The Urological Association of Asia clinical guideline for urinary stone disease

The Urological Association of Asia, consisting of 25 member associations and one affiliated member since its foundation in 1990, has planned to develop Asian guidelines for all urological fields. The field of stone diseases is the third of its guideline projects. Because of the different climates, and social, economic and ethnic environments, the clinical practice for urinary stone diseases widely varies among the Asian countries. The committee members of the Urological Association of Asia on the clinical guidelines for urinary stone disease carried out a surveillance study to better understand the diversity of the treatment strategy among different regions and subsequent systematic literature review through PubMed and MEDLINE database between 1966 and 2017. Levels of evidence and grades of recommendation for each management were decided according to the relevant strategy. Each clinical question and answer were thoroughly reviewed and discussed by all committee members and their colleagues, with suggestions from expert representatives of the American Urological Association and European Association of Urology. However, we focused on the pragmatic care of patients and our own evidence throughout Asia, which included recent surgical trends, such as miniaturized percutaneous nephrolithotomy and endoscopic combined intrarenal surgery. This guideline covers all fields of stone diseases, from etiology to recurrence prevention. Here, we present a short summary of the first version of the guideline - consisting 43 clinical questions - and overview its key practical issues.

Influence of diuretic (furosemide) on contrast medium distribution in computed tomography urography of high-grade hydronephrosis in children

Introduction

Diuretics improve visualization of the urinary tract in computed tomography urography in adults, as well as in magnetic resonance urography in adults and children. Also, diuretics can help to diagnose upper urinary tract obstruction in intravenous urography, ultrasonography or dynamic scintigraphy. However, there are still missing data on evaluation of furosemide usefulness in computed tomography urography examinations in children with suspected congenital anomalies of the urinary tracts.

The aim of this study was to compare the homogeneity of contrast medium distribution in high-grade hydronephrosis in pediatric computed tomography urographies performed with and without use of diuretic (furosemide).

Materials and method

We have restrospectively analyzed computed tomography urography image series performed in the Department of Pediatric Radiology, in children with suspected congenital anomalies of the kidney and the urinary tract. Kidney units with high-grade hydronephrosis were divided in two groups: non-furosemide (n = 25) and furosemide (n = 28) group, where diuretic in dose 1 mg/kg, with maximum 20 mg, was administered intravenously 3–5 min before contrast medium administration. Subjective image quality and diagnostic confidence were evaluated by two independent radiologists and compared between study groups.

Results

There were no significant differences in subjective image quality and diagnostic confidence between furosemide and non-furosemide groups.

Conclusions

Addition of furosemide to computed tomography urography does not improve homogeneity of contrast medium distribution in hydronephrotic kidneys in children.

3D reconstruction of CT scans aid in preoperative planning for sarcomatoid renal cancer: A case report and mini-review

Contrast-enhanced multi-slice computed tomography (MSCT) is commonly used in the diagnosis of complex malignant tumours. This technology provides comprehensive and accurate information about tumour size and shape in relation to solid tumours and the affected adjacent organs and tissues. This case report demonstrates the benefit of using MSCT 3D imaging for preoperative planning in a patient with late-stage (T4) sarcomatoid renal cell carcinoma, a rare renal malignant tumour. The surgical margin on the liver was negative, and no metastases to veins, lungs or other organs were detected by abdominal and chest contrast-enhanced CT. Although sarcomatoid histology is considered to be a poor prognostic factor, the patient is alive and well 17 months after surgery. The MSCT imaging modality enables 3D rendering of an area of interest, which assists surgical decision-making in cases of advanced renal tumours. In this case, as a result of MSCT 3D reconstruction, the patient received justified surgical treatment without compromising oncological principles.

Imaging for the diagnosis and response assessment of renal tumours

PURPOSE

Imaging plays a key role throughout the renal cell carcinoma (RCC) patient pathway, from diagnosis and staging of the disease, to the assessment of response to therapy. This review aims to summarise current knowledge with regard to imaging in the RCC patient pathway, highlighting recent advances and challenges.

METHODS

A literature review was performed using Medline. Particular focus was paid to RCC imaging in the diagnosis, staging and response assessment following therapy.

RESULTS

Characterisation of small renal masses (SRM) remains a diagnostic conundrum. Contrast-enhanced ultrasound (CEUS) has been increasingly applied in this field, as have emerging technologies such as multiparametric MRI, radiomics and molecular imaging with 99mtechnetium-sestamibi single photon emission computed tomography/CT. CT remains the first-line modality for staging of locoregional and suspected metastatic disease. Although the staging accuracy of CT is good, limitations in determining nodal status persist. Response assessment following ablative therapies remains challenging, as reduction in tumour size may not occur. The pattern of enhancement on CT may be a more reliable indicator of treatment success. CEUS may also have a role in monitoring response following ablation. Response assessments following anti-angiogenic and immunotherapies in advanced RCC is an evolving field, with a number of alternative response criteria being proposed. Tumour response patterns may vary between different immunotherapy agents and tumour types; thus, future response criteria modifications may be inevitable.

CONCLUSION

The diagnosis and characterisation of SRM and response assessment following targeted therapy for advanced RCC are key challenges which warrant further research.

Low-Tube-Voltage CT Urography Using Low-Concentration-Iodine Contrast Media and Iterative Reconstruction: A Multi-Institutional Randomized Controlled Trial for Comparison with Conventional CT Urography

OBJECTIVE

To compare the image quality of low-tube-voltage and low-iodine-concentration-contrast-medium (LVLC) computed tomography urography (CTU) with iterative reconstruction (IR) with that of conventional CTU.

MATERIALS AND METHODS

This prospective, multi-institutional, randomized controlled trial was performed at 16 hospitals using CT scanners from various vendors. Patients were randomly assigned to the following groups: 1) the LVLC-CTU (80 kVp and 240 mgI/mL) with IR group and 2) the conventional CTU (120 kVp and 350 mgI/mL) with filtered-back projection group. The overall diagnostic acceptability, sharpness, and noise were assessed. Additionally, the mean attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM) in the urinary tract were evaluated.

RESULTS

The study included 299 patients (LVLC-CTU group: 150 patients; conventional CTU group: 149 patients). The LVLC-CTU group had a significantly lower effective radiation dose (5.73 ± 4.04 vs. 8.43 ± 4.38 mSv) compared to the conventional CTU group. LVLC-CTU showed at least standard diagnostic acceptability (score ≥ 3), but it was non-inferior when compared to conventional CTU. The mean attenuation value, mean SNR, CNR, and FOM in all pre-defined segments of the urinary tract were significantly higher in the LVLC-CTU group than in the conventional CTU group.

