Search Results (393)

Posterior acoustic shadowing is a key diagnostic feature in ultrasound imaging of calcified lesions, such as gallbladder and kidney stones. However, conventional assessment relies primarily on qualitative interpretation, and its underlying structural characteristics remain insufficiently quantified. This study aimed to quantitatively characterize posterior acoustic shadows using wavelet-based texture analysis and to investigate their diagnostic relevance across different expert-defined shadow confidence groups. Ultrasound B-mode images were analyzed from gallbladder stone and kidney stone datasets. Regions of interest (ROIs) were extracted from gallbladder and kidney stone images across three shadow confidence levels (50–60%, 60–80%, and >80%), and multi-scale wavelet features were computed. The results demonstrated a substantial reduction in high-frequency components with increasing attenuation. Total detail energy decreased by approximately 80% in the gallbladder group and 55–60% in the kidney group from low to high shadow confidence levels. Similarly, normalized ratios (E_{detail/approx} and E_detail/total showed consistent decreases, with inter-group differences of approximately 2.3–2.5-fold at 50–60%, which converged to negligible levels (<2.4% difference) at >80%. These findings suggest that wavelet-based energy distributions may provide acoustically interpretable quantitative descriptors of posterior shadow formation in ultrasound stone imaging. Full article

Purpose: This study aimed to determine whether positive admission urine culture is associated with stone burden, renal involvement, pathogen distribution, and measured urinary biochemical profiles in men and women with calcium oxalate stones. Methods: We retrospectively analyzed adults who underwent percutaneous nephrolithotomy or ureterorenoscopy for upper urinary tract stones between 2016 and 2020. Calcium oxalate stones were defined as stones containing ≥50% calcium oxalate monohydrate and/or dihydrate by Fourier transform infrared spectroscopy. Patients were compared by sex and then stratified by admission urine culture status within each sex. Results: Among 1,257 patients, 878 were men and 379 were women. Women had a higher culture-positive rate than men (59.6% vs. 28.2%, p < 0.001), despite lower 24-hour urinary calcium, uric acid, sodium, potassium, phosphorus, and chloride. In men, culture positivity was associated with recurrent stones, renal stone location, larger maximum stone diameter, and lower eGFR, but not with measured 24-hour urinary parameters. In women, culture positivity was associated with renal stone location, larger maximum stone diameter, lower eGFR, and modestly lower urinary calcium. Escherichia coli predominated among culture-positive women, whereas men showed a broader pathogen distribution. Conclusions: Positive admission urine culture was associated with greater stone burden and renal involvement in calcium oxalate stone disease, without a uniformly higher measured urinary biochemical profile. Culture status may provide clinically relevant phenotypic information alongside measured urinary biochemical assessment, although interpretation is limited by the absence of key CaOx-related urinary parameters such as oxalate, citrate, and supersaturation indices. Full article

This in vitro study examined the influence of supersaturation level on the efficacy of different inhibitors in preventing the crystallization of calcium oxalate, uric acid, and cystine. Kinetic–turbidimetric assays were used to determine the induction time of crystallization (t_i) in the absence and presence of different inhibitors. For calcium oxalate, the inhibitory effects of citrate, hydroxycitrate, tartronate, and phytate decreased significantly as the Ca²⁺ concentration increased from 220 mg/L to 240 mg/L. The polyhydroxycarboxylic compounds (citrate, hydroxycitrate, tartronate) can form complexes with calcium ions, decreasing overall supersaturation. Even though phytate also forms complexes with calcium, its urinary concentration is much lower than that of calcium, so the decrease in supersaturation can be considered negligible. For uric acid, theobromine and two of its metabolites (3-methylxanthine and 7-methylxanthine) inhibited the formation of these crystals. For each compound, the efficacy of inhibition decreased as the supersaturation of uric acid increased. For cystine, the inhibitory effect of N-acetylcysteine was lower at pH 4.5 and 5.0 than at pH 6.0. These studies of the crystallization of calcium oxalate, uric acid, and cystine showed that the efficacy of crystallization inhibitors decreased as the level of supersaturation increased. The results demonstrate that, in patients prone to kidney stone formation, the effectiveness of crystallization inhibitors can be improved by reducing the supersaturation of the specific stone-forming compound. Full article

