The mean Hounsfield unit range acquired from different slices produces superior predictive accuracy for pyonephrosis in obstructive uropathy.

PURPOSE: To determine the non-contrast computer tomography imaging features of pyonephrosis and evaluate the predictive value of Hounsfield units (HUs) in different hydronephrotic region slices. MATERIALS AND METHODS: We retrospectively reviewed data from patients with hydronephrosis who had renal-ureteral calculi. All patients were categorized into pyonephrosis and simple hydronephrosis groups. Baseline characteristics, the mean HU values in the maximal hydronephrotic region (uHU) slice, and the range of uHU in different slices (ΔuHU) were compared between the two groups. Univariate and multivariate analyses were performed to identify risk factors for pyonephrosis. RESULTS: Among the 181 patients enrolled in the current study, 71 patients (39.2%) were diagnosed with pyonephrosis. The mean dilated pelvis surface areas were comparable between patients with pyonephrosis and simple hydronephrosis (822.61 mm² vs. 877.23 mm², p=0.722). Collecting system debris (p=0.022), a higher uHU (p=0.038), and a higher ΔuHU (p<0.001) were identified as independent risk factors for pyonephrosis based on multivariate analysis. The ΔuHU sensitivity and specificity were 88.7% and 86.4%, respectively, at a cutoff value of 6.56 (p<0.001), whereas the sensitivity and specificity for detecting pyonephrosis at a uHU cutoff value of 7.96 was 50.7% and 70.9%, respectively (p=0.003). CONCLUSIONS: Non-contrast computer tomography was shown to accurately distinguish simple hydronephrosis from pyonephrosis in patients with obstructive uropathy. Evaluation of the ΔuHU in different slices may be more reliable than the uHU acquired from a single slice in predicting pyonephrosis.

Ultrasound accuracy in evaluating renal calculi in Maysan province.

Renal calculi are a common clinical presentation. While ultrasound (US) is a widely used imaging modality for kidney stone diagnosis due to its accessibility and lower cost, its accuracy compared to computerized tomography (CT), the gold standard, remains understudied. This cross-sectional study evaluated the diagnostic accuracy of ultrasound for detecting and characterizing kidney stones compared to computed tomography (CT). Fifty-six patients with suspected kidney stones based on flank pain underwent abdominal ultrasound to assess stone presence, size, location, and the severity of any hydronephrosis (kidney swelling). These findings were then confirmed with a subsequent non-contrast CT scan. There was a fair agreement between US and CT (Kappa = 0.368) for detecting the stone location. The US could not detect 7 (12.5%) stones, being less sensitive in the middle and upper calyx compared to CT. There was a fair agreement between the US and CT (Kappa = 0.394) for detecting the severity of hydronephrosis. The US was less sensitive to moderate and severe hydronephrosis compared to CT. The abdominal ultrasound demonstrated excellent reliability for stone size measurement (intraclass correlation = 0.924), with CT measurements only slightly larger on average (mean difference 0.9 mm). Although abdominal ultrasound provides reliable stone size assessment, its capacity to accurately localize stones and assess hydronephrosis severity is limited.

The safety and efficacy of Sotn ureteroscopy for renal and upper ureteral calculi: a prospective multicenter randomized controlled trial.

