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Background Midureteral stenosis is very rare in children and can cause congenital hydronephrosis. We report our experience treating children with congenital midureteral stenosis at our center, focusing on the differences in preoperative diagnosis and treatment compared with other congenital obstructive uropathies. Methods We retrospectively reviewed the medical records of 26 children diagnosed with congenital midureteral stenosis at our center between January 2007 and December 2020, such as preoperative examination methods, intraoperative conditions, and postoperative follow-up results. Results Of the 1625 children treated surgically for ureteral narrowing, only 26 (1.6%) were diagnosed with midureteral stenosis, including 15 infants and 11 children. Eighteen (69.2%) were boys, 13 (50%) were affected on the left side, and 23 (88.5%) had isolated ureteral stenosis. Overall, 13 (50%) of the children presented with prenatal hydronephrosis, and 13 (50%) presented with abdominal pain or a mass. All the children had undergone urinary ultrasound and intravenous urography preoperatively; the diagnostic rate of ultrasound was 92.3%. Only 7 (26.9%) children had undergone pyelography. All the children had undergone surgery. The ureteral stenotic segment was less than 1 cm long in 25 (96.2)% of the children. The mean follow-up duration was 22 months (range: 6–50 months). One child developed anastomotic strictures. Urinary tract obstruction was relieved in the other children without long-term complications. Conclusions Congenital midureteral stenosis is rare, accounting for 1.6% of all ureteral obstructions, and its diagnosis is crucial. Urinary ultrasound has a high diagnostic rate and should be the first choice for midureteral stenosis. Retrograde pyelography can be used when the diagnosis is difficult, but routine retrograde pyelography is not recommended. Congenital ureteral stenosis has a relatively short lesion range, largely within 1 cm. The treatment is mainly resection of the stenotic segment and end-to-end ureteral anastomosis, with a good prognosis.

Introduction Pyelocalyceal diverticulum is a rare disease sometimes difficult to distinguish from cysts. We report a case of urothelial carcinoma originating from a pyelocalyceal diverticulum, difficult to distinguish from cystic renal cell carcinoma preoperatively. Case presentation A 51‐year‐old Japanese man complained of gross hematuria. Computed tomography revealed a solid mass in one of the many cystic lesions in the left kidney. He was diagnosed with left cystic renal cell carcinoma and underwent retroperitoneal laparoscopic nephrectomy. Pathological examination revealed high‐grade invasive urothelial carcinoma arising within the renal pyelocalyceal diverticulum. The definitive diagnosis was high‐grade invasive urothelial carcinoma (pT3). In retrospect, the retrograde pyelography findings indicated the cyst and urinary tract connection. Residual ureterectomy and adjuvant chemotherapy were later performed. The patient has since been recurrence‐free. Conclusion Whether cystic renal cell carcinoma is suspected on imaging, pyelocalyceal diverticulum should be considered a differential diagnosis, though unlikely to be encountered in daily practice.

OBJECTIVE To present long-term outcome of Yang-Monti ileal ureter, with a focus on patients with mild/moderate loss of kidney function and solitary kidney. PATIENTS AND METHODS Between March 2001 and December 2019, Yang-Monti ileal ureter was performed on 36 patients with ureteric defects and median age 46.5 years. Of these, 4, 14, 15 and 3 patients had stage 1, stage 2, stage 3a and stage 4a chronic kidney disease, respectively; 6 had solitary kidney. Patients were regularly followed for complications, morphological, and functional outcome. RESULTS Ureteric stricture etiology was iatrogenic (16), Bilharzial (7), tuberculous (4), retroperitoneal fibrosis (5), malignancy (3), and gunshot injury (1). The median (range) ureteric defect length was 11 (8-16) cm. Four grade 1/2 postoperative Clavien-Dindo complications were noted. Median follow-up was 68 months (range 12-215). Intestinal obstruction developed in 1 patient and urinary tract infection in 10. At last follow-up, serum creatinine, split renographic clearance, and estimated glomerular filtration rate showed significant improvement compared to preoperative values, in the whole series, in cases with chronic kidney disease (stages 2, 3a and 3b) and solitary kidney. Four cases with chronic kidney disease (stage 3) showed deterioration of the kidney function parameters. Magnetic resonance urography showed improvement of hydronephrosis in most patients. No metabolic complications were noted. CONCLUSION Yang-Monti Ileal ureter is durable and effective in improving kidney function with few complications. It can be safely used in cases of mild/moderate kidney function loss and solitary kidney. A threshold eGFR

Background The incidence of ectopic kidneys is 1:12,000 clinically and 1:900 postmortem. Patients with pelvic mal-rotated kidneys are more susceptible to recurrent urinary tract infections, recurrent renal stones, and renal injury. Fusion of the kidney lower poles is relatively common compared to other types of renal anomalies. Case presentation We present the case of a 36-year-old Sudanese female patient who presented with a long history of recurrent urinary tract infections unresponsive to antibiotics. Ultrasound scan revealed bilateral pelvic kidneys. Computed tomography (CT) urography confirmed bilateral ectopic fused kidneys, with the left kidney mal-rotated (renal pelvis facing upwards and laterally). Kidney infection secondary to vesicoureteral reflux was diagnosed. Antibiotics were prescribed according to culture and sensitivity. The patient responded well to ciprofloxacin. Conclusion A history of recurrent urinary tract infections without an apparent cause is highly suggestive of renal anomaly and should be investigated expediently. Ultrasonography or CT imaging may be utilized to aid in diagnosis. Early recognition may help prevent the high risk of end-stage renal failure associated with anomalies.

Upper urinary tract obstructions (UTOs) are blockages that inhibit the flow of urine through its normal course, leading to impaired kidney function. Imaging plays a significant role in the initial diagnosis of UTO, with anatomic imaging (primarily ultrasound (US) and non-contrast computed tomography (CT)) serving as screening tools for the detection of the dilation of the urinary collecting systems (i.e., hydronephrosis). Whether hydronephrosis represents UTO or a non-obstructive process is determined by functional imaging (typically nuclear medicine renal scintigraphy). If these exams reveal evidence of UTO but no discernable source, multiphase contrast enhanced CT urography and/or dynamic contrast enhanced MR urography (DCE-MRU) may be performed to delineate a cause. These are often performed in conjunction with direct ureteroscopic evaluation. While contrast-enhanced CT currently predominates, it can induce renal injury due to contrast induced nephropathy (CIN), subject patients to ionizing radiation and is limited in quantifying renal function (traditionally assessed by renal scintigraphy) and establishing the extent to which hydronephrosis is due to functional obstruction. Traditional MRI is similarly limited in its ability to quantify function. DCE-MRU presents concerns regarding nephrogenic systemic fibrosis (NSF), although decreased with newer gadolinium-based contrast agents, and regarding cumulative gadolinium deposition in the basal ganglia. DCE-MR CEST urography is a promising alternative, employing new MRI contrast agents and imaging schemes and allowing for concurrent assessment of renal anatomy and functional parameters. In this review we highlight clinical challenges in the diagnosis and management of UTO, identify key advances in imaging agents and techniques for DCE-MR CEST urography and provide perspective on how this technique may evolve in clinical importance.

We report the reliability of computerized tomography urography and ureteroscopy in the diagnosis and management of upper tract urothelial carcinoma.From 2015 to November 2018 we prospectively collected and retrospectively analyzed 244 cases of ureteroscopy with available preoperative computerized tomography urography. Computerized tomography urography was categorized as positive, suspicious, unlikely and negative. Correspondence between imaging, ureteroscopy and histology was analyzed. The therapeutic indication, based on 2020 EAU Guidelines and patient clinical data, was recorded before and after ureteroscopy. Cohen's Kappa was used for agreement analysis. Logistic regression was used for prediction of positive ureteroscopy.Ureteroscopy was positive for upper tract urothelial carcinoma in 107/115 (93%), 48/77 (62.3%), 15/27 (55.6%) and 12/25 (48%) cases with positive, suspicious, unlikely and negative computerized tomography urography, respectively. On cytohistology the result was confirmed in 164/182 (90.1%) cases. The positive predictive value of a filling defect, stenosis, thickening and hydronephrosis on computerized tomography urography was 87.7% (121/138 cases), 65.6% (21/32), 69.6% (64/92) and 79.7% (59/74), respectively. On multivariate analysis a filling defect (95% CI 2.76-11.5, OR 5.63, p0.0001) or hydronephrosis (1.04-6.18, OR 2.52, p=0.04) was associated with ureteroscopy outcome. Among cases with positive computerized tomography urography and ureteroscopy, the lesions differed in dimensions (20/107), number (14/107) and site (11/107), for a total of 45/107 (42.1%) cases. The indication of elective treatment changed after ureteroscopy in 37/76 (48.1%) cases (Kappa=0.31), as 17/28 (60.7%), 11/20 (55%) and 11/28 (39.2%) indications were confirmed for endoscopic management, ureterectomy and nephroureterectomy, respectively.The complementary use of computerized tomography urography and ureteroscopy in the diagnostic workup of upper tract urothelial carcinoma should be evaluated.