Chronic Kidney Disease of Unknown Etiology (CKDu) is an ongoing global health concern, particularly affecting agricultural communities in equatorial regions. Unlike traditional chronic kidney disease (CKD), CKDu occurs without common risk factors such as diabetes, hypertension, or kidney stones. Its etiology remains poorly understood, with environmental exposures, occupational hazards, and genetic susceptibility proposed as contributing factors. Omic technologies including genomics, transcriptomics, proteomics, metabolomics, and exposomics offer promising avenues to elucidate CKDu pathogenesis by enabling comprehensive molecular profiling and identification of biomarkers. Recent genomic studies have explored single nucleotide polymorphisms (SNPs) linked to kidney injury susceptibility, while transcriptomic analyses have identified differential expression of genes involved in oxidative stress and tubular injury pathways. Proteomic investigations have revealed candidate urinary biomarkers such as heat shock proteins and inflammatory mediators, and metabolomic profiling has highlighted alterations in amino acid and energy metabolism in affected individuals. Exposomic approaches are beginning to characterize cumulative chemical exposures, including pesticides and heavy metals, in endemic regions. This narrative review synthesizes current evidence on the application of omics approaches in CKDu research, highlights knowledge gaps, and proposes future directions for integrating multi-omics studies with machine learning and artificial intelligence approaches. Advancing omics-based investigations may provide critical insights into disease mechanisms, improve diagnostic precision, and inform targeted interventions for vulnerable populations. Full article

Background: Renal colic is a common emergency department (ED) presentation requiring rapid and accurate diagnosis. Point-of-care ultrasound (POCUS) is a fast, radiation-free alternative to CT. The Copetti sign—a rhythmic anteroposterior oscillation of the affected kidney—has been proposed as a dynamic sonographic marker of distal ureteral stones. Methods: In this prospective observational study (June–September 2025), 44 adult patients with suspected renal colic were enrolled at a single-center ED in Baggiovara, Modena, Italy. All underwent standardized POCUS to detect the Copetti sign prior to confirmatory imaging. Clinical, laboratory, and sonographic variables were collected. Associations between the Copetti sign, stone location, stone size, hydronephrosis, urinoma, and management strategy were explored. Associations with conservative management were considered exploratory. Results: The Copetti sign was identified in 70.5% of patients and was significantly associated with distal ureteral stones (74.2% vs. 25.8%, p = 0.005). Copetti-positive patients were more often managed conservatively (77.4% vs. 38.5%, p = 0.019), although this likely reflects the underlying clinical-imaging phenotype and local treatment decisions rather than a validated prognostic endpoint. Conclusions: In this prospective pilot cohort, the Copetti sign was frequently observed and was strongly associated with distal ureteral stone location. Copetti-positive patients were also more often managed conservatively, although this should be interpreted as an exploratory association reflecting clinical decision-making rather than a validated prognostic endpoint. Full article

Melamine, characterized by its high nitrogen content, has been illegally added to food and feed to falsely increase apparent protein levels. However, melamine and its metabolites pose serious risks to human and animal health, including kidney stones, renal failure, and even death, as well as potential carcinogenic effects. Therefore, accurate detection of trace melamine is of great importance and urgency. Electrochemical sensors based on nanomaterials have been widely used for melamine detection due to their high sensitivity, good selectivity, rapid response, and simple operation. In this work, a composite nanosheet-structured electrode was fabricated, and a dense layer of gold nanoparticles was modified on its surface to enhance electrochemical performance. Cyclic voltammetry and electrochemical impedance spectroscopy measurements indicated that this electrode exhibited highly sensitive electrochemical properties. In addition, differential pulse voltammetry was employed for melamine detection, and the results showed a wide linear range of 20–500 nM with an LOD of 4.7 nM. The proposed electrode enabled the detection of melamine in milk samples, exhibiting good anti-interference ability and long-term stability. Full article

Objectives: This study compared the risk profiles, nutrient intake, and kidney function of calcium oxalate stone formers with and without enteric hyperoxaluria. Methods: Thirty-seven patients with calcium oxalate stone disease and enteric hyperoxaluria (cases) and 37 sex- and age-matched idiopathic calcium oxalate stone formers (controls) were enrolled. Patients did not receive any nutritional counseling prior to the start of the study, and they discontinued medications affecting urinary parameters four weeks before their study participation. Anthropometric, clinical, and metabolic parameters were recorded. Dietary and 24-h urinary variables were measured under the habitual diet and under a balanced, standardized diet. The [¹³C₂] oxalate absorption and calcium loading tests were carried out. Results: The median [¹³C₂] oxalate absorption was significantly higher in cases (14.8%) than in controls (8.9%). Under the balanced diet, hypocitraturia, hypomagnesuria, low urine volume and pH value were significantly more common in the case group, whereas hypercalciuria occurred more frequently in the control group, affecting 45.9% of controls and 5.4% of cases. Furthermore, the control group exhibited a greater reduction in urinary calcium excretion under the balanced diet. Urinary oxalate excretion and the ion-activity product index of calcium oxalate were significantly higher under both diets, with a greater decline observed in the case group under the balanced diet. The estimated glomerular filtration rate (eGFR) was lower in cases. A multivariable linear regression analysis revealed a significant association between urine pH and eGFR. Conclusions: Calcium oxalate stone formers with and without enteric hyperoxaluria benefit from a balanced diet and sufficient fluid intake. The reduction in urinary oxalate excretion and the biochemical risk of recurrent calcium oxalate stone formation were even more pronounced in patients with enteric hyperoxaluria. Particular attention should be paid to low urine pH, as it is hypothesized to be a potential indicator of impaired kidney function. Full article

