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Hydronephrosis, characterized by the dilation of the renal pelvis and calyces, often results from obstructive uropathy, commonly due to ureterolithiasis. However, rare congenital anomalies, such as a retrocaval ureter (RCU)-where the ureter passes behind the inferior vena cava- can also cause hydronephrosis. This case report describes an 11-year-old male presenting with right-sided flank pain and hematuria. Initial ultrasonography and noncontrast CT revealed right hydronephrosis without ureteral stones. Subsequently, contrast-enhanced CT urography found an abnormality in the course of the right ureter behind the inferior vena cava. He was diagnosed with right retrocaval ureter with hydronephrosis, and managed by surgical resection of the retrocaval segment and uretero-ureteral anastomosis. The postoperative course was uneventful. RCU usually presents in the third or fourth decade of life, however, it should be in the differential diagnosis of hydronephrosis in the pediatric population. The diagnosis of RCU is often delayed and missed till advanced imaging like CT urography is sought for unexplained hydronephrosis. If left untreated, it may lead to chronic renal failure. Therefore, emphasis should be placed on timely diagnosis and management of retrocaval ureter.

Purpose: To assess the proportion of upper tract urothelial carcinomas (UTUC) that are evident without the excretory phase at CT urography (CTU), and the proportion of potentially avoidable radiation. Methods: UTUCs diagnosed between January 2008-December 2017 were retrospectively identified from a population-based cancer registry. For each patient, US, non-urographic CT, and MRI exams were assessed for a primary mass and secondary imaging findings (hydronephrosis, urinary tract thickening, luminal distention, fat stranding, and lymphadenopathy/metastatic disease). CTUs were assessed for primary and secondary findings, and whether the tumor was evident as a filling defect on excretory phase. The dose-length product (DLP) of potentially avoidable excretory phases was calculated as a fraction of total DLP. Results: 288 patients (mean age, 72±11 years, 165 males) and 545 imaging examinations were included. Of 192 patients imaged with 370 non-urographic CTs, a primary mass was evident in 154 (80.2%), secondary findings were evident in 172 (89.6%), and primary or secondary findings were evident in 179 (93.2%). Of 175 CTUs, primary and secondary findings were evident in 157 (89.7%) and 166 (94.9%) examinations, respectively, and primary or secondary findings were evident in 170/175 (97.1%). 131/175 (74.9%) UTUCs were evident as a filling defect, including the 5/175 (2.9%) UTUCs without primary or secondary findings. Of 144 CTUs with available DLP data, the proportion of potentially avoidable radiation was 103.7/235.8 (44.0%) Gy⋅cm. Conclusion: In our population, almost all UTUCs were evident via primary or secondary imaging findings without requiring the excretory phase. These results support streamlining protocols and pathways. [ABSTRACT FROM AUTHOR]

Purpose: To compare image quality and detection accuracy of renal stones between deep learning image reconstruction (DLIR) and Adaptive Statistical Iterative Reconstruction-Veo (ASIR-V) reconstructed virtual non-contrast (VNC) images and true non-contrast (TNC) images in spectral CT Urography (CTU). Methods: A retrospective analysis was conducted on images of 70 patients who underwent abdominal-pelvic CTU in TNC phase using non-contrast scan and contrast-enhanced corticomedullary phase (CP) and excretory phase (EP) using spectral scan. The TNC scan was reconstructed using ASIR-V70 % (TNC-AR70), contrast-enhanced scans were reconstructed using AR70, DLIR medium-level (DM), and high-level (DH) to obtain CP-VNC-AR70/DM/DH and EP-VNC-AR70/DM/DH image groups, respectively. CT value, image quality and kidney stones quantification accuracy were measured and compared among groups. The subjective evaluation was independently assessed by two senior radiologists using the 5-point Likert scale for image quality and lesion visibility. Results: DH images were superior to AR70 and DM images in objective image quality evaluation. There was no statistical difference in the liver and spleen (both P > 0.05), or within 6HU in renal and fat in CT value between VNC and TNC images. EP-VNC-DH had the lowest image noise, highest SNR, and CNR, and VNC-AR70 images had better noise and SNR performance than TNC-AR70 images (all p < 0.05). EP-VNC-DH had the highest subjective image quality, and CP-VNC-DH performed the best in lesion visibility. In stone CT value and volume measurements, there was no statistical difference between VNC and TNC (P > 0.05). Conclusion: The DLIR-reconstructed VNC images in CTU provide better image quality than the ASIR-V reconstructed TNC images and similar quantification accuracy for kidney stones for potential dose savings.The study highlights that deep learning image reconstruction (DLIR)-reconstructed virtual non-contrast (VNC) images in spectral CT Urography (CTU) offer improved image quality compared to traditional true non-contrast (TNC) images, while maintaining similar accuracy in kidney stone detection, suggesting potential dose savings in clinical practice.

Genitourinary fistulas are a well-recognized complication of various gynecological, obstetrical, and endourological interventions. The incidence of uretero-uterine fistula is very rare compared to other genitourinary fistulas. Few cases are reported in literature regarding the uretero- uterine fistula following manual vacuum aspiration of retained product of placenta. We report a case of 28 year multi-parous women who had presented with complain of involuntary passage of urine following manual vacuum aspiration for retained product of conception. Common tests for suspicion of uretero-uterine fistula include cystoscopy, triple swab test, and CT urography. Our patient was diagnosed in CT urography and was managed by exploratory laparotomy with end-to-end anastomosis of the right ureter, DJ stenting, and repair of a uterine perforation. Due to relatively rare incidence of this condition, there has not been a specific guideline for management. A multimodality and multidisciplinary approach have been proposed for the management of uretero-uterine fistulas.

