Upper and Lower Tract Urothelial Imaging Using Computed Tomography Urography

Predicting preoperative muscle invasion status for bladder cancer using computed tomography-based radiomics nomogram

OBJECTIVES

The aim of the study is to assess the efficacy of the established computed tomography (CT)-based radiomics nomogram combined with radiomics and clinical features for predicting muscle invasion status in bladder cancer (BCa).

METHODS

A retrospective analysis was conducted using data from patients who underwent CT urography at our institution between May 2018 and April 2023 with urothelial carcinoma of the bladder confirmed by postoperative histology. There were 196 patients enrolled in all, and each was randomized at random to either the training cohort (n = 137) or the test cohort (n = 59). Eight hundred fifty-one radiomics features in all were retrieved. For feature selection, the significance test and least absolute shrinkage and selection operator (LASSO) approaches were utilized. Subsequently, the radiomics score (Radscore) was obtained by applying linear weighting based on the selected features. The clinical and radiomics model, as well as radiomics-clinical nomogram were all established using logistic regression. Three models were evaluated using analysis of the receiver operating characteristic curve. An area under the curve (AUC) and 95% confidence intervals (CI) as well as specificity, sensitivity, accuracy, negative predictive value, and positive predictive value were included in the analysis. Radiomics-clinical nomogram's performance was assessed based on discrimination, calibration, and clinical utility.

RESULTS

After obtaining 851 radiomics features, 12 features were ultimately selected. Histopathological grading and tortuous blood vessels were included in the clinical model. The Radscore and clinical histopathology grading were among the final predictors in the unique nomogram. The three models had an AUC of 0.811 (95% CI, 0.742-0.880), 0.845 (95% CI, 0.781-0.908), and 0.896 (95% CI, 0.846-0.947) in the training cohort and in the test cohort they were 0.808 (95% CI, 0.703-0.913), 0.847 (95% CI, 0.739-0.954), and 0.887 (95% CI, 0.803-0.971). According to the DeLong test, the radiomics-clinical nomogram's AUC in the training cohort substantially differed from that of the clinical model (AUC: 0.896 versus 0.845, p = 0.015) and the radiomics model (AUC: 0.896 versus 0.811, p = 0.002). The Delong test in the test cohort revealed no significant difference among the three models.

CONCLUSIONS

CT-based radiomics-clinical nomogram can be a useful tool for quantitatively predicting the status of muscle invasion in BCa.

Imaging in Upper Tract Urothelial Carcinoma: A Review

Medical imaging is a critical tool in the detection, staging, and treatment planning of upper urinary tract urothelial carcinoma (UTUC). This article reviews the strengths and weaknesses of the different imaging techniques and modalities available clinically. This includes multidetector computed tomography (CT), multiparametric magnetic resonance imaging (MRI), ultrasound (US), and positron emission tomography (PET) for the detection, staging, and management of UTUC. In addition, we review the imaging techniques that are being developed and are on the horizon but have not yet made it to clinical practice. Firstly, we review the imaging findings of primary UTUC and the techniques across multiple modalities. We then discuss imaging findings of metastatic disease. Lastly, we describe the role of imaging in the surveillance after resection of primary UTUC based upon current guidelines.

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.

Clinical Implication of Borderline CT-Morphological Metastatic Spread in Bladder Cancer: What You See Is Not Always What You Got

INTRODUCTION

Palliative radical cystectomy (pRC) may be offered to selected bladder cancer (BC) patients with grievous local symptoms. However, there is only scarce information on perioperative complications and prognosis, especially in the case of metastatic spread. We intended to analyze morbidity and oncological outcome in this patient subgroup.

MATERIALS

Patients undergoing pRC because of BC with radiologic evidence of metastases were included in this retrospective study. Perioperative adverse events (AEs) were graded by the Clavien-Dindo Classification system. All patients underwent CT-based surveillance, and questionnaires were sent for survival follow-up in predefined intervals. Oncological outcome and predictive markers were assessed in univariate and multivariate analyses, using log-rank tests and Cox-regression analyses.

RESULTS

Between 2004 and 2016, 77 patients were identified. Median age at surgery was 70 years (IQR 66-77) and the median follow-up time was 12 months (IQR 4-44). Preoperative staging revealed pulmonary, hepatic, bone, peritoneal, and various other metastasis in 46/77 (60%), 14/77 (18%), 11/77 (14%), 5/77 (7%), and 11/77 (14%) cases, respectively. Most frequently observed symptoms at the time of pRC were severe gross hematuria (n = 41) and intense pain (n = 11). Most AEs were of minor grade (83%). The median length of stay was 20 days. Median CSS was 13 months with a 5-year CSS of 34%. Intriguingly and unsuspectedly, preoperatively suspicious lung lesions were confirmed during surveillance only in 33%, respectively. In multivariate analysis, intraoperative blood transfusions (HR = 2.25, 95% CI: 1.09-4.63, p = 0.028) were significantly associated with decreased CSS. The best outcome was observed in patients with only subpleural metastases (CSS 80 months, p = 0.039) and normal CRP- and Hb values.

