Multiparametric MR Urography: State of the Art

MR urography (MRU) is an imaging technique that provides comprehensive evaluation of the kidneys, pelvicalyceal system, ureters, and urinary bladder. Although CT urography (CTU) remains the first-line imaging modality for the urinary tract, incremental improvements in MRU have allowed simultaneous imaging of the kidneys, collecting system, and urinary bladder with superior contrast resolution and tissue characterization, equivalent visualization of the upper tracts, and similar specificity for detection of noncalculous diseases of the collecting system compared with that of CTU. MRU has evolved into an alternative to CTU in the broader patient population and a first-line examination in specific patient populations for which CTU is less preferred. This subgroup includes pediatric patients, pregnant patients, patients needing recurring studies, and patients with poor renal function or severe allergies to iodinated contrast material. The most common techniques encompassing a conventional MRU examination include static-fluid T2-weighted imaging and gadolinium-enhanced urothelial and excretory phase imaging. The addition of dynamic contrast-enhanced MRI and diffusion-weighted imaging results in multiparametric MRU that increases diagnostic accuracy. Newer techniques, such as parallel imaging, compressed sensing, radial k-space sampling, and deep learning-based image reconstruction, can shorten examination times and improve image quality and patient compliance. Successful MRU interpretation relies on technique optimization, knowledge of various urinary tract pathologic conditions, and familiarity with different sequences, potential interpretive pitfalls, and artifacts. ©RSNA, 2025 Supplemental material is available for this article.

External ureteral involvement as a result of ovarian cancer initially suspected as endometriosis leading to the diagnosis of squamous cell carcinoma

Ovarian squamous cell carcinoma [SCC] is a rare and aggressive malignancy that can mimic benign gynecological disorders, often leading to diagnostic delays and suboptimal management. Ureteral obstruction and subsequent hydroureteronephrosis due to extrinsic compression are atypical initial presentations of ovarian SCC. A 39-year-old female presented with nausea, vomiting, anuria, and bilateral hydroureteronephrosis, initially suspected to be endometriosis. Given the severity of acute kidney injury, emergent hemodialysis was initiated. Imaging demonstrated bilateral distal ureteral obstruction, necessitating percutaneous nephrostomy and subsequent referral for definitive management. Intraoperative findings revealed extensive fibrosis and adhesions, warranting left salpingo-oophorectomy and bilateral ureteroneocystostomy with double-J stent placement. Histopathological analysis confirmed ovarian SCC with direct ureteral invasion and hepatic metastases. Despite surgical intervention and palliative systemic therapy, the disease exhibited rapid progression, ultimately culminating in patient mortality. This case underscores the diagnostic complexities of ovarian SCC presenting with obstructive uropathy and highlights the necessity of maintaining a high index of suspicion for malignancy in patients with bilateral hydroureteronephrosis of unclear etiology. A timely, multidisciplinary approach integrating urological and oncological expertise is paramount in optimizing clinical outcomes.

Urologic Imaging of Collecting System and Ureters: Cancers and Mimics

Urothelial carcinoma can arise from any portion of the urothelial lining extending from the kidneys to the urethra, with morphologic subtypes including papillary, polypoid, infiltrative, and ulcerative growth patterns. Imaging plays a crucial role in detecting upper and lower urinary tract tumors and in differentiating them from other benign mimics. Computed tomographic urography (CTU) is the imaging modality of choice for the diagnosis of urothelial carcinoma as well as for noninvasive surveillance following treatment. CTU allows evaluation of recurrent primary tumor while evaluating for metastatic disease in a single study.

Urologic Imaging of the Bladder: Cancers and Mimics

Bladder cancer (BC) represents a significant global health challenge with notable incidence and mortality rates. Despite treatment advancements, its management remains complex, requiring a multidisciplinary approach. Imaging techniques play a pivotal role in diagnosis, staging, and treatment planning by aiding lesion localization, differentiation, and assessment of tumor extent. Primary modalities like computed tomography and MRI offer detailed anatomic insights. Imaging provides valuable insights into tumor biology, vascular patterns, and molecular profiles, enabling personalized medicine strategies to optimize therapeutic efficacy and minimize adverse effects, crucial for improving BC management and prognosis.

Morphologic Urologic Imaging

Imaging plays an important role in the evaluation of the urologic organs. Radiographs, fluoroscopy, ultrasound, computed tomography, and MRI are all modalities that can be used to answer various clinical questions. In this article we provide an overview of the most common imaging examinations performed using these modalities to assess the urologic structures.

Renal vessel pseudoaneurysm as a cause of recurrent haematuria

Pseudoaneurysm is a common vascular abnormality marked by arterial wall disruption, with complications that can arise unpredictably and carry high morbidity and mortality rates. This case study emphasises the management of recurrent haematuria and clot retention in a young man presenting to the emergency department. It underscores the importance of early recognition and management of recurrent haematuria and clot retention caused by pseudoaneurysm, emphasising the critical role of multidisciplinary collaboration in optimising patient outcomes.

Imaging of Upper Tract Urothelial Carcinoma

Upper tract urothelial carcinoma (UTUC) originates in the renal pelvis or ureters and typically affects elderly patients, with its incidence increasing over the past few decades. UTUC is a distinct clinical entity with more aggressive clinical behavior than that of lower tract urothelial carcinoma. Due to the significant challenge of acquiring an adequate tissue sample for biopsy, comprehensive risk stratification is required for treatment planning, including radical nephroureterectomy and kidney-sparing management. Imaging plays an important integrated role in risk assessment along with endoscopy and pathologic examination. Lifelong surveillance is required after treatment due to the high incidence of recurrent and metachronous tumors. Lynch syndrome is a frequently unrecognized genetic disorder associated with UTUC that warrants specific attention in patient management. UTUC may manifest with diverse imaging findings, including filling defects, wall thickening, and mass-forming lesions. CT urography is the preferred modality for diagnosis and staging or restaging of UTUC, with numerous technical variations. Efforts have been made to optimize image quality and radiation exposure. Due to its poor sensitivity for small lesions, use of MR urography is limited to special clinical scenarios (eg, when patients have contraindications to iodinated contrast agents). Fluorine 18 fluorodeoxyglucose PET helps to detect metastatic lesions. Image-guided biopsy may be considered for uncertain lesions. Radiologists need to be familiar with the imaging findings and their differential diagnoses. ©RSNA, 2024 Supplemental material is available for this article.

Qualitative and quantitative analysis of solid renal tumors by high-frame-rate contrast-enhanced ultrasound

OBJECTIVE

To analyze the characteristics of high-frame-rate contrast-enhanced ultrasound (H-CEUS) in solid renal tumors using qualitative and quantitative methods.

METHODS

Seventy-five patients who underwent preoperative conventional ultrasound (US), conventional contrast-enhanced ultrasound (C-CEUS), and H-CEUS examination of renal tumors were retrospectively analyzed, with a total of 89 renal masses. The masses were divided into the benign (30 masses) and malignant groups (59 masses) based on the results of enhanced computer tomography and pathology. The location, diameter, shape, border, calcification, and color doppler blood flow imaging (CDFI) of the lesions were observed by US, and the characteristics of the C-CEUS and H-CEUS images were qualitatively and quantitatively analyzed. The χ² test or Fisher's exact probability method was used to compare the US image characteristics between the benign and malignant groups, and the image characteristics of C-CEUS and H-CEUS between the benign and malignant groups. Moreover, the nonparametric Mann-Whitney test was used to compare the differences in C-CEUS and H-CEUS time-intensity curve (TIC) parameters.