Objective To investigate the effect of dual-energy CT (DECT) virtual non-contrast (VNC) images reconstructed by deep learning image reconstruction (DLIR) on the image quality and measurements of renal calculus in CT urography (CTU). Methods The clinical and imaging data of 90 patients who underwent abdominal and pelvic non-contrast CT examination followed by a nephrographic-phase DE CTU during September 2022 to April 2023 were retrospectively analyzed. The non-contrast CT images were reconstructed with ASIR-V with 70% weight (TNC-AR70). Four groups of VNC images were reconstructed based on medium level and high level DLIR for venous phase and delay phase, namely venous phase-VNC-DLIR medium (VP-VNC-DM), venous phase-VNC-DLIR high (VP-VNC-DH), delay phase-VNC-DLIR medium (DP-VNC-DM), and delay phase-VNC-DLIR high (DP-VNC-DH). The radiation doses of TNC and VNC in venous phase and delay phase were recorded. The mean CT value, image noise (SD), signal-to-noise ratio (SNR) and contrast-to-noise (CNR) were recorded and compared among the five groups. Two radiologists independently assessed the overall image qua-lity and lesion visibility with 5-point Likert scale. Additionally, according to results of TNC, Bland-Altman was used to analyze the measurement differences between VNC and TNC in mean CT value and mean size of renal calculus. Results In the objective assessments, the image quality of the VNC-DH group was better than that of TNC-AR70, and there was no statistically significant difference in CT value among the five groups of images (P>0.05). DP-VNC-DH showed the lowest SD and the highest SNR and CNR values. In the subjective assessments, DP-VNC-DH achieved the best subject scores on image qua-lity, and VP-VNC-DH achieved the best subject scores on lesion visibility. Furthermore, Bland-Altman analysis showed that there was a strong overall agreement between VNC and TNC for renal calculus characterization (all P>0.005). Conclusions VNC generated by DLIR may provide high-quality image compared with the non-contrast images reconstructed with ASIR-V 70% in CTU.The combination of the VNC images generated by DLIR-H from venous phase and delay phase could replace TNC scanning,reducing the radiation dose of CTU scans.

Abstract Purpose To investigate the value of CT urography (CTU) indicators in the quantitative differential diagnosis of bladder urothelial carcinoma (BUC) and inverted papilloma of the bladder (IPB). Material and methods The clinical and preoperative CTU imaging data of continuous 103 patients with histologically confirmed BUC or IPB were retrospectively analyzed. The imaging data included 6 qualitative indicators and 7 quantitative measures. The recorded clinical information and imaging features were subjected to univariate and multivariate logistic regression analysis to find independent risk factors for BUC, and a combined multi-indicator prediction model was constructed, and the prediction model was visualized using nomogram. ROC curve analysis was used to calculate and compare the predictive efficacy of independent risk factors and nomogram. Results Junction smoothness, maximum longitudinal diameter, tumor-wall interface and arterial reinforcement rate were independent risk factors for distinguishing BUC from IPB. The AUC of the combined model was 0.934 (sensitivity = 0.808, specificity = 0.920, accuracy = 0.835), and its diagnostic efficiency was higher than that of junction smoothness (AUC=0.667, sensitivity = 0.654, specificity = 0.680, accuracy = 0.660), maximum longitudinal diameter (AUC=0.757, sensitivity = 0.833, specificity = 0.604, accuracy = 0.786), tumor-wall interface (AUC=0.888, sensitivity = 0.755, specificity = 0.808, accuracy = 0.816) and Arterial reinforcement rate (AUC=0.786, sensitivity = 0.936, specificity = 0.640, accuracy = 0.864). Conclusion Above qualitative and quantitative indicators based on CTU and the combination of them may be helpful to the differential diagnosis of BUC and IPB, thus better assisting in clinical decision-making. Key points 1. Bladder urothelial carcinoma (BUC) and inverted papilloma of the bladder (IPB) exhibit similar clinical symptoms and imaging presentations. 2. The diagnostic value of CT urography (CTU) in distinguishing between BUC and IPB has not been documented. 3. BUC and IPB differ in lesion size, growth pattern and blood supply. 4. The diagnostic efficiency is optimized by integrating multiple independent risk factors into the prediction model.

Computed Tomography Urography (CTU) is a multiphase CT examination optimized for imaging kidneys, ureters, and bladder, complemented by post-contrast excretory phase imaging. Different protocols are available for contrast administration and image acquisition and timing, with different strengths and limits, mainly related to kidney enhancement, ureters distension and opacification, and radiation exposure. The availability of new reconstruction algorithms, such as iterative and deep-learning-based reconstruction has dramatically improved the image quality and reducing radiation exposure at the same time. Dual-Energy Computed Tomography also has an important role in this type of examination, with the possibility of renal stone characterization, the availability of synthetic unenhanced phases to reduce radiation dose, and the availability of iodine maps for a better interpretation of renal masses. We also describe the new artificial intelligence applications for CTU, focusing on radiomics to predict tumor grading and patients’ outcome for a personalized therapeutic approach. In this narrative review, we provide a comprehensive overview of CTU from the traditional to the newest acquisition techniques and reconstruction algorithms, and the possibility of advanced imaging interpretation to provide an up-to-date guide for radiologists who want to better comprehend this technique.

Anatomic variations in the urogenital tract have generally been diagnosed through intravenous urography as a modality of choice. In recent years, computerized tomography (CT) urogram has replaced the traditional intravenous imaging of the genitourinary tract. Hematuria, tumoral mass, obstructive uropathy, and congenital collecting system abnormalities are indications for CT imaging. In this report, we present a young woman with intermittent right flank pain and recent urinary tract infection. Her history was also positive for spontaneous abortion. She was referred to the Radiology Clinic for a CT urography. Our aim, in this case report, is to highlight the role of CT urography in the early diagnosis of anatomical variations of the urogenital system and appropriate prevention of clinical progression.

