CT Urography for Evaluation of the Ureter

Hematuria in the ER patient: optimizing detection of upper tract urothelial cancer - A pictorial essay

Upper tract urothelial carcinoma (UTUC) is a rare and challenging subset of the more frequently encountered urothelial carcinomas (UCs), comprising roughly 5-7% of all UCs and less than 10% of all renal tumors. Hematuria is a common presenting symptom in the emergency setting, often prompting imaging to rule out serious etiologies, with UTUC especially posing as a diagnostic challenge. These UTUC lesions of the kidney and ureter are often small, mimicking other pathologies, and are more aggressive than typical UC of the bladder, emphasizing the importance of timely and accurate diagnosis. Multidetector computed tomography urography (CTU) is the standard imaging modality for diagnosis, tumor staging, and surgical planning. Various postprocessing techniques like multiplanar reconstructions, maximal intensity projection (MIP) images, and 3D volumetric rendering technique (VRT) are crucial for accurate detection. In addition, 3D cinematic rendering (CR) is a novel technique that employs advanced illumination models, producing images with realistic shadows and increased surface detail, outperforming traditional VRT. We will review the distinctive imaging features between UTUC and infiltrating mimicking lesions on CTU in patients who presented with hematuria, in conjunction with advanced postprocessing techniques, ultimately improving diagnostic confidence and preoperative planning in the emergency context.

Imaging of Urologic Trauma

Urologic trauma encompassed a wide range of injuries affecting the urologic tract, resulting from various traumatic events or iatrogenic procedures. This review explores the clinical presentation, diagnostic strategies, and management approaches of urologic trauma, emphasizing the critical role of imaging, particularly computed tomography, in accurately assessing and guiding treatment decisions. Renal, ureteral, bladder, and urethral trauma are comprehensively discussed, including mechanisms of injury, classification systems, and therapeutic interventions. In addition, we discuss potential complications such as post-traumatic urinoma, delayed bleeding, urinary fistula, perinephric abscess, pyelonephritis, and hydronephrosis.

Intraureteral Metastasis From Colon Cancer Mimicking Primary Ureteral Carcinoma on FDG PET/CT

ABSTRACT

Hematogenous or lymphatic intraureteral metastasis from distant primary cancer is very rare. We present contrast-enhanced CT and FDG PET/CT findings in a case of intraureteral metastasis from colonic adenocarcinoma 3 years after colectomy. The intraureteral showed moderate enhancement on contrast-enhanced CT and increased FDG uptake on PET/CT mimicking a primary ureteral carcinoma. This case suggests that metastatic tumor of the ureter should be considered in the differential diagnosis in patients with hypermetabolic ureteral lesion and known malignancy.

Deep-learning-based method for the segmentation of ureter and renal pelvis on non-enhanced CT scans

This study aimed to develop a deep-learning (DL) based method for three-dimensional (3D) segmentation of the upper urinary tract (UUT), including ureter and renal pelvis, on non-enhanced computed tomography (NECT) scans. A total of 150 NECT scans with normal appearance of the left UUT were chosen for this study. The dataset was divided into training (n = 130) and validation sets (n = 20). The test set contained 29 randomly chosen cases with computed tomography urography (CTU) and NECT scans, all with normal appearance of the left UUT. An experienced radiologist marked out the left renal pelvis and ureter on each scan. Two types of frameworks (entire and sectional) with three types of DL models (basic UNet, UNet3 + and ViT-UNet) were developed, and evaluated. The sectional framework with basic UNet model achieved the highest mean precision (85.5%) and mean recall (71.9%) on the test set compared to all other tested methods. Compared with CTU scans, this method had higher axial UUT recall than CTU (82.5% vs 69.1%, P < 0.01). This method achieved similar or better visualization of UUT than CTU in many cases, however, in some cases, it exhibited a non-ignorable false-positive rate. The proposed DL method demonstrates promising potential in automated 3D UUT segmentation on NECT scans. The proposed DL models could remarkably improve the efficiency of UUT reconstruction, and have the potential to save many patients from invasive examinations such as CTU. DL models could also serve as a valuable complement to CTU.

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.

FDG PET/CT in a Case of Primary Lymphoma of the Ureter

ABSTRACT

Primary lymphoma of the ureter is extremely rare. We describe the contrast-enhanced CT and FDG PET/CT findings in a case of diffuse large B-cell lymphoma transformed from mucosa-associated lymphoid tissue lymphoma limited to the left ureter. Contrast-enhanced CT showed 2 short-segment circumferential thickening and enhancement of the left pelvic and intramural ureteral wall. The thickened ureteral wall showed significantly increased FDG uptake mimicking urothelial carcinoma.

Detection and characterization of urinary stones using material-specific images derived from contrast-enhanced dual-energy CT urography

OBJECTIVE

To determine the accuracy of material-specific images derived from contrast-enhanced dual-energy CT urography (DECTU) in detecting and measuring urinary stones in comparison with that of unenhanced images and its utility in calcified stone differentiation.