CONCLUSION

The diagnostic acceptability and quantitative image quality of LVLC-CTU with IR are not inferior to those of conventional CTU. Additionally, LVLC-CTU with IR is beneficial because both radiation exposure and total iodine load are reduced.

Magnetic resonance imaging (MRI) of the renal sinus

This article presents methods to improve MR imaging approach of disorders of the renal sinus which are relatively uncommon and can be technically challenging. Multi-planar Single-shot T2-weighted (T2W) Fast Spin-Echo sequences are recommended to optimally assess anatomic relations of disease. Multi-planar 3D-T1W Gradient Recalled Echo imaging before and after Gadolinium administration depicts the presence and type of enhancement and relation to arterial, venous, and collecting system structures. To improve urographic phase MRI, concentrated Gadolinium in the collecting systems should be diluted. Diffusion-Weighted Imaging (DWI) should be performed before Gadolinium administration to minimize T2* effects. Renal sinus cysts are common but can occasionally be confused for dilated collecting system or calyceal diverticula, with the latter communicating with the collecting system and filling on urographic phase imaging. Vascular lesions (e.g., aneurysm, fistulas) may mimic cystic (or solid) lesions on non-enhanced MRI but can be suspected by noting similar signal intensity to the blood pool and diagnosis can be confirmed with MR angiogram/venogram. Multilocular cystic nephroma commonly extends to the renal sinus, however, to date are indistinguishable from cystic renal cell carcinoma (RCC). Solid hilar tumors are most commonly RCC and urothelial cell carcinoma (UCC). Hilar RCC are heterogeneous, hypervascular with epicenter in the renal cortex compared to UCC which are centered in the collecting system, homogeneously hypovascular, and show profound restricted diffusion. Diagnosis of renal sinus invasion in RCC is critically important as it is the most common imaging cause of pre-operative under-staging of disease. Fat is a normal component of the renal sinus; however, amount of sinus fat correlates with cardiovascular disease and is also seen in lipomatosis. Fat-containing hilar lesions include lipomas, angiomyolipomas, and less commonly other tumors which engulf sinus fat. Mesenchymal hilar tumors are rare. MR imaging diagnosis is generally not possible, although anatomic relations should be described to guide diagnosis by percutaneous biopsy or surgery.

Analysis of Intravenous Urography Findings in a Tertiary Reference Center

Objective

To analyze intravenous urography (IVU) findings in a tertiary reference center.

Materials and Methods

A retrospective, observational study was conducted in a tertiary reference center. The radiology reports of 1,470 patients subjected to IVU in the period from January 2008 to December 2012 were retrieved from the tertiary reference center databases. Patients' demographic characteristics, type of care (inpatient or outpatient), and IVU radiologic findings were reviewed and analyzed.

Results

Of 1470 patients, approximately two-thirds were males. The mean age of the patients was 39.12±14.80 years (range: 2-95). Most of them were inpatients (92.9%; 1365/1470). The IVU findings were abnormal in 68.8% (1012/1470) of patients. Urinary tract calculi were the most frequent type of calculi observed among patients (36.8%; 541/1470), and the kidney was the most frequently affected organ by calculi (66.5%; 541/814). Hydronephrosis was the second most frequent finding, being observed in 29.7% (436/1470) of patients.

Conclusion

The presence urinary tract calculi was the most frequent IVU finding, revealing that urolithiasis could be the main indication for IVU.

Computed tomography urography with iterative reconstruction algorithm in congenital urinary tract abnormalities in children - association of radiation dose with image quality

Purpose

To assess the extent to which a radiation dose can be lowered without compromising image quality and diagnostic confidence in congenital urinary tract abnormalities in children by using a CT scanner with an iterative reconstruction algorithm.

Material and methods

120 CT urography image series were analysed retrospectively. Image series were divided into four study groups depending on effective radiation dose (group 1: 0.8-2 mSv; group 2: 2-4 mSv; group 3: 4-6 mSv; group 4: 6-11 mSv). Objective and subjective image quality were investigated. In objective analysis, measurements of attenuation and standard deviation (SD) in five regions of interest (ROIs) were performed in 109 excretory image series, and image noise was evaluated. In subjective analysis, two independent radiologists evaluated 138 kidney units for subjective image quality and diagnostic confidence.

Results

There were no significant differences in image noise in objective evaluation between the following study groups: 2 vs. 3 and 3 vs. 4 in all ROIs (with the only exception in spleen SD measurement between study groups 2 vs. 3), while there was significantly more image noise in group 2 in comparison to group 4. For all other ROIs in all study groups, there was more image noise on lower dose images. There were no significant differences in pairwise comparisons between study groups in subjective image quality. Diagnostic confidence was not significantly different between all study groups.

Conclusions

Low-dose CT urography can be a valuable method in congenital urinary tract abnormalities in children. Despite poorer image quality, diagnostic confidence is not significantly compromised in examinations performed with lower radiation doses.

Multidetector computed tomography has replaced conventional intravenous excretory urography in imaging of the kidneys: A scoping review of multidetector computed tomography findings in renal tuberculosis

BACKGROUND

Tuberculosis (TB) is a worldwide infectious disease burden, especially in non-developed countries, with increased morbidity and mortality among human immunodeficiency virus (HIV)-infected patients. Extrapulmonary TB is rare and renal TB is one of the commonest manifestations. The end result of renal TB is end-stage renal disease; however, this can be avoided if the diagnosis is made early. The diagnosis of renal TB is challenging because of the non-specific presentation and low sensitivity of clinical tests. Although the sequel of TB infection in the kidney causes varying manifestations depending on the stage of the disease, multidetector computed tomography (MDCT) is capable of demonstrating early findings. We performed a 20-year scoping review of MDCT findings in renal TB to promote awareness.

AIM

To identify specific MDCT imaging characteristics of renal TB, promote early diagnosis and increase awareness of the typical imaging features.

METHODS AND MATERIAL

We searched published and unpublished literature from 1997 to 2017 using a combination of search terms on electronic databases. We followed the Joanna Briggs Institute guidelines.

RESULTS

A total of 150 articles were identified, of which 145 were found through electronic search engines and 5 were obtained from grey literature. Seventy-nine articles that fulfilled our inclusion criteria were reviewed. These included original research, case reports, literature review, organisational reports and grey literature.