Background/Objectives: Kidney stone patients struggle to attain the recommended fluid intake. Prior work has focused on the strength of habits (i.e., context–behavior associations) for fluid intake, but given the variability in the contexts of daily life, the scope of efforts to create opportunities to drink across contexts may also be important. Methods: A cross-sectional study was conducted among adults with a history of kidney stones (N = 265). Participants identified situations in which they made an effort to have a glass of water nearby (opportunity creation), rated the experienced automaticity of water intake (i.e., habit strength, measured via the Self-Report Behavioral Automaticity Index), and reported past-week fluid intake volumes. Latent class analysis was used to identify distinct subgroups based on the contexts in which individuals created opportunities to drink, and multivariable linear regression was used to examine the associations between habit strength, class membership, and daily fluid intake. Results: Three latent classes were identified based on the scope of opportunity creation across contexts: widespread (27.9% of the sample; water intake: 41.2 $\pm$ 17.1 fl oz), selective (43.4%; water intake: 32.6 $\pm$ 16.33 fl oz), and limited (28.7%; water intake: 19.01 $\pm$ 16.08 fl oz). The widespread class reported stronger habits (22.45 $\pm$ 6.43) and higher water intake than the selective (19.97 $\pm$ 6.20) or limited classes (14.38 $\pm$ 6.81) (all Ps < 0.001). Stronger habits significantly predicted higher daily water intake (b = 0.90, SE = 0.16, p < 0.001). No significant association was found between habit strength and total fluid intake volume (b = 1.06, SE = 0.74, p = 0.17). Conclusions: Habit strength positively predicted water intake for all classes. To increase fluid intake, clinical interventions should help patients develop drinking habits tied to specific daily contexts. Full article

Background: Entrustable Professional Activities (EPAs) that transform competencies into distinct, assessable clinical tasks have not yet been developed for US nephrology fellowships. We created and achieved consensus on a set of nephrology-specific EPAs and aligned them with Accreditation Council for Graduate Medical Education (ACGME) competency standards. Methods: This study was conducted within the University of New Mexico nephrology fellowship program. An initial EPA list was generated by the study team using program objectives, a literature review, and clinician insight. Study participants included eight faculty nephrologists and one nephrology fellow, who completed an online-based three-round modified Delphi consensus-building processes. Each EPA was rated on a five-point Likert scale with consensus requiring strict criteria. Finalized EPAs were independently mapped to ACGME nephrology program requirements. Results: Nine study participants (100% response rate) completed all survey rounds. Through iterative consensus, utilizing strict criteria, a final list of 22 distinct EPAs was created, covering 10 core domains of practice including dialysis management, acute kidney injury, chronic kidney disease, electrolyte abnormalities, hypertension, kidney stones, glomerular disease, pregnancy, transplant care, and education. Finalized EPAs were mapped to 38 different ACGME-required sub-competencies, showcasing diversity and applicability to national expectations. Conclusions: We developed the first consensus-based set of EPAs geared for US nephrology fellowship programs, providing a foundation for standardized assessment and curriculum development that could be implemented across nephrology fellowship programs nationally. Full article