METHODS

105 patients with 202 urinary stones (121 had confirmed composition by infrared spectroscopy) underwent triphasic (unenhanced, portal venous (VP) and excretory phase (EP)) DECTU. Material-specific images were derived in VP and EP with calcium-water, calcium-iodine and CaOxalate_Dihydrate (COD)-Hydroxyapatite (HAP) as basis material pairs. Stone number and size were recorded on unenhanced images and VP and EP material-specific images, where stone densities were also measured. Material densities of calcified stones (pure calcium oxalate [pCaO, n = 34], mixed calcium oxalate [mCaO, n = 14], mixed carbonate phosphate [mCaP, n = 70]) were compared and thresholds for differentiating these stones were determined using receiver operating characteristic analysis.

RESULTS

All 202 urinary stones were detected on the unenhanced, calcium (water) and calcium (iodine) images in VP. While the detection rate was significantly decreased to 58 and 64% using calcium (water) and calcium (iodine) images in EP, respectively (all p < 0.001). Stone sizes measured on calcium (iodine) images in VP was similar to that of unenhanced images (10.6 vs 10.7 mm, p > 0.05). Significant differences in material densities were found among pCaO, mCaO and mCaP on COD(HAP) images with AUC of 0.72-0.74 for differentiating these stones.

CONCLUSION

Material-specific images in VP derived from DECTU allow reliably detecting and measuring urinary tract stones in comparison with unenhanced images and can identify calcified stones with moderate diagnostic performance to provide potential 33% dose reduction.

ADVANCES IN KNOWLEDGE

Material-specific images, especially the calcium (iodine) images in VP allow for reliable detection of urinary stones.Stone size measurement should be performed on the calcium (iodine) images in VP.Material density measurements on COD-HAP (VP) material decomposition images can be used to differentiate among pure calcium oxalate, mixed calcium oxalate and mixed carbonate phosphate stones with AUC of 0.72-0.74.

FDG-Avid Malakoplakia of the Ureter Mimicking Malignancy

ABSTRACT

Malacoplakia is a rare chronic granulomatous disease and frequently associated with Escherichia coli infection. We describe the contrast-enhanced CT and FDG PET/CT findings in a case of bladder and ureteral malakoplakia with E. coli urinary tract infection. Contrast-enhanced CT showed multiple enhancing mural nodules in the bladder and left ureter, ranging from several millimeters to 3.1 cm. The ureteral nodules showed significantly increased FDG uptake with SUVmax of 20.4, due to histiocyte, lymphocyte, and plasma cell infiltrates revealed by histopathology.

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.

A case of ureteral stenosis due to ureteritis probably associated with rheumatoid arthritis

Ureteritis associated with the immunological disorder is rarely reported, and most cases in this category are small vessel vasculitis and immunoglobulin G4-related disease. Rheumatoid arthritis (RA)-associated ureteritis is uncommon, and underlying aetiology is unclear. We present a patient with ureteritis who had a medical history of RA and was successfully treated with steroids and immunosuppressant. A 49-year-old woman who had been treated for RA and atopic dermatitis suffered from gross haematuria for 5 successive days. Contrast-enhanced computed tomography (CT) showed right-dominant upper urinary tract dilatation with enhanced thickened wall. The haematuria continued accompanied with intermittent right back and lower abdominal pain, and the following CT image taken after 3 months presented the progression to bilateral hydronephrosis. Ureteral stents were placed, and antibiotic therapy was introduced for obstructive pyelonephritis. Ureterocystoscopy and following biopsy from the upper ureteral tract showed a chronic inflammatory change in the histopathology, and we finally considered the stenosing ureteritis to be caused by immune-mediated mechanism related to RA. After starting steroid therapy with methotrexate, therapeutic response was obtained to remove the stents. In the cases of ureteritis or ureteral stenosis of unknown aetiology with a medical history of immunological disorders, we should consider the underlying immune-activated state and try to test contrast-enhanced CT and histological examination before performing a surgical procedure. After excluding the common causes of ureteritis or ureteral stenosis, these tests would support the appropriate diagnosis.

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.

CT of the urinary tract revisited

Computed tomography (CT) of the abdomen is usually appropriate for the initial imaging of many urinary tract diseases, due to its wide availability, fast scanning and acquisition of thin slices and isotropic data, that allow the creation of multiplanar reformatted and three-dimensional reconstructed images of excellent anatomic details. Non-enhanced CT remains the standard imaging modality for assessing renal colic. The technique allows the detection of nearly all types of urinary calculi and the estimation of stone burden. CT is the primary diagnostic tool for the characterization of an indeterminate renal mass, including both cystic and solid tumors. It is also the modality of choice for staging a primary renal tumor. Urolithiasis and urinary tract malignancies represent the main urogenic causes of hematuria. CT urography (CTU) improves the visualization of both the upper and lower urinary tract and is recommended for the investigation of gross hematuria and microscopic hematuria, in patients with predisposing factors for urologic malignancies. CTU is highly accurate in the detection and staging of upper tract urothelial malignancies. CT represents the most commonly used technique for the detection and staging of bladder carcinoma and the diagnostic efficacy of CT staging improves with more advanced disease. Nevertheless, it has limited accuracy in differentiating non-muscle invasive bladder carcinoma from muscle-invasive bladder carcinoma. In this review, clinical indications and the optimal imaging technique for CT of the urinary tract is reviewed. The CT features of common urologic diseases, including ureterolithiasis, renal tumors and urothelial carcinomas are discussed.