CONCLUSION

Multidetector computed tomography can reproduce images comparable with intravenous excretory urography; together with advantages of being able to better assess the renal parenchyma and surrounding spaces, it is important in suggesting the diagnosis of renal TB and clinicians should consider including MDCT when investigating patients with recurrent urinary tract infection not responding to usual antimicrobial therapy.

Value of Magnetic Resonance Urography Versus Computerized Tomography Urography (CTU) in Evaluation of Obstructive Uropathy: An Observational Study

BACKGROUND

Obstructive uropathy is a common public health issue that requires imaging research for providing necessary information. The data is important for determining treatment options, and may influence selective management choices.

OBJECTIVE

The aim of the study is to determine whether magnetic resonance urography or computerized tomography urography is the best imaging modality among patients with suspected obstructive uropathy.

METHODS

Seventy patients; referred from the emergency department for the evaluation of renal colic or hematuria that highly suggested urinary tract abnormalities, were prospectively enrolled. Thirty five women and 35 men were categorized with a mean age of 43.52 years and the mean body weight of 61.31 kg. All participants underwent abdominal ultrasonography and clinical examination to detect the causes of urinary obstruction. Pregnant women were excluded from the study. Both magnetic resonance urography and computerized tomography urography were performed within 30 days of each analysis.

RESULTS

Only 54.3% of the participants had urinary stones. Mean size of the renal stone was 11 mm; while mean size of the ureteral stone was 3.8 mm. The approach of magnetic resonance is not only limited to diagnosis, but is also effectively involved in the real time investigations. MRU has more reliability in terms of the diagnosis and anatomic presentation of the kidneys along with the vasculature. All cases of urinary stones were detected by computed tomography (100%); whereas, 78.9% cases were detected by magnetic resonance urography.

CONCLUSION

Computerized tomography urography is more sensitive in detecting kidney stones; whereas, magnetic resonance urography is better in detecting pathology behind the development of kidney stones.

Integration of CT urography improves diagnostic confidence of 68Ga-PSMA-11 PET/CT in prostate cancer patients

Background

To prove the feasibility of integrating CT urography (CTU) into ⁶⁸Ga-PSMA-11 PET/CT and to analyze the impact of CTU on assigning focal tracer accumulation in the ureteric space to either ureteric excretion or metastatic disease concerning topographic attribution and diagnostic confidence.

Methods

Ten prostate cancer patients who underwent ⁶⁸Ga-PSMA-11 PET/CT including CTU because of biochemical relapse or known metastatic disease were retrospectively analyzed. CTU consisted of an excretory phase 10 min after injection of 80 mL iodinated contrast material. Ureter opacification at CTU was evaluated using the following score: 0, 0% opacification; 1, < 50%; 2, 50–99%; 3, 100%. Topographic attribution and confidence of topographic attribution of focal tracer accumulation in the ureteric space were separately assessed for ⁶⁸Ga-PSMA-11 PET/CT without and with CTU. Diagnostic confidence was evaluated using the following score: 0, < 25% confidence; 1, 26–50%; 2, 51–75%; 3, 76–100%.

Results

At CTU, mean ureter opacification score was 2.6 ± 0.7. At ⁶⁸Ga-PSMA-11 PET/CT without CTU, mean confidence of topographic attribution of focal tracer accumulation was 2.5 ± 0.7 in total and 2.6 ± 0.7 for metastatic disease. At ⁶⁸Ga-PSMA-11 PET/CT with CTU, mean confidence of topographic attribution of focal areas of tracer accumulation was significantly higher with 2.9 ± 0.2 in total and 2.7 ± 0.9 for metastatic disease (p < 0.001). In 4 of 34 findings (12%) attribution to either ureteric excretion or metastatic disease was discrepant between ⁶⁸Ga-PSMA-11 PET/CT without and with CTU (n.s).

Conclusions

Integration of CTU into ⁶⁸Ga-PSMA-11 PET/CT is feasible and increases diagnostic confidence of assigning focal areas of tracer accumulation in the ureteric space to either metastatic disease or ureteric excretion.

Intravenous vs. oral hydration administration for optimal ureteral opacification in computer tomographic urography

PURPOSE

Computed tomographic urography (CTU) is the gold standard in the radiologic detection of urinary tract disease. The goals of CTU protocols are to garner fully distended and opacified collecting systems, ureters, and bladder for adequate evaluation. Multiple techniques have been reported in the literature to optimize urinary tract visualization and enhance genitourinary assessment. However, currently no strict guidelines exist regarding the preferred method for optimal urinary tract opacification in CTU.

MATERIALS AND METHODS

During the year 2013, a retrospective chart review of CTU examinations were done at either an academic institution where IV hydration was routinely administered or at an outpatient imaging center where oral hydration was preferred. Two attending radiologists experienced in cross-sectional body imaging, retrospectively reviewed all the images, blinded to the method of hydration. The reviewers were asked to quantify ureteral distension as well as to grade urinary tract opacification.

RESULTS

A total of 176 patients and 344 ureters were analyzed. Mean maximal ureteral widths were largest in the mid ureter, followed closely by the proximal ureter. Mean opacification scores showed no statistical significance between hydration methods, stratified by ureteral segment.

CONCLUSION

Our study results show that oral hydration is easy to implement, produces ureteral distention and opacification similar to CTU studies with IV hydration, without loss of diagnostic quality in our select patient population. Although not statistically significant, the oral hydration protocol is more cost effective, requires less hospital resources, and may be a useful step toward cost-containment strategies pertinent in today's healthcare landscape.

CT Imaging of Emergent Renal Conditions

The kidneys are paired intra-abdominal organs which provide essential functions and maintain homeostasis throughout the human body. Numerous disease processes affect the kidneys and cause acute renal dysfunction or other potentially catastrophic complications. These conditions can be broadly categorized into obstructive, infectious, hemorrhagic, traumatic, and vascular diseases. Imaging plays a vital role in the work-up and diagnosis of acute and emergent renal conditions. Evaluation of emergent renal conditions with a focus on CT imaging is discussed.

Upper tract urothelial cancer

While urothelial carcinoma is a very common tumor, involvement of the upper tract is relatively uncommon. Consequently, there are no consensus imaging recommendations for upper tract disease. CT urography is the dominant imaging modality for the upper tract, but despite its excellent performance characteristics and being widely accepted as standard of care there is great variability in how CTU exams are performed across practices. MR urography has limited current application, but has the potential to become more mainstream in the future with continued technical advances. Upper tract urothelial carcinoma can manifest as a variety of appearances: a papillary lesion, focal wall thickening, focal enhancement, or as an infiltrative lesion. Pelvicalyceal location is about twice as common as in the ureter. Tumors in the pelvicalyceal location often manifest as an irregular enhancing soft tissue attenuation filling defect, and may be sessile or polypoid in morphology. Within the ureter, 73% are located in the distal segment.