RESULTS

Significant differences in gender, surgical approach, echogenicity, and CDFI were observed between the malignant and benign groups (p = 0.003, < 0.001, < 0.001, = 0003). Qualitative analysis also revealed significant differences in the mode of wash-out and fill-in direction between C-CEUS and H-CEUS in the malignant group (p = 0.041, 0.002). In addition, the homogeneity of enhancement showed significant differences between the two contrast models in the benign group (p = 0.009). Quantitative analysis indicated that the TIC parameters peak intensity (PI), deceleration time (DT) /2, area under the curve (AUC), and mean transition time (MTT) were significantly lower in the H-CEUS model compared to the C-CEUS model in both the benign and malignant groups. (all p < 0.001). In contrast, ascending slope of rise curve (AS) was significantly higher in the H-CEUS model compared to the C-CEUS model in the malignant group (p = 0.048).

CONCLUSIONS

In renal tumors, H-CEUS shows clearer internal enhancement of the mass and the changes in the wash-out period. The quantitative TIC parameters PI, DT/2, AUC, and MTT were lower in H-CEUS compared to C-CEUS. Both the quantitative and qualitative analyses indicated that H-CEUS better displays the characteristics of solid renal masses compared with C-CEUS.

Role of Multidetector Computed Tomography Urography in Evaluating Obstructive Uropathy in a Tertiary Hospital in Rural India

INTRODUCTION

This study aims to evaluate the role of multidetector computed tomography (MDCT) urography in cases of obstructive uropathy to determine the cause, side, site, and level of obstruction and to differentiate between acute and chronic cases of obstructive uropathy based on imaging features.

METHODS

Using Cochran's formula, a sample size of 121 patients was calculated. The patients underwent computed tomography (CT) urography to assess the obstructing agents causing obstructive uropathy. The conducted scan had four phases: the non-contrast phase, corticomedullary phase, nephrographic phase, and excretory phase. We assessed the obstructive agents and the changes they caused in the urinary tract.

RESULTS

A total of 74 patients (61.16%) had calculus as their obstructive agent, followed by stricture (14.88%). The obstructive agents were intraluminal in 102 patients (84.3%) and extraluminal in 19 patients (15.7%). The ureter was the most common site of obstruction, accounting for 41.32%. The acute cases were 66 (54.55%), and the chronic cases were 55 (45.45%). A statistically significant (p<0.05) association was found using the chi-square test in the comparison of the enhancement and excretion of the kidneys and the type of case (acute or chronic). A statistically significant (p<0.05) association was found using the chi-square test in the comparison of the distribution of the secondary findings, such as perinephric fat stranding and perinephric fluid collection, and the type of case (acute or chronic).

CONCLUSION

MDCT urography is a highly reliable method of imaging the cause of obstructing agents in cases of obstructive uropathy and the damage caused by them. The type of enhancement and excretion and the secondary findings play an important role in determining the acuteness or the chronicity of the obstructive agent.

Spectroscopic diagnosis and metabolite characterization of cisplatin resistance regulated by FDFT1 in bladder cancer tissue

As is the case for most solid tumours, chemotherapy remains the backbone in the management of metastatic disease. However, the occurrence of chemotherapy resistance is a cause to worry, especially in bladder cancer. Extensive evidence indicates molecular changes in bladder cancer cells to be the underlying cause of chemotherapy resistance, including the reduced expression of farnesyl-diphosphate farnesyltransferase 1 (FDFT1) - a gene involved in cholesterol biosynthesis. This can likely be a hallmark in examining the resistance and sensitivity of chemotherapy drugs. This work performs spectroscopic analysis and metabolite characterization on resistant, sensitive, stable-disease and healthy bladder tissues. Raman spectroscopy has detected peaks at around 1003 cm-1 (squalene), 1178 cm-1 (cholesterol), 1258 cm-1 (cholesteryl ester), 1343 cm-1 (collagen), 1525 cm-1 (carotenoid), 1575 cm-1 (DNA bases) and 1608 cm-1 (cytosine). The peak parameters were examined, and statistical analysis was performed on the peak features, attaining significant differences between the sample groups. Small-angle x-ray scattering (SAXS) measurements observed the triglyceride peak together with 6th, 7th and 8th - order collagen peaks; peak parameters were also determined. Neutron activation analysis (NAA) detected seven trace elements. Carbon (Ca), magnesium (Mg), chlorine (Cl) and sodium (Na) have been found to have the greatest concentration in the sample groups, suggestive of a role as a biomarker for cisplatin resistance studies. Results from the present research are suggested to provide an important insight into understanding the development of drug resistance in bladder cancer, opening up the possibility of novel avenues for treatment through personalised interventions.

Is the excretory phase necessary to identify upper tract urothelial neoplasms at CT urography? A 10-year population-based study

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.

Retrocaval Ureter as a Rare Cause of Hydroureteronephrosis: A Case Report

Retrocaval ureter (RCU), also known as pre-ureteral vena cava or circumcaval ureter, is a rare congenital anomaly caused by inferior vena cava (IVC) dysgenesis, leading to the right ureter coursing behind the IVC. RCU results in obstructive proximal hydroureteronephrosis, remaining asymptomatic until the third decade when hydronephrosis develops. Diagnosis relies on imaging modalities like intravenous urography (IVU), ultrasonography, computed tomography urography (CTU), magnetic resonance urography, and nuclear scintigraphy. CTU provides comprehensive 3D evaluation. We report a novel case of a 50-year-old male with RCU complicated by a concurrent distal ureteral calculus. CTU demonstrated the characteristic "S-shaped" proximal ureteral deformity and its aberrant posterior course relative to the IVC, enabling accurate preoperative diagnosis. The co-occurrence of RCU with ureteral calculus is notably rare, underlining the necessity of an exhaustive diagnostic process. The patient successfully underwent a combined surgical intervention, consisting of laparoscopic ureteroureterostomy for RCU correction and ureteroscopic lithotripsy for calculus removal, showcasing a minimally invasive approach to simultaneously address both conditions. This report underscores the significance of advanced cross-sectional imaging in diagnosing RCU and demonstrates the effectiveness of integrated minimally invasive surgical techniques in treating complex urological anomalies. By documenting this case, we contribute to the broader understanding and awareness of RCU among clinicians, potentially guiding more prompt recognition and comprehensive management of this rare condition.

Computed tomography-based prediction model for identifying patients with high probability of non-muscle-invasive bladder cancer

PURPOSE

To investigate computed tomography (CT)-based prediction model for identifying patients with high probability of non-muscle-invasive bladder cancer (NMIBC).