Post-Surgical Imaging Assessment in Rectal Cancer: Normal Findings and Complications

Rectal cancer (RC) is one of the deadliest malignancies worldwide. Surgery is the most common treatment for RC, performed in 63.2% of patients. The type of surgical approach chosen aims to achieve maximum residual function with the lowest risk of recurrence. The selection is made by a multidisciplinary team that assesses the characteristics of the patient and the tumor. Total mesorectal excision (TME), including both low anterior resection (LAR) and abdominoperineal resection (APR), is still the standard of care for RC. Radical surgery is burdened by a 31% rate of major complications (Clavien-Dindo grade 3-4), such as anastomotic leaks and a risk of a permanent stoma. In recent years, less-invasive techniques, such as local excision, have been tested. These additional procedures could mitigate the morbidity of rectal resection, while providing acceptable oncologic results. The "watch and wait" approach is not a globally accepted model of care but encouraging results on selected groups of patients make it a promising strategy. In this plethora of treatments, the radiologist is called upon to distinguish a physiological from a pathological postoperative finding. The aim of this narrative review is to identify the main post-surgical complications and the most effective imaging techniques.

Ultrasonographic and contrast-enhanced CT imaging diagnosis of idiopathic renal hematuria with bilateral hydronephrosis and hydroureter in a dog

A 5-year-old spayed female Maltese presented with a 1-week history of severe hematuria. Abdominal ultrasonography and thoracic, and abdominal computed tomography identified bilateral hydronephrosis and hydroureter due to an obstruction at the left ureter and urinary bladder lesion with no evidence of metastasis. After surgical removal of the material and placement of a temporary ureteral stent, the patient was able to urinate normally. Histological examination revealed a massive blood clot. Based on our review of the literature, this is the first published report describing the imaging diagnosis of obstructive hydronephrosis and hydroureter induced by idiopathic renal hematuria in a dog.

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.

The Impact of Ureteral Access Sheath Size on Perioperative Parameters and Postoperative Ureteral Stricture in Retrograde Intrarenal Surgery

OBJECTIVE

To investigate the effect of the diameter of UAS used during RIRS on operative parameters, perioperative ureteral injury, and ureteral stricture development.

MATERIAL AND METHOD

The study was designed as a prospective randomized controlled trial and included 320 patients who underwent RIRS. The patients were divided into two groups according to UAS diameter (9.5/11.5 Fr (Group 1) and 12/14 Fr (Group 2)) were used during the operation. At the end of the operation, ureteral injury was checked visually using semi-rigid ureterorenoscopy and classified according to the ureter injury scale. In the postoperative first year, the control CT urography images used to newly developed ureteral dilation.

RESULTS

There was no statistical difference between the two groups in terms of patient and stone characteristics, operative time, postoperative stone-free rate, and postoperative infection development parameters. In Group 1, 30 (18.8%) of the patients had low-grade and 8 (5%) of the patients had high-grade ureteral injury while in Group 2, 44 (27.5%) had low-grade and 19 (11.9%) had high-grade ureteral injury (p=0.013). In the postoperative period, ureteral stricture was found in 5 (1.6%) patients, of whom 4 (2.5%) were in Group 2 and 1 (0.6%) (p=0.371).

CONCLUSION

The results of our study showed that the use of a 12/14 Fr UAS in patients who are not previously stented, increases the risk of high grade ureteral injuries, however, despite this increase there is no difference in ureteral stricture formation.

FDG PET/CT in a Case of Lynch Syndrome With Synchronous Inverted Urothelial Papilloma of the Bladder, Urothelial Carcinoma of the Ureter, and Jejunal Adenocarcinoma

ABSTRACT

A 64-year-old man was referred because of the right ureteral obstruction. CT urography showed an intraluminal enhancing mass in the right midureter and an enhancing nodule in the bladder wall. FDG PET/CT showed increased FDG uptake of the ureteral mass and an unexpected hypermetabolic lesion in the jejunum. The patient underwent transurethral resection of the bladder tumor, right laparoscopic nephroureterectomy, and partial enterectomy. Inverted urothelial papilloma of the bladder, high-grade urothelial carcinoma of the right ureter, and jejunal adenocarcinoma were confirmed by histopathology. Genetic testing of the jejunal adenocarcinoma revealed MSH2 germline mutation, confirming the diagnosis of Lynch syndrome.

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.

Multimodality imaging review of focal renal lesions

Background

Focal lesions of the kidney comprise a spectrum of entities that can be broadly classified as malignant tumors, benign tumors, and non-neoplastic lesions. Malignant tumors include renal cell carcinoma subtypes, urothelial carcinoma, lymphoma, post-transplant lymphoproliferative disease, metastases to the kidney, and rare malignant lesions. Benign tumors include angiomyolipoma (fat-rich and fat-poor) and oncocytoma. Non-neoplastic lesions include infective, inflammatory, and vascular entities. Anatomical variants can also mimic focal masses.