Fibrosis imaging: Current concepts and future directions

Fibrosis plays an important role in many different pathologies. It results from tissue injury, chronic inflammation, autoimmune reactions and genetic alterations, and it is characterized by the excessive deposition of extracellular matrix components. Biopsies are routinely employed for fibrosis diagnosis, but they suffer from several drawbacks, including their invasive nature, sampling variability and limited spatial information. To overcome these limitations, multiple different imaging tools and technologies have been evaluated over the years, including X-ray imaging, computed tomography (CT), ultrasound (US), magnetic resonance imaging (MRI), positron emission tomography (PET) and single-photon emission computed tomography (SPECT). These modalities can provide anatomical, functional and molecular imaging information which is useful for fibrosis diagnosis and staging, and they may also hold potential for the longitudinal assessment of therapy responses. Here, we summarize the use of non-invasive imaging techniques for monitoring fibrosis in systemic autoimmune diseases, in parenchymal organs (such as liver, kidney, lung and heart), and in desmoplastic cancers. We also discuss how imaging biomarkers can be integrated in (pre-) clinical research to individualize and improve anti-fibrotic therapies.

Review on diagnosis and management of urolithiasis in pregnancy: an ESUT practical guide for urologists

PURPOSE

Management of urolithiasis in pregnancy can be challenging for most urologists with diagnostic and treatment dilemma to ensure the best outcome for both mother and fetus. We wanted to review the literature for urolithiasis in pregnancy with a practical management guide for urologists.

METHODS

A non-systematic review of literature was carried out for all English language literature using Medline. To ensure a more comprehensive search, the review of diagnosis and management of pregnant patients with urolithiasis was carried out separately, by two authors independently. Due to diagnostic complexity, investigations (US, CT, MRI) carried out were assessed separately.

RESULTS

Our search included diagnostic studies such as US, CT and MRI (73, 20 and 27 articles, respectively) and management studies (55 articles in total). Details on etiology, radiation risk, safety of various diagnostic modalities, medications and treatment options are covered through an evidence-based approach. We provide a practical guide for urologists in what is clearly a stressful situation for patient and physician alike.

CONCLUSIONS

Urolithiasis in pregnancy needs a careful multidisciplinary management to achieve good outcomes for both mother and baby. Our review shows that a balanced approach for diagnosis and treatment seems to achieve the best outcomes in pregnancy.

Diagnostic yield of CT urography in the evaluation of hematuria in young patients in a military population

PURPOSE

To assess the diagnostic yield of a computed tomography urography (CTU) study in patients less than 50 years of age, who have a history of military service, and who are at increased risk of urological cancers secondary to harmful practices and work-related exposures.

METHODS

137 Consecutive patients who underwent CTU between 2012 and 2013 for new onset of hematuria were included. Initial review of the clinical interpretations of the CTU studies grouped the studies into negative and positive exams for any urological findings. Review of the patients' medical records and subsequent radiology studies determined microscopic versus gross hematuria at presentation and any findings after their CTU study consistent with a urological malignancy. The positive exams were reviewed by second readers, blinded to the clinical interpretation of the initial CTU studies, who first read the unenhanced images. The readers characterized findings as visible on non-contrast CT alone or they requested contrast-enhanced images. Each urological finding was recorded for each patient.

RESULTS

Of the 137 included patients, 84 had micro-hematuria and 53 had gross hematuria. There were a total of 99 negative examinations of the 137 included patients. Contrast was requested 14 times to confirm 11 benign cysts. No findings concerning for malignancy were found by the readers or on subsequent record reviews for each patient.

CONCLUSION

An unenhanced CT may be appropriate to evaluate new onset microscopic, and possibly gross hematuria, in patients younger than 40, even in patients at increased risk of urologic cancer.

[Microscopic hematuria : Reasonable and risk-adapted diagnostic evaluation]

BACKGROUND

Microscopic hematuria that is not explained by an obvious underlying condition is a frequent and often an incidental finding that commonly triggers urological or nephrological evaluation. Potential underlying conditions range from benign to severe malignant diseases of the kidneys and urinary tract.

MATERIALS AND METHODS

A nonsystematic literature search was performed, focusing on potential urological and nephrological causes of hematuria. National and international guidelines were considered and diagnostic as well as follow-up strategies are discussed. We provide a recommendation for practices in the clinical evaluation of hematuria.

RESULTS

The overall prevalence for microscopic hematuria is estimated at approximately 2%, whereas risk populations show an increase to around 30%. In 13-35% of patients presenting with microscopic hematuria, a medical or surgical intervention is required. Malignant tumors of the kidneys or urinary tract can be diagnosed in 2.6-4% of all patients and in up to 25.8% of at-risk populations. "Idiopathic microscopic hematuria" without an obvious underlying medical condition accounts for approximately 80% of patients with asymptomatic hematuria. After exclusion of nephrological diseases, standard diagnostic procedures by means of medical history, physical and laboratory examination as well as ultrasound of the kidneys and the urinary tract should be performed. In the presence of risk factors, an extended diagnostic work-up using cystoscopy, urinary cytology, and cross-sectional imaging of the upper urinary tract is indicated.

CONCLUSION

Evidence-based strategies of a risk-adapted diagnostic evaluation for microscopic hematuria are not available. The development of reliable clinical and molecular markers offers great potential for the identification of patients at higher risk for harboring severe diseases.

CT imaging of solid renal masses: pitfalls and solutions

Computed tomography (CT) remains the first-line imaging test for the characterisation of renal masses; however, CT has inherent limitations, which if unrecognised, may result in errors. The purpose of this manuscript is to present 10 pitfalls in the CT evaluation of solid renal masses. Thin section non-contrast enhanced CT (NECT) is required to confirm the presence of macroscopic fat and diagnosis of angiomyolipoma (AML). Renal cell carcinoma (RCC) can mimic renal cysts at NECT when measuring <20 HU, but are usually heterogeneous with irregular margins. Haemorrhagic cysts (HC) may simulate solid lesions at NECT; however, a homogeneous lesion measuring >70 HU is essentially diagnostic of HC. Homogeneous lesions measuring 20-70 HU at NECT or >20 HU at contrast-enhanced (CE) CT, are indeterminate, requiring further evaluation. Dual-energy CT (DECT) can accurately characterise these lesions at baseline through virtual NECT, iodine overlay images, or quantitative iodine concentration analysis without recalling the patient. A minority of hypo-enhancing renal masses (most commonly papillary RCC) show indeterminate or absent enhancement at multiphase CT. Follow-up, CE ultrasound or magnetic resonance imaging (MRI) is required to further characterise these lesions. Small (<3 cm) endophytic cysts commonly show pseudo-enhancement, which may simulate RCC; this can be overcome with DECT or MRI. In small (<4 cm) solid renal masses, 20% of lesions are benign, chiefly AML without visible fat or oncocytoma. Low-dose techniques may simulate lesion heterogeneity due to increased image noise, which can be ameliorated through the appropriate use of iterative reconstruction algorithms.