METHODS

This retrospective study evaluated 147 consecutive patients who underwent contrast-enhanced CT and surgery for bladder cancer. Using corticomedullary-to-portal venous phase images, two independent readers analyzed bladder muscle invasion, tumor stalk, and tumor size, respectively. Three-point scale (i.e., from 0 to 2) was applied for assessing the suspicion degree of muscle invasion or tumor stalk. A multivariate prediction model using the CT parameters for achieving high positive predictive value (PPV) for NMIBC was investigated. The PPVs from raw data or 1000 bootstrap resampling and inter-reader agreement using Gwet's AC1 were analyzed, respectively.

RESULTS

Proportion of patients with NMIBC was 81.0% (119/147). The CT criteria of the prediction model were as follows: (a) muscle invasion score < 2; (b) tumor stalk score > 0; and (c) tumor size < 3 cm. From the raw data, PPV of the model for NMIBC was 92.7% (51/55; 95% confidence interval [CI] 82.4-98.0) in reader 1 and 93.3% (42/45; 95% CI 81.7-98.6) in reader 2. From the bootstrap data, PPV was 92.8% (95% CI 85.2-98.3) in reader 1 and 93.4% (95% CI 84.9-99.9) in reader 2. The model's AC1 was 0.753 (95% CI 0.647-0.859).

CONCLUSION

The current CT-derived prediction model demonstrated high PPV for identifying patients with NMIBC. Depending on CT findings, approximately 30% of patients with bladder cancer may have a low need for additional MRI for interpreting vesical imaging-reporting and data system.

What do we see when we do not see the bladder? Review of the main urinary diversion techniques and their complications

OBJECTIVE

To review the different types of urinary diversion surgeries (UDS) in order to recognize the expected findings in a postoperative study, using different imaging techniques. To recognize the main postoperative complications, both early and late.

CONCLUSION

UDS are surgical procedures whose purpose is to redirect urine flow after cystectomy, generally in an oncologic context. The imaging evaluation of urological surgeries is often a radiological challenge, with CT being the most commonly used image modality. Therefore, it is essential to know the main surgical techniques, the expected postoperative findings and the optimization of imaging techniques for early diagnosis and correct evaluation of postoperative complications.

Role of Multidetector Computed Tomography Urography in the Evaluation of Obstructive Uropathy: A Review

Obstructive uropathy, a prevalent clinical problem, can irreparably harm the kidneys if not treated promptly. As a result, accurate diagnosis is necessary for prompt management. This study examines the utility of multidetector computed tomography (MDCT) urography in identifying obstructive uropathy. PubMed, Google, Embase, Medline, and other electronic databases were used to search the English-language literature. The search phrases were obstructive urinary infections or urinary bladder or kidneys or MDCT. The authors' expertise and experience in the subject area aided in archiving pertinent publications. Even though the dilated upper tract of the ureters can be seen, ultrasonography (USG) has limitations because it cannot show the middle portion of the ureters, even if they are dilated mostly due to bowel gas artifacts. The USG does not emphasize the functioning of the renal tract. To evaluate obstructive uropathy, MDCT urography plays a very important role. For speedy, effective therapy, it provides a quick diagnosis of the source of obstruction.

A retrospective survey to establish institutional diagnostic reference levels for CT urography examinations based on clinical indications: preliminary results

Objective. To establish institutional diagnostic reference levels (IDRLs) based on clinical indications (CIs) for three- and four-phase computed tomography urography (CTU).Methods. Volumetric computed tomography dose index (CTDIvol), dose-length product (DLP), patients' demographics, selected CIs like lithiasis, cancer, and other diseases, and protocols' parameters were retrospectively recorded for 198 CTUs conducted on a Toshiba Aquilion Prime 80 scanner. Patients were categorised based on CIs and number of phases. These groups' 75th percentiles of CTDIvoland DLP were proposed as IDRLs. The mean, median and IDRLs were compared with previously published values.Results. For the three-phase protocol, the CTDIvol(mGy) and DLP (mGy.cm) were 22.7/992 for the whole group, 23.4/992 for lithiasis, 22.8/1037 for cancer, and 21.2/981 for other diseases. The corresponding CTDIvol(mGy) and DLP (mGy.cm) values for the four-phase protocol were 28.6/1172, 30.6/1203, 27.3/1077, and 28.7/1252, respectively. A significant difference was found in CTDIvoland DLP between the two protocols, among the phases of three-phase (except cancer) and four-phase protocols (except DLP for other diseases), and in DLP between the second and third phases (except for cancer group). The results are comparable or lower than most studies published in the last decade.Conclusions. The CT technologist must be aware of the critical dose dependence on the scan length and the applied exposure parameters for each phase, according to the patient's clinical background and the corresponding imaging anatomy, which must have been properly targeted by the competent radiologist. When clinically feasible, restricting the number of phases to three instead of four could remarkably reduce the patient's radiation dose. CI-based IDRLs will serve as a baseline for comparison with CTU practice in other hospitals and could contribute to national DRL establishment. The awareness and knowledge of dose levels during CTU will prompt optimisation strategies in CT facilities.

Computed Tomography Urography: State of the Art and Beyond

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.

Can 3-Phase Computed Tomography Urography Be Used to Characterize Adrenal Nodules? Results in 145 Patients

OBJECTIVE

The aim of the study is to determine whether computed tomography (CT) urography (CTU) can characterize incidental adrenal nodules.

METHODS

This retrospective cohort study was performed at an academic medical center. Patients were identified by free text search of CTU reports that contained the terms "adrenal mass" "adrenal nodule" and "adrenal lesion." Computed tomography urography technique consisted of unenhanced images and postcontrast images obtained at 100 seconds and 15 minutes. The final cohort included 145 patients with 151 adrenal nodules. Nodules were considered lipid-rich adenomas or myelolipomas based on unenhanced imaging characteristics. Absolute and relative washout values were calculated for the remaining nodules, using a cutoff of 60% and 40%, respectively, to diagnose adenomas. Reference standard for lipid-poor adenomas and malignant nodules was histopathology or imaging/clinical follow-up. Mann-Whitney U test was used for comparison of continuous variables, and Fisher exact test was used for categorical variables.

RESULTS

One hundred nodules were lipid-rich adenomas and 3 were myelolipomas. Forty-eight nodules were indeterminate at unenhanced CT, corresponding to 39 lipid-poor adenomas and 9 malignant nodules based on reference standards. Both absolute and relative washout correctly characterized 71% of nodules (34/48), with a sensitivity of 67% and specificity of 89%. Overall, 91% of all adrenal nodules (137/151) were correctly characterized by CTU alone. Lipid-poor adenomas were smaller than malignant nodules (P < 0.01) and were lower in attenuation on unenhanced and delayed images (P < 0.01).

CONCLUSIONS

Adrenal nodules detected at 3-phase CTU can be accurately characterized, potentially eliminating the need for subsequent adrenal protocol CT or magnetic resonance imaging.

Quantitative assessment of renal obstruction in multi-phase CTU using automatic 3D segmentation of the renal parenchyma and renal pelvis: A proof of concept

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 < 0.001) between hydronephrotic and normal kidneys, and combining both indicators yielded 100% accuracy.

Conclusions

The novel algorithm enables accurate 3D segmentation of the renal parenchyma and pelvis and estimates the amount of contrast media in multi-phase CTU examinations. This serves as a proof-of-concept for the ability to extract from routine CTU indicators that alert to the presence of renal obstruction and estimate its severity.