Main body of the abstract

A range of imaging modalities are available to facilitate characterization; ultrasound (US), contrast-enhanced ultrasound (CEUS), computed tomography (CT), magnetic resonance (MR) imaging, and positron emission tomography (PET), each with their own strengths and limitations. Renal lesions are being detected with increasing frequency due to escalating imaging volumes. Accurate diagnosis is central to guiding clinical management and determining prognosis. Certain lesions require intervention, whereas others may be managed conservatively or deemed clinically insignificant. Challenging cases often benefit from a multimodality imaging approach combining the morphology, enhancement and metabolic features.

Short conclusion

Knowledge of the relevant clinical details and key imaging features is crucial for accurate characterization and differentiation of renal lesions.

1.5 vs 3 Tesla Magnetic Resonance Imaging: A Review of Favorite Clinical Applications for Both Field Strengths-Part 2

ABSTRACT

The second part of this review deals with experiences in neuroradiological and pediatric examinations using modern magnetic resonance imaging systems with 1.5 T and 3 T, with special attention paid to experiences in pediatric cardiac imaging. In addition, whole-body examinations, which are widely used for diagnostic purposes in systemic diseases, are compared with respect to the image quality obtained in different body parts at both field strengths. A systematic overview of the technical differences at 1.5 T and 3 T has been presented in part 1 of this review, as well as several organ-based magnetic resonance imaging applications including musculoskeletal imaging, abdominal imaging, and prostate diagnostics.

Contrast-enhanced ultrasonography promotes differential diagnosis of ureteral neoplasms

OBJECTIVE

To compare the diagnostic value of contrast-enhanced ultrasonography (CEUS) with baseline ultrasound (B-US) in ureteral neoplasms.

METHODS

Retrospective analysis, comprising clinical presentation, image appearances, and diagnostic results on B-ultrasound and CEUS, considering pathological result as a gold-standard, was conducted on the clinical information of 39 patients with ureteral neoplasms. CT urography was used to detect and confirm the presence of ureteral neoplasms. Both B-ultrasound and CEUS investigations of those 39 patients under study were performed by a senior radiologist.

RESULTS

Pathological outcomes established 27 ureteral malignancies and 12 ureteral benignancies. Ureteral malignancies were observed to occur in older patients than benignancies (p = 0.002). Only the morphological indicator of the ureteric wall on B-ultrasound was different in ureteral malignancies and benignancies (p = 0.030). Tumors with hyperenhancement, larger width, and hyperenhanced ureteric wall were easily diagnosed as malignant on CEUS, whereas iso-/hypoenhanced, narrower, and iso-/hypoenhanced ureteric wall indicated benign tumors. Moreover, the lesion widths, enhanced morphologies of the ureteric wall, and the ureteral wall's linear boundaries on CEUS were different between high- and low-stage ureteral urothelial carcinomas (p = 0.012, 0.002, 0.001, respectively).

CONCLUSION

The display of microvessels in ureteral neoplasms was significantly enhanced by CEUS, thus contributing to the differential diagnosis of ureteral neoplasms while assisting the staging of ureteral urothelial carcinoma.

ADVANCES IN KNOWLEDGE

The imaging features of different ureteral neoplasms on CEUS were analyzed in this study. The diagnostic performances of CEUS and B-ultrasound in ureteral urothelial carcinomas were also explored.

Postoperative complications of colorectal cancer

Colorectal cancer is the third most common cancer, and surgery is the most common treatment. Several surgical options are available, but each is associated with a range of potential complications. The timely and efficient identification of these complications is vital for effective clinical management of these patients in order to minimise their morbidity and mortality. This review aims to describe the range of commonly performed surgical treatments for colorectal surgery. In addition, frequent post-surgical complications are explored with investigative options explained and illustrated.

Clinical characteristics of urinary tract endometriosis: A one-year national series of 232 patients from 31 endometriosis expert centers (by the FRIENDS group)

OBJECTIVE

To review prospectively the clinical characteristics of patients suffering from urinary tract endometriosis (UTE) in France, in 2017.

STUDY DESIGN

We conducted a prospective observational multicenter study including women managed surgically for UTE in 31 French endometriosis expert centers (FRIENDS group) from January 1, 2017 to December 31, 2017. We distinguished patient with isolated bladder endometriosis ("IBE") or isolated ureteral endometriosis ("IUE") and patients associating both locations (mixed locations "ML"). Surgeons belonging to FRIENDS group enrolled patients by filling a 24 items questionnaire the day of the surgery and 6 weeks later. Data on the locations of UTE, preoperative assessment, urinary symptoms and associated pelvic locations were collected in a single anonymized database.

RESULTS

A total of 232 patients from 31 centers were included. IBE concerned 82 patients (35.3%), IUE 126 patients (54.4%) ML 24 patients (10.3%). 111 patients reported urinary symptoms (47.8%). IUE was more often asymptomatic than the rest of the locations (59.5% versus 43.3%, OR 1,92, p = 0.017). Associated deep infiltrating endometriosis (DIE) lesions were found in 193 patients (83.1%). IUE was significantly associated with other DIE lesions (82.5% versus 66%, OR2.4, p = 0.006), particularly with rectum or sigmoid nodules (57.1% versus 36.8%, OR 2.3, p = 0.002) and retrocervical space nodules (31.7% versus 19.8%, OR 1.9, p = 0.05).