Application of Curved MPR Algorithm to High Resolution 3 Dimensional T2 Weighted CISS Images for Virtual Uncoiling of Membranous Cochlea as an Aid for Cochlear Morphometry

INTRODUCTION

With the use of various surgical techniques, types of implants, the preoperative assessment of cochlear dimensions is becoming increasingly relevant prior to cochlear implantation. High resolution CISS protocol MRI gives a better assessment of membranous cochlea, cochlear nerve, and membranous labyrinth. Curved Multiplanar Reconstruction (MPR) algorithm provides better images that can be used for measuring dimensions of membranous cochlea.

AIM

To ascertain the value of curved multiplanar reconstruction algorithm in high resolution 3-Dimensional T2 Weighted Gradient Echo Constructive Interference Steady State (3D T2W GRE CISS) imaging for accurate morphometry of membranous cochlea.

MATERIALS AND METHODS

Fourteen children underwent MRI for inner ear assessment. High resolution 3D T2W GRE CISS sequence was used to obtain images of cochlea. Curved MPR reconstruction algorithm was used to virtually uncoil the membranous cochlea on the volume images and cochlear measurements were done.

RESULTS

Virtually uncoiled images of membranous cochlea of appropriate resolution were obtained from the volume data obtained from the high resolution 3D T2W GRE CISS images, after using curved MPR reconstruction algorithm mean membranous cochlear length in the children was 27.52 mm. Maximum apical turn diameter of membranous cochlea was 1.13 mm, mid turn diameter was 1.38 mm, basal turn diameter was 1.81 mm.

CONCLUSION

Curved MPR reconstruction algorithm applied to CISS protocol images facilitates in getting appropriate quality images of membranous cochlea for accurate measurements.

Spontaneous rupture of the renal pelvis due to obstruction of pelviureteric junction by renal stone: A case report and review of the literature

Spontaneous rupture of the urinary collecting system with extravasation of the urine is a very rare condition. This situation is commonly associated with an obstructing urinary stone. Herein, we report a case of an 86-year-old patient who has admitted to the emergency service with left flank pain continuing for 7 days and pain has exacerbated in the past 24 h. The patient had nausea, vomiting, and tenderness on the left side of the abdomen and left flank region. The patient was diagnosed with an 8 mm left kidney stone a month ago, and hydration and oral analgesics were recommended to the patient. Spontaneous rupture of the renal pelvis and urinary extravasation were detected by contrast-enhanced computed tomography scan. Double-J ureteral stent was placed to control symptoms and eliminate extravasation. In this paper, diagnosis and treatment options for spontaneous renal pelvis rupture are discussed.

Clinical significance of incidentally detected bladder wall thickening on computed tomography

PURPOSE

To evaluate the clinical significance of incidentally detected bladder wall thickening (BWT) on computed tomography (CT).

METHODS

A retrospective analysis was performed on 34,793 cystoscopy cases between January 2004 and December 2013. Among these, patients who underwent cystoscopy for the sole indication of incidentally detected BWT on CT were selected. Patients were categorized into the diffuse or focal group depending on the extent of BWT. Suspicious lesions on cystoscopy were biopsied to confirm histologic subtype. The incidence and predictive factors of bladder malignancy were examined.

RESULTS

A total of 167 (0.5%) patients received cystoscopy for incidentally detected BWT on CT, of which 11 (6.6%) patients were diagnosed with bladder malignancy. When a suspicious lesion was identified on cystoscopy, 11 of 25 (44%) patients were found to have a bladder malignancy. Of the 15 patients with diffuse BWT, 5 (33.3%) were diagnosed with bladder malignancy, consisting of carcinoma in situ in 2 patients, high-grade carcinoma in 2 patients and muscle invasive disease in 1 patient. Of the 10 patients with focal BWT, 6 (60.0%) were diagnosed with bladder malignancy, of which 3 patients had high-grade disease. On multivariate logistic regression analysis, focal BWT [95% confidence interval (CI) 1.400-25.357, P = 0.016] and atypical cells in urine cytology (95% CI 2.631-63.446, P = 0.002) were positively associated with bladder malignancy.

CONCLUSIONS

Incidentally detected BWT on CT can be suggestive of bladder malignancy. Therefore, further work-up including cystoscopy and urine cytology should be performed to assess bladder malignancy.

Dose reduction in CT urography and vasculature phantom studies using model-based iterative reconstruction

To evaluate the feasibility of radiation dose reduction using model-based iterative reconstruction (MBIR) for evaluating the ureters and vasculature in a phantom, a tissue-equivalent CT dose phantom was scanned using a 64-channel CT scan-ner. Tubes of varying diameters filled with different dilutions of a contrast agent, simulating ureters or vessels, were inserted into the center of the phantom. Each combination was scanned using an existing renal protocol at 140 kVp or 120 kVp, yielding a display volumetric CT dose index (CTDIvol) of 24 mGy. The scans were repeated using reduced scan techniques to achieve lower radiation doses down to 0.8 mGy. The images were reconstructed using filtered back-projection (FBP) and model-based iterative reconstruction (MBIR). The noise and contrast-to-noise ratio (CNR) was measured for each contrast object. Comparisons between the two reconstruction methods at different dose levels were evaluated using a factorial design. At each CTDIvol the measured image noise was lower using MBIR compared to FBP (p < 0.0001). At low doses, the percent change in measured image noise between FBP and MBIR was larger. For the 12 mm object simulating a ureter or large vessel with an HU of 600, the measured CNR using MBIR at a CTDIvol of 1.7 mGy was greater than the CNR of FBP at a CTIDvol of 24 mGy (p < 0.0001). For the 5 mm object simulating a medium-sized vessel with a HU of 250, the mea-sured CNR using MBIR at a CTDIvol of 1.7 mGy was equivalent to that of FBP at a CTDIvol of 24 mGy. For the 2 mm, 100 HU object simulating a small vessel, the measured CNR using MBIR at a CTDIvol of 1.7 mGy was equivalent to that of FBP at a CTDIvol of 24 mGy. Low-dose (3.6 mGy) CT imaging of vasculature and ureter phantoms using MBIR results in similar noise and CNR compared to FBP at approximately one-sixth the dose. This suggests that, using MBIR, a one milliSievert exam of the ureters and vasculature may be clinically possible whilst still maintaining adequate image quality.