BACKGROUND: Sotn ureteroscopy is a new lithotripsy procedure developed on the basis of ureteroscopy and includes a rigid ureteral access sheath, standard mirror, lithotripsy mirror, and Sotn perfusion aspirator. Thus, we performed a prospective multicenter randomized controlled trial comparing the safety and efficacy of Sotn ureteroscopy in the treatment of renal and upper ureteral calculi. METHODS: In this study, 224 patients with renal and upper ureteral calculi were randomly divided equally into study and control groups from March 2018 to March 2022. All the patients were approved by the hospital ethics committee (proof number: ZF-2018-164-01 and ZF-2018-165-01) of the Second Affiliate Hospital of Guangzhou University of Chinese Medicine in China. The primary outcome was stone-free rate (SFR) assessed by computed tomography on the 1st day and month after treatment and operation duration. The secondary outcome was postoperative complication rate. RESULTS: In total, for upper ureteral calculi, the SFR of 1 day after operation of the Sotn ureteroscopy group was significantly higher than the rigid ureteroscopy group (83.6% vs. 60%, P=0.006). Moreover, operative time (33.7±1.80 vs. 52.9±2.73 min, P<0.005) of the Sotn ureteroscopy group was significantly lower than the rigid ureteroscopy group. Additionally, the SFR of 1 day after operation and operative time for the study group (Sotn ureteroscopy combined with flexible ureteroscopy) and the control group (flexible ureteroscopy alone) were 63.2% and 36.8% (P=0.005), 65.6±4.06 and 80.3±4.91 (P=0.023), respectively. However, there were no significant differences in the SFR of 1 month after operation, success rate of ureteral access sheath placement, and postoperative complications between the two groups (P>0.05). In subgroups with stone diameters ≥1.5 cm and stone CT values ≥1000 Hounsfield units, Sotn ureteroscopy showed more advantages in terms of the SFR of 1 day after operation. Importantly, complications such as ureteral injury, sepsis, fever, and severe hematuria were not statistically different between the two groups (P>0.05). CONCLUSIONS: For renal and upper ureteral calculi, Sotn ureteroscopy has the advantage of a higher SFR of 1 day after the operation and a shorter operative time, suggesting that the Sotn ureteroscopy may have further potential applications in clinics.

Ultrasound-guided renal puncture followed by endoscopically guided tract dilatation vs standard fluoroscopy-guided percutaneous nephrolithotomy for non-opaque renal stones; a randomized clinical trial.

This study was designed to evaluate the non-inferiority of ultrasound puncture followed by endoscopically guided tract dilatation compared to the standard fluoroscopy-guided PCNL. Forty patients with non-opaque kidney stones eligible for PCNL were randomly divided into two groups. The standard fluoroscopy-guided PCNL using the Amplatz dilator was performed in the XRAY group. In the SONO group, the Kidney was punctured under an ultrasound guide followed by tract dilatation using a combination of the Amplatz dilator based on the tract length and an endoscopically guided tract dilatation using a bi-prong forceps in cases of short-advancement. The primary outcome was successful access. In 90% of cases in the XRAY and 95% in the SONO group access dilatation process was performed uneventfully at the first attempt (p = 0.5). In 45% of cases in the SONO group, bi-prong forceps were used as salvage for short-advancement. In one case in the X-ray group over-advancement occurred. One month after surgery, the stone-free rate on the CT-scan was 75% for the X-ray group and 85% for the SONO group (p = 0.4). There were no significant differences in operation time, hospitalization duration, transfusion, or complication rates between the two groups. We conclude that ultrasound-guided renal puncture, followed by endoscopically guided tract dilatation can achieve a high success rate similar to X-ray-guided PCNL while avoiding the harmful effects of radiation exposure and the risk of over-advancement.

A machine learning approach using stone volume to predict stone-free status at ureteroscopy.

INTRODUCTION: To develop a predictive model incorporating stone volume along with other clinical and radiological factors to predict stone-free (SF) status at ureteroscopy (URS). MATERIAL AND METHODS: Retrospective analysis of patients undergoing URS for kidney stone disease at our institution from 2012 to 2021. SF status was defined as stone fragments < 2 mm at the end of the procedure confirmed endoscopically and no evidence of stone fragments > 2 mm at XR KUB or US KUB at 3 months follow up. We specifically included all non-SF patients to optimise our algorithm for identifying instances with residual stone burden. SF patients were also randomly sampled over the same time period to ensure a more balanced dataset for ML prediction. Stone volumes were measured using preprocedural CT and combined with 19 other clinical and radiological factors. A bagged trees machine learning model with cross-validation was used for this analysis. RESULTS: 330 patients were included (SF: n = 276, not SF: n = 54, mean age 59.5 ± 16.1 years). A fivefold cross validated RUSboosted trees model has an accuracy of 74.5% and AUC of 0.82. The model sensitivity and specificity were 75% and 72.2% respectively. Variable importance analysis identified total stone volume (17.7% of total importance), operation time (14.3%), age (12.9%) and stone composition (10.9%) as important factors in predicting non-SF patients. Single and cumulative stone size which are commonly used in current practice to guide management, only represented 9.4% and 4.7% of total importance, respectively. CONCLUSION: Machine learning can be used to predict patients that will be SF at the time of URS. Total stone volume appears to be more important than stone size in predicting SF status. Our findings could be used to optimise patient counselling and highlight an increasing role of stone volume to guide endourological practice and future guidelines.