Objective To identify clinicopathological or radiological factors that may predict a diagnosis of upper urinary tract urothelial cell carcinoma (UTUC) to inform which patients can proceed directly to radical nephroureterectomy (RNU) without the delay for diagnostic ureteroscopy (URS). Patients and Methods All consecutive patients investigated for suspected UTUC in a high-volume UK centre between 2011 and 2017 were identified through retrospective analysis of surgical logbooks and a prospectively maintained pathology database. Details on clinical presentation, radiological findings, and URS/RNU histopathology results were evaluated. Multivariate regression analysis was performed to evaluate predictors of a final diagnosis of UTUC. Results In all, 260 patients were investigated, of whom 230 (89.2%) underwent URS. RNU was performed in 131 patients (50.4%), of whom 25 (9.6%) proceeded directly without URS - all of whom had a final histopathological diagnosis of UTUC - and 15 (11.5%) underwent RNU after URS despite no conclusive histopathological confirmation of UTUC. Major surgery was avoided in 77 patients (33.5%) where a benign or alternative diagnosis was made on URS, and 14 patients (6.1%) underwent nephron-sparing surgery. Overall, 178 patients (68.5%) had a final diagnosis of UTUC confirmed on URS/RNU histopathology. On multivariate logistic regression analysis, a presenting complaint of visible haematuria (hazard ratio [HR] 5.17, confidence interval [CI] 1.91-14.0; P = 0.001), a solid lesion reported on imaging (HR 37.8, CI = 11.7-122.1; P < 0.001) and a history of smoking (HR 3.07, CI 1.35-6.97; P = 0.007), were predictive of a final diagnosis of UTUC. From this cohort, 51 (96.2%) of 53 smokers who presented with visible haematuria and who had a solid lesion on computed tomography urogram had UTUC on final histopathology. Conclusion We identified specific factors which may assist clinicians in selecting which patients may reliably proceed to RNU without the delay of diagnostic URS. These findings may inform a prospective multicentre analysis including additional variables such as urinary cytology. [ABSTRACT FROM AUTHOR]

Computed Tomography Urography (CTU) is a multiphase CT examination optimized for imaging kidneys, ureters, and bladder, complemented by post-contrast excretory phase imaging. Different protocols are available for contrast administration and image acquisition and timing, with different strengths and limits, mainly related to kidney enhancement, ureters distension and opacification, and radiation exposure. The availability of new reconstruction algorithms, such as iterative and deep-learning-based reconstruction has dramatically improved the image quality and reducing radiation exposure at the same time. Dual-Energy Computed Tomography also has an important role in this type of examination, with the possibility of renal stone characterization, the availability of synthetic unenhanced phases to reduce radiation dose, and the availability of iodine maps for a better interpretation of renal masses. We also describe the new artificial intelligence applications for CTU, focusing on radiomics to predict tumor grading and patients' outcome for a personalized therapeutic approach. In this narrative review, we provide a comprehensive overview of CTU from the traditional to the newest acquisition techniques and reconstruction algorithms, and the possibility of advanced imaging interpretation to provide an up-to-date guide for radiologists who want to better comprehend this technique. [ABSTRACT FROM AUTHOR]

Inguinoscrotal bladder herniation (IBH) is a rare type of inguinal hernia associated with significant urologic complications such as acute renal failure, hydronephrosis, obstructive uropathy, and sepsis. Diagnosis of this condition can be made with common imaging modalities including excretory urography, retrograde cystography, computed tomography (CT), and magnetic resonance imaging. We present the classic symptomatology and imaging findings of inguinoscrotal bladder herniation on CT urogram in two patients. Although the majority of IBH are diagnosed intraoperatively, radiologists and the surgical team should be aware of this diagnosis when working up a patient, as preoperative diagnosis is crucial to assist with surgical planning and avoid intraoperative complications. Level of evidence: 4. [ABSTRACT FROM AUTHOR]

Background/aim: Dual-energy computed tomography scans can provide significant benefits to the urinary system. The aim of this study is to determine the limitations and benefits of using dual energy CT urography in patients with urinary system stones and cysts. Materials and methods: In the analysis of the images, the virtual noncontrasted images obtained from the combined nephrogenic-excretory phase and the true noncontrasted images were evaluated. The true noncontrast images were accepted as the gold standard for stone detection. Results: Eighty-three different stones were detected in 26 of the 115 patients included in the study. Sensibilities of virtual noncontrast images in detecting urinary system stones were 66.7% and 65.4% according to the first and second radiologists, respectively. In this study, 32 hyperdense cysts were detected. According to iodine map images, there was no enhancement in 26 of 32 cysts; only 5 cysts showed minimal contrast enhancement. One patient could not decide on contrast enhancement. Conclusion: As a result, if CT urography is performed with dual energy, it can provide additional information in patients with urinary system disorder. [ABSTRACT FROM AUTHOR]

Introduction: Non-visible haematuria (NVH) is associated with a small risk of upper-tract urothelial carcinoma (UTUC), though there is little consensus on its investigation, particularly with regard to upper-tract imaging. This study aimed to determine whether the presentation of UTUC can guide investigation of NVH in patients under 60 years old. Methods: All patients investigated at our one-stop haematuria clinics under a cancer pathway were reviewed during a 5-year period, with all patients undergoing cystoscopy and upper-tract imaging. Retrospective analysis of all UTUC cases from our urological cancer multidisciplinary team meeting database over a 10-year period was also undertaken. Results: 2,129 patients with a median age of 67 years underwent urgent investigation for haematuria between March 2015 and February 2020. 449 cases presented with NVH, of whom 124 (27.6%) were under 60. Out of 21 cases of UTUC, only 2 presented with NVH; both were over the age of 60 years. Factors that independently predicted diagnosis with urinary-tract malignancy were age ≥60 (OR 3.70, p < 0.001), visible haematuria (OR 2.50, p = 0.006), and suspicious cystoscopic findings (OR 58.06, p < 0.001). Review of all 119 UTUC cases over 10 years found 6 cases (5.0%) presenting with NVH, with one (0.8%) also presenting under 60 years. Conclusion: Diagnosis with UTUC is rare in patients presenting with NVH under the age of 60 years. Routine use of CTU in this low-risk group is best avoided, with ultrasonography constituting a safer first-line upper-tract imaging modality. Guidelines that risk-stratify NVH patients may be effective in reducing unnecessary investigations. [ABSTRACT FROM AUTHOR]

Uro-lymphatic fistulas are rare, and involve communication between the renal collecting system and the lymphatic system. The disorder is usually caused by the obstruction of lymphatic vessels due to several diseases, leading to chyluria. Here, we report the case of a patient with a uro-lymphatic fistula, considered to be associated with urolithiasis.