Is Regular Radiographic Upper Urinary Tract Imaging for Surveillance of Non-Muscle Invasive Bladder Cancer Justified?

Patients with non-muscle invasive (NMI) urothelial bladder cancer (BC) are at increased risk for the development of a secondary upper-urinary-tract urothelial carcinoma (UTUC). We aimed to assess the usefulness of routine upper-tract imaging surveillance during NMIBC follow-up in a patient cohort of a tertiary academic center. All routine upper-tract-imaging scans using computerized tomography urography (CTU) between 2003 and 2016 were assessed for UTUC detection. A total of 315 patients were analyzed. Initial tumor stage was Ta in 207 patients (65.7%), T1 in 98 patients (31.1%) and pure CIS in 10 patients (3.2%). A total of 149 (47.3%) presented with low-grade (LG), and 166 (52.7%) with high-grade (HG) disease. Median follow-up was 48 months (IQR: 55). Four patients (1.2%) were diagnosed with UTUC during follow-up. All four patients presented with initial Ta HG BC. Two of the patients (50%) were diagnosed by routine upper tract imaging. The other two patients were diagnosed after development of symptoms. The 5- and 10-year UTUC-free survival was 98.5% (standard error (SE) 0.9) and 97.6% (SE 1.3), respectively. UTUCs were detected exclusively in patients with initial HG disease, indicating that upper-tract surveillance might only be necessary in these patients.

Magnetic resonance urography: a practical approach to preparation, protocol and interpretation

Magnetic resonance urography (MRU) is an important MRI application that provides noninvasive comprehensive morphological and functional evaluation of the kidneys and urinary tract. It can be used to assess congenital anomalies of the kidney and urinary tract, which often present as urinary tract dilation. In children, MRU allows for high tissue contrast and high spatial resolution without requiring ionizing radiation. Magnetic resonance urography requires patient preparation in the form of pre-examination intravenous hydration, placement of a urinary catheter, and the administration of diuretics at the time of the exam. The imaging protocol is based on T2-weighted images for anatomical assessment and dynamic post-contrast images for functional evaluation. These images are then used to generate quantitative and graphic results including contrast transit and excretion time as well as to calculate differential renal function. This review focuses on a simple approach to pediatric MRU acquisition and interpretation based on clinical cases and the authors' experience.

Benefit of including CT urography in [68Ga]PSMA-11 PET/CT with low-dose CT: first results from a larger prostate cancer cohort analysis

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 was 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.

Ureteral reimplantation for pediatric vesicoureteral reflux and primary obstructive megaureter: Transvesicoscopic cohen vs. Politano-Leadbetter approaches

BACKGROUND

Transvesicoscopic approaches for ureteral reimplantation (UR) are effective surgical techniques with which to resolve vesicoureteral reflux (VUR) or primary obstructive megaureter (POM) in pediatric patients. However, the effectiveness of different UR surgical methods for these two diseases is still unclear.

PURPOSE

To compare the effects of Cohen's cross-trigonal and Politano-Leadbetter techniques in children in need of UR.

METHODS

A retrospective chart review was performed for consecutive patients who underwent UR at our institution between May 2018 and November 2019, including those treated for vesicoureteral reflux (VUR) or primary obstructive megaureter (POM). Patients who underwent Cohen's technique included in Group C, and those who underwent the Politano-Leadbetter technique were included in Group P. Patient characteristics, perioperative parameters, and short-term postoperative outcomes were compared.

RESULTS

Forty-six patients who underwent unilateral UR were included in the analysis. At presentation, those in Group P (N = 22, 12 diagnosed with VUR and 10 with POM) did not differ from those in Group C (N = 24, 12 diagnosed with VUR and 12 with POM) with respect to age, sex, disease type or severity. For VUR patients, reflux was clinically resolved for all patients in both groups; however, only a 75% resolution rate was observed in Group C, with 3 patients experiencing persistent low-grade, clinically insignificant reflux, while a 100% resolution rate was found in Group P (P > 0.05). Among POM patients, the obstruction was resolved for all those in Group P and for 90% of those in Group C; this difference was also not statistically significant (P > 0.05). At the 1-year follow-up, the ureteral diameter (P < 0.05) and anterior-posterior renal pelvic diameter (APRPD) (P < 0.05) of Group P were significantly reduced, and differential renal function (DRF) (P < 0.05) was slightly improved compared with that in Group C in both VUR and POM patients.

CONCLUSIONS

Politano-Leadbetter and Cohen are both reliable techniques for UR in children with VUR or POM, and the short-term outcomes of these methods in solving reflux and obstruction are comparable. Besides traditional Cohen's technique, Politano-Leadbetter's technique maybe a potential choice for ureteral reimplantation in children.

CURVED MULTIFORMAT IMAGING OF STRUCTURAL MRI AS A BIOMARKER FOR PROFILING OF VARIOUS DEMENTIA - AN ALGORITHMIC APPROACH WITH MR/PET

BACKGROUND

Dementia is one of the most common clinical entities for which neuroimaging is done for diagnosis and characterization of the sub-types.

OBJECTIVE

Advanced neuroimaging modalities like MR-PET have added to the armamentarium of the neuroradiologists for the diagnosis of specific types of dementia syndromes. However, advanced molecular imaging is expensive and is not widely available particularly in underdeveloped countries. Structural imaging with MRI in addition to the clinical work up remains the most useful approach to the diagnosis of dementia in our setup.

MATERIAL AND METHODS

We describe a simple technique of curved multiplanar reconstruction of brain images with the use of a simple reconstruction software which can help in recognition of pattern of atrophy in dementias and thus improve the diagnostic accuracy of structural MRI.

RESULTS

Using this approach of pattern recognition, we suggest a simplified algorithm for diagnosis of sub-types of dementia.

CONCLUSIONS

In our study, we applied this technique for demonstration of pattern of atrophy which correlated with metabolic changes on PET in a variety of dementia cases using simultaneous MR-PET imaging and may act as a low cost and reliable biomarker to profile dementia subtypes. To the best of our knowledge this is the first study to show the utility of curved multiplanar reconstruction in dementias.

CT-urography: a nationwide survey by the Italian Board of Urogenital Radiology

Computed tomography-urography is currently the imaging modality of choice for the assessment of the whole urinary tract, giving the possibility to detect and characterize benign and malignant conditions. In particular, computed tomography-urography takes advantage from an improved visualization of the urinary collecting system due to acquisition of delayed scan obtained after excretion of intravenous contrast medium from the kidneys. Nevertheless, the remaining scans are of great help for identification, characterization, and staging of urological tumors. Considering the high number of diseases, urinary segment potentially involved and patients' features, scanning protocols of computed tomography-urography largely vary from one clinical case to another as well as selection and previous preparation of the patient. According to the supramentioned considerations, radiation exposure is also of particular concern. Italian radiologists were asked to express their opinions about computed tomography-urography performance and about its role in their daily practice through an online survey. This paper collects and summarizes the results.

Management, Surveillance Patterns, and Costs Associated With Low-Grade Papillary Stage Ta Non-Muscle-Invasive Bladder Cancer Among Older Adults, 2004-2013

IMPORTANCE

Low-risk non-muscle-invasive bladder cancer (NMIBC) is associated with extremely low rates of progression and cancer-specific mortality; however, patients with low-risk NMIBC may often receive non-guideline-recommended and potentially costly surveillance testing and treatment.