Intraoperative computed tomography for detection of residual stones in endourology procedures: systematic review and meta-analysis.

BACKGROUND: Success rates in endourological procedures, notably percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS), have demonstrated suboptimal outcomes, leading to more reinterventions and radiation exposure. Recently, the use of intraoperative computed tomography (ICT) scans has been hypothesized as a promising solution for improving outcomes in endourology procedures. With this considered, we conducted a comprehensive systematic review and meta-analysis encompassing all available studies that evaluate the impact of the use of intraoperative CT scans on surgical outcomes compared to conventional fluoroscopic-guided procedures. METHODS: This systematic review was conducted in accordance with PRISMA guidelines. Multiple databases were systematically searched up to December of 2023. This study aimed to directly compare the use of an ICT scan with the standard non-ICT-guided procedure. The primary endpoint of interest was success rate, and the secondary endpoints were complications and reintervention rates, while radiation exposure was also evaluated. Data extraction and quality assessment were performed following Cochrane recommendations. Data was presented as an Odds ratio with 95%CI across trials and a random-effects model was selected for pooling of data. RESULTS: A comprehensive search yielded 533 studies, resulting in the selection of 3 cohorts including 327 patients (103 ICT vs 224 in non-ICT). Primary outcome was significantly higher in the experimental group versus the control group (84.5% vs 41.4% respectively, 307 patients; 95% CI [3.61, 12.72]; p<0.00001; I2=0). Reintervention rates also decreased from 32.6% in the control to 12.6% in the ICT group (OR 0.34; 95%CI [0.12,0.94]; p =0.04; I2= 48%), whereas complication rates did not exhibit significant differences. Radiation exposure was also significantly reduced in two of the included studies. CONCLUSION: This meta-analysis highlights a favorable outcome with intraoperative CT scan use in PCNL procedures, showing a considerable increase in SFR when compared to standard fluoroscopy and nephroscopy. Despite limited studies, our synthesis underscores the potential of ICT scans to significantly reduce residual stones and their consequences for endourology patients, as reinterventions and follow-up ionizing radiation studies.

Is supine a preferred position for percutaneous nephrolithotomy in the pediatric age group? A randomized controlled study.

BACKGROUND: The aim is to evaluate supine versus prone position in mini-percutaneous nephrolithotomy in pediatric renal urolithiasis management. METHODS: A randomized controlled trial was constructed to evaluate supine versus prone position in pediatric PCNL. Seventy pediatric patients with a stone burden ≥1.5 cm were randomized into two groups. RESULTS: Sixty-three patients were available for evaluation in our study with no significant difference in the perioperative demographic data. The supine group showed a shorter operation time of 43.9 min compared to 73.5 min in the prone group. The stone-free rate was higher in the supine group, with a 93.9% SFR compared to 83.3% in the prone group. The supine group showed a shorter hospital stay of 2.0±1.0 days, compared to 3.20±1.56 days in the prone group. No significant difference was seen in the perioperative complication rate and fluoroscopy time between both groups. CONCLUSIONS: Supine mini-percutaneous nephrolithotomy is safe and effective in managing pediatric renal stones, with a higher stone-free rate, less operative time, and less hospital stay compared to the prone position.

Can shear wave elastography predict the success of shock­wave lithotripsy used in renal stones treatment? A prospective study.