Abstract Background Omentum and bowel loops are commonly seen in inguinal hernia. An unusual case of extraperitoneal herniation of ureter was detected in hernial sac with other contents, on computed tomography (CT) urography. Case presentation A 54-year-old male presented with inguinal hernia, with no previous history of surgery or trauma. Pre-operative screening showed a unilateral hydroureteronephrosis involving the pelvicalyceal system and entire ureter. No calculus was visualized in the ureter on ultrasound. On non-contrast CT (NCCT) followed by CT urography, the ureter was seen descending into the hernia sac causing hydroureteronephrosis. The patient subsequently underwent mesh repair surgery of the inguinal hernia with meticulous reduction of the herniated contents including the ureter, resulting in complete resolution of the hydroureteronephrosis. Conclusion An isolated extraperitoneal inguinal herniation of the ureter without concomitant urinary bladder involvement is extremely rare, especially with no prior history of trauma or surgery, as seen in our case. The case also exemplifies the role of pre-operative imaging as a protocol in cases of inguinal hernia to prevent per-operative complications.

Abstract Background The purpose was to assess radiation dose, image quality, and diagnostic performance of reduced-dose scanning with iterative reconstruction (IR) compared with standard-dose with filtered back projection (FBP) with CT urography for detection of bladder tumor. This study was prospectively conducted on 21 patients with bladder masses. All patients were subjected to two scanning protocols: protocol A (standard dose with FBP) and protocol B (additional limited scan to the pelvis at delayed phase with low dose with IR). Based on body weight (< or > 80 kg), each protocol was subdivided into 2 protocols A1 (130 kVp) and A2 (130 kVp) and protocols B1 (80 kVp) and B2 (110 kVp). Radiation dose was assessed in terms of mean CT dose index (CTDI), Dose-length product (DLP) and effective dose (ED). Image quality and diagnostic accuracy were compared in both groups. Results Mean CTDI, DLP and ED were reduced by average 72.3 % in the 80 kVp protocol (B1) and by 36.3% in 110 kVp (B2) protocol compared to standard-dose protocols. There were significantly lower SNR (signal to noise ratio) between protocol A1 and B1 at aorta and psoas muscles. Subjective image quality analysis revealed no statistically significant differences between the protocol A2 and B2 whereas there were significant differences between protocol A1and B1 as regards to visual image noise and overall image quality. Diagnostic accuracy was identical among different protocols. Conclusion CT urography with IR scanning showed reduced radiation dose and no difference in detection of urothelial carcinomas from standard dose with FBP despite of degraded image quality in 80 kVp scanning.

Purpose: Quantitative evaluation of renal obstruction is crucial for preventing renal atrophy. This study presents a novel method for diagnosing renal obstruction by automatically extracting objective indicators from routine multi-phase CT Urography (CTU). Material and methods: The study included multi-phase CTU examinations of 6 hydronephrotic kidneys and 24 non-hydronephrotic kidneys (23,164 slices). The developed algorithm segmented the renal parenchyma and the renal pelvis of each kidney in each CTU slice. Following a 3D reconstruction of the parenchyma and renal pelvis, the algorithm evaluated the amount of the contrast media in both components in each phase. Finally, the algorithm evaluated two indicators for assessing renal obstruction: the change in the total amount of contrast media in both components during the CTU phases, and the drainage time, ''T1/2'', from the renal parenchyma. Results: The algorithm segmented the parenchyma and renal pelvis with an average dice coefficient of 0.97 and 0.92 respectively. In all the hydronephrotic kidneys the total amount of contrast media did not decrease during the CTU examination and the T1/2 value was longer than 20 min. Both indicators yielded a statistically significant difference (p

Purpose: To determine the diagnostic yield of computed tomography urography (CTU) in patients evaluated for hematuria with negative cystoscopy and to assess the added value of CTU when compared with ultrasound (US) in this patient population. Methods: A retrospective study was conducted of patients who underwent CTU within 12 months of negative cystoscopy for workup of hematuria at our institution from January 2016 to December 2017. Computed tomography urography findings were recorded and compared to clinical diagnoses to determine diagnostic yield. Computed tomography urography and US findings were compared in patients who underwent both examinations. Patient characteristics (age, sex, smoking history, and hematuria subtype) were reported. Results: A total of 657 patients met the inclusion criteria, including 108 patients aged 50 years and younger. No cause for hematuria was identified in 41% of patients overall and 58% of patients aged 50 years and younger. The most common diagnoses were benign prostatic hyperplasia and urolithiasis, accounting for 25% and 21% of patients, respectively; 0.6% of patients were diagnosed with an upper urinary tract malignancy, all older than 50 years. Although US was superior or equal to CTU for diagnosis in 83% of patients who underwent both examinations, US had a 0% sensitivity for detection of upper urinary tract malignancy. Conclusion: The low diagnostic yield of CTU and low prevalence of upper urinary tract malignancy in patients evaluated for hematuria with negative cystoscopy, particularly those aged 50 years and younger, call into question the appropriateness of multiphasic CTU as a first-line imaging modality in this population. [ABSTRACT FROM AUTHOR]

Ureteral fibroepithelial polyps are rare, accounting for approximately 2–6% of all ureteral tumors. They can be diagnosed by ultrasonography, computed tomography, and retrograde pyelography; however, diagnosis can be difficult. Management is by resection of the polyp, and endoscopic resection is the standard treatment. Partial ureteral resection and ureteral reconstruction may be necessary depending on the size and location of the polyp. Imaging follow-ups for approximately a year post-surgery are recommended. This clinical case report aimed to highlight a case of a fibroepithelial ureteral polyp that was managed by endoscopic resection.

Ureteral fibroepithelial polyps are benign, mesodermal neoplasms that can cause upper urinary tract obstruction. The preoperative diagnosis of this disease is challenging, but multidetector computed tomography (CT), particularly CT urography in the excretory phase, can be used to detect the features of ureteral polyps. We illustrated a case preoperatively diagnosed as upper ureteral tract obstruction due to ureteral tumor based on clinical presentation and CT imaging. However, the histopathological report revealed ureteral fibroepithelial polyps. Ureteral fibroepithelial polyps should be considered as a rare cause of urinary obstruction when the clinical presentation and imaging findings are atypical for more common etiologies.