Percutaneous nephrolithotomy (PCNL) is a standard procedure for large renal stones. Contrast (traditionally) as well as air is being used to delineate pelvi-calyceal system (PCS) to perform initial puncture. Contrast, when used has certain disadvantages including poor differentiation of anterior and posterior calyces. In this interim analysis of 122 patients of a prospective study subjects were stratified in two groups: in group 1, contrast was used while in group 2, air was used to delineate PCS. Out of 122,103 patients underwent puncture by contrast or air exclusively while 19 patients required mix of contrast and air (14 patients failed puncture using contrast while 5 using air). Mean dosage of radiation exposure (8.43 vs. 14.26 mGy), duration of radiation exposure (0.66 vs. 1.02 min), access time (3.72 vs. 5.84 min), were less in group 2 as compared to group 1. 84.5% of patients underwent puncture in single attempt in group 2 as compared to 56.25% in group 1. Five patients had post-operative fever and one had trans-pleural tract dilation. Complete stone clearance was seen in 94.8% of patients using air to only 75% of patients using contrast. Conclusion: Air pyelogram is a feasible, safe, cost effective and efficient access alternative to contrast pyelogram and in difficult situation a mixture of both is better than using one.

Background: Urinary stones affect 8%–15% of the world population. In Nigeria, contemporary reports have shown that the incidence of urinary stones is rising. The distal ureter has been described as the most common location of ureteric stones. This study seeks to review our experience in the ureteroscopic management of distal ureteric stones with a view to appraising the stone clearance rate and the complications seen in our patients. Patients and Methods: This descriptive study reviewed the record of 21 patients, who had semirigid ureteroscopy and pneumatic lithotripsy for distal ureteric stone between October 2015 and September 2018. All patients had computed tomography urography preoperatively to locate the stone. Data on patients' demographics, indication for the surgery, location and size of stone, preoperative double-J (DJ) placement, postoperative DJ stent placement, intraoperative and postoperative complications, and status of stone clearance were retrieved and subjected to statistical analysis. Results: The mean age of the patients was 37.95 ± 11.09 (range, 21–67) years. The mean stone size was 8.06 ± 2.87 mm with a range of 4.8 mm–15.0 mm. Out of the 21 patients, 20 (95.2%) had the procedure for recurrent ureteric colic and 1 (48%) was for hematuria. Four (19.0%) patients had DJ stent preoperatively, whereas 17 (81.0%) patients did not have. Fourteen (66.7%) patients had intraoperative ureteric dilatation. Postoperative DJ stent was placed in 17 (81.0%) patients, whereas 4 (19.0%) patients did not have. Three (14.3%) patients had mucosal flap, 6 (14.3%) had mucosal abrasion, 2 (9.5%) had bleeding, 1 (4.8%) patient had transient hematuria postoperatively, and 2 (9.5%) patients had urinary tract infection. Nineteen (90.5%) patients had complete clearance in a single surgery. Two (9.5%) patients had symptomatic residual fragments that required repeat ureteroscopy. Conclusion: Our study has shown that ureteroscopy is a useful and safe technique in the removal of stones in distal ureter.

Multidetector computed tomographic urography (MDCTU) is not yet sufficient to be used in the clinical staging of upper tract urothelial carcinoma (UTUC). This study aimed to compare the diagnostic accuracy of MDCTU T stage classification and pathologic T staging for UTUC. We retrospectively evaluated 125 patients with UTUC who underwent preoperative MDCTU. A single radiologist classified the MDCTU pattern of the tumors as either low or advanced T stage for localized or locally advanced tumors, respectively. The diagnostic values of MDCTU for locally advanced tumors and the kappa agreement between MDCTU and pathologic T stage were investigated. Among 85 pathologic low T stage (Ta–T2) tumors, 71 low T stage tumors were correctly detected by MDCTU, while 30 out of 40 advanced T stage (T3–T4) tumors were correctly diagnosed by MDCTU. MDCTU led to under-staging in 8% (10/125) tumors and over-staging in 11.2% (14/125) tumors. Therefore, the overall accuracy of MDCTU in the diagnosis of low and advanced T stage tumors was 80.8% (101/125 patients). The sensitivity for advanced T stage tumors was 75% (30/40), the specificity was 83.5% (71/85), and the positive and negative predictive values were 68.1% (30/44) and 87.6% (71/81), respectively. The kappa agreement value between the MDCTU T stage and pathologic T stage was 0.57 (95% confidence interval (CI) 0.42–0.72), which was statistically significant (P = 0.001). MDCTU T stage classification may be relatively accurate for the detection and staging of UTUC correspondence with a pathologic stage.

OBJECTIVE: To evaluate the diagnostic accuracy of magnetic resonance urography (MRU) and determine its value for detecting ureteric obstruction. METHODS: The electronic databases, including PubMed, Embase and the Cochrane library, were systematically searched for studies published throughout September 2018. The summary of sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and receiver operating characteristic (ROC) curves was assessed to evaluate the diagnostic accuracy of MRU. Subgroup analyses were conducted based on the mean age of the included patients (adults or children). RESULTS: Eight studies with a total of 594 patients were included. The summary of the sensitivity and specificity of MRU for diagnosing ureteric obstruction was 0.94 and 0.87, respectively. Furthermore, the pooled PLR and NLR were 7.33 and 0.07, respectively. The DOR of MRU for detecting ureteric obstruction was 95.12. In addition, the summary of the area under the ROC of MRU was 0.96. Finally, the specificity, PLR and area under the ROC of MRU for diagnosing ureteric obstruction in adults were higher than children, while the sensitivity of MRU in adults was lower than children. CONCLUSIONS: These findings suggested a relatively high diagnostic value of MRU for detecting ureteric obstruction. Moreover, the diagnostic accuracy of MRU in adults was higher than in children. KEY MESSAGE: Magnetic resonance urography (MRU) in detecting ureteric obstruction has relatively better sensitivity, specificity, PLR, NLR, DOR and AUC. The diagnostic value, including specificity, PLR and AUC of MRU in adults, was higher than in children, while the sensitivity of MRU in adults was lower than in children.

Purpose: To investigate the association between preoperative retrograde pyelography (RGP), conducted to evaluate upper tract urothelial carcinoma (UTUC), and intravesical recurrence (IVR) after radical nephroureterectomy (RNU). Materials and Methods: Of 114 patients that underwent RNU, 72 patients without preoperative ureteroscopy and a history of bladder tumor were selectively enrolled. Variables associated with IVR were identified. Results: RGP was performed at a mean duration of 24.9 days prior to RNU in 41 (56.1%) of study subjects. During the mean follow-up period of 64.5 months, IVRs were identified in 32 (44.4%) patients at 22.3±18.8 (mean±SD) months after RNU. Despite similar tumor characteristics in the RGP and non-RGP groups, the incidence of IVR was considerably higher in the RGP group (63.4%) than in the non-RGP group (19.4%, p pT2; 53.1% vs. 17.5%), preoperative hemoglobin (12.8±1.36 vs. 13.9±1.65), preoperative creatinine (1.29±0.32 vs. 1.11±0.22), and preoperative RGP (81.3% vs. 37.5%), respectively. Multivariate Cox regression model showed that tumor location (p=0.020, HR=2.742), preoperative creatinine level (p=0.004, HR=6.351), and preoperative RGP (p=0.045, HR=3.134) independently predicted IVR. Conclusion: Given the limitations of retrospective single-center series, performance of RGP before RNU was shown to have a negative effect on IVR after surgery.