OBJECTIVE: To evaluate the usage of shear wave elastography (SWE) in the prediction of the success rate of shock­wave lithotripsy (SWL) treatment of renal stones. PATIENTS AND METHODS: In the present study, SWL was performed for 100 patients presented with renal stones in the duration from May 2022 to August 2023. The patients were divided into 2 groups SWL responders and non-responders. The study compared between the 2 groups in terms of baseline parameters of the patients as age, sex, body mass index (BMI), stone size, stone location, stone density (HU), skin-to-stone distance (SSD), the degree of hydronephrosis and the stone elastography values. RESULTS: There was no statistically significant relation between stone-free rate and degree of obstruction (p = 0.628), stone size (p = 0.390) upper calyceal location (p = 0.17), middle calyceal location (p = 0.66), and renal pelvis location (p = 1.0). Nevertheless, a statistically significant relation was found as regards lower calyceal location, stone density (HU), and stone Elastography values using multivariate analysis. CONCLUSIONS: Measurement of stone density by shear wave elastography (SWE) can be used as an alternative to HU in decision-making before SWL. SWL success depends mainly on stone site, HU, and SWE values.

Identification of kidney stones in KUB X-ray images using VGG16 empowered with explainable artificial intelligence.

A kidney stone is a solid formation that can lead to kidney failure, severe pain, and reduced quality of life from urinary system blockages. While medical experts can interpret kidney-ureter-bladder (KUB) X-ray images, specific images pose challenges for human detection, requiring significant analysis time. Consequently, developing a detection system becomes crucial for accurately classifying KUB X-ray images. This article applies a transfer learning (TL) model with a pre-trained VGG16 empowered with explainable artificial intelligence (XAI) to establish a system that takes KUB X-ray images and accurately categorizes them as kidney stones or normal cases. The findings demonstrate that the model achieves a testing accuracy of 97.41% in identifying kidney stones or normal KUB X-rays in the dataset used. VGG16 model delivers highly accurate predictions but lacks fairness and explainability in their decision-making process. This study incorporates the Layer-Wise Relevance Propagation (LRP) technique, an explainable artificial intelligence (XAI) technique, to enhance the transparency and effectiveness of the model to address this concern. The XAI technique, specifically LRP, increases the model's fairness and transparency, facilitating human comprehension of the predictions. Consequently, XAI can play an important role in assisting doctors with the accurate identification of kidney stones, thereby facilitating the execution of effective treatment strategies.

Advancements in Uric Acid Stone Detection: Integrating Deep Learning with CT Imaging and Clinical Assessments in the Upper Urinary Tract.

INTRODUCTION: Among upper urinary tract stones, a significant proportion comprises uric acid stones. The aim of this study was to use machine learning techniques to analyze CT scans and blood and urine test data, with the aim of establishing multiple predictive models that can accurately identify uric acid stones. METHODS: We divided 276 patients with upper urinary tract stones into two groups: 48 with uric acid stones and 228 with other types, identified using Fourier-transform infrared spectroscopy. To distinguish the stone types, we created three types of deep learning models and extensively compared their classification performance. RESULTS: Among the three major types of models, considering accuracy, sensitivity, and recall, CLNC-LR, IMG-support vector machine (SVM), and FUS-SVM perform the best. The accuracy and F1 score for the three models were as follows: CLNC-LR (82.14%, 0.7813), IMG-SVM (89.29%, 0.89), and FUS-SVM (29.29%, 0.8818). The area under the curves for classes CLNC-LR, IMG-SVM, and FUS-SVM were 0.97, 0.96, and 0.99, respectively. CONCLUSION: This study shows the feasibility of utilizing deep learning to assess whether urinary tract stones are uric acid stones through CT scans, blood, and urine tests. It can serve as a supplementary tool for traditional stone composition analysis, offering decision support for urologists and enhancing the effectiveness of diagnosis and treatment.

Ureteral wall thickness as a predictor for non-invasive treatment success for steinstrasse. Can we save time?