Objective: To investigate the application value of CT angiography (CTA) combined with CT urography (CTU) in the clinical treatment of patients with severe closed renal injury. Methods: The clinical data of 9 patients with severe closed renal injury admitted to our hospital from January 2017 to December 2019 were collected and analyzed. On admission, emergency CT scan was performed to understand the situation of renal contusion, and then CTA combined with CTU was further performed. According to the examination results, appropriate treatment options (conservative treatment, selective renal artery interventional embolization treatment, surgical treatment) were selected. Result: All the 9 patients were treated successfully. Conservative treatment was performed in 4 cases and renal artery interventional embolization in 5 cases (2 cases were treated with operation after renal artery embolization). The patients were followed up for 3-8 months and recovered well without obvious complications. Conclusion: Renal artery CTA combined with CTU examination can provide anatomic information of renal vessels, renal pelvis, ureter, adjacent organs, etc., determine the degree of injury, provide good preoperative guidance for interventional and surgical treatment, especially combined with selective renal artery embolization, which can maximize the renal function and improve the rescue rate, which has important clinical application value. [ABSTRACT FROM AUTHOR]

In this review article, we will discuss the gamut of abnormalities involving the ureters. In the emergency department, ureterolithiasis is the most common indication for imaging abdomen and pelvis. However, spectrum of ureteral abnormalities including congenital, infectious and inflammatory, primary and secondary ureteral malignancies, retroperitoneal fibrosis rare described in this article may be encountered. Thus, we will describe acute subacute as well as chronic conditions that may affect ureter. Knowledge of common, as well as rare entities and their imaging features, is of utmost importance to enable appropriate management. [ABSTRACT FROM AUTHOR]

Background: Omentum and bowel loops are commonly seen in inguinal hernia. An unusual case of extraperitoneal herniation of ureter was detected in hernial sac with other contents, on computed tomography (CT) urography. Case presentation: A 54-year-old male presented with inguinal hernia, with no previous history of surgery or trauma. Pre-operative screening showed a unilateral hydroureteronephrosis involving the pelvicalyceal system and entire ureter. No calculus was visualized in the ureter on ultrasound. On non-contrast CT (NCCT) followed by CT urography, the ureter was seen descending into the hernia sac causing hydroureteronephrosis. The patient subsequently underwent mesh repair surgery of the inguinal hernia with meticulous reduction of the herniated contents including the ureter, resulting in complete resolution of the hydroureteronephrosis. Conclusion: An isolated extraperitoneal inguinal herniation of the ureter without concomitant urinary bladder involvement is extremely rare, especially with no prior history of trauma or surgery, as seen in our case. The case also exemplifies the role of pre-operative imaging as a protocol in cases of inguinal hernia to prevent per-operative complications. [ABSTRACT FROM AUTHOR]

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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 <50 years old. Investigating these subgroups with CT urography may be unnecessary and result in increased patient morbidity and health-care costs. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. Development of CTU-image quality could improve bladder cancer diagnostics. [ABSTRACT FROM AUTHOR]

Although inguinal hernia repair is one of the most common surgical procedures, finding a retroperitoneal structure, such as the ureter, is a rather rare occurrence. Ureteroinguinal hernias may arise in the presence or absence of obstructive uropathy, the latter raising difficulties in diagnosis for the general surgeon performing a regular inguinal hernia surgery. This study aims to collect the relevant literature describing the diagnosis and management of ureteroinguinal hernias and update it with a case encountered in our clinic. The following study was reported following the SCARE guidelines. The relevant literature describes less than 150 cases of ureteroinguinal hernias overall, considering the 1.7% prevalence of inguinal hernias in the general population. With only 20% of these hernias being described as extraperitoneal, such an encounter becomes an extremely rare finding. Our clinical experience brings a case of a 75-year-old male with frequent urinary tract infections and a large irreducible inguinoscrotal hernia of about 20/12 cm located at the right scrotum. The patient underwent an open inguinal hernia repair technique under general anesthesia, incidentally finding an extraperitoneal ureteral herniation. Segmental ureterectomy was performed with uneventful recovery. Intraoperatively, finding an incidental ureteroinguinal hernia raises concerns about probable urinary tract complications during regular hernia repair surgery and whether the diagnosis is likely to happen prior to surgical intervention. Although imaging is rarely indicated in inguinal hernias, the case reports show that a pelvic CT scan with urography in symptomatic patients with urinary symptoms will provide accurate confirmation of the diagnosis. The relevant literature is limited due to the rarity of respective cases, thus making standardized management of such cases unlikely.

Background: The purpose was to assess radiation dose, image quality, and diagnostic performance of reduced-dose scanning with iterative reconstruction (IR) compared with standard-dose with filtered back projection (FBP) with CT urography for detection of bladder tumor. This study was prospectively conducted on 21 patients with bladder masses. All patients were subjected to two scanning protocols: protocol A (standard dose with FBP) and protocol B (additional limited scan to the pelvis at delayed phase with low dose with IR). Based on body weight (< or > 80 kg), each protocol was subdivided into 2 protocols A1 (130 kVp) and A2 (130 kVp) and protocols B1 (80 kVp) and B2 (110 kVp). Radiation dose was assessed in terms of mean CT dose index (CTDI), Dose-length product (DLP) and effective dose (ED). Image quality and diagnostic accuracy were compared in both groups. Results: Mean CTDI, DLP and ED were reduced by average 72.3 % in the 80 kVp protocol (B1) and by 36.3% in 110 kVp (B2) protocol compared to standard-dose protocols. There were significantly lower SNR (signal to noise ratio) between protocol A1 and B1 at aorta and psoas muscles. Subjective image quality analysis revealed no statistically significant differences between the protocol A2 and B2 whereas there were significant differences between protocol A1and B1 as regards to visual image noise and overall image quality. Diagnostic accuracy was identical among different protocols. Conclusion: CT urography with IR scanning showed reduced radiation dose and no difference in detection of urothelial carcinomas from standard dose with FBP despite of degraded image quality in 80 kVp scanning. [ABSTRACT FROM AUTHOR]