Purpose: The current study evaluated the prevalence of urologic disease among patients with hematuria referred for computerized tomography (CT) urography to determine which patients require investigation with CT urography. Methods: We retrospectively reviewed radiology reports of 1046 CT urograms performed for the indication of microscopic (43.7%) or gross hematuria (56.3%). Urological findings were categorized as negative, benign, or suspicious (pathologically confirmed) for malignancy. Results: Of 1046 CT urograms performed, 53.5% were negative, 36.4% were benign, and 10% were suspicious for malignancy. The most common benign finding was urolithiasis (22.3%). Overall, urinary tract malignancies were present in 3.6% of patients, and the rate was significantly higher ( P < .001) for gross (5.8%) than microscopic hematuria (0.9%). CT urography identified 0.6% patients with upper urinary tract malignancies; the malignancy rate was significantly higher ( P = .038) for gross (1%) than microscopic hematuria (0%), and no significant sex ( P = 1.00; male = 0.6%, female = 0.6%) or age ( P = .600; < 50 years = 0%, ≥ 50 years = 0.7%) differences were observed. Logistic regression revealed that being male was associated with gross hematuria (odds ratio [OR] = 2.92), and that both age and gross hematuria (ORs = 1.06 and 5.13, respectively) were associated with malignancy. Conclusions: CT urography found no upper urinary tract malignancies in 99.4% of patients presenting with hematuria, including all patients with microscopic hematuria and those with gross hematuria

Antegrade pyelography (APG) is a useful modality for imaging the upper urinary tract. Little scientific evidence exists concerning optimal pressure while performing an APG. Methods of implementation seem to vary between hospitals as no specific guideline exists. Our aim was to describe current practice patterns in pre-procedural prophylaxis, describe methods of contrast administration, and estimate rate of complications during APG as reported by urologist, in order to stimulate discussion on defining guidelines. A digital questionnaire with 16 questions concerning APG was set out among EAU members via an ESUI twitter link. Fifty urologists from different centers responded. Outcomes were use of antibiotics, used pressure in upper urinary tract, and estimated urosepsis prevalence. Percentages and confidence intervals (95% CI) were calculated. Forty-two percent (95% CI 30–56) of respondents stated that antibiotic prophylaxis was always administered. Fifty-two percent (95% CI 38–65) of urologists sometimes performed a pre-procedural culture. Seventy percent (95% CI 56–81) indicated that administration of contrast during APG was performed using a syringe. A local guideline was only used in 8% of cases (95% CI 2.8–17.9) The self-estimated average percentage of urosepsis as a result of performing an APG was mentioned to be 4% (range 0–20%). Despite a considerable risk of urosepsis, no guideline or consensus exists on how to perform APG. This is urgently needed in order to prevent complications. Low response rate is a major limitation of these findings.

Due to the special anatomy and physiology of the avian urinary system, the value of diagnostic imaging techniques differs from the use in mammals. The diagnostic imaging methods regularly used in practice to evaluate the avian kidneys are often limited to traditional radiography and ultrasonography, whereas other imaging modalities (urography, scintigraphy, computed tomography, MRI) are rarely used. Furthermore endoscopy may be performed and taking a renal biopsy may be considered. The article describes common indications for imaging techniques used to diagnose urinary tract disease as well as its anatomic and pathologic demonstration.

Objectives: To describe the feasibility and safety of ultrasound-guided percutaneous ante- grade pyelography (US-PAP) in pet guinea pigs (Cavia porcellus) with suspected ureteral obstruction. Materials and methods: Six adult pet guinea pigs (4 females and 2 males, all intact) were evaluated for suspected ureteral obstruction. The mean weight of the guinea pigs was 0.8 ± 0.25 kg (range 0.4–1.1 kg), and mean age was 4.07 ± 1.63 years (range 2–7 years). All ani- mals were free from comorbid diseases, had clinical signs of urologic disease and were referred based on either strong clinical suspicion of, or diagnostic imaging of ureteral obstruction. Data on signalment and clinical examination findings, response to anaesthesia and imaging findings were recorded. Results: Partial ureteral obstruction was confirmed in all guinea pigs but one, in which a complete ureteral obstruction occurred. Uroliths were in both ureters of 5 cases and in both the left renal pelvis and ureters in 1 case. All guinea pigs showed a normal appetite and regular defaecation within 2 h following the procedure. No intraoperative or immediate post- operative complications were encountered after the procedure. The only complication was contrast medium leakages in the subcapsular perinephric, retroperitoneal and, in one case, peritoneal space, which caused no overt clinical consequences afterwards. In one male patient, mobilisation of the ureteral calculus occurred and the urolith was found in the urin- ary bladder on the radiograph taken after contrast medium injection. Clinical significance: The US-PAP technique is a useful, safe and easy-to-perform diagnostic tool in guinea pigs with hydronephrosis and hydroureter.

Congenital abnormalities of the kidney and urinary tract include a wide range of malformations ranging from asymptomatic to life-threatening conditions. Although pediatric urogenital system imaging is based on the use of US (pre- and postnatal), voiding cystourethrography and scintigraphic study, magnetic resonance (MR) urography plays a fundamental role in the classification and management of congenital abnormalities of the kidney and urinary tract, giving an overview of the different clinical pictures, thanks to its panoramicity and high anatomical detail. In fact the anomalies of the urinary tract are phenotypically variable because they can affect simultaneously several segments of different embryonic derivation, with complex clinical pictures; they can appear both as isolated phenotypes or as complex malformative conditions, involving renal parenchyma, collecting system and bladder. A deep knowledge of this complex embryogenesis and its possible phenotypic patterns allows a correct interpretation of MR urography images. We describe the embryology and pathophysiology of congenital abnormalities of the kidney and urinary tract as well as MR urography technique and findings. Congenital abnormalities of the kidney and urinary tract are classified into four groups: (1) obstruction (proximal, middle and distal), (2) budding with respect to the Wolffian duct (site and number of ureter), (3) ascent and rotation (ectopia, malrotation and fusion of kidney) and (4) anomaly of metanephric differentiation (dysplasia, megapolicalycosis).

Three-phase CT urography (CTU) is the gold standard for evaluating the upper urinary tract in patients with hematuria. We aimed to evaluate the accuracy of CTU for detecting upper urothelial cell carcinomas (UCC) in patients with hematuria and negative cystoscopy. Secondly, we aimed to determine the tumor visibility on each CTU phase. This retrospective study included all patients with hematuria referred to CTU after a negative cystoscopy during 2016 and 2017. The original CTU reports were dichotomized as negative or positive. All patient charts were reviewed after a minimum of 18-month follow-up in order to register missed cancers. The results of biopsies and clinical follow-up were used as the reference standard. Two reviewers retrospectively evaluated the tumor visibility of each CT sequence in all true-positive CTUs. We included 376 patients with hematuria who underwent CTU after a negative cystoscopy. Macroscopic and microscopic hematuria occurred in 87% (327) and 13% (49), respectively. The incidence of upper urothelial cell carcinoma was 1.9% (7), and the sensitivity of CTU was 100% (95% CI, 59–100), specificity was 99% (95% CI, 98–100), positive predictive value was 88% (95% CI, 47–99), and negative predictive value was 100% (95% CI, 99–100). The accuracy was 99% (95% CI, 90–100). All UCCs were visible on the nephrographic phase for both reviewers. CTU is highly accurate for detecting upper UCCs. All cases were seen on the nephrographic phase. This suggests that the CTU protocol can be simplified. • CT urography is highly accurate for detecting upper urothelial cell carcinomas. • All cancers were seen on the nephrographic phase. • All cancers were detected in patients with macroscopic hematuria.