OBJECTIVE

To describe current surveillance and treatment practices, cancer outcomes, and costs of care for low-grade papillary stage Ta (low-grade Ta) NMIBC and identify factors associated with increased cost of care.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study identified 13 054 older adults (aged 66-90 years) diagnosed with low-grade Ta tumors in the Surveillance, Epidemiology and End Results-linked Medicare database from January 1, 2004, through December 31, 2013. Medicare claims data through December 31, 2014, were also reviewed. Data were analyzed from April 1 to October 6, 2021.

EXPOSURES

Surveillance testing and treatment among patients with low-grade Ta NMIBC.

MAIN OUTCOMES AND MEASURES

The primary outcome was patterns in population-level surveillance and treatment practice over time among patients with low-grade Ta NMIBC. Secondary outcomes were recurrence (defined as receipt of subsequent transurethral resection of bladder tumor >3 months after index diagnosis of NMIBC and initial transurethral resection of bladder tumor), progression (defined as receipt of definitive treatment for bladder cancer), and costs of care.

RESULTS

Among 13 054 patients who met inclusion criteria, 9596 (73.5%) were male and 3458 (26.5%) were female, with a median age of 76 years (IQR, 71-81 years). A total of 403 patients (3.1%) were Black, 120 (0.9%) were Hispanic, 12 123 (92.9%) were White, and 408 (3.1%) were of other races and/or ethnicities. Rates of surveillance cystoscopy increased over the study period (from 79.3% in 2004 to 81.5% in 2013; P = .007), with patients receiving a median of 3.0 cystoscopies per year (IQR, 2.0-4.0 per year). Rates of upper tract imaging (particularly computed tomography or magnetic resonance imaging) also increased over the study period (from 30.4% in 2004 to 47.0% in 2013; P < .001), with most patients receiving a median of 2.0 imaging tests per year (IQR, 1.0-2.0 per year). The use of urine cytologic testing or other urine biomarker assessment also increased (from 44.8% in 2004 to 54.9% in 2013; P < .001). Rates of adherence to current guidelines were similar over time (eg, a median of 4398 patients [55.2%] received ≤2 cystoscopies per year in 2004-2008 vs a median of 2736 patients [53.8%] in 2009-2013; P = .11), suggesting overuse of all surveillance testing modalities. With regard to treatment, 2250 patients (17.2%) received intravesical bacillus Calmette-Guérin, and 792 patients (6.1%) received intravesical chemotherapy (excluding receipt of a single perioperative dose). Among all patients with low-grade Ta NMIBC, 217 (1.7%) experienced disease recurrence and 52 (0.4%) experienced disease progression. The total annual median costs of low-grade Ta surveillance testing and treatment increased by 60% (from $34 792 in 2004 to $53 986 in 2013), with higher 1-year median expenditures noted among those with disease recurrence ($76 669) vs no disease recurrence ($53 909) at the end of the study period.

CONCLUSIONS AND RELEVANCE

In this cohort study, despite low rates of disease recurrence and progression, rates of surveillance testing increased during the study period. The annual cost of care also increased over time, particularly among patients with recurrent disease. Efforts to improve adherence to current practice guidelines, with the focus on limiting overuse of surveillance testing and treatment, may mitigate associated increasing costs of care.

Very late diagnosed Retrocaval ureter: A case report of a very rare entity in Cameroon, sub-Sahara Africa

INTRODUCTION AND IMPORTANCE

Retrocaval ureter (RCU) is a rare congenital anomaly usually associated with upper urinary tract stasis, in which the ureter itself passes behind the inferior vena cava. RCU is often misdiagnosed and can lead to serious complications related to the upper urinary tract stasis.

CASE PRESENTATION

We report the case of a 57-year-old female who presented with 1-year history of intermittent right flank pain, of gradual onset. She was diagnosed with right RCU, with advanced functional deterioration of the kidney, managed by nephrectomy. The postoperative course was uneventful.

CLINICAL DISCUSSION

RCU results in varying degrees of hydronephrosis and thus, in a non-specific clinical presentation. Most cases are asymptomatic, discovered only during imaging or surgery for unrelated conditions or at autopsy. A late diagnosis can lead to an obstructive nephropathy which can be very harmful to the kidney.

CONCLUSION

RCU is a very rare entity. The diagnosis can sometimes be late in under-medicalized settings, and must be taken into consideration in front of any hydronephrosis associated or not with intermittent flank pain. RCU-related complications can be very serious. Fish hook sign may be absent in case of nonfunctional kidney and must not exclude the diagnosis. Emphasis should be placed on prenatal diagnosis and routine abdominal ultrasound for early detection.

Comparison of static-fluid or excretory magnetic resonance urography with computed tomography urography for visualization of nondilated renal pelvises and ureters in healthy Beagles

OBJECTIVE

To assess the usefulness of magnetic resonance urography (MRU) for the visualization of nondilated renal pelvises and ureters in dogs and to compare our findings for MRU versus CT urography (CTU).

ANIMALS

9 healthy Beagles.

PROCEDURES

Dogs underwent CTU, static-fluid MRU, and excretory MRU, with ≥ 7 days between procedures. Contrast medium was administered IV during CTU and excretory MRU, whereas urine in the urinary tract was an intrinsic contrast medium for static-fluid MRU. For each procedure, furosemide (1 mg/kg, IV) was administered, and reconstructed dorsal plane images were acquired 3 minutes (n = 2) and 7 minutes (2) later. Images were scored for visualization of those structures and for image quality, diameters of renal pelvises and ureters were measured, and results were compared across imaging techniques.

RESULTS

Excretory MRU and CTU allowed good visualization of the renal pelvises and ureters, whereas static-fluid MRU provided lower visualization of the ureters. Distention of the renal pelvises and ureters was good in excretory MRU and CTU. Distention of the ureters in static-fluid MRU was insufficient compared with that in CTU and excretory MRU. Distinct artifacts were not observed in CTU and excretory MRU images. Static-fluid MRU images had several mild motion artifacts.

CLINICAL RELEVANCE

Our findings indicated that excretory MRU with furosemide administration was useful for visualizing nondilated renal pelvises and ureters of dogs in the present study. When performing MRU for the evaluation of dogs without urinary tract dilation, excretory MRU may be more suitable than static-fluid MRU.

The accuracy of computed tomography in the diagnosis of upper urinary tract urothelial carcinoma in correlation with the final histopathology: A retrospective study in 275 patients at a Tertiary Urology Institute

Introduction:

Because the reports in the literature of radiologic investigations for upper tract urothelial cancer (UTUC) are limited by the number of patients, and included patients with different pathologies, we aimed to study the overall accuracy of computed tomography (CT) in the diagnosis of UTUC and their accuracy on predicting tumor location.

Methods:

A retrospective review from 1990 to 2017 included patients who were treated for UTUC. Unenhanced CT scan was obtained first using Multi-Detector Computed Tomography (MDCT, Philips Medical Systems), then nonionic contrast medium, containing 350 mg iodine/ml was injected at 4 mL/s. Analysis was performed using SPSS^®.