Purpose: Retrograde pyelography (RPG) is used in some centers to further evaluate patients with incompletely opacified segments on CT urography (CTU). This study intends to evaluate the utility of this imaging combination in terms of the yield of abnormal findings on the follow up RPG. Methods: In this retrospective study, we searched the radiology database over a three-year period (11/1/2015–10/30/2018) for patients who had a CTU and then a diagnostic RPG within 180 days. Images and reports were reviewed from this period for patients who met the inclusion criteria. Results: 292 patients underwent a CTU with follow up RPG over the search period. 131/292 RPGs (44.9%) were performed because the CTU described at least one incompletely opacified ureteral segment. Of the 148 ureters evaluated in these 131 patients, 4 ureters (2.7%) showed an abnormality on follow up retrograde pyelogram—two revealed a stricture at the unfilled segment, and two revealed contour irregularity in the distal ureter (biopsy showed urothelial cell carcinoma in these two). Conclusion: There is a relatively low yield for detecting ureteral abnormalities when a retrograde pyelogram is performed after a CTU to evaluate an incompletely opacified ureteral segment—2.7% in our study, with only two of these incompletely opacified segments containing urothelial cancer (1.4%). In these two cases, a ureteral abnormality was visible on the CTU and RPG would seem to have a very low yield for follow up of unopacified ureteral segments if the ureters are otherwise normal-appearing on CTU and there is no hydronephrosis. [ABSTRACT FROM AUTHOR]

Introduction and Objectives. Our study's objective is to discuss and illustrate cases of Müllerian duct anomalies (MDA) associated with unilateral renal agenesis (URA). Material and Methods. We have reviewed our database for a period of seven years (between January 2013 and March 2020) using as key-point "renal agenesis" or "solitary kidney" looking for associated Müllerian duct anomalies. All the pediatric patients have been investigated by ultrasound as screening and follow-up method and one child has been investigated by ultrasound (US) and intravenous pyelography (IVP). All the adult patients have been investigated by sectional imaging methods, more CT urography than MRI exams. Results. We have found a total number of 52 cases of URA (27 of them being female), but we selected only 8 female cases confirmed after imaging investigations with URA and MDA. Patients have been 13 to 39 years old with an average age of 25 years. URA have been located on the left side in 4 cases and on the right side in 4 cases. We excluded from our study the cases who had only one of the anomalies (only renal agenesis or only Müllerian duct anomalies) and also the cases associating to URA extra - Müllerian anomalies like vascular anomalies (inferior vena cava anomalies - azygos continuation), duplicated collecting system or ectopic ovary. MDA have been represented by didelphys uterus (5 cases, one uncertain - possible didelphys uterus, but CT scan was unable to provide a certain diagnosis), bicornuate uterus (2 cases) and indeterminate uterus (probably communicating unicornuate uterus with a rudimentary, hypoplastic left horn versus asymmetric septate uterus - 1 case). Another associated genital anomalies found in our patients have been endometriosis and leiomyofibroma (one case) and Gartner duct cyst (1 case). From our selected cases, two of them had some associated renal anomalies on the solitary kidney like pelviureteric junction obstruction (PUJO) with grade III hydronephrosis (HN) and a possible vesicoureteral reflux (VUR). Four of the patients have been diagnosed with Herlyn-Werner-Wunderlich syndrome. Conclusions. Imaging investigations in patients with associated URA and MDA is essential for further prognostic of the disease. MDCT is an excellent diagnostic tool for associated congenital anomalies of kidney and urinary tract (CAKUT) on solitary kidney but for associated genital anomalies, MRI is the gold standard method. [ABSTRACT FROM AUTHOR]

Abstract Background To prove the feasibility of integrating CT urography (CTU) into 68Ga-PSMA-11 PET/CT and to analyze the impact of CTU on assigning focal tracer accumulation in the ureteric space to either ureteric excretion or metastatic disease concerning topographic attribution and diagnostic confidence. Methods Ten prostate cancer patients who underwent 68Ga-PSMA-11 PET/CT including CTU because of biochemical relapse or known metastatic disease were retrospectively analyzed. CTU consisted of an excretory phase 10 min after injection of 80 mL iodinated contrast material. Ureter opacification at CTU was evaluated using the following score: 0, 0% opacification; 1, < 50%; 2, 50–99%; 3, 100%. Topographic attribution and confidence of topographic attribution of focal tracer accumulation in the ureteric space were separately assessed for 68Ga-PSMA-11 PET/CT without and with CTU. Diagnostic confidence was evaluated using the following score: 0, < 25% confidence; 1, 26–50%; 2, 51–75%; 3, 76–100%. Results At CTU, mean ureter opacification score was 2.6 ± 0.7. At 68Ga-PSMA-11 PET/CT without CTU, mean confidence of topographic attribution of focal tracer accumulation was 2.5 ± 0.7 in total and 2.6 ± 0.7 for metastatic disease. At 68Ga-PSMA-11 PET/CT with CTU, mean confidence of topographic attribution of focal areas of tracer accumulation was significantly higher with 2.9 ± 0.2 in total and 2.7 ± 0.9 for metastatic disease (p

Supernumerary kidney is a rare clinical entity with fused supernumerary kidney being even rarer. Caudally located fused right supernumerary kidney with multiple nephrolithiasis was diagnosed in a 69-years-old lady by Computed Tomography Urography. A separate renal artery arising from the abdominal aorta as well as separate renal vein draining into the inferior vena cava was present along with right sided bifid collecting system. Embryological basis of origin of supernumerary kidney, its diagnosis, clinical significance and management are discussed.