Objective To model the risk of radiation-induced malignancy from computed tomography urography (CTU) in evaluation of gross hematuria and contrast this with the benefits of urinary tract cancer detection when compared to renal ultrasound. Methods A PUBMED-based literature search was performed to identify model inputs. Estimates of radiation-induced malignancy rates were obtained from the Biological Effects of Ionizing Radiation VII report with dose extrapolation using the linear no-threshold model. Results Male gender and age over 50 years were associated with a relative risk of upper tract malignancy of 2.04 and 2.95, respectively. The risk of upper tract malignancy missed by renal ultrasound ranged from 0.055% in females under 50 to 0.51% in males over 50. Risk of CTU-induced malignancy with associated loss of life expectancy ranged from 0.25% and 0.027 years in females under 50 to 0.08% and 0.0054 years in males over 50. For CTU to be superior to renal ultrasound, an undiagnosed upper tract malignancy would have to carry a loss of life expectancy of 49.2 years in females under 50, 13.4 years in males under 50, 2.6 years in females over 50, and 1.1 years in males over 50. Conclusion In low-risk patients, CTU for evaluation of gross hematuria may carry a significant risk of radiation-induced secondary malignancy relative to the diagnostic benefit offered over renal ultrasound

Computerized tomography urography is used to evaluate patients with gross or microscopic hematuria. Computerized tomography urography is a high radiation dose scan and, thus, it confers a higher risk of secondary malignancy. A computerized tomography urography split bolus protocol reduces radiation exposure but it may reduce sensitivity. In this study we used a theoretical cohort of patients with hematuria in which to model the risk of missing malignancies against the benefit of averting secondary malignancies.We calculated the prevalence of renal cell carcinoma and upper tract urothelial carcinoma in patients with hematuria by pooled analysis of cohort studies, which in conjunction with split bolus sensitivity allows for the estimation of missed malignancies. The number of prevented secondary malignancies was calculated from lifetime attributable risk estimates. Sensitivity analyses were run to determine the minimum sensitivity required for a net population benefit.Estimates of split bolus computerized tomography urography sensitivity ranged from 80% to 100% (mean 95.2%). At the low estimate of 80% sensitivity split bolus computerized tomography urography was beneficial in men and women with microscopic hematuria at ages less than 50 and less than 60 years, respectively. An increase in sensitivity to 90% improved the benefit 1 decade in each gender, representing 68.8% of patients with microscopic hematuria. The overall population of patients with microscopic hematuria benefited from split bolus computerized tomography urography at 91.1% sensitivity. However, in patients with gross hematuria the threshold for an overall population benefit was high at 98.4% sensitivity.Exposure to ionizing radiation risks causing secondary malignancy. These data indicate that split bolus computerized tomography urography may be performed safely in 70% of the population of patients with microscopic hematuria. However, it is not currently advisable in patients with gross hematuria or in other patients at high risk.

Trauma to the genitourinary system includes blunt and penetrating injuries to bladder and ureters. These are rare injuries and are overlooked as other abdominal and pelvic injuries often take priority. Delayed diagnosis can lead to significant morbidity and mortality. Computed tomography has taken a central role in the imaging of the ureters and bladder. This article reviews the anatomic relationships, mechanisms of injury, and clinical presentation to help physicians determine when bladder and ureteral injuries should be suspected and further imaging should be pursued. Radiologic evaluation of bladder and ureteral injury with CT cystography and CT urography, respectively, will be reviewed. CT cystography and CT urography are effective tools in identifying potentially serious injuries to the genitourinary system. Timely recognition of these injuries can be crucial for the overall management and prognosis.

Purpose To describe the morphology and function of duplicated collecting systems in pediatric patients undergoing functional MR urography (fMRU). Methods This is a HIPAA compliant IRB approved retrospective study of all patients with duplicated renal collecting systems undergoing fMRU at our institution between 2010 and 2017. Two pediatric radiologists evaluated the studies to determine the presence, morphology and function of duplicated collecting systems using both T2-weighted and dynamic post-contrast fat saturated T1-weighted images. Assessed morphologic features included pelvic and calyceal dilation, partial or complete ureteral duplication, ureteral dilation, ectopic ureteral insertion and ureteroceles. Functional analysis was carried out per moiety. Results A total of 86 examinations (63 girls; 23 boys), median age 2.6 years (Standard Deviation 6.4 years, interquartile range: 0.4–10.3 years) and 107 kidneys (39 right; 30 left and 19 bilateral), which yielded 214 evaluable moieties, were included in the final sample. One hundred and sixty-three (76.1%) of the moieties had normal morphological features and normal functional results (average calyceal transit time and renal transit time of 2 min 28 s and 3 min 16 s, respectively). The remaining 51 moieties (23.8%) were hypoplastic or dysplastic. Seventy-seven (35.9%) had pelvic and calyceal dilation. Slightly more than half of the kidneys had complete ureteral duplication (60/107; 56%); 50 (50/107, 46.7%) had ectopic ureters (23 intra- and 27 extravesical) and 9 (9/107, 8.4%) had ureteroceles. Conclusion fMRU provides comprehensive information regarding the morphology and function of duplicated renal collecting systems in children. In particular, fMRU is useful for assessing barely or non-functioning renal poles and ectopic ureters.

Upper urinary tract urothelial carcinoma is staged using the TNM classification of malignant tumors. Preoperative TNM is important for treatment planning. Computed tomography urography is now widely used for clinical survey of upper urinary tract carcinoma because of its diagnostic accuracy. Computed tomography urography is recommended as the first-line imaging procedure in several guidelines. Several reports stated that computed tomography urography is also useful for staging. However, no educational and practical reviews detailing the T staging of upper urinary tract urothelial carcinomas using imaging are available. We discuss the scanning protocol, T staging using computed tomography urography, limitations, magnetic resonance imaging, computed tomography comparison and pitfalls in imaging of upper urinary tract urothelial carcinoma. A recent study reported the high diagnostic accuracy of computed tomography urography with respect to T3 or higher stage tumors. To date, images that show a Tis-T2 stage have not been reported, but various studies are ongoing. Although magnetic resonance imaging has lower spatial resolution than computed tomography urography, magnetic resonance imaging can be carried out without radiation exposure or contrast agents. Magnetic resonance imaging also offers the unique ability of diffusion-weighted imaging without contrast agent use. Some researchers reported that diffusion-weighted imaging is useful not only for detecting lesions, but for predicting the T stage and tumor grade. We recommend the appropriate use of computed tomography and magnetic resonance while considering the limitations of each modality and the pitfalls in upper urinary tract urothelial carcinoma imaging.

Computed tomography urography (CTU) has emerged as the modality of choice for imaging the urinary tract within the past few decades. It is a powerful tool that enables detailed anatomic evaluation of the urinary tract in order to identify primary urothelial malignancies, benign urinary tract conditions, and associated abdominopelvic pathologies. As such, there have been extensive efforts to optimize CTU protocol. This article reviews the published literature on CTU protocol optimization, including contrast bolus timing, dose reduction, reconstruction algorithms, and ancillary practices. There have been many advances in CTU techniques, which allow for imaging diagnosis of a wide spectrum of diseases while minimizing radiation dose and maximizing urinary tract distension and opacification.

Ureteric entrapment within the sacroiliac joint (SIJ) is very rare. However, we experienced a case of a 77-year-old woman who presented with right hydronephrosis during a routine health check. Computed tomography and retrograde pyelography showed entrapment of the right ureter at the level of the SIJ, with a right proximal hydroureter, which was confirmed during surgery. Herein, we described this case and present a review of the literature on similar cases.

The aim is to evaluate the age-related changes and relationship of renal apparent diffusion coefficient (ADC) against the morphological and functional changes detected by functional magnetic resonance urography (fMRU) in children with pelvicalyceal dilation, with suspected or known ureteropelvic junction obstruction. We retrospectively analyzed fMRUs with diffusion-weighted imaging (DWI) of the kidney in 35 subjects (25 males; median age: 7.1 years, range: 0.3–22.7 years) with 70 kidneys (40 with pelvicalyceal dilation and 30 with no pelvicalyceal dilation). Inclusion criteria were pelvicalyceal dilation, the absence of duplex kidneys and no ureteric dilation. DWI was performed with 3 diffusion gradient directions (b values = 0, 200, 500, 800 and 1,000 s/mm2). Metrics for fMRU included calyceal and renal transit times (CTT, RTT), time-to-peak (TTP), differential renal function based on volume (vDRF), Patlak number (pDRF) and combined volume and Patlak number (vpDRF). The grades of pelvicalyceal dilation, cortical thinning and corticomedullary differentiation were evaluated. The relationship between ADC values and the fMRU parameters was analyzed. ADC increases with age in kidneys without pelvicalyceal dilation (R2=0.37, P 0.07). The median ADC of kidneys without pelvicalyceal dilation was 3.73×10−3 mm2/s (range: 2.78–5.37×0−3 mm2/s) and the median ADC of kidneys with pelvicalyceal dilation was 3.82×10−3 mm2/s (range: 2.70–5.70×10−3 mm2/s). There was no correlation between ADC and the absolute differences of vDRF or pDRF (P>0.33). Renal ADC does not correlate with morphological and functional results of fMRU changes in children with pelvicalyceal dilation due to suspected or known ureteropelvic junction obstruction.