Results:

Of 275 patients, complete data on CT was available on 270 (98%) patients. CT reported only two false positive and six false negative results and the overall accuracy was 96-97%. In comparison to the final pathological reports, CT/CTU detected 85% of the tumor location of in the renal pelvic and 50% of the calyceal tumors. In ureteric tumors, they detected distal (66/71= 93%) more than proximal ureteric tumors (60%).

Conclusion:

In our cohort, CT/ CTU has a high overall accuracy (97%) in diagnosing UTUC, capability to well visualize tumors of distal ureter and renal pelvis, but could miss calyceal tumors. The matter to rely only on CT without ureteroscopic biopsy in the diagnosis of UTUC especially if radical surgery is planned needs further prospective studies.

Split vs. Single Bolus CT Urography: Comparison of Scan Time, Image Quality and Radiation Dose

The purpose of this study was to compare the scan time, image quality and radiation dose of CT urograms (CTU) using a split vs. single bolus contrast media injection technique. A total of 241 consecutive CTUs performed between August 2019-February 2020 were retrospectively reviewed. There were three study groups: Group 1, <50 years old, 50/80 cc split-bolus administered at 0 and 700 s post initiation of injection, with combined nephrographic and excretory phases; group 2, ≥50 years old, same split-bolus protocol; and group 3, ≥50 years old, 130 cc single bolus injection, with nephrographic and excretory phases acquired at 100 s and 460 s post injection initiation. The recorded data elements were scan time, number of excretory phases, imaging quality based on opacification of the urinary collecting system (<50%, 50–75%, 75–100%), and dose-length product (DLP). Associations between group and categorical variables were assessed (Chi-square); mean scan time and DLP were compared (one-way ANOVA). Following analysis, proportionally fewer CTUs required a repeat excretory phase in group 3 (32/112, 28.6%) than in groups 1 (25/48, 52.1%) and 2 (37/80, 46.3%) (p = 0.006). Mean scan time was significantly lower in group 3 (678 s) than in groups 1 (1046 s) and 2 (978 s) (p < 0.0001). There was no association between groups and image quality (p = 0.13). DLP was higher in group 3 (1422 ± 837 mGy·cm) than in groups 1 (1041 ± 531 mGy·cm) and 2 (1137 ± 646 mGy·cm) (p = 0.003). In conclusion, single bolus CTU resulted in significantly fewer repeat phases and faster scan time at the expense of a slightly higher radiation dose.

Second Malignancies after Radiation Therapy: Update on Pathogenesis and Cross-sectional Imaging Findings

A wide spectrum of second cancers occur as late complications of radiation therapy (RT) used to treat various malignancies. In addition to the type and dose of radiation, lifestyle, environmental, and genetic factors are important to the development of second malignancies in cancer survivors. Typically, RT-induced malignancies (RTIMs) are biologically aggressive cancers with a variable period of 5-10 years for hematologic malignancies and 10-60 years for solid tumors between RT and the development of the second cancer. Although carcinomas and leukemias commonly develop after low-dose RT, sarcomas occur in tissues or organs that receive high-dose RT. Angiosarcomas and unclassified pleomorphic sarcomas are the two most common RT-associated sarcomas; other sarcomas include malignant peripheral nerve sheath tumors, leiomyosarcomas, osteosarcomas, chondrosarcomas, and dedifferentiated or pleomorphic liposarcomas. Select RTIMs show tumor genetic characteristics that allow accurate diagnosis. Nearly all cutaneous angiosarcomas after RT for breast cancer and 90% of RT-associated malignant peripheral nerve sheath tumors are characterized by MYC gene amplifications and loss of H3 K27me3 expression, respectively. Classic papillary thyroid carcinomas that develop after RT frequently harbor RET/PTC rearrangements and have a favorable prognosis, despite their advanced stage at patient presentation. Select RTIMs demonstrate characteristic imaging findings and typically develop in the prior radiation field. Imaging is essential to early diagnosis, characterization, localization, and staging of RTIMs. Familiarity of radiologists with the diverse spectrum of RTIMs is essential for early diagnosis and optimal management. An invited commentary by Shapiro is available online. ^©RSNA, 2021.

Imaging of ureter: a primer for the emergency radiologist

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.

Low-dose CT urography using deep learning image reconstruction: a prospective study for comparison with conventional CT urography

OBJECTIVES

To compare the image quality of low-dose CT urography (LD-CTU) using deep learning image reconstruction (DLIR) with conventional CTU (C-CTU) using adaptive statistical iterative reconstruction (ASIR-V).

METHODS

This was a prospective, single-institutional study using the excretory phase CTU images for analysis. Patients were assigned to the LD-DLIR group (100kV and automatic mA modulation for noise index (NI) of 23) and C-ASIR-V group (100kV and NI of 10) according to the scan protocols in the excretory phase. Two radiologists independently assessed the overall image quality, artifacts, noise and sharpness of urinary tracts. Additionally, the mean CT attenuation, signal-to-noise ratio (SNR) and contrast-to-noise (CNR) in the urinary tracts were evaluated.

RESULTS

26 patients each were included in the LD-DLIR group (10 males and 16 females; mean age: 57.23 years, range: 33-76 years) and C-ASIR-V group (14 males and 12 females; mean age: 60 years, range: 33-77 years). LD-DLIR group used a significantly lower effective radiation dose compared with the C-ASIR-V group (2.01 ± 0.44 mSv vs 6.9 ± 1.46 mSv, p < 0.001). LD-DLIR group showed good overall image quality with average score >4 and was similar to that of the C-ASIR-V group. Both groups had adequate and similar attenuation value, SNR and CNR in most segments of urinary tracts.

CONCLUSION

It is feasibility to provide comparable image quality while reducing 71% radiation dose in low-dose CTU with a deep learning image reconstruction algorithm compared to the conventional CTU with ASIR-V.

ADVANCES IN KNOWLEDGE

(1) CT urography with deep learning reconstruction algorithm can reduce the radiation dose by 71% while still maintaining image quality.

Renal Forniceal Rupture in the Setting of Obstructing Ureteral Stones: An Analysis of Stone Characterization and Urologic Intervention Pattern

Introduction and Objective: Forniceal rupture due to obstructing ureterolithiasis (FROU) is a seldom encountered radiographic finding, but the impact of this diagnosis and influence on stone management has not been well studied in the literature. The purpose of the study is to examine stone characteristics and intervention patterns of patients with radiographic evidence of FROU. Materials and Methods: A retrospective analysis of all patients with radiographic evidence of FROU was compared with patients with obstructing ureteral stones without forniceal ruptures (noFROU). All patients presented to our Emergency Department from January 2015 until December 2018. Data analyzed included patient demographics, clinical presentation, stone characteristics, and management pattern. Primary outcome was need for hospital admission and surgical intervention. Results: Thirty-two patients with FROU (mean age = 45) were compared with 50 patients with noFROU (mean age = 57). Univariate analysis revealed that age, history of diabetes mellitus, history of hypertension, days of symptoms, degree of hydronephrosis, and degree of perinephric stranding were associated with forniceal rupture (p ≤ 0.05). On multivariate analysis, only degree of perinephric stranding remained significant (p ≤ 0.05). Average maximum axial stone diameter in the FROU group was 5.1 mm vs 4.7 mm in the noFROU group (p = 0.66). Overall, 68.8% of stones were located within the distal ureter in the FROU group vs 48.8% in the noFROU group (p = 0.09). There was no difference in hospital admission (FROU 37.5% vs noFROU 44%, p = 0.56) and need for surgical intervention (FROU 50% vs noFROU 48%, p = 0.86). There were no 30-day complications in patients with FROU. Conclusions: Ureteral stone location and size does not seem to impact the presence of FROU. FROU may be an alarming reported finding but its presence does not appear to impact clinical outcomes or affect urological management, including admission or need for urologic intervention.