Kidney stone disease is a common urinary system disorder with a continuously rising global incidence, posing a major public health challenge. As a classic traditional Chinese medicine for the treatment of kidney stones, Lysimachia christinae Hance (LCH) has not yet been fully elucidated in terms of its pharmacological mechanism. In this study, a rat model of calcium oxalate kidney stones and a calcium oxalate monohydrate (COM)-induced injury model of human renal tubular epithelial (HK-2) cells were established. Combined with transcriptomic analysis and experimental verification, the therapeutic effect and underlying molecular mechanism of LCH against kidney stones were systematically explored. Results demonstrated that LCH extract significantly reduced serum levels of blood urea nitrogen (BUN) and creatinine (Cr), as well as renal tissue levels of kidney injury molecule-1 (KIM-1) and cystatin-C (Cys-C) in rats with calcium oxalate crystal-induced renal injury, and diminished calcium oxalate crystal deposition and adhesion in rat renal tissues as well as HK-2 cells, thus exerting a robust renoprotective effect. Mechanistically, transcriptome sequencing indicated that the anti-nephrolithiasis effect of LCH was closely related to the inhibition of oxidative stress and ferroptosis. LCH extract reversed CaOx crystal-induced upregulation of NADPH oxidase 2 (NOX2) and downregulation of superoxide dismutase 2 (SOD2), reduced intracellular oxygen species (ROS) levels, downregulated the expression of transferrin receptor 1 (TFR1) and acyl-CoA synthetase long-chain family member 4 (ACSL4) while upregulating that of ferritin heavy chain 1 (FTH1), solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4), and diminished intracellular iron accumulation, thereby effectively ameliorating crystal-mediated renal injury. The present study demonstrates that the therapeutic effect of LCH on kidney stones is closely related to the regulation of the NOX2/ROS signaling axis and ferroptosis, providing novel theoretical evidence for its clinical application. Full article

Objectives: To develop and rigorously evaluate a Hybrid Multi-Path Attention Convolutional Neural Network (HMPA-CNN) for the classification of kidney diseases across heterogeneous institutional datasets and imaging modalities. Materials and Methods: The proposed HMPA-CNN employs dual parallel pathways to disentangle spatial (3 × 3 convolutions) and textural (5 × 5 convolutions) representations, followed by attention-based feature recalibration and gated fusion. Performance was assessed on five geographically distinct datasets comprising 29,148 CT and MRI images collected from Turkey, Bangladesh, Jordan, Iraq, and publicly available international sources. The evaluation framework included three-class tumor discrimination, four-class renal pathology classification, six-class tumor subtyping, binary kidney stone detection, and chronic kidney disease (CKD) assessment under cross-modality conditions. Results: The model achieved 99.76% overall accuracy on the KidneyNeXt three-class dataset, 99.96% on the four-class multi-institutional CT dataset, and 99.74% on the independent Jordan cohort under a four-class configuration. In the more granular six-class tumor subtyping task, overall accuracy was 96.36%. The same architecture achieved 93.85% overall accuracy on the MRI-based CKD classification task, suggesting that the framework can be adapted to a different imaging modality. Across most classification tasks, specificity exceeded 99%, with benign–malignant misclassification remaining below 2%. Performance declined to 91.96% for kidney stone detection, reflecting the intrinsic difficulty of small-object localization in axial CT images. Conclusions: The dual-path architecture consistently preserved high discriminative performance across institutions, diagnostic granularities, and imaging modalities. Its stable specificity and low benign–malignant confusion suggest potential utility as a supportive tool within renal imaging workflows, particularly for screening and structured diagnostic assistance. Clinically, benign–malignant misclassification is the most critical error, as it may delay oncologic evaluation or lead to unnecessary follow-up. Therefore, the model should be used as a decision-support tool rather than an autonomous diagnostic system. Further prospective validation is required to determine its impact in routine clinical practice. Full article

Background/Objectives: There is a seemingly high prevalence of dietary supplement use in the kidney stone population. We aimed to understand patients’ perceptions of dietary supplements and their role in the management of kidney stones. Methods: We performed a standardized survey of patients presenting for management of kidney stones. We investigated the knowledge and use of apple cider vinegar (ACV), turmeric, and cranberry extract, as well as opinions on the safety of dietary supplements and sources of information. Descriptive statistics were used to summarize demographic and survey data. Results: Ninety-five patients were surveyed; 18 (18.9%) patients reported using ACV, 19 (20%) reported using cranberry extract, and 11 (11.6%) reported using turmeric. Similar numbers reported having heard of these dietary supplements being used for kidney stone prevention and/or treatment. Most patients believed these dietary supplements to be probably (ACV, n = 61, 64.2%; cranberry, n = 62, 65.3%; turmeric, n = 61, 64.2%) or definitely (ACV, n = 22, 23.2%; cranberry, n = 28; 29.5%; turmeric, n = 22, 23.2%) safe. For those who had heard about these supplements being used to treat or prevent kidney stones, friends/family (n = 25, 26.3%), online websites (n = 21, 22.1%), and social media (n = 15, 15.8%) were the most common sources of information. Conclusions: Apple cider vinegar, turmeric and cranberry extract have unknown risks or benefits in the management of kidney stones. Furthermore, their impact on stone pathophysiology remains unclear; however, many of our surveyed patient population uses them. Our study provides insight into patients’ use and perception of dietary supplements that clinicians should consider in the management of kidney stones. Further studies are needed to better counsel patients on the safety and efficacy of dietary supplements. Full article