Emphysematous pyelonephritis (EPN) is a life-threatening renal infection characterized by the formation of gas within the renal parenchyma and collecting duct system, as well as perinephric tissues. We herein report a case of bilateral EPN accompanied by the urinary tract infection caused by spherical growth of Candida albicans in a patient with underlying diabetes mellitus and prostate cancer. The diagnosis was assisted by computed tomography, urography, and gram staining. Despite immediate percutaneous catheter drainage and a 4-week course of antifungal treatment, the C. albicans infection was refractory, as indicated by continuous isolation from the urine, and the patient eventually died. A local autopsy of urinary organs revealed C. albicans in the renal tissue. EPN caused by Candida species frequently occurs in men, and almost all cases have underlying poorly controlled diabetes. This condition is subject to delayed diagnosis, which may lead to extended disease and high mortality. Candida species should be considered as causative microorganism for refractory EPN in patients with poorly controlled diabetes who are receiving antibiotic treatment. Gram staining may contribute to an early diagnosis of EPN caused by Candida species, which may require long-term antifungal therapy.

Objective To investigate the anatomic relationship between ureter and oblique lateral interbody fusion access by using contrast-enhanced computed tomographic urography. Methods Contrast-enhanced computed tomographic urography data of 234 patients were retrospectively analyzed. The angle of inclination (∠α) of bilateral ureters, the angle between bilateral surgical accesses (∠β), the insertion angle of surgical access (∠γ), and the angle between ureter and outer margin of ipsilateral surgical access (∠e) at L2/3, L3/4, and L4/5 levels were measured and analyzed. Results ∠α gradually increased from L2/3 to L4/5. ∠β gradually decreased from L2/3 to L4/5, and at each level the left-sided ∠β was larger than right-sided ∠β. ∠e were positive at L2/3 and left-sided L3/4. The right-sided ∠e at L3/4 and the bilateral sided ∠e at L4/5 were negative, and the right-sided ∠e at L4/5 had the largest absolute value. Conclusions The bilateral ureters gradually descents from the lateral margin to the anteromedial margin on the surface of psoas major muscle. The range of bilateral surgical accesses for oblique lateral interbody fusion gradually decreases from L2/3 to L4/5, and the left-sided access is larger than the right-sided when at the same level. Ureters at the right-sided L3/4 level and bilateral L4/5 levels are at high risk of being injured. In particular, the right ureter at the L4/5 level is most likely to be injured.

Introduction Congenital hydronephrosis (CH) is a condition with dilated renal pelvis with or without dilation of renal calyces. Aim To examine the role of magnetic resonance urography in the detection of congenital hydronephrosis in comparison to dynamic renal scintigraphy (DRS). Patients and methods Resarch included 58 (n=58) patients with diagnosis of congenital unilateral or bilateral dilatation of kidney duct system. Each patient had a one-time or multiple hospitalization at the Nephrology Department of the Pediatric Clinic, with performed: ultrasound which confirmed CH, voiding cystourethrography / voiding urosonography was confirmed based on which the vesicoureteral reflux (VUR) was established / excluded, dynamic renal scintigraphy and magnetic urography (analysis was made by CHOP-fMRU software) on the basis of which the uterine anatomy and the relative renal function were evaluated. Results Male patients were represented in 40 cases (69%). The average age was 4.4 ± 4.3 years with the youngest patient at the age of 2 months, and the oldest was 17 years old. According to diagnostic entities, the most common diagnosis was ureteropelvic junction (UPJ) obstruction in over half of cases (30 or 51.7%), followed by subjects with ureterovesical junction (UVJ) obstruction (11 or 19%), VUR was recorded in 9 (15.5%) cases, and pyelon fissus in 7 (12.1%), and one case (1.7%) was recorded with bilateral megaureter. Comparison of the value of the renal function obtained with DRS and CHOP-fMRU methods shows that there were no statistically significant differences between two methods. In the case of right kidney, the mean DRS value was 53.4 ± 18.4% (range 13-100%), while CHOP-fMRU was 51.8 ± 22.4 (range 0-96.7%). In the case of left kidney, the average value according to the DRS method was 46.9 ± 18.9% (range 0-87%) and according to CHOP-fMRU 47.6 ± 21.5% (range 8.3-100%). The correlation coefficients of both right and left kidneys show a highly statistically significant correlation between these two methods. Conclusion Magnetic resonance urography in the pediatric population in CH based on results should be an integral part of the management of these patients, especially in congenital obstructive uropathy, in complex and associated congenital anomalies, as it provides morphological and functional data on the state of the kidneys and urinary tract.

INTRODUCTION The objective of this study was to compare the frequency and entity, in computed tomography (CT) urography, of streak artefacts on the urinary tract generated by two contrast agents with a different iodine concentration and osmolarity. METHODS Computed tomography scans including an excretory renal phase, performed on adult subjects in the period May-July 2020, were retrospectively evaluated in consensus by three expert radiologists, to detect any streak artefacts located in the urinary tract. Patients were administered either 1.6 mL/kg of Iodixanol 320 mgI/mL or 1.3 mL/kg of Iomeprol 400 mgI/mL. RESULTS In total, 144 CT scans were analysed, subdivided into two groups administered either Iodixanol (71/144 (49.3%) patients) or Iomeprol (73/144 (50.7%) patients). In 41% cases, no beam hardening artefacts were found; among these, 12/59 (20.3%) patients had received Iodixanol and 47/59 (79.7%) Iomeprol. In the Iodixanol group, the mean contrast density on the renal pelvis was 2565.6 HU and streak artefacts occurred in 59/71 cases (83.1%); in 33/59 (55.9%) cases, the artefacts were marked, and in 26/59 (44.1%) minimal. In the Iomeprol group, the mean contrast density on the renal pelvis was 1666 HU and streak artefacts occurred in 26/73 cases (35.6%); in 7/26 (27%) cases, the artefacts were marked and in 19/26 (73%) minimal. CONCLUSION The study data demonstrate a significant difference in the attenuation values of iodine urine in the excretory system between the Iodixanol and Iomeprol group. Iodixanol induced a higher frequency and burden of artefacts, compared to Iomeprol.

Objectives: Studies show insufficient sensitivity of virtual non-contrast (VNC) reconstructions for stone detection in dual-energy CT urography (DE-CTU). The aim of this study was to investigate if side-by-side-evaluation of both VNC and post-contrast images could increase the sensitivity of single-phase split bolus DE-CTU. Methods: Consecutive patients with haematuria who underwent split bolus DE-CTU on the same dual-source DE-CT scanner were retrospectively enrolled in the study. Intravenous furosemide and oral hydration were employed. Two readers, independently and then jointly in two separate sessions, recorded the location and the longest axial stone diameter on three randomised sets of images: separate VNC and post-contrast images, and side-by-side-reconstructions. True non-contrast (TNC) images served as the standard of reference. Results: A total of 83 urinary stones were detected on TNC images. Independent reader side-by-side-evaluation of VNC and post-contrast images yielded higher stone detection sensitivity (76 and 84%, respectively) compared to evaluation of only VNC (71 and 81%, respectively) or post-contrast images (64 and 80%, respectively). The sensitivity of joint reader evaluation of side-by-side-images reached almost 86% and was not significantly different from TNC images (p = 0.77). All stones larger than 3 mm were correctly detected by side-by-side-evaluation. Dose reduction of 55% could be achieved by omitting TNC scans. Conclusion: Side-by-side-VNC and post-contrast image evaluation enable detection of clinically significant urolithiasis on single-phase split bolus DE-CTU with significant dose reduction. Advances in knowledge: This study shows that single-phase DE-CTU is feasible if VNC imaging is simultaneously utilised with post-contrast images.

