcium oxalate stone patients, 12 controls without urolithiasis), and the results were consistent with clinical diagnosis and imaging data. Moreover, the visual system was used to analyze 8 urine samples (4 patients and 4 controls), and showed good consistency with clinical diagnosis and computed tomography imaging results. These findings suggest that the method has potential application for the metabolic assessment of urolithiasis.

Spontaneous Forniceal Rupture Identified by Point-of-care Ultrasound.

Spontaneous forniceal rupture is one of the rarest diagnoses of abrupt onset abdominal pain. Moreover, urolithiasis is the most prevalent cause and coexistent condition. Delayed-phased Contrast-enhanced computed tomography scans or intravenous pyelograms are needed for an exact diagnosis in most circumstances. Herein, we report a case of a healthy middle-aged female who presented to the emergency department with flank and abdominal pain. The diagnosis of forniceal rupture was made by the emergency point of care ultrasound. To the best of our knowledge, this is one of the first cases of spontaneous forniceal rupture secondary to urolithiasis diagnosed by the physician-performed ultrasound before confirmation of the diagnosis with computed tomography. In conclusion, emergency physicians and surgeons should be aware of rare conditions like spontaneous forniceal rupture and its sonographic findings to make a rapid diagnosis of urine extravasation so that unwanted complications are avoided. Key Words: Renal stone, Ultrasound, Forniceal rupture, Renal colic, Urinoma.

Comparative Evaluation of Diagnostic Quality in Native Low-dose CT without and with Spectral Shaping employing a Tin Filter in Urolithiasis with implanted Ureteral Stent. / Vergleichende Untersuchung zur diagnostischen Qualität nativer Niedrigdosis-CT ohne und mit spektraler Filterung mittels Zinnfilter bei Urolithiasis mit einliegender Harnleiterschiene.

PURPOSE: Spectral shaping employing a tin filter can be used for dose reduction in CT of the abdomen in patients with urolithiasis. As ureteral stents may be in direct contact with the calculus, a good image quality is mandatory. The goal of this study was to obtain data of the effect of tin filtering on image quality and dose in patients with urolithiasis in direct contact with ureteral stents. MATERIALS AND METHODS: 84 examinations (conventional low dose vs. modified low dose protocol with tin filtering, randomized) were performed in 65 patients (48 men, 17 women, age 55.0 ±â€Š15.2 years (18-90 years), maximum of one examination per protocol). Image quality and visibility of the calculus was rated on a 5-point-Likert scale by 2 experienced radiologists. Quantitative indicators of image quality were signal-to-noise-(SNR) and contrast-to-noise-ratios (CNR) as well as a figure-of-merit (FOM). RESULTS: With a non-inferiority margin of 0.5 points of the 5-point Likert scale, there was non-inferiority of the examinations with tin filter regarding image quality (95 % CI 4.1-4.3, rejection limit 3.5). Non-inferiority regarding visibility of the calculus could be shown (calculus size: 1-2.4 mm: 95 % CI 3.39-4.12; limit 2.73; 2.4-3.8mm: 95 % CI 4.09-4.47; limit 3.65; > 3.8mm: all maximal ratings). Average values of CNR were significantly higher using tin filters (17.0 vs. 10.6). Doses were significantly reduced in the modified protocol (effective dose 1.2 mSv vs. 1.5 mSv; size-specific dose estimate 2.33 mGy vs. 3.09 mGy) with non-significant effect in the subgroup of patients with BMI ≥ 35. CONCLUSION: Even with direct contact between a calculus and ureteral stent, radiation reduced examinations by spectral shaping by tin filters are non-inferior to examinations without tin filtering at a concurrent significant dose reduction. KEY POINTS: · Spectral shaping by tin filter is suitable for dose reduction.. · The image quality in patients with ureteral stents with tin filtering is non-inferior to that in a conventional low-dose protocol.. CITATION FORMAT: · Axer B, Garbe S, Hadizadeh DR. Comparative Evaluation of Diagnostic Quality in Native Low-dose CT without and with Spectral Shaping employing a Tin Filter in Urolithiasis with implanted Ureteral Stent. Fortschr Röntgenstr 2022; 194: 1358 - 1366.