Retrocaval ureter or preureteral vena cava: Lest we forget this rare cause of hydronephrosis

Retrocaval ureter or circumcaval ureter is a rare congenital abnormality arising from dysgenesis of the inferior vena cava (IVC) that results in the right ureter coursing behind and medial to the IVC. The ideal nomenclature for the anomaly is preureteral vena cava, keeping in mind the aberrant embryology. It can result in hydronephrosis and is a rare cause of long-standing cyclical pain abdomen. Ultrasound, intravenous urography, nuclear scintigraphy, computed tomography urography (CTU) and magnetic resonance urography (MRU) have been used in the diagnosis of this abnormality but CTU, with its ability to depict the abnormality in three dimensions gives the most "wholesome" solution to its diagnosis. When symptomatic, the condition is treated surgically, either by laparoscopic or open surgery. The characteristic imaging findings that can help clinch the diagnosis are described as a reminder for this infrequently encountered cause for pain abdomen and hydronephrosis.

Comprehensive MR Urography Protocol: Equally Good Diagnostic Performance and Enhanced Visibility of the Upper Urinary Tract Compared to Triple-Phase CT Urography

Objectives

To prospectively compare the diagnostic performance and the visualization of the upper urinary tract (UUT) using a comprehensive 3.0T- magnetic resonance urography (MRU) protocol versus triple-phase computed tomography urography (CTU).

Methods

During the study period (January-2014 through December-2015), all consecutive patients in our tertiary university hospital scheduled by a urologist for CTU to exclude UUT malignancy were invited to participate. Diagnostic performance and visualization scores of 3.0T-MRU were compared to CTU using Wilcoxon matched-pairs test.

Results

Twenty patients (39 UUT excreting units) were evaluated. 3.0T-MRU and CTU achieved equal diagnostic performances. The benign etiology of seven UUT obstructions was clarified equally with both methods. Another two urinary tract malignant tumors and one benign extraurinary tumor were detected and confirmed. Diagnostic visualization was slightly better in the intrarenal cavity areas with CTU but worsened towards distal ureter. MRU showed consistently slightly better visualization of the ureter. In the comparison, full 100% visualizations were detected in all areas in 93.6% (with 3.0T-MRU) and 87.2% (with CTU) and >75% visualization in 100% (3.0T-MRU) and 93.6% (CTU). Mean CTU effective radiation dose was 9.2 mSv.

Conclusions

Comprehensive 3.0T-MRU is an accurate imaging modality achieving comparable performance with CTU; since it does not entail exposure to radiation, it has the potential to become the primary investigation technique in selected patients.

Trial Registration

ClinicalTrials.gov NCT02606513

Recommendations for the improvement of bladder cancer quality of care in Canada: A consensus document reviewed and endorsed by Bladder Cancer Canada (BCC), Canadian Urologic Oncology Group (CUOG), and Canadian Urological Association (CUA), December 2015

This initiative was undertaken in response to concerns regarding the variation in management and in outcomes of patients with bladder cancer throughout centres and geographical areas in Canada. Population-based data have also revealed that real-life survival is lower than expected based on data from clinical trials and/or academic centres. To address these perceived shortcomings and attempt to streamline and unify treatment approaches to bladder cancer in Canada, a multidisciplinary panel of expert clinicians was convened last fall for a two-day working group consensus meeting. The panelists included urologic oncologists, medical oncologists, radiation oncologists, patient representatives, a genitourinary pathologist, and an enterostomal therapy nurse. The following recommendations and summaries of supporting evidence represent the results of the presentations, debates, and discussions. Methodology

Split-Bolus Portal Venous Phase Dual-Energy CT Urography: Protocol Design, Image Quality, and Dose Reduction

OBJECTIVE

The purpose of this study is to evaluate the image quality of split-bolus portal venous phase urography and the potential reduction of radiation dose by using a second-generation dual-source dual-energy CT (DECT) scanner.

MATERIALS AND METHODS

DECT urography was performed in 84 patients. Unenhanced CT was performed 20 minutes after drinking 800 mL of water. The split-bolus protocol consisted of a sequence of injections, as follows: 200 mL of normal saline (2.0 mL/s), 50 mL of contrast medium (2.5 mL/s) at 0 second, 70 mL of contrast medium (2.5 mL/s) at 360 seconds, and a saline flush of 25 mL. The scan was started at 420 seconds. Virtual unenhanced images were reconstructed from contrast-enhanced images. The mean CT density and signal-to-noise ratio (SNR) of the renal parenchyma, vessels, upper urinary tract, normal reference tissues, and tumors were measured for image quantitative analysis. Image quality and opacification of the collecting systems were rated by two radiologists using 3- or 4-point scales.

RESULTS

The SNR of all measured sites, except the renal pelvis, showed a statistically significant correlation (p < 0.001) between the true unenhanced and virtual unenhanced images. The overall sensitivity of stone detection was 87.5% (28/32) in virtual unenhanced images. Image quality of the renal parenchyma, arteries, and veins was excellent in 59.5%, 75.0%, and 97.6% of cases, respectively. Opacification of the intrarenal collecting systems, proximal, middle, and distal ureters, and bladder was complete in 92.9%, 83.9%, 78.6%, 77.4%, and 26.2% of patients, respectively. Omitting the unenhanced scan can reduce the mean radiation dose from 15.6 to 6.7 mSv.

CONCLUSION

Portal venous phase split-bolus DECT urography provides sufficient image quality with potential to reduce radiation exposure.