Uniform circumferential bladder wall thickening is almost always due to benign disease, with the differential diagnosis including any type of cystitis, neurogenic bladder, and chronic mechanical bladder outlet obstruction. An axial portal venous phase contrast-enhanced CT image through the pelvis in a patient who had undergone transurethral resection of a bladder tumor and topical treatment with BCG 6 months earlier demonstrates marked asymmetric thickening of the bladder wall on the left side laterally and anteriorly (arrow). On CT urography, affected patients usually present with diffuse circumferential bladder wall thickening [[20]], although a minority will have asymmetric areas of bladder wall thickening that mimic urothelial neoplasms (Fig. An axial portal venous phase contrast-enhanced CT image through the pelvis in a patient who had had a transurethral resection of a bladder tumor followed by topical mitomycin therapy demonstrates the bladder wall to be irregularly thickened, with lobulated mass-like thickening particularly along the right lateral and anterior walls (arrows). Coronal imaging can be helpful to localize the abnormality. b An axial portal venous phase contrast-enhanced CT image through the pelvis in a different female patient with incontinence demonstrates high attenuation material in a crescentic shape in the periurethral region, consistent with the carbon-coated bead type of bulking agent. c A coronal image from this same female patient's CT helps localize the agent. [Extracted from the article]

Purpose: The aim of this pictorial essay is to demonstrate several cases where the diagnosis would have been difficult or impossible without the excretory phase image of CT urography. Methods: A brief discussion of CT urography technique and dose reduction is followed by several cases illustrating the utility of CT urography. Results: CT urography has become the primary imaging modality for evaluation of hematuria, as well as in the staging and surveillance of urinary tract malignancies. CT urography includes a non-contrast phase and contrast-enhanced nephrographic and excretory (delayed) phases. While the three phases add to the diagnostic ability of CT urography, it also adds potential patient radiation dose. Several techniques including automatic exposure control, iterative reconstruction algorithms, higher noise tolerance, and split-bolus have been successfully used to mitigate dose. The excretory phase is timed such that the excreted contrast opacifies the urinary collecting system and allows for greater detection of filling defects or other abnormalities. Sixteen cases illustrating the utility of excretory phase imaging are reviewed. Conclusions: Excretory phase imaging of CT urography can be an essential tool for detecting and appropriately characterizing urinary tract malignancies, renal papillary and medullary abnormalities, CT radiolucent stones, congenital abnormalities, certain chronic inflammatory conditions, and perinephric collections. [ABSTRACT FROM AUTHOR]

Purpose: 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. Methods: This article reviews the published literature on CTU protocol optimization, including contrast bolus timing, dose reduction, reconstruction algorithms, and ancillary practices. Conclusion: 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. [ABSTRACT FROM AUTHOR]

Purpose: To summarize knowledge on upper urinary tract carcinoma (UTUC) regarding diagnostic procedures, risk factors and prognostic markers. Methods: A scoping review approach was applied to search literature in Pubmed, Web of Science, and Embase. Consensus was reached through discussions at Consultation on UTUC in Stockholm, September 2018. Results: Tumor stage and grade are the most important prognostic factors. CT urography (CTU) including corticomedullary phase is the preferred imaging modality. A clear tumor on CTU in combination with high-grade UTUC in urine cytology identifies high-risk UTUC, and in some cases indirect staging can be obtained. Bladder urine cytology has limited sensitivity, and in most cases ureterorenoscopy (URS) with in situ samples for cytology and histopathology are mandatory for exact diagnosis. Image-enhancing techniques, Image S1 and narrow-band imaging, may improve tumor detection at URS. Direct confocal laser endomicroscopy may help to define grade during URS. There is strong correlation between stage and grade, accordingly correct grading is crucial. The correlation is more pronounced using the 1999 WHO than the 2004 classification: however, the 1999 system risks greater interobserver variability. Using both systems is advisable. A number of tissue-based molecular markers have been studied. None has proven ready for use in clinical practice. Conclusions: Correct grading and staging of UTUC are mandatory for adequate treatment decisions. Optimal diagnostic workup should include CTU with corticomedullary phase, URS with in situ cytology and biopsies. Both WHO classification systems (1999 and 2004) should be used to decrease risk of undergrading or overtreatment. [ABSTRACT FROM AUTHOR]

Objectives: To develop a U‐Net–based deep learning approach (U‐DL) for bladder segmentation in computed tomography urography (CTU) as a part of a computer‐assisted bladder cancer detection and treatment response assessment pipeline. Materials and methods: A dataset of 173 cases including 81 cases in the training/validation set (42 masses, 21 with wall thickening, 18 normal bladders), and 92 cases in the test set (43 masses, 36 with wall thickening, 13 normal bladders) were used with Institutional Review Board approval. An experienced radiologist provided three‐dimensional (3D) hand outlines for all cases as the reference standard. We previously developed a bladder segmentation method that used a deep learning convolution neural network and level sets (DCNN‐LS) within a user‐input bounding box. However, some cases with poor image quality or with advanced bladder cancer spreading into the neighboring organs caused inaccurate segmentation. We have newly developed an automated U‐DL method to estimate a likelihood map of the bladder in CTU. The U‐DL did not require a user‐input box and the level sets for postprocessing. To identify the best model for this task, we compared the following models: (a) two‐dimensional (2D) U‐DL and 3D U‐DL using 2D CT slices and 3D CT volumes, respectively, as input, (b) U‐DLs using CT images of different resolutions as input, and (c) U‐DLs with and without automated cropping of the bladder as an image preprocessing step. The segmentation accuracy relative to the reference standard was quantified by six measures: average volume intersection ratio (AVI), average percent volume error (AVE), average absolute volume error (AAVE), average minimum distance (AMD), average Hausdorff distance (AHD), and the average Jaccard index (AJI). As a baseline, the results from our previous DCNN‐LS method were used. Results: In the test set, the best 2D U‐DL model achieved AVI, AVE, AAVE, AMD, AHD, and AJI values of 93.4 ± 9.5%, −4.2 ± 14.2%, 9.2 ± 11.5%, 2.7 ± 2.5 mm, 9.7 ± 7.6 mm, 85.0 ± 11.3%, respectively, while the corresponding measures by the best 3D U‐DL were 90.6 ± 11.9%, −2.3 ± 21.7%, 11.5 ± 18.5%, 3.1 ± 3.2 mm, 11.4 ± 10.0 mm, and 82.6 ± 14.2%, respectively. For comparison, the corresponding values obtained with the baseline method were 81.9 ± 12.1%, 10.2 ± 16.2%, 14.0 ± 13.0%, 3.6 ± 2.0 mm, 12.8 ± 6.1 mm, and 76.2 ± 11.8%, respectively, for the same test set. The improvement for all measures between the best U‐DL and the DCNN‐LS were statistically significant (P < 0.001). Conclusion: Compared to a previous DCNN‐LS method, which depended on a user‐input bounding box, the U‐DL provided more accurate bladder segmentation and was more automated than the previous approach. [ABSTRACT FROM AUTHOR]