CONCLUSION

Our study reports the second largest series of patients operated from a UTE and shows that ureteral location seems more frequent, less symptomatic and more frequently associated to other DIE locations than bladder endometriosis.

A new method to visualize and to spare the ureters during SBRT for oligo metastatic patients

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Ureteral injury following abdominal irradiation may have serious consequences.

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Urography CT scan is a simple procedure to spare ureters during SBRT.

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Using a urography CT scan can significantly reduce the dose to the ureters.

This article describes a ureter-sparing procedure used to treat lymph node metastases with SBRT. We delivered 35 Gy in 5 fractions of 7 Gy to patients with lesions located less than 7 mm from the ureters using a urography CT scan for planification. Two dosimetry plans were created, one using a CT scan urography-based contour and the other using the native phase. PTV coverage were not statistically different but this technique was able to significantly reduce median delivered Dmax to the ureters. These preliminary results demonstrate the feasibility of locating the ureters in a planning CT scan to protect them.

Imaging Manifestations of Genitourinary Tuberculosis

The genitourinary region is one of the most common sites of extrapulmonary tuberculosis (TB) involvement. The imaging features of genitourinary TB are protean and can mimic other entities, including malignancy, and pose a diagnostic dilemma. Hematogenous seeding and lymphatic spread of mycobacteria from pulmonary, tonsillar, and nodal TB are implicated in the pathogenesis of genitourinary TB. In addition, contiguous extension from the urinary tract and sexual transmission are described as sources of genital TB. Genitourinary TB can be indolent and results in nonspecific signs and symptoms; thus, imaging has a vital role in the working diagnosis for these cases. Classic uroradiologic signs of genitourinary TB are primarily described from the era of intravenous urography and conventional radiography. Now, CT, CT urography, MRI, and US are used in the diagnosis and management. Familiarity with the imaging features of genitourinary TB may help guide the diagnosis and, in turn, lead to timely management. US has a vital role in the evaluation of scrotal and female genital TB. MRI offers superior soft-tissue contrast resolution and excellent depiction of anatomic detail. The various imaging manifestations of genitourinary TB are highlighted. ^©RSNA, 2021.

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.

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.

Congenital Anomalies of the Upper Urinary Tract: A Comprehensive Review

The upper urinary tract is the most common human system affected by congenital anomalies. Congenital anomalies of the kidneys and ureters comprise a wide spectrum of disorders ranging from simple variants with no clinical significance to complex anomalies that may lead to severe complications and end-stage renal disease. They may be classified as anomalies of renal form, which are subclassified as structural anomalies (eg, persistent fetal lobulation, hypertrophied column of Bertin, and dromedary hump) and fusion anomalies (eg, horseshoe kidney and pancake kidney); anomalies of renal position (eg, renal malrotation, simple renal ectopia, and crossed renal ectopia) and renal number (eg, renal agenesis and supernumerary kidney); and abnormalities in development of the urinary collecting system (eg, pyelocaliceal diverticulum, megacalycosis, ureteropelvic junction obstruction, duplex collecting system, megaureter, ectopic ureter, and ureterocele). US is usually the first imaging modality used because of its low cost, wide availability, and absence of ionizing radiation. Intravenous urography and voiding cystourethrography are also useful, mainly for characterization of the collecting system and vesicoureteral reflux. However, intravenous urography has been replaced by CT urography and MR urography. These imaging methods not only allow direct visualization of the collecting system but also demonstrate the function of the kidneys, the vascular anatomy, adjacent structures, and complications. Comprehension of congenital anomalies of the upper urinary tract is crucial for an accurate diagnosis and correct management. The authors discuss the spectrum of these anomalies, with emphasis on embryologic development, imaging findings, clinical manifestations, and complications. Online supplemental material is available for this article. ^©RSNA, 2021.

Image-guided study of swine anatomy as a tool for urologic surgery research and training

PURPOSE

To describe the anatomy of the swine urinary system using computed tomography and to discuss the role of this animal as an experimental model for urological procedures.

METHODS

Three male Landrace pigs underwent computed tomography and the anatomy of the urinary system and renal circulation was analyzed and described.

RESULTS

In all animals, 2 kidneys, 2 ureters and one bladder were identified. Each kidney presented a single renal artery vascularization, with a mean diameter on the right of 4.45 and 5.31 mm on the left (p < 0.0001) and single renal vein drainage, with a mean diameter on the right of 5.78 and 5.82 mm on the left (p = 0.0336). The average renal length was 9.85 cm on the right and 10.30 cm on the left (p < 0.0001). The average renal volume was 113.70 cm3 on the right and 109.70 cm3 on the left (p < 0.0001). The average length of the ureter was 19.78 cm on the right and 22.08 cm on the left (p < 0.0001). The average bladder volume was 423.70 cm3.

CONCLUSIONS

The data obtained show similarities with human anatomy, suggesting the viability of the swine model for planning preclinical trials, basic research, refinement in experimental surgery and surgical training for urological procedures.

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.

Split-bolus CT urography with synchronous nephrographic and excretory phase in dogs: comparison of image quality with three-phase CT urography and optimal allocation ratio of contrast medium

BACKGROUND

Computed tomography urography (CTU), based on the excretion of contrast medium after its injection, allows visualization of the renal parenchyma and the renal collecting system.