PURPOSE: We aimed to define factors affecting the non-invasive overall treatment success (medical expulsive therapy (MET) ± shock wave lithotripsy (SWL)) for uncomplicated ureteral steinstrasse (SS) clearance. METHODS: We retrospectively evaluated consecutive patients who underwent SWL for renal stones between 2017 and 2021. Patients with uncomplicated SS were included. All patient's demographic and radiological data, e.g., age, gender, pre-SWL stenting, SS site, type, leading stone size in widest diameter (< 10 mm and ≥ 10 mm), ureteral wall thickness (UWT) in mm against the leading stone were collected. If SS was diagnosed, medical treatment was given for 4 weeks. In case of MET failure, either SWL for the leading stones + MET or direct URS was done. Non-invasive treatment success (SFR) was considered if complete clearance of SS occurred with no complications or the need for invasive intervention. RESULTS: A total of 145 patients were included with mean age of 45.9 ± 12.4 years. SFR in case of MET only occurred in 27.9%. Complications happened in 26 patients (17.9%). Non-invasive treatment SFR was achieved in 78 patients (53.8%) totally where SS type I, leading stone size ≤ 10 mm type and decreased UWT around the leading stone increased treatment success. CONCLUSION: Ureteral wall thickness is an important factor predicting SS management success. Besides the decreased UWT, non-invasive management should be offered for type I SS with leading stone ≤ 10 mm.

Evaluation of Technologist-Controlled Factors Used During CT Kidney Stone Examinations.

PURPOSE: To identify technologist-controlled factors to decrease dose and improve image quality and evaluate their use during computed tomography (CT) kidney stone examinations. METHODS: Online scholarly databases were searched to acquire peer-reviewed, published articles involving methods of optimizing radiation dose during CT. These articles were reviewed, and the technologist-controlled factors identified were protocol selection, patient centering in the bore, and scan length. The author retrospectively reviewed CT kidney stone examinations performed at a free-standing emergency department to evaluate the use of these factors. RESULTS: Technologists consistently chose the correct scan protocol. Reviewed literature was used to determine the acceptable variance for positioning at isocenter and overscanning beyond anatomical landmarks. All patient positioning was off-center in the vertical direction, and in 3 of those examinations, patient positioning was off-center more than the 3 cm threshold. Horizontal off-center positioning was less frequent. All examinations had some amount of overscan, with 73.1% of patients being overscanned more than the determined threshold of 10% of total scan length. DISCUSSION: Accurate labeling of protocols at the console assist technologists in choosing protocols correctly. Technologists were inconsistent with patient centering and scan range. The amount of which images were off-center was consistent with previous research studies, while the amount of overscan was less than that found in previous studies. CONCLUSION: Technologists have an important role in optimizing patient radiation dose. Education and quality assurance could help technologists gain awareness of these factors and use them effectively.

Cone Beam Computed Tomography-Assisted Percutaneous Nephrolithotomy in a Hybrid Operating Room: Optimization of Patient Selection.

Background: Cone beam computed tomography (CBCT) enables intraoperative cross-sectional and three-dimensional imaging of the urinary tract. CBCT in a hybrid operating room can be used for intraoperative detection of residual stones and potential additional stone extraction at the end of percutaneous nephrolithotomy (PCNL). This study describes our initial experience with intraoperative CBCT during PCNL and analyzes its role in potentially improving its outcomes. Methods: We conducted a single-center retrospective cohort study at a tertiary referral hospital between 2018 and 2021. The study aimed to evaluate the outcome of patients who underwent intraoperative noncontrast CBCT scan during PCNL. The CBCT scan was performed when the urologist determined the kidney to be endoscopically stone-free. In case any residual fragments were imaged, an additional effort was made to extract them. Patients were divided into three groups based on treatment outcome: stone-free upon CBCT, not stone-free with additional stone extraction after CBCT, and not stone-free without additional stone extraction. Procedure and patient characteristics were recorded to identify factors associated with additional stone extraction during CBCT-assisted PCNL. Results: A total of 102 procedures were included in this study. Intraoperative CBCT scans showed residual calcifications in 58 (57%) cases. In 39 cases, which is 38% of the total population and 61% of the cases with residual calcifications, one or more residual fragments imaged on the intraoperative CBCT-scan were extracted additionally within the same procedure. A higher Guy's Stone Score was associated with a higher likelihood of additionally extracting stones as a result of the CBCT. Conclusions: CBCT-assisted PCNL in a hybrid operating room can lead to additional stone extraction in the same procedure in 37% of all cases and in over 60% of the cases in which residual fragments are imaged. The value of CBCT-assisted PCNL appears to increase in the case of more complex stone surgery cases.