Computerized tomographic urography is the diagnostic tool of choice for evaluating hematuria. In keeping with the ALARA (As Low As Reasonably Achievable) principle, we evaluated a triple bolus computerized tomography protocol designed to reduce radiation exposure.Patients with macroscopic or microscopic hematuria were prospectively randomized to conventional computerized tomography (100) or triple bolus computerized tomography (100). The triple bolus computerized tomography protocol entails 2 scans: pre-contrast scan followed by 3 contrast injections at 40 seconds, 60 seconds and 20 minutes prior to the second scan to capture all 3 phases. The conventional computerized tomography protocol requires 4 scans: pre-contrast scan, and 3 post-contrast scans at the corticomedullary, nephrographic and excretory phases. Radiation exposure and the detection of urological pathology were recorded based on radiology reports.There were no differences in patient demographics or body mass index between the 2 groups. Triple bolus computerized tomography exposed patients to 33% less radiation (1,715 vs 1,145 mGy*cm for conventional vs triple bolus computerized tomography; p0.001). For macroscopic hematuria, the pathology detection rates were 70% for triple bolus and 73% for conventional computerized tomography (p=0.72). For microscopic hematuria, the detection rates were 59% for triple bolus and 50% for conventional computerized tomography (p=0.68). In both groups, the rates of detection of urolithiasis, renal cysts, urological masses, bladder pathology and prostate pathology were no different between triple bolus and conventional computerized tomography.In both the settings of macroscopic and microscopic hematuria evaluation, triple bolus computerized tomography significantly reduces radiation exposure while providing equivalent detection of genitourinary pathology compared to conventional computerized tomography. The ability to detect upper tract filling defects was not specifically tested.

Objectives The aim of the study was to describe renal pelvis (RP) and ureteral ultrasonographic measurements in a population of cats with confirmed benign ureteral obstruction (UO) by antegrade pyelography. The secondary objective was to further describe clinical findings associated with minimally dilated obstructed kidneys in an attempt to better understand its occurrence. Methods Retrospective case series of cats diagnosed with benign UO were confirmed by antegrade pyelography. Medical records were reviewed and signalment, diagnostic imaging results, serum creatinine (SCr) concentration and urine culture results were recorded. Each obstructed kidney was categorized into two groups: group 1 included all RP measurements ⩽4 mm and group 2 included all RP measurements >4 mm. Results A total of 82 cats with 114 obstructed ureters met the inclusion criteria. Fifty (61%) cats had a unilateral UO and 32 (39%) had a bilateral UO. Thirty (26%) kidneys were included in group 1 while 84 (74%) were included in group 2. Nine (8%) kidneys had an RP dilation ⩽2 mm. Median RP and ureteral diameters were 6.6 mm (range 1.1–37.0 mm) and 3.2 mm (range 0.0–11.0 mm), respectively. RP size correlated positively with ureteral diameter in the study population ( P Conclusions and relevance Feline UO may be associated with minimal RP dilation and the severity of RP and ureteral dilation can be highly variable. Absence of significant RP dilation does not rule out UO in cats.

Purpose This article reviews imaging manifestations of complicated pyelonephritis associated with chronic renal stones disease, in particular xanthogranulomatous pyelonephritis (XGP) and emphysematous pyelonephritis (EPN), as potential mimics of other renal diseases and malignances and provides helpful tips and differentiating features that may alert the radiologist to suspect a diagnosis of infection. Materials and methods A retrospective review of the records from 6 adult patients (5 females and 1 male, mean age 72,3 years) with diagnosis of XGP associated with chronic nephrolithiasis and 7 adult patients (6 females and 1 male, mean age 59,3 years) with diagnosis of EPN associated with chronic nephrolithiasis from January 2010 to January 2020 was carried out. Computed tomography urography (CTU) with at least an unenhanced scan, and the parenchymal and excretory phases after contrast medium administration performed at our Teaching Hospital were included. When available images related to conventional radiography, ultrasound (US) and magnetic resonance imaging of the same patients, the comparison with CTU images was carried out. Conclusion A possible diagnosis of XGP or EPN must always be taken into account when a pyelonephritis is associated with untreated kidney stones, especially whenever clinical presentation is atypical, current therapy is not effective and imaging shows features of dubious interpretation. Due to their rarity and atypical presentation, a multidisciplinary approach is required and an expert radiologist represents a key figure in the multidisciplinary team as he can help to differentiate between benign and malignant lesions and thus avoid unnecessary radical surgical procedures.

Introduction The protocol for preparation of computed tomography urography (CTU) examinations at our hospital was changed in 2013 to improve the quality of urinary bladder filling in the excretory phase. The aim of this study was to evaluate the quality of urinary bladder filling on CTU after different doses of furosemide were administered to patients with macroscopic hematuria. Methods The cohort was 215 patients who underwent elective CTU due to macroscopic hematuria between 2014 and 2018. 5 mg furosemide were administrated to 100 patients, 2.5 mg to 100 patients and 0 mg to 15 patients. Contrast medium layered bladders were excluded, leaving 193 patients: 92, 89 and 12 in each group. Urinary bladder volume was calculated in corticomedullary (CMP) and excretory phase (EP). Bladder distension was classified as satisfactory or not. Attenuation of bladder content in EP was noted. Results Average volume in EP was 370 ± 224 ml (28–1052) after 5 mg furosemide, 274 ± 120 ml (43–628) after 2.5 mg and 180 ± 104 ml (53–351) after 0 mg. 85% of the bladders were satisfactory distended after 5 mg, 80% after 2.5 mg and 58% after 0 mg. Average attenuation was 266 ± 89 HU (103–524) after 5 mg, 362 ± 156 HU (118–948) after 2.5 mg and 761 ± 331 HU (347–1206) after 0 mg. The differences in volume and attenuation were significant. Conclusion 5 mg furosemide is preferred rather than 2.5 mg in preparation for CTU examinations of patients with macroscopic hematuria. There was no difference between the doses concerning rate of satisfactory bladder distension, but the higher dose resulted in larger bladder volume and more suitable attenuation of bladder content. Implications for practice Development of CTU-image quality could improve bladder cancer diagnostics.

Summary Introduction Functional renal imaging, most commonly with MAG3 nuclear medicine renal scan, is recommended in the evaluation of children with urinary tract dilation (UTD) suspected of obstructive uropathy. Alternatively, renal function can be evaluated with functional Magnetic Resonance Urography (fMRU), which has superior anatomic detail. However, there are not enough data comparing both methods’ equivalency. In this study, we compare the functional and obstruction parameters of fMRU and MAG3 in a pediatric cohort presenting with obstructive uropathy. Study design This is an IRB-approved retrospective review of all children undergoing fMRU at a single, free-standing children's hospital between May 2008 and September 2017. Patients who also underwent a MAG3 renal scan within 6 months and who had no interval surgical intervention were included in the study. Bladder catheterization was performed prior to both imaging studies. Results 735 children had 988 fMRU studies performed during the study period. 37 unique patients (13 girls and 24 boys) with median age of 6 months (range: 2 mo–19 y) were included in the final sample. Median time interval between studies was 70 days (range 6–179 days). The majority of participants (26/37, 70.3%) presented with UTD P3 and had diagnosis of uretero-pelvic junction obstruction (UPJO) in 21/37. Differential renal function (DRF) was used to group 10 fMRU and 9 MAG3 patients as normal; 9 fMRU and 11 MAG3 as mild; 11 fMRU and 6 MAG3 as moderate; and 7 fMRU and 6 MAG3 as severe; Wilcoxon signed-rank test (p = 0.5106). Results were similar for DRF among patients with and without duplex kidneys. In the analysis of obstruction, using reference standard T½ MAG3 ≥ 20 min, a greater or equal than 6 min renal transit time (RTT) from fMRU showed a specificity of 94%, a sensitivity of 62%, and an AUC of 0.827. Discussion and conclusions The differential renal function determined by MAG3 and fMRU in children was not statistically different, therefore we concluded that it was similar and potentially equivalent. Better correlation was shown in patients who had normal split kidney function. While the tests are clinically equivalent, the variability of DRF within each clinical category (i.e., normal, mild, moderate, severe) is not surprising, because MAG3 does not clearly differentiate the dilated collecting system from the functional parenchymal tissue, while fMRU does. Using MAG3 as the gold standard, fMRU was 94.74% specific and 5% more sensitive in detecting UPJO with a RTT of 6min vs. 8min.