OBJECTIVES

To determine the optimal contrast medium dose allocation ratio to apply in split-bolus CTU in dogs.

METHODS

This prospective, experimental, exploratory study used 8 beagles. In 3-phase CTU, unenhanced-, nephrographic-, and excretory-phase images were obtained with a single injection of 600 mg iodine/kg iohexol. In split-bolus CTU, two different contrast medium allocation ratios (30% and 70% for split CTU 1; 50% and 50% for split CTU 2) were used. Unenhanced phase image and a synchronous nephrographic-excretory phase image were acquired.

RESULTS

Although the attenuation of the renal parenchyma was significantly lower when using both split CTUs than the 3-phase CTU, based on qualitative evaluation, the visualization score of the renal parenchyma of split CTU 1 was as high as that of the 3-phase CTU, whereas the split CTU 2 score was significantly lower than those of the two others. Artifacts were not apparent, regardless of CTU protocol. The diameter and opacification of the ureter in both split CTUs were not significantly different from those using 3-phase CTU.

CONCLUSIONS

Split-bolus CTU with a contrast medium allocation ratio of 30% and 70% is feasible for evaluating the urinary system and allows sufficient enhancement of the renal parenchyma and appropriate distention and opacification of the ureter, with similar image quality to 3-phase CTU in healthy dogs. Split-bolus CTU has the advantages of reducing radiation exposure and the number of CT images needed for interpretation.

Ultra-high-resolution CT urography: Importance of matrix size and reconstruction technique on image quality

PURPOSE

To evaluate the image quality of CT urography (CTU) obtained with ultra-high-resolution CT (U-HRCT) reconstructed with hybrid iterative reconstruction (IR) and model-based IR algorithms.

METHOD

Forty-eight patients who underwent CTU using the U-HRCT system were enrolled in this retrospective study. Excretory phase images were reconstructed with three protocols: Protocol A: 1024-matrix, 0.25 mm-thickness, and model-based IR; Protocol B: 1024-matrix, 0.25 mm-thickness, and hybrid IR; Protocol C: 512-matrix, 0.5 mm-thickness, and model-based IR. Objective image noise and contrast-to-noise ratio (CNR) of the renal pelvis were compared among the protocols. Three-dimensional maximum intensity projection CTU images were generated from each image data set, and image quality was evaluated by two radiologists.

RESULTS

Protocol C yielded the lowest objective image noise and highest CNR, whereas Protocol A had highest image noise and lowest CNR (P <  0.01). Regarding the detailed delineation of urinary tract structures on the images, the mean visual score was significantly higher for Protocol A than for Protocols B and C (P <  0.001), and the mean score for subjective image noise was significantly lower for Protocol A than for Protocols B and C (P <  0.001).

CONCLUSIONS

CTU with a 1024-matrix and model-based IR depicted the structures of the urinary system in the most detail.

Extrapulmonary Tuberculosis: Pathophysiology and Imaging Findings

Extrapulmonary tuberculosis (TB) represents approximately 15% of all TB infections. It is difficult to diagnose on the basis of imaging characteristics and clinical symptoms, and biopsy is required in many cases. Radiologists must be aware of the imaging findings of extrapulmonary TB to identify the condition in high-risk patients, even in the absence of active pulmonary infection. In extrapulmonary TB, the lymphatic system is most frequently affected. The presence of necrotic lymph nodes and other organ-specific imaging features increases the diagnostic probability of extrapulmonary TB. Disseminated infection and central nervous system involvement are the most frequent manifestations in immunosuppressed patients. Renal disease can occur in immunocompetent patients with very long latency periods between the primary pulmonary infection and genitourinary involvement. In several cases, gastrointestinal, solid-organ, and peritoneal TB show nonspecific imaging findings. Tuberculous spondylitis is the most frequent musculoskeletal manifestation. It is usually diagnosed late and affects multiple vertebral segments with extensive paraspinal abscess. Articular disease is the second most frequent musculoskeletal manifestation, and synovitis is its predominant imaging finding.^©RSNA, 2019.

Ureteral cancer: Complete ureteral obstruction on computed tomography urography is associated with periureteral fat invasion

OBJECTIVE

To determine predictive factors for periureteral fat invasion of ureteral cancer on computed tomography (CT) urography.

MATERIALS AND METHODS

Consecutive 77 patients with CT urography and surgically proven ureteral cancer were retrospectively evaluated. Three independent radiologists with different experiences in interpreting CT urography analyzed radiologic findings as follows: (a) periureteral infiltration (absent; equivocal; or present); (b) ureteral obstruction (complete obstruction or not); (c) lesion length; (d) lesion width; (e) hydronephrosis grade; and (f) renal atrophy (present or not). We analyzed univariate and multivariate logistic regression. We assessed sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of significant parameters.