Beyond ureterolithiasis: gamut of abnormalities affecting the ureter

Nephrolithiasis is the most common condition involving the ureters. However, various other entities can affect the ureters, albeit less frequently. Imaging plays a crucial role in diagnosis, management, and follow-up of ureteral pathology. In the past decade, computed tomography urography has replaced traditional methods of ureteral imaging due to its high spatial resolution, multiplanar imaging, and rapid acquisition time. More recently, magnetic resonance urography has also been explored in evaluating ureteral abnormalities. In this review, we briefly discuss current imaging techniques used in assessment of the ureters and present a diverse group of diseases affecting the ureters. We begin with primary and secondary ureteral malignancies, followed by uncommon infectious/inflammatory diseases that can involve the ureters including tuberculosis, xanthogranulomatous pyelonephritis, and graft-versus-host disease. We then discuss the imaging characteristics of endometriosis and retroperitoneal fibrosis as two important examples of pelvic and retroperitoneal processes that occasionally obstruct the ureters and present with clinical symptoms similar to that of renal stones. We end with a brief discussion of miscellaneous conditions that affect the ureters, including ureteral hemorrhage, ureteral intussusception, ureteral pseudodiverticulosis, Malacoplakia, and ureteritis cystica. Knowledge of these entities and their characteristic imaging manifestations along with patient's clinical presentation allows accurate diagnosis and timely patient management.

Low tube voltage computed tomography urography using low-concentration contrast media: Comparison of image quality in conventional computed tomography urography

PURPOSE

The aim of the present study was to investigate the feasibility and image quality of excretory CT urography performed using low iodine-concentration contrast media and low tube voltage.

MATERIALS AND METHODS

This prospective study enrolled 63 patients who undergoing CT urography. The subjects were randomized into two groups of an excretory phase CT urography protocol and received either 240 mg I/mL of contrast media and 80 kVp of tube voltage (low-concentration protocol, n=32) or 350 mg I/mL and 120 kVp (conventional protocol, n=31). Two readers qualitatively evaluated images for sharpness of the urinary tract, image noise, streak artifact and overall diagnostic acceptability. The mean attenuation, signal-to-noise ratio, contrast-to-noise ratio and figure of merit were measured in the urinary tract. The non-inferiority test assessed the diagnostic acceptability between the two protocol groups.

RESULTS

The low-concentration protocol showed a significantly lower effective radiation dose (3.44 vs. 5.70 mSv, P<.001). The diagnostic acceptability was significantly lower in the low-concentration protocol with iterative reconstruction algorithm than in the conventional protocol (4.06±0.45 vs. 4.50±0.37, P<.001), however, all subjects showed at least more than standard diagnostic acceptability and the difference resided in the predefined non-inferiority margin. The signal-to-noise ratio, contrast-to-noise ratio and figure of merit were significantly higher in the low-concentration protocol along the entire urinary tract (P<.001).

CONCLUSION

CT urography using 240 mg I/mL iodine contrast media, 80 kVp tube voltage and an iterative reconstruction algorithm is beneficial to reduce radiation dose and iodine load, and its objective image quality and subjective diagnostic acceptability is not inferior to that of conventional CT urography.

Value of Computed Tomography for Predicting the Outcome After Percutaneous Nephrolithotomy

Introduction

Computerized tomography of the urinary tract (CT-UT) has been established as the diagnostic procedure of choice for urinary stones. This study aimed to evaluate its role in predicting the outcome of percutaneous nephrolithotomy (PCNL) in terms of stone free rate and residual fragments.

Method

This prospective cohort study was conducted on 34 patients in the Urology Department of Theodor Bilharz Research Institute from January 2013 to March 2014. The patients who had large and/or multiple renal stones, including staghorn stones, in 19 renal units scheduled for PCNL were included in this study. All had a pre-operative CT-UT to determine the stones’ characteristics and renal anatomy. CT-UT, together with a kidney-Ureter-Bladder (KUB) film, was taken on the first post-operative day. The data were analyzed by SPSS version 17 using independent-samples t-test and the chi-squared test.

Results

CT-UT showed a statistical significant sensitivity in detecting residual fragments over standard KUB, yet this significance was lost when corrected to significant residual. Stone size and density were independent factors for the presence of residual stones.

Conclusion

CT-UT post PCNL was sensitive to detect residual fragments, yet it showed no superiority over standard KUB in detecting significant residual.

Ureteral Dilatation with No Apparent Cause on Intravenous Urography: Normal or Abnormal? A Pilot Study

A pilot study was done in 18 adults to assess the significance of ureteral dilatation having no apparent cause seen on Intravenous Urography (IVU). A clinicoradiological evaluation was undertaken to evaluate the cause of ureteral dilatation, including laboratory investigations and sonography of the genitourinary tract. This was followed, if required, by CT Urography (using a modified technique). In 9 out of 18 cases, the cause of ureteral dilatation on laboratory investigations was urinary tract infection (6) and tuberculosis (3). In the remaining 9 cases, CTU identified the cause as extrinsic compression by a vessel (3), extrinsic vascular compression of the ureter along with ureteritis (2), extrinsic vascular impression on the right ureter and ureteritis in the left ureter (1), ureteral stricture (2), and ureteral calculus (1). Extrinsic vascular compression and strictures did not appear to be clinically significant in our study. Hence, ureteral dilatation without any apparent cause on intravenous urogram was found to be clinically significant in 12 out of 18 (66.6%) cases. We conclude that ureteral dilatation with no apparent cause on IVU may indicate urinary tract tuberculosis, urinary tract infection (E. coli), or a missed calculus. Thus, cases with a dilated ureter on IVU, having no obvious cause, should undergo a detailed clinicoradiological evaluation and CTU should be used judiciously.

Drainage-related ultrasonography (DRUS): a novel technique for discriminating obstructive and nonobstructive hydroureters in children

BACKGROUND

Despite advances in urologic imaging, the paucity of an optimal technique that accurately clarifies obstructive and nonobstructive hydroureter exists.

OBJECTIVE

This study was conducted to introduce a novel and modified ultrasonographic technique, known as drainage-related ultrasonography (DRUS), discriminating obstructive and nonobstructive, nonrefluxing hydroureter.

MATERIALS AND METHODS

A total of 358 children (mean age, 3.7 years) with 418 nonrefluxing hydroureter were included. These children were composed of two groups of obstructive nonrefluxing (141 children with 157 dilated ureters) and nonobstructive, nonrefluxing (217 children with 261 hydroureter). The definite diagnosis regarding the subtype of hydroureter was derived from appropriate investigation. The maximum diameter of the dilated ureter, which was observed on ultrasonography, was recorded before and after 3 h of catheterization, as D1 and D2, respectively. To assess the D ratio, a formula was developed, that is, [(|D1 - D2|)/D1] × 100. Values were recorded and cutoff points were set to discriminate between subtypes.