Urothelial carcinoma (UC) is the fourth most frequent tumor in Western countries and upper tract urothelial carcinoma (UTUC), affecting pyelocaliceal cavities and ureter, accounts for 5–10% of all UCs. Computed tomography urography (CTU) is now considered the imaging modality of choice for diagnosis and staging of UTUC, guiding disease management. Although its specificity is very high, both benign and malignant diseases could mimic UTUCs and therefore have to be well-known to avoid misdiagnosis. We describe CTU findings of upper urinary tract carcinoma, features that influence disease management, and possible differential diagnosis.

Background: Castleman Disease (CD) of the kidney is extremely rare. In this study, we have presented a case of CD of the left kidney and comprehensively described the findings of computed tomography urography. Case Presentation: The case involved unusual imaging characteristics of the focal central cystic area. Conclusion: The small and regular cyst-like structures and the hyperdense mass relative to the renal parenchyma in plain scans might help distinguish the CD of the kidney from other hypervascular tumors.

To investigate the diagnostic value of computed tomography (CT) urography findings of anterior nutcracker syndrome (NCS).The study included patients with left renal vein (LRV) compression at the aortomesenteric portion at CT urography who underwent renal venography or cystoscopy. Patients with a renocaval pressure gradient of ≥3 mmHg on renal venography or bloody urine jetting from the left ureteral orifice on cystoscopy were defined as the NCS group; the remaining patients comprised the non-NCS group. CT findings were analysed using the jetting of contrast medium flow from the LRV to the inferior vena cava (jetting sign), aortomesenteric distance, presence of collateral veins, and a dilatation ratio of LRV diameter at the aortomesenteric portion (arterial phase/delayed phases). Clinical findings, including age, gender, and body-mass-index, were also analysed. CT features and clinical findings were compared between the NCS and non-NCS groups. Diagnostic performance of CT parameters was assessed using receiver operating characteristic curve analysis.A total of 70 patients (21 men, mean age 44.4 ± 17.2 years) with NCS (n=13) and non-NCS (n=57) were included. Younger age (40 years), presence of the jetting sign, and a lower dilatation ratio of LRV diameter between the arterial and delayed phases (1.7) were found to be significant independent factors for predicting the NCS group (OR 24.5, 18.9, 19.4, respectively, p0.05 for all). The combination of the presence of the jetting sign and a dilatation ratio of LRV diameter of1.7 obtained the highest AUC of 0.88.The jetting sign and the dilatation ratio of LRV diameter between the arterial and delayed phases can both be very useful in the diagnosis of anterior nutcracker syndrome during CT urography.

Teaching point: A fibroepithelial polyp is an intraluminal, long, slender neoplasm that frequently occurs in the ureteropelvic junction and upper ureter.

To determine predictive factors for periureteral fat invasion of ureteral cancer on computed tomography (CT) urography.Consecutive 77 patients with CT urography and surgically proven ureteral cancer were retrospectively evaluated. Three independent radiologists with different experiences in interpreting CT urography analyzed radiologic findings as follows: (a) periureteral infiltration (absent; equivocal; or present); (b) ureteral obstruction (complete obstruction or not); (c) lesion length; (d) lesion width; (e) hydronephrosis grade; and (f) renal atrophy (present or not). We analyzed univariate and multivariate logistic regression. We assessed sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of significant parameters.Periureteral fat invasion was surgically identified in 33.8 % (26/77). For reader 1, periureteral infiltration (odds ratio [OR] = 3.330), complete ureteral obstruction (OR = 18.965), and renal atrophy (OR = 3.116) were significant in univariate analysis (p 0.05), while only complete ureteral obstruction was significant in multivariate analysis (OR = 12.779; p = 0.018). For reader 2 (OR = 4.172; p = 0.019) and 3 (OR = 9.459; p = 0.035), only complete ureteral obstruction was significant in univariate analysis. Sensitivity, specificity, PPV, and NPV of complete ureteral obstruction were 96.2 % (25/26), 43.1 % (22/51), 46.3 % (25/54), and 95.7 % (22/23) for reader 1, 84.6 % (22/26), 43.1 % (22/51), 43.1 % (22/51), and 84.6 % (22/26) for reader 2, and 96.2 % (25/26), 27.5 % (14/51), 40.3 % (25/62), and 93.3 % (14/15) for reader 3, respectively.Complete ureteral obstruction on CT urography is highly sensitive for extra-ureteral extension of ureteral cancer. Ureteral cancer without complete ureteral obstruction may be less likely to invade periureteral fat.

Background Calyceal diverticulum is the cystic eventration of the upper urinary tract within the renal parenchyma, which gives the first impression of a simple renal cyst and therefore can easily be misdiagnosed. We conducted a study to assess the role of static-fluid magnetic resonance (MR) urography in the differentiation of renal parenchymal cysts and calyceal diverticulum in comparison with focused renal ultrasonography (US). Methods Focused renal US, static-fluid, and excretory MR urography studies of 45 children who were admitted to our pediatric nephrology department with a diagnosis of renal cyst were reviewed retrospectively. Excretory MR urography was accepted as gold standard for the diagnosis of calyceal diverticulum. Sensitivity and specificity of focused renal US and static fluid MR urography in the diagnosis of renal calyceal diverticulum were assessed. Interobserver agreement between three radiologists in the diagnosis of calyceal diverticulum on MRI was also evaluated. Results The study included 29 patients (13 boys and 16 girls) aged between 6-18 years (mean 11.5 ± 4.1). Five calyceal diverticula and 24 solitary renal parenchymal cysts were diagnosed. The sensitivity and the specificity of focused renal US were 40% and 100% in the diagnosis of calyceal diverticulum. The sensitivity and the specificity of static-fluid MR urography were 100% and 91.6%, respectively. The degree of interobserver agreement was excellent for the diagnosis of diverticulum for static-fluid MR urography (κ = 0.86, 95% CI: 0.71-1.00). Conclusions Static-fluid MR urography can be successfully used in children for the differentiation of renal parenchymal cyst and calyceal diverticulum due to its high sensitivity and specificity, without exposing children to ionizing radiation or intravenous contrast agents.

To develop a 3D U-Net-based deep learning model for automated segmentation of kidney and renal mass, and detection of renal mass in corticomedullary phase of computed tomography urography (CTU). Data on 882 kidneys obtained from CTU data of 441 patients with renal mass were used to learn and evaluate the deep learning model. The CTU data of 35 patients with small renal tumors (diameter ≤ 1.5 cm) were used for additional testing. The ground truth data for the kidney, renal tumor, and cyst were manually annotated on corticomedullary phase images of CTU. The proposed segmentation model for kidney and renal mass was constructed based on a 3D U-Net. The segmentation accuracy was evaluated through the Dice similarity coefficient (DSC). The volume of the maximum 3D volume of interest of renal tumor and cyst in the predicted segmentation by the model was used as an identification indicator, while the detection performance of the model was evaluated by the area under the receiver operation characteristic curve. The proposed model showed a high accuracy in segmentation of kidney and renal tumor, with average DSC of 0.973 and 0.844, respectively. It performed moderately in the renal cyst segmentation, with an average DSC of 0.536 in the test set. Also, this model showed good performance in detecting renal tumor and cyst. The proposed automated segmentation and detection model based on 3D U-Net shows promising results for the segmentation of kidney and renal tumor, and the detection of renal tumor and cyst. • The segmentation model based on 3D U-Net showed high accuracy in segmentation of kidney and renal neoplasm, and good detection performance of renal neoplasm and cyst in corticomedullary phase of CTU. • The segmentation model based on 3D U-Net is a fully automated aided diagnostic tool that could be used to reduce the workload of radiologists and improve the accuracy of diagnosis. • The segmentation model based on 3D U-Net would be helpful to provide quantitative information for diagnosis, treatment, surgical planning, etc.