RESULTS

Periureteral fat invasion was surgically identified in 33.8 % (26/77). For reader 1, periureteral infiltration (odds ratio [OR] = 3.330), complete ureteral obstruction (OR = 18.965), and renal atrophy (OR = 3.116) were significant in univariate analysis (p < 0.05), while only complete ureteral obstruction was significant in multivariate analysis (OR = 12.779; p = 0.018). For reader 2 (OR = 4.172; p = 0.019) and 3 (OR = 9.459; p = 0.035), only complete ureteral obstruction was significant in univariate analysis. Sensitivity, specificity, PPV, and NPV of complete ureteral obstruction were 96.2 % (25/26), 43.1 % (22/51), 46.3 % (25/54), and 95.7 % (22/23) for reader 1, 84.6 % (22/26), 43.1 % (22/51), 43.1 % (22/51), and 84.6 % (22/26) for reader 2, and 96.2 % (25/26), 27.5 % (14/51), 40.3 % (25/62), and 93.3 % (14/15) for reader 3, respectively.

CONCLUSION

Complete ureteral obstruction on CT urography is highly sensitive for extra-ureteral extension of ureteral cancer. Ureteral cancer without complete ureteral obstruction may be less likely to invade periureteral fat.

Synchronous Bilateral Carcinoma of the Ureters. Report of a Case and a Short Discussion of the Literature

BACKGROUND/AIM

The strategy for treatment of bilateral simultaneous renal pelvic and/or ureteral tumors has not been established and is dependent on individual decision.

CASE REPORT

We herein report the case of an elderly man who was examined for fatigue at the emergency department and subsequently diagnosed with bilateral ureteral cancer. The most common histologic type of ureteral cancer is urothelial (transitional epithelium) cancer and though it is rare, it can be synchronously present in the contralateral ureter. Computed tomography-urography (CTU) has very good results regarding diagnosis and surgical treatment and -though not preferred in our case-, it has shown promising results.

CONCLUSION

We believe that conservative treatment is a viable therapeutic option for simultaneous bilateral renal pelvic and/or ureteral tumors in selected patients. Yet, this treatment has seldom been performed, although standard therapy with bilateral nephroureterectomy inevitably requires the support of hemodialysis or renal transplantation.

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.

Diagnostic Accuracy of Ultrasound and MRI in the Mapping of Deep Pelvic Endometriosis Using the International Deep Endometriosis Analysis (IDEA) Consensus

OBJECTIVES

The primary aim was to investigate the diagnostic accuracy of transvaginal ultrasound (TVS) and magnetic resonance imaging (MRI) in the mapping of deep pelvic endometriosis (DE) in a diseased population. The secondary aim was to offer first insights into the clinical applicability of the new International Deep Endometriosis Analysis group (IDEA) consensus for sonographic evaluation, which was also adapted for MRI and surgical reporting in this study.

METHODS

The study was a prospective observational cohort study. In this study, consecutive women planned for surgical treatment for DE underwent preoperative mapping of pelvic disease using TVS and MRI (index tests). The results were compared against the intraoperative findings with histopathological confirmation (reference standard). In case of disagreement between intraoperative and pathology findings, the latter was prioritised. Index tests and surgical findings were reported using a standardised protocol based on the IDEA consensus.

RESULTS

The study ran from 07/2016 to 02/2018. One-hundred and eleven women were approached, but 60 declined participation. Out of the 51 initially recruited women, two were excluded due to the missing reference standard. Both methods (TVS and MRI) had the same sensitivity and specificity in the detection of DE in the upper rectum (UpR) and rectosigmoid (RS) (UpR TVS and MRI sensitivity and specificity 100%; RS TVS and MRI sensitivity 94%; TVS and MRI specificity 84%). In the assessment of DE in the bladder (Bl), uterosacral ligaments (USL), vagina (V), rectovaginal septum (RVS), and overall pelvis (P), TVS had marginally higher specificity but lower sensitivity than MRI (Bl TVS sensitivity 89%, specificity 100%, MRI sensitivity 100%, specificity 95%; USL TVS sensitivity 74%, specificity 67%, MRI sensitivity 94%, specificity 60%; V TVS sensitivity 55%, specificity 100%, MRI sensitivity 73%, specificity 95%; RVS TVS sensitivity 67%, specificity 100%, MRI sensitivity 83%, specificity 93%; P TVS sensitivity 78%, specificity 97%, MRI sensitivity 91%, specificity 91%). No significant differences in diagnostic accuracy between TVS and MRI were observed except USL assessment (p=0.04) where MRI was significantly better and pouch of Douglas obliteration (p=0.04) where MRI was significantly better and pouch of Douglas obliteration (κ) = 0.727 [p=0.04) where MRI was significantly better and pouch of Douglas obliteration (κ) = 0.727 [p=0.04) where MRI was significantly better and pouch of Douglas obliteration (p=0.04) where MRI was significantly better and pouch of Douglas obliteration (.

CONCLUSION

We found that both imaging techniques had overall good agreement with the reference standard in the detection of deep pelvic endometriosis. This is the first study to date involving the IDEA consensus for ultrasound, its modified version for MRI, and intraoperative reporting of deep pelvic endometriosis in clinical practice.

Imaging protocols for CT urography: results of a consensus conference from the French Society of Genitourinary Imaging

OBJECTIVES

To develop technical guidelines for computed tomography urography.

METHODS

The French Society of Genitourinary Imaging organised a Delphi consensus conference with a two-round Delphi survey followed by a face-to-face meeting. Consensus was strictly defined using a priori criteria.