Therapeutic interventions within the urinary system are often limited by the complex and tortuous anatomy of the renal pelvis and ureters, restricting access to deep regions and increasing the risk of mucosal trauma. In this study, we present a multifunctional, magnetically controlled ferrofluid droplet robotic platform engineered for high deformability and precision navigation. A custom electromagnetic actuation system was developed and optimized via COMSOL Multiphysics (version 6.3, COMSOL Inc., Stockholm, Sweden) simulations to generate programmable magnetic fields. Experimental validation in both simplified environments and anatomically realistic 3D-printed urinary tract models demonstrated the droplets’ capacity for controlled locomotion, reversible deformation, and traversing constrictions significantly smaller than their resting diameter. The droplets’ locomotion and extreme deformability are governed by the dynamic balance between the applied magnetic gradient forces, the restoring interfacial tension of the ferrofluid, and the fluidic viscous drag. Quantitatively, the droplets achieved robust translational velocities up to 260 mm/s under single-coil actuation (51 mT, 20 Hz) and 108 mm/s under a more stable dual-coil configuration (51 mT, 8.3 Hz). Furthermore, two clinically relevant functionalities were successfully executed: rapid vibration-induced release of encapsulated dye for targeted drug delivery, and the precise mechanical capture and transport of artificial kidney stones. These results establish a highly versatile platform for minimally invasive urological procedures, highlighting the immense potential of soft magnetic microrobotics for integrated therapeutic applications. Full article

Background and Clinical Significance: Over recent decades, percutaneous nephrolithotomy (PCNL) has emerged as a primary treatment, firmly establishing itself as the cornerstone approach for managing large kidney stones. Postoperative bleeding commonly stems from an arteriovenous fistula (AVF), a connection between a damaged artery with high flow and a damaged vein with low flow, or from a pseudoaneurysm (PA), which involves arterial blood leaking into the tissue, causing a localized hematoma. The preferred technique for addressing such vascular complications is selective trans-arterial angioembolization, widely regarded as the gold standard. Case Presentation: In this article, we present the case of a 42-year-old woman who experienced delayed bleeding eight years after PCNL and a previous angioembolization. The patient presented with macroscopic hematuria, and further investigations, including cystoscopy, contrast-enhanced abdominal-pelvic CT, and angiography, were performed. To stop the bleeding, we identified and performed selective angioembolization (SAE) of a small arterial branch arising from an inferior branch of the right renal artery. Conclusions: To the best of our knowledge, this is the initial documented instance of delayed bleeding manifesting eight years post-PCNL and angioembolization. This occurrence is exceptionally rare, given that the patient exhibited no urological signs or symptoms over the intervening years, and no predictive or risk factors were identified. Full article

Background: Accurate differentiation of kidney diseases such as cysts, tumors, stones, and normal tissue from computed tomography (CT) images remains challenging due to overlapping visual characteristics and variability in data distributions. While deep learning approaches have shown promising results, many existing studies rely on image-level data splitting and focus primarily on accuracy, which may lead to overly optimistic performance and limited clinical reliability. Methods: This study proposes KDH-Net (Kidney Disease Hybrid Network), a hybrid deep learning framework for multiclass kidney disease characterization that integrates EfficientNetB0, ResNet50, and MobileNetV2 through feature-level fusion. A two-stage training strategy is adopted to enhance optimization stability. To ensure realistic performance assessment, experiments on the primary dataset are conducted under a patient-level evaluation protocol, eliminating potential data leakage. The framework further incorporates calibration analysis, statistical validation, and explainable artificial intelligence to evaluate prediction reliability and interpretability. Results: On the patient-level dataset, KDH-Net achieves an overall accuracy of 0.93 with a macro-average F1-score of 0.91, demonstrating balanced performance across all classes. Confidence analysis indicates meaningful alignment between prediction confidence and correctness, while Grad-CAM visualizations highlight anatomically relevant regions associated with each class. Conclusions: The results demonstrate that KDH-Net provides a stable, reliable, and interpretable framework for kidney CT characterization. The proposed system is designed to support clinical decision-making by offering trustworthy predictions under realistic evaluation conditions, rather than replacing clinical expertise. Full article