Purpose: We are developing a computerized segmentation tool for the inner and outer bladder wall as a part of an image analysis pipeline for CT urography (CTU). Materials and Methods: A data set of 172 CTU cases was collected retrospectively with Institutional Review Board (IRB) approval. The data set was randomly split into two independent sets of training (81 cases) and testing (92 cases) which were manually outlined for both the inner and outer wall. We trained a deep‐learning convolutional neural network (DL‐CNN) to distinguish the bladder wall from the inside and outside of the bladder using neighborhood information. Approximately, 240 000 regions of interest (ROIs) of 16 × 16 pixels in size were extracted from regions in the training cases identified by the manually outlined inner and outer bladder walls to form a training set for the DL‐CNN; half of the ROIs were selected to include the bladder wall and the other half were selected to exclude the bladder wall with some of these ROIs being inside the bladder and the rest outside the bladder entirely. The DL‐CNN trained on these ROIs was applied to the cases in the test set slice‐by‐slice to generate a bladder wall likelihood map where the gray level of a given pixel represents the likelihood that a given pixel would belong to the bladder wall. We then used the DL‐CNN likelihood map as an energy term in the energy equation of a cascaded level sets method to segment the inner and outer bladder wall. The DL‐CNN segmentation with level sets was compared to the three‐dimensional (3D) hand‐segmented contours as a reference standard. Results: For the inner wall contour, the training set achieved the average volume intersection, average volume error, average absolute volume error, and average distance of 90.0 ± 8.7%, −4.2 ± 18.4%, 12.9 ± 13.9%, and 3.0 ± 1.6 mm, respectively. The corresponding values for the test set were 86.9 ± 9.6%, −8.3 ± 37.7%, 18.4 ± 33.8%, and 3.4 ± 1.8 mm, respectively. For the outer wall contour, the training set achieved the values of 93.7 ± 3.9%, −7.8 ± 11.4%, 10.3 ± 9.3%, and 3.0 ± 1.2 mm, respectively. The corresponding values for the test set were 87.5 ± 9.9%, −1.2 ± 20.8%, 11.9 ± 17.0%, and 3.5 ± 2.3 mm, respectively. Conclusions: Our study demonstrates that DL‐CNN‐assisted level sets can effectively segment bladder walls from the inner bladder and outer structures despite a lack of consistent distinctions along the inner wall. However, even with the addition of level sets, the inner and outer walls may still be over‐segmented and the DL‐CNN‐assisted level sets may incorrectly segment parts of the prostate that overlap with the outer bladder wall. The outer wall segmentation was improved compared to our previous method and the DL‐CNN‐assisted level sets were also able to segment the inner bladder wall with similar performance. This study shows the DL‐CNN‐assisted level set segmentation tool can effectively segment the inner and outer wall of the bladder. [ABSTRACT FROM AUTHOR]

Background: Computed tomography urography (CTU) is an efficient radiological examination for the evaluation of urinary system disorders. However, the procedure exposes patients to a substantial amount of radiation dose associated with increased cancer risks. Objectives: To determine computed tomography (CT) dose index following CTU and to evaluate organs equivalent doses and cancer-induced risks. Materials and Method: A prospective cohort study was carried out at a tertiary health facility in Kano, Northwestern Nigeria. Ethical approval was sought and obtained. Patients Demographics scan parameters and CT radiation dose data were obtained from patients that had CTU procedure. Effective dose (ED), organ equivalent doses, and cancer risks were estimated using SPSS statistical software version 16 and CT dose calculator software. Results: A total of 56 consented patients were included in the study, consisting of 29 males and 27 females. Radiation dose data for CTU was estimated as follows: dose length product (2,320 mGy*cm), computed tomography dose index (9.67 mGy), and ED (34.5 mSv). The probability of cancer risks was also estimated to be 600 per a million CTU examinations. Conclusion: The study revealed that the radiation dose for CTU is considerably high with increase in cancer risks probability. Variations in ED between studies suggest that optimization is not fulfilled. Patient radiation dose estimate should be taken into consideration when imaging protocols are planned for CTU. [ABSTRACT FROM AUTHOR]

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.

Abstract Objectives To evaluate the usefulness of adding diffusion-weighted MRI (DW-MRI) to CT urography (CTU) for diagnosing upper tract urothelial carcinoma (UTUC). Materials and methods We retrospectively evaluated 102 high-risk patients with UTUC who underwent both CTU and DW-MRI. The diagnostic performance of CTU and DW-MRI was evaluated in all the patients. Then, the diagnostic performance of DW-MRI in the patients with positive CTU findings was assessed based on the types of CTU findings (mass formation, wall thickening, and small filling defects). The diagnostic performance of DW-MRI and selective urine cytology sampling in these patients was also compared. Results The sensitivity of DW-MRI (92%) was less than that of CTU (98%) (P = 0.25), since DW-MRI could not detect any small papillary tumors. The specificity of DW-MRI (91%) was greater than that of CTU (78%) (P = 0.065), since DW-MRI could discriminate some benign conditions from UTUC. Among the 59 positive CTU lesions, DW-MRI correctly diagnosed all 41 mass-forming lesions and improved the accuracy from 36% using CTU alone to 79% for 14 wall-thickening lesions but could not add any additional information for 4 small filling-defect lesions. Among the 44 patients with positive CTU findings who underwent selective urine cytology sampling, the sensitivity of DW-MRI (95%) was significantly greater than that of selective urine cytology sampling (56%) (P < 0.001). Conclusions The addition of DW-MRI would be useful for both mass-forming and wall-thickening lesions. DW-MRI has the potential to reduce the frequency of selective urine cytology sampling for such lesions. Highlights • DW-MRI could not detect any small papillary urothelial carcinoma detected using CTU. • All mass-forming lesions with positive DW-MRI findings were urothelial carcinoma. • Some benign conditions could be discriminated from urothelial carcinoma using DW-MRI. • The sensitivity of DW-MRI was greater than that of selective urine cytology sampling. [ABSTRACT FROM AUTHOR]