RESULTS

Forty-two expert uro-radiologists completed both survey rounds with no attrition between the rounds. Ninety-six (70%) of the initial 138 statements of the questionnaire achieved final consensus. An intravenous injection of 20 mg of furosemide before iodinated contrast medium injection was judged mandatory. Improving the quality of excretory phase imaging through oral or intravenous hydration of the patient or through the use of an abdominal compression device was not deemed necessary. The patient should be imaged in the supine position and placed in the prone position only at the radiologist's request. The choice between single-bolus and split-bolus protocols depends on the context, but split-bolus protocols should be favoured whenever possible to decrease patient irradiation. Repeated single-slice test acquisitions should not be performed to decide of the timing of excretory phase imaging; instead, excretory phase imaging should be performed 7 min after the injection of the contrast medium. The optimal combination of unenhanced, corticomedullary phase and nephrographic phase imaging depends on the context; suggestions of protocols are provided for eight different clinical situations.

CONCLUSION

This expert-based consensus conference provides recommendations to standardise the imaging protocol for computed tomography urography.

KEY POINTS

• To improve excretory phase imaging, an intravenous injection of furosemide should be performed before the injection of iodinated contrast medium. • Systematic oral or intravenous hydration is not necessary to improve excretory phase imaging. • The choice between single-bolus and split-bolus protocols depends on the context, but split-bolus protocols should be favoured whenever possible to decrease patient irradiation.

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.

Computed tomography (CT) in the evaluation of bladder and ureteral trauma: indications, technique, and diagnosis

INTRODUCTION

Trauma to the genitourinary system includes blunt and penetrating injuries to bladder and ureters. These are rare injuries and are overlooked as other abdominal and pelvic injuries often take priority. Delayed diagnosis can lead to significant morbidity and mortality. Computed tomography has taken a central role in the imaging of the ureters and bladder.

METHODS

This article reviews the anatomic relationships, mechanisms of injury, and clinical presentation to help physicians determine when bladder and ureteral injuries should be suspected and further imaging should be pursued. Radiologic evaluation of bladder and ureteral injury with CT cystography and CT urography, respectively, will be reviewed.

CONCLUSION

CT cystography and CT urography are effective tools in identifying potentially serious injuries to the genitourinary system. Timely recognition of these injuries can be crucial for the overall management and prognosis.

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.

68Ga PSMA-11 PET with CT urography protocol in the initial staging and biochemical relapse of prostate cancer

Background

⁶⁸Ga-labelled prostate specific membrane antigen (PSMA) ligand PET/CT is a promising modality in primary staging (PS) and biochemical relapse (BCR) of prostate cancer (PC). However, pelvic nodes or local recurrences can be difficult to differentiate from radioactive urine. CT urography (CT-U) is an established method, which allows assessment of urological malignancies. The study presents a novel protocol of ⁶⁸Ga-PSMA-11 PET/CT-U in PS and BCR of PC.

Methods

A retrospective review of PSMA PET/CT-U preformed on 57 consecutive patients with prostate cancer. Fifty mL of IV contrast was administered 10 min (range 8–15) before the CT component of a combined PET/CT study, acquired approximately 60 min (range 40–85) after administration of 166 MBq (range 91–246) of ⁶⁸Ga-PSMA-11. PET and PET/CT-U were reviewed by two nuclear medicine physicians and CT-U by a radiologist. First, PET images were reviewed independently followed by PET/CT-U images. Foci of activity which could not unequivocally be assessed as disease or urinary activity were recorded. PET/CT-U was considered of potential benefit in final interpretation when the equivocal focal activity in PET images corresponded to opacified ureter, bladder, prostate bed, seminal vesicles, or urethra. Student’s T test and Pearson’s correlation coefficient was used for assessment of variables including lymph node size and standardized uptake value.

Results

Overall 50 PSMA PET/CT-U studies were performed for BCR and 7 for PS. Median PSA with BCR and PS were 2.0 ± 11.4 ng/ml (0.06–57.3 ng/ml) and 18 ± 35.3 ng/ml (6.8–100 ng/ml), respectively. The median Gleason-score for both groups was 7 (range 6–10). In BCR group, PSMA PET was reported positive in 36 (72%) patients, CT-U in 11(22%) patients and PET/CT-U in 33 (66%) patients. In PS group, PSMA PET detected the primary site in all seven patients, of which one patient with metastatic nodal disease had negative CT finding. Of 40 equivocal foci (27/57 patients) on PET, 11 foci (10/57 patients, 17.5%) were localized to enhanced urine on PET/CT-U, hence considered of potential benefit in interpretation. Of those, 3 foci (3 patients) were solitary sites of activity on PSMA imaging including two local and one nodal site and 4 foci (3 patients) were in different nodal fields.

Conclusions

PET/CT-U protocol is a practical approach and may assist in interpretation of ⁶⁸Ga-PSMA-11 imaging by delineation of the contrast opacified genitourinary system and matching focal PSMA activity with urinary contrast.

Electronic supplementary material

The online version of this article (10.1186/s40644-017-0133-5) contains supplementary material, which is available to authorized users.