RESULTS

Obstructive versus nonobstructive subtypes of nonrefluxing hydroureter were clarified with 78.5 % sensitivity and 83.4 % specificity, by setting a cutoff point of 22 % for the D ratio. Regardless of the cutoff point assigned to the reduction in D (D2 compared with D1), DRUS revealed 93.9 % sensitivity, 80.6 % specificity, 63.2 % positive predictive value, and 97.4 % negative predictive value in discriminating upper from lower obstruction.

CONCLUSION

DRUS affords favorable results in terms of differentiating between obstructive and nonobstructive, nonrefluxing hydroureter, as well as between upper and lower obstruction in obstructive cases. It has the potential to become an efficient imaging modality in the diagnostic algorithm of hydroureter.

CT urography and hematuria: a retrospective analysis of 771 patients undergoing CT urography over a 1-year period

BACKGROUND

Computed tomography (CT) urography is now used in the work-up of patients with hematuria. The dose of contrast medium and radiation varies considerably between the different CT protocols.

PURPOSE

To study the disease prevalence in a consecutive group of patients with hematuria undergoing CT urography with a low dose of contrast medium and radiation.

MATERIAL AND METHODS

From 1 April 2007 to 31 March 2008, using the Radiological Information System (RIS) as well as electronic patient records, demographic data, reason for referral, and diagnosis were obtained for all patients undergoing CT urography due to hematuria. The patients were followed for 3 years.

RESULTS

A total of 771 patients had hematuria diagnosed at the time of referral. In 137 patients (18%), a tumor and / or a complex cyst was found in the urinary tract (renal, ureteral, or bladder), in 68 (9%) a calculi, in 118 (15%) other disease (i.e. infection or anomaly) was found. No abnormalities were found at CT urography in 455 (58%) of the patients with hematuria. Lesions were found more frequently in patients with visible hematuria than in patients with non-visible hematuria (48% vs. 29%). No malignant tumor or complex cyst was found in the kidneys or the ureters in patients with nonvisible hematuria.

CONCLUSION

CT urography with its low dose of contrast medium and radiation is a useful diagnostic imaging test for investigating patients with hematuria.

Precision of computed tomography urography in diagnosing transitional cell carcinoma

Introduction:

Computed tomography urography (CTU) has largely replaced excretion urography. Indications for CTU include patients with haematuria and for upper tract surveillance in those with known transitional cell carcinoma (TCC). Reporting of a possible TCC can lead to complex clinical decisions regarding further investigation and management. The aim of this study is to ascertain the positive predictive value (PPV) of such reports in a large tertiary centre.

Methods:

Examinations performed from January 2010 to August 2012 were retrospectively identified. Subsequent diagnosis of TCC was confirmed by histology, cytology or accepted by uro-oncology MDT with absence of histological proof. The PPV of reported TCCs was calculated overall, by tumour site and presentation.

Results:

A total of 1199 CTU investigations were performed. Analysis revealed the PPV of a reported TCC was 67% for kidney, 44% for ureteric and 85% for bladder lesions. Overall PPV was 68% and 51% for the upper tracts. In patients who attended the haematuria clinic, the PPV was 82% and 88% when positive cytology was included.

Conclusion:

CTU is an appropriate replacement for excretion urography. However, prompt invasive assessment of the entire urinary tract still remains necessary to confirm a suspected TCC.

CT Urography for Evaluation of the Ureter

Over the past decade, computed tomographic (CT) urography has emerged as the primary imaging modality for evaluating the urinary tract in various clinical settings, including the initial workup of hematuria. With the widespread implementation of CT urography, it is critical for radiologists to understand normal ureteral anatomy and the varied appearance of pathologic ureteral conditions at CT urography. Pathologic findings at CT urography include congenital abnormalities, filling defects, dilatation, narrowing, and deviations in course. These abnormalities are reviewed, along with the indications for CT urography, current imaging protocols with specific techniques for optimal evaluation of the ureter, and dose reduction strategies.

Isolated renal pelvis rupture secondary to blunt trauma: Case report

INTRODUCTION

Isolated rupture of the renal pelvis is a very rare condition and thus causes delays in the diagnosis of the rupture. It is most commonly seen in the setting of obstructive ureteric calculus. Other rare causes include neoplasms, trauma, and iatrogenic procedures. Diagnosis is usually established on computed tomography (CT) which demonstrates the extravasation of the contrast in the peripelvic, perinephric, or retroperitoneal collections.

PRESENTATION OF CASE

A 27-year-old male patient was admitted to our hospital due to multiple traumas associated with motor vehicle accidents. The patient had clear urine output. A large pelvic rupture was detected by abdominal contrast-enhanced CT and after consulting with other departments, emergency repair of the renal pelvis was performed and a ureteral stent was implanted.

DISCUSSION

Only a few isolated cases of pelvis rupture with resultant extravasation have been reported in the literature. The treatment of pelvic rupture should be preceded by the removal of underlying causes, followed by conservative management. However, surgical intervention should be warranted in the emergency cases presenting with the symptoms that may impede the decision-making process and in the cases whose diagnosis cannot be clarified by radiological techniques.

CONCLUSION

Renal pelvic injury must be considered in the differential diagnosis of blunt trauma. Surgical intervention may be necessary in some cases. We present a case who underwent surgery due to isolated renal pelvis rupture caused by blunt abdominal trauma.

[Oncological diseases and postoperative alterations of the bladder and urinary tract]

In the challenging evaluation of upper urinary tract malignancies multidetector computed tomography (CT) has become the standard imaging method. Cross sectional imaging not only allows the detection and visualization of the tumor itself but also provides nodal and metastasis staging in one examination (one-stop-shop). The majority of urothelial carcinomas are located in the urinary bladder. In this case, CT and more recently magnetic resonance imaging (MRI) can also deliver decisive information regarding TNM classification. A combination of clinical, histological, morphological and functional parameters allows both risk stratification and a targeted therapy based on the individual tumor stage.

Diagnosis and staging of bladder cancer

Bladder cancer (BCa) is a heterogeneous disease with a variable natural history. Most patients (70%) present with superficial tumors (stages Ta, T1, or carcinoma in situ). However, 3 out of 10 patients present with muscle-invasive disease (T2-4) with a high risk of death from distant metastases. Moreover, roughly between 50% and 70% of superficial tumors do recur, and approximately 10% to 20% of them progress to muscle-invasive disease. However, BCa has a relatively low ratio of mortality versus incidence of new cases. In consequence, there is the danger of overdiagnosis and overtreatment.