A 5-month-old, male French bulldog was presented with a history of urinary incontinence. Abdominal ultrasound showed changes compatible with a ureterocele and a bilobed right kidney. Excretory computed tomographic urography was consistent with right-sided duplex kidney, ureter duplex and ectopic ureterocele. To the authors' knowledge, this is the first description of a duplex kidney with an ectopic ureterocele diagnosed with ultrasound and contrast enhanced computed tomography in a dog. After the imaging diagnosis, a neoureterocystostomy was performed. In the follow-up examination the dog presented with mild incontinence which was treated medically using phenylpropanolamine.Eine 5 Monate alte, männliche Französische Bulldogge wurde aufgrund von Harninkontinenz vorgestellt. Bei der Ultraschalluntersuchung des Abdomens zeigte sich eine Ureterozele sowie eine bilobulierte rechte Niere. Durch exkretorische computertomografische Urografie ließen sich rechtsseitig eine Doppelniere, ein Doppelureter sowie eine ektopische Ureterozele nachweisen. Nach Wissen des Autors ist dies die erste Beschreibung einer Doppelniere im Zusammenhang mit einer ektopischen Ureterozele beim Hund, die durch Sonografie und Computertomografie nachgewiesen wurde. Die ektopische Ureterozele wurde im Anschluss an die bildgebende Diagnostik mittels Neoureterozystostomie chirurgisch versorgt. In der Kontrolluntersuchung zeigte der Patient noch eine geringgradige Inkontinenz, die mit Phenylpropanolamin weiter behandelt wurde.

BACKGROUND Accuracy of 68Ga-PSMA-11 PET/CT may be hampered by ureter accumulation, mimicking lymph node metastases depending on localization and configuration. The benefit of CT urography for differentiation of lymph node metastasis from urinary tract activity was evaluated in a "PET/CT with low-dose CT" setting. METHODS Retrospective analysis of PET/CT for primary staging, biochemical recurrence or local treatment planning in patients with prostate cancer. For CT urography (CTU), iodinated contrast agent was administered 10 minutes prior to image acquisition. All potential pathologic (peri)ureteral tracer uptake were assigned to excretory ureteral accumulation or pathological lesion. To assess additional provided benefit of CTU all foci were rated with an introduced scoring system (ranging from 0 pts: CTU not needed, up to 3 pts: no differentiation possible without CTU). Success of ureter contrasting was assessed by measurement of Hounsfield units. Besides benefit for reading urography-enhanced PET/CT, the possible impact on subsequent patient treatment was evaluated. RESULTS A number of n=247 patients were included in this study. By CT urography, it was possible to identify each ureter on low-dose CT, with its major part contrasted. In 120/247 (48.6%) patients, urography increased the diagnostic confidence while providing substantial support for interpretation in 60 (24.3%) cases. In 42 (17.0%) patients, urography was clinically relevant (up-/downstaging) with potential impact on subsequent patient care. In 30 of these 42 cases (12.1% of all), discrepant treatment would have resulted from a misdiagnosed tracer accumulation without urography. CONCLUSIONS CT urography benefits the interpretation of 68Ga-PSMA-11 PET/CT with low-dose CT and leads to discrepant patient treatment in a small but significant subset of patients (12% in our cohort). The implementation of CT urography into standard protocols of 68Ga-PSMA-11 PET/CT with low-dose CT is recommended.

Background Computed tomography urography (CTU), based on the excretion of contrast medium after its injection, allows visualization of the renal parenchyma and the renal collecting system. Objectives To determine the optimal contrast medium dose allocation ratio to apply in split-bolus CTU in dogs. Methods This prospective, experimental, exploratory study used 8 beagles. In 3-phase CTU, unenhanced-, nephrographic-, and excretory-phase images were obtained with a single injection of 600 mg iodine/kg iohexol. In split-bolus CTU, two different contrast medium allocation ratios (30% and 70% for split CTU 1; 50% and 50% for split CTU 2) were used. Unenhanced phase image and a synchronous nephrographic-excretory phase image were acquired. Results Although the attenuation of the renal parenchyma was significantly lower when using both split CTUs than the 3-phase CTU, based on qualitative evaluation, the visualization score of the renal parenchyma of split CTU 1 was as high as that of the 3-phase CTU, whereas the split CTU 2 score was significantly lower than those of the two others. Artifacts were not apparent, regardless of CTU protocol. The diameter and opacification of the ureter in both split CTUs were not significantly different from those using 3-phase CTU. Conclusions Split-bolus CTU with a contrast medium allocation ratio of 30% and 70% is feasible for evaluating the urinary system and allows sufficient enhancement of the renal parenchyma and appropriate distention and opacification of the ureter, with similar image quality to 3-phase CTU in healthy dogs. Split-bolus CTU has the advantages of reducing radiation exposure and the number of CT images needed for interpretation.

The AUA (American Urological Association) guidelines for asymptomatic microscopic hematuria recommend that patients undergo computerized tomography urography, which is associated with high doses of ionizing radiation. To our knowledge the associated risk of secondary malignancy and mortality remains unknown. We modeled the risk of malignancy and associated mortality due to ionizing radiation from computerized tomography urography relative to the additional diagnostic benefit offered over renal ultrasound.We performed a PubMed® based literature search to identify model inputs. We obtained estimates of age and gender specific radiation induced secondary malignancy and mortality rates from the BEIR (Biologic Effects of Ionizing Radiation) VII Phase 2 report with dose extrapolation using the linear no threshold model.Patients with asymptomatic microscopic hematuria had a 0.053% and 0.48% prevalence of upper tract urothelial carcinoma and renal cell carcinoma, respectively. Ultrasound had 77% sensitivity for upper tract urothelial carcinoma and 82% sensitivity for renal cell carcinoma. The effective radiation dose of computerized tomography urography was 31.7 mSv. Based on these inputs a population of 100,000 patients with asymptomatic microscopic hematuria would include 53.1 and 478 patients with upper tract urothelial carcinoma and renal cell carcinoma, respectively. On ultrasound alone 98.2 cases of upper urinary tract malignancy would be missed. An additional 149 cases of secondary malignancy would be caused by computerized tomography urography associated radiation with 101 fatalities. A total of 1,018.3 computerized tomography urography studies would need to be performed to detect an additional case of upper tract malignancy.Based on current risk models computerized tomography urography for asymptomatic microscopic hematuria may be associated with a small but significant risk of secondary malignancy relative to the additional diagnostic benefit offered.

Background Incidence of simultaneous renal cyst with calyceal diverticula in contralateral kidney is rare in children. A minimally invasive procedure in different sittings is often recommended. Case presentation A Chinese 15-month-old boy presented to the Urology department of a tertiary care center with right flank pain. He was subjected to magnetic resonance urography and was diagnosed as having right renal cyst and contralateral calyceal diverticula. He underwent robotic cyst decortication and calyceal diverticulectomy using da Vinci robot. His postoperative period was uneventful. He was discharged on fifth postoperative day. Histopathology was consistent with simple renal cyst. Conclusions Robotic combined cyst decortication and contralateral diverticulectomy is feasible in selected small children. However, it demands adequate technical skill and experience.

PURPOSE To evaluate the best collimation used in wide volume (WV) mode to cover the abdomen in computed tomography (CT) urography in terms of radiation dose and image quality. MATERIALS AND METHODS This study was performed on a 320×0.5mm detector row CT unit. The first part identified the lowest volume CT dose index (CTDIvol) by using the topograms data of 25 medium size patients (13 men and 12 women; mean age: 52±9 [SD] years; age range: 46-68 years) using different collimations on WV from 6cm to 16cm and the one of the helical mode for the same coverage length. The second part consisted of a clinical evaluation of this result including 45 medium size patients (32 men and 13 women; mean age: 68±14 [SD] years; age range: 45-72 years). The qualitative evaluation included several items based on a 5-point Likert scale. RESULTS The first part of the study indicated that a collimation of 10cm (200×0.5mm) in WV mode with 5 volumes had the lowest CTDIvol (2.78±0.35mGy; range: 2.35-3.21mGy) compared to helical mode (4.38±0.48mGy, range: 3.75-4.95mGy). In the second part, the mean radiation dose reduction by comparison with helical mode was 44.03%±0.36% (P

Computed tomography (CT) urography is the best noninvasive method of evaluating the upper urinary tract for urothelial malignancies. However, the utility of CT urography is heavily contingent on the use of proper image acquisition protocols. This article focuses on the appropriate protocols for optimizing CT urography acquisitions, including contrast administration and the timing of imaging acquisitions, as well as the use of ancillary techniques to increase collecting system distention. In addition, imaging findings are discussed that should raise concern for urothelial carcinoma at each of the 3 segments of the urinary tract: the intrarenal collecting systems, ureters, and bladder.