CT Urography Findings of Upper Urinary Tract Carcinoma and Its Mimickers: A Pictorial Review

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.

ACR Appropriateness Criteria® Recurrent Lower Urinary Tract Infections in Females

Urinary tract infections (UTIs) in women are common, with an overall lifetime risk over >50%. UTIs are considered recurrent when they follow complete clinical resolution of a previous UTI and are usually defined as at least three episodes of infection within the preceding 12 months. An uncomplicated UTI is classified as a UTI without structural or functional abnormalities of the urinary tract and without relevant comorbidities. Complicated UTIs are those occurring in patients with underlying structural or medical problems. In women with recurrent uncomplicated UTIs, cystoscopy and imaging are not routinely used. In women suspected of having a recurrent complicated UTI, cystoscopy and imaging should be considered. CT urography or MR urography are usually appropriate for the evaluation of recurrent complicated lower urinary tract infections or for women who are nonresponders to conventional therapy, develop frequent reinfections or relapses, or have known underlying risk factors. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

"Renal emergencies: a comprehensive pictorial review with MR imaging"

Superior soft-tissue contrast and high sensitivity of magnetic resonance imaging (MRI) for detecting and characterizing disease may provide an expanded role in acute abdominal and pelvic imaging. Although MRI has traditionally not been exploited in acute care settings, commonly used in biliary obstruction and during pregnancy, there are several conditions in which MRI can go above and beyond other modalities in diagnosis, characterization, and providing functional and prognostic information. In this manuscript, we highlight how MRI can help in further assessment and characterization of acute renal emergencies. Currently, renal emergencies are predominantly evaluated with ultrasound (US) or computed tomography (CT) scanning. US may be limited by various patient factors and technologist experience while CT imaging with intravenous contrast administration can further compromise renal function. With the advent of rapid, robust non-contrast MRI, and magnetic resonance angiography (MRA) imaging studies with short scan times, free-breathing techniques, and lack of ionization radiation, the utility of MRI for renal evaluation might be superior to CT not only in diagnosing an emergent renal process but also by providing functional and prognostic information. This review outlines the clinical manifestations and the key imaging findings for acute renal processes including acute renal infarction, hemorrhage, and renal obstruction, among other entities, to highlight the added value of MRI in evaluating the finer nuances in acute renal emergencies.

Assessment of ureteric diameter using contrast-enhanced helical abdominal computed tomography

Background

Assessment of ureteric size is imperative for diagnosis of urinary tract abnormalities especially with regard to obstructive pathologies. The ureteric opacification and distension obtained from contrast-enhanced computed tomography allows for differentiation from surrounding soft tissue and better assessment of ureteric diameter. Abdominal computed tomographic scans are commonly requested for the evaluation of the urinary tract, and we therefore aim to establish a normal reference value of the ureteral diameter using contrast-enhanced computed tomographic scans of the abdomen.

Method

With the purpose of establishing our local normogram of ureteric diameter, we did a retrospective study of archived images of 170 patients referred to the radiology department of a tertiary hospital for contrast-enhanced abdominal CT from January 2016 to June 2018. The largest transverse dimension along the course of the ureter beginning 1–2 cm below the ureteropelvic junction was measured at the delayed phase and obtained data subjected to analysis using SAS software version 9.3 with statistical level of significance set at 0.05.

Result

A total number of 340 ureters in 170 patients were analyzed with the mean age of 47.9 years (range 1.0–94.0 years) and male-to-female ratio of 1.2:1. The mean left ureteric diameter of all patients was 4.3 mm (range 1.7–8.0 mm) while the mean right ureteric diameter of all patients was 4.4 mm (range 1.5–8.0 mm). Ninety-five percent of ureters in our study measured 6.9 mm and less with no significant difference in ureteric sizes across gender and ages.

Conclusion

The mean CT normogram for ureteric caliber is 4.3–4.4 mm with no significant age and gender difference and 7 mm proposed as upper limit of normal.

MRI of Bladder Cancer: Local and Nodal Staging

Accurate staging of bladder cancer (BC) is critical, with local tumor staging directly influencing management decisions and affecting prognosis. However, clinical staging based on clinical examination, including cystoscopy and transurethral resection of bladder tumor (TURBT), often understages patients compared to final pathology at radical cystectomy and lymph node (LN) dissection, mainly due to underestimation of the depth of local invasion and the presence of LN metastasis. MRI has now become established as the modality of choice for the local staging of BC and can be additionally utilized for the assessment of regional LN involvement and tumor spread to the pelvic bones and upper urinary tract (UUT). The recent development of the Vesical Imaging-Reporting and Data System (VI-RADS) recommendations has led to further improvements in bladder MRI, enabling standardization of image acquisition and reporting. Multiparametric magnetic resonance imaging (mpMRI) incorporating morphological and functional imaging has been proven to further improve the accuracy of primary and recurrent tumor detection and local staging, and has shown promise in predicting tumor aggressiveness and monitoring response to therapy. These sequences can also be utilized to perform radiomics, which has shown encouraging initial results in predicting BC grade and local stage. In this article, the current state of evidence supporting MRI in local, regional, and distant staging in patients with BC is reviewed. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:649-667.

The effects of rectal cancer surgery on the anatomical localisation of ureters - a prospective observational study

Introduction

Anatomical changes after surgery and fibrotic adhesions increase the organ laceration risk, including that of the ureter, in recurrent cases and secondary operations. The aim of this study was to investigate the changes in the anatomical localisations of the ureters via computed tomography urography in patients undergoing rectal cancer surgery.

Material and methods

The study involved prospectively collected data on the changes of ureteral location preoperatively and postoperatively in patients with operated rectal cancer. Distances (mm) of ureters determined midline in the computed tomography urogram phase.

Results

A total of 18 patients were included. The mean distances between the right (R₁) and left (L₁) ureters and the mid-vertebral line before the surgery were 30.9 ±5.4 mm and 34.5 ±9.9 mm, respectively. The postoperative distances between them (R₂ and L₂) were 26.4 ±9.1 mm and 29.5 ±9.9 mm, respectively. The R₂ measurement showed that 83.3% (15/18) of the right ureters had deviated medially, whereas 16.7% (3/18) of them had deviated laterally. The L₂ measurements showed that 88.8% (16/18) of the left ureters had deviated medially, whereas 11.2% (2/18) of them had deviated laterally. The differences between the preoperative and postoperative measurements of the right and left ureter positions were 4.5 ±9.2 mm and 4.9 ±4.6 mm, respectively, with the displacement in the left ureter being statistically significant (p ≤ 0.001).