Kidney collecting system anatomy applied to endourology - a narrative review.

OBJECTIVE: To evaluate the surgical anatomy of the kidney collecting system through a narrative review of the literature, highlighting its importance during diagnosis and its approach during surgical procedures for the treatment of renal stones. MATERIAL AND METHODS: We carried out a review about the anatomy of the kidney collecting system. We analyzed papers published in the past 40 years in the databases Pubmed, Embase and Scielo, and we included only papers in English and excluded case reports, editorials and opinions of specialists. RESULTS: Renal collecting system could be divided in four groups: A1 - kidney midzone (KM), drained by minor calyx that are dependent on the superior or the inferior caliceal groups; A2 - KM drained by crossed calyx, one draining into the superior caliceal group and another draining into the inferior caliceal group; B1 - KM drained by a major caliceal group independent of both the superior and inferior groups; and B2 - KM drained by minor calyx entering directly into the renal pelvis. Some details and anatomic variations of the collecting system are related to clinical and radiological aspects, particularly perpendicular calyces, interpyelocalyx space, position of calyces in relation to renal border, classification of the renal collecting system, infundibular diameter and the angle between the lower infundibulum and renal pelvis. CONCLUSION: The knowledge of intra-renal collecting system divisions and variations as the angle between the renal pelvis and lower infundibula, position of the calices in relationship with renal edge and the diameter and position of the calyces are important for the planning of minimally invasive renal surgeries.

Safety and Efficacy of "Dusting and Pop-Dusting" with High-Power Laser for Treatment of Large Pediatric Stones with Ureteroscopy and Lasertripsy: Prospective Outcomes from a University Teaching Hospital.

Introduction: The wide use of high-power laser has changed the landscape of ureteroscopy and lasertripsy (URSL). We wanted to look at the role and outcomes of high-power holmium:yttrium-aluminum-garnet laser for URSL in pediatric stone disease. Methods: A prospective analysis of consecutive pediatric patients treated with "Dusting and Pop-dusting" using a high-power laser was done between January 2016 and March 2022. The project was registered with our audit committee. Data were analyzed for patient demographics, stone characteristics, operative details, procedural outcomes, and complications. Stone-free rate (SFR) was defined as fragments ≤2 mm on postoperative ultrasound imaging 2-3 months after the procedure. Results: A total of 35 patients underwent 43 procedures (1.2 procedure/patient) during the study period with a mean age of 9.4 years (range 1-16 years) and a male:female ratio of 13:22. The stone location was in the kidney in 32 (91.4%) patients of which 8 were in multiple renal locations. The mean stone size was 18 mm (range 10-39 mm), with the pre- and post-stent rates of 37% and 56%, respectively. An access sheath was used in 19 (44%) procedures. The overall SFR on ultrasound scan was 94% (n = 33) with no procedural complications noted in our series and a mean length of stay of 0.9 days. Conclusion: Pediatric URSL using a high-power laser achieves a high SFR even for large and multiple renal stones with no complications noted in our prospective series. Parents must, however, be counseled about the need for staged procedures, which might be needed for large stones.

[Imaging in nephroureterolithasis]. / Bildgebung bei Nephroureterolithiasis.

In the acute diagnostics of a suspected nephroureterolithiasis, ultrasonography should be the examination modality of choice. In cases of suspected urolithiasis, unclear flank pain with fever or in cases of a solitary kidney, a noncontrast computed tomography (CT) scan should always subsequently be performed. If the sonography findings are inconclusive in pregnant women a magnetic resonance imaging (MRI) examination can be considered. If there are indications for urinary diversion, a retrograde imaging study should be performed as part of the urinary diversion. This or CT imaging is also suitable for preinterventional imaging before shock wave lithotripsy, percutaneous nephrolithotomy or ureteroscopy. Postinterventional imaging is not always necessary and sonography is often sufficient. In a conservative treatment approach an abdominal plain X­ray can be used for follow-up assessment.