Conclusions

Rectal cancer surgery causes medially deviated changes in the positions of the ureters.

Update on MR urography (MRU): technique and clinical applications

Magnetic resonance imaging of the upper tract (pyelocalyces and ureters) or MR Urography (MRU) is technically possible and when performed correctly offers similar visualization of the upper tracts and for detection of non-calculous diseases of the collecting system similar specificity but with lower sensitivity compared to CTU. MRU provides the ability to simultaneously image the kidneys and urinary bladder with improved soft tissue resolution, better tissue characterization and when combined with assessment of the upper tract, a comprehensive examination of the urinary system. MRU requires meticulous attention to technical details and is a longer more demanding examination compared to CTU. Advances in MR imaging techniques including: parallel imaging, free-breathing motion compensation techniques and compressed sensing can dramatically shorten examination times and improve image quality and patient tolerance for the exam. This review article discusses updates in the MRU technique, summarizes clinical indications and opportunities for MRU in clinical practice and reviews advantages and disadvantages of MRU compared to CTU.

What a difference a delay makes! CT urogram: a pictorial essay

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.

CT urography: how to optimize the technique

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.

Application of Iterative Metal Artifact Reduction Algorithm to CT Urography for Patients With Hip Prostheses

OBJECTIVE. The purpose of this study is to retrospectively assess the impact of iterative metal artifact reduction (IMAR) with iterative reconstruction (IR) on the image quality and diagnostic performance of CT urography in the evaluation of patients with hip prostheses, compared with IR alone. MATERIALS AND METHODS. CT urography examinations that were reconstructed using IR with and without IMAR were analyzed for 57 patients (29 women and 28 men; mean age, 74 years [range, 22-94 years]) with hip prostheses (40 unilateral and 17 bilateral). For quantitative analysis, image noise within the bladder was measured. Two radiologists (radiologist 1 [RAD1] and radiologist 2 [RAD2]) qualitatively evaluated the images using both a 5-point scale to assess the degree of visualization of artifacts and a 6-point scale to determine diagnostic confidence in visualization of the bladder, ureters, prostate or uterus, pelvic calcifications, and genitourinary abnormalities involving the bladder, distal ureters, prostate, uterus, and ovaries. RESULTS. The combination of IMAR and an IR technique provided improvement in quantitative and qualitative measurements (p < 0.05). Forty-three genitourinary abnormalities were detected in 29 patients. Quantitative and qualitative comparisons of scans obtained with and without the use of IMAR, respectively, revealed image noise of 99.6 versus 173.3 HU and the following radiologist scores: for improvement of artifacts, 3.2 versus 1.6 (for RAD1) and 3.1 versus 1.6 (for RAD2); for visualization of the bladder, 3.6 versus 1.5 (RAD1) and 3.8 versus 1.6 (RAD2); visualization of the ureters, 3.8 versus 1.6 (RAD1) and 3.9 versus 1.7 (RAD2); visualization of the uterus, 4.3 versus 2.8 (RAD1) and 4.3 versus 2.6 (RAD2); visualization of the prostate, 4.5 versus 2.3 (RAD1) and 4.5 versus 2.2 (RAD2); diagnostic confidence for calcifications, 4.7 versus 3.5 (RAD1) and 4.7 versus 3.3 (RAD2); and diagnostic confidence for genitourinary abnormalities, 5.0 versus 3.2 (RAD1) and 4.8 versus 2.9 (RAD2), respectively. CONCLUSION. The addition of IMAR to IR led to statistically significant improvement in the retrospective diagnostic performance and image quality of CT urography for patients with hip prostheses, compared with IR alone.

Comparison of the Harms, Advantages, and Costs Associated With Alternative Guidelines for the Evaluation of Hematuria

IMPORTANCE

Existing recommendations for the diagnostic testing of hematuria range from uniform evaluation of varying intensity to patient-level risk stratification. Concerns have been raised about not only the costs and advantages of computed tomography (CT) scans but also the potential harms of CT radiation exposure.

OBJECTIVE

To compare the advantages, harms, and costs associated with 5 guidelines for hematuria evaluation.

DESIGN, SETTING, AND PARTICIPANTS

A microsimulation model was developed to assess each of the following guidelines (listed in order of increasing intensity) for initial evaluation of hematuria: Dutch, Canadian Urological Association (CUA), Kaiser Permanente (KP), Hematuria Risk Index (HRI), and American Urological Association (AUA). Participants comprised a hypothetical cohort of patients (n = 100 000) with hematuria aged 35 years or older. This study was conducted from August 2017 through November 2018.

EXPOSURES

Under the Dutch and CUA guidelines, patients received cystoscopy and ultrasonography if they were 50 years or older (Dutch) or 40 years or older (CUA). Under the KP and HRI guidelines, patients received different combinations of cystoscopy, ultrasonography, and CT urography or no evaluation on the basis of risk factors. Under the AUA guidelines, all patients 35 years or older received cystoscopy and CT urography.

MAIN OUTCOMES AND MEASURES

Urinary tract cancer detection rates, radiation-induced secondary cancers (from CT radiation exposure), procedural complications, false-positive rates per 100 000 patients, and incremental cost per additional urinary tract cancer detected.

RESULTS

The simulated cohort included 100 000 patients with hematuria, aged 35 years or older. A total of 3514 patients had urinary tract cancers (estimated prevalence, 3.5%; 95% CI, 3.0%-4.0%). The AUA guidelines missed detection for the fewest number of cancers (82 [2.3%]) compared with the detection rate of the HRI (116 [3.3%]) and KP (130 [3.7%]) guidelines. However, the simulation model projected 108 (95% CI, 34-201) radiation-induced cancers under the KP guidelines, 136 (95% CI, 62-229) under the HRI guidelines, and 575 (95% CI, 184-1069) under the AUA guidelines per 100 000 patients. The CUA and Dutch guidelines missed detection for a larger number of cancers (172 [4.9%] and 251 [7.1%]) but had 0 radiation-induced secondary cancers. The AUA guidelines cost approximately double the other 4 guidelines ($939/person vs $443/person for Dutch guidelines), with an incremental cost of $1 034 374 per urinary tract cancer detected compared with that of the HRI guidelines.

CONCLUSIONS AND RELEVANCE

In this simulation study, uniform CT imaging for patients with hematuria was associated with increased costs and harms of secondary cancers, procedural complications, and false positives, with only a marginal increase in cancer detection. Risk stratification may optimize the balance of advantages, harms, and costs of CT.

Update on Gadolinium-Based Contrast Agent-Enhanced Imaging in the Genitourinary System

OBJECTIVE. The purpose of this article is to review gadolinium-based contrast agent (GBCA)-enhanced MRI applications in the genitourinary system. CONCLUSION. Nephrogenic systemic fibrosis is rare or nonexistent with standard dosing of group II GBCAs. Gadolinium retention, cost, and examination times are emerging considerations affecting GBCA use. GBCA is unnecessary to diagnose adrenal adenomas, simple cysts, and some Bosniak category II cysts; however, it is required to determine solid or septal renal mass enhancement. Biparametric prostate MRI requires high-quality and reproducible DWI; therefore, dynamic contrast-enhanced MRI remains valuable in selected prostate MRI examinations.