CONCLUSION

pRC can be performed with acceptable perioperative morbidity and mortality. Pulmonary lesions seem to have a risk of false-positive results and should be biopsied in all uncertain cases. Localization of lung metastases together with preoperative CRP- and Hb levels seem to play a prognostic role.

Clinical Guidelines for Female Lower Urinary Tract Symptoms (second edition)

The present article is an abridged English translation of the Japanese Clinical Guidelines for Female Lower Urinary Tract Symptoms (second edition), published in September 2019. These guidelines consist of a total of 212 pages and are unique worldwide in that they cover female lower urinary tract symptoms other than urinary incontinence. They contain two algorithms for "primary treatment" and "specialized treatment," respectively. These guidelines, consisting of six chapters, address a total of 26 clinical questions including: (i) treatment algorithms; (ii) what are female lower urinary tract symptoms?; (iii) epidemiology and quality of life; (iv) pathology and illness; (v) diagnosis; and (vi) treatment. When the patient's symptoms mainly involve voiding and post-micturition symptoms, specialized treatment should be considered. In the event of voiding symptoms concurrent with storage symptoms, residual urine should be measured; if the residual urine volume is <100 mL, then diagnosis and treatment for storage symptoms is prioritized, and if the volume is ≥100 mL, then specialized treatment should be considered. When storage symptoms are the primary condition, then the patient is subject to the primary treatment algorithm. Specialized treatment for refractory overactive bladder includes botulinum toxin injection and sacral nerve stimulation. For stress urinary incontinence, surgical treatment is indicated, such as urethral slings. The two causes of voiding symptoms and post-micturition symptoms are lower urinary tract obstruction and detrusor underactivity (underactive bladder). Mechanical lower urinary tract obstruction, such as pelvic organ prolapse, is expected to improve with surgery.

Stage Migration for Upper Tract Urothelial Cell Carcinoma

INTRODUCTION

Upper tract urothelial carcinomas (UTUCs) account for 5% to 10% of urothelial cancers. The phenomenon of stage migration in tumors has been evident with increased use and higher resolution of cross-sectional imaging. Using the National Cancer Database, we analyzed trends in stage at presentation and overall survival for UTUCs.

PATIENTS AND METHODS

We analyzed UTUCs in the renal pelvis or ureter from 2004 to 2016. Pathologic tumor stage data were available for 71.3% of patients and clinical tumor staging were available for 28.7% of patients. Five-year overall survival was analyzed comparing patients between 2004-2007 and 2008-2011. Tumor stage was categorized as early (0-1), intermediate (2-3), or late (4) for survival analyses. Linear regression and Kaplan-Meier analyses were utilized.

RESULTS

A total of 37,210 renal pelvic and 23,200 ureteral origin UTUC cases were evaluated. Stage migration toward stage 0 and stage 4 was observed. There was a significant increase in proportion of stage 0 Ta/Tis (22.8%-33.4%, R² = 0.86, P < .001) and stage 4 (22.3%-26.4%, R² = 0.57, P = .003) disease for renal pelvic tumors, and a significant decrease in stages 1, 2, and 3. For UTUCs of ureteral origin, diagnosis at stage 0 Ta/Tis (37.6%-44.7%, R² = 0.53, P = .005) and stage 4 (10.9%-14.6%, R² = 0.63, P = .001) increased significantly, with significant reductions in stage 1 and 2. There was no difference in 5-year overall survival for ureteral or renal pelvic UTUCs for patients during 2004-2007 versus 2008-2011 when stratified by early, intermediate, or late stage.

CONCLUSION

There is a stage migration toward stage 0 and stage 4 disease for UTUC. Five-year survival data from 2004 to 2011 remained stable across early, intermediate, and late stage groups.

State-of-the-Art Renal Imaging in Children

Imaging modalities for diagnosing kidney and urinary tract disorders in children have developed rapidly over the last decade largely because of advancement of modern technology. General pediatricians and neonatologists are often the front line in detecting renal anomalies. There is a lack of knowledge of the applicability, indications, and nephrotoxic risks of novel renal imaging modalities. Here we describe the clinical impact of congenital anomalies of the kidneys and urinary tract and describe pediatric-specific renal imaging techniques by providing a practical guideline for the diagnosis of kidney and urinary tract disorders.

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.

Upper urinary tract urothelial carcinoma on multidetector CT: spectrum of disease

Urothelial carcinoma of the upper urinary tract (UUT) is a relatively uncommon genitourinary malignancy, accounting for about 5-7% of urothelial tumors. The significant features of this tumor are multifocality and high rate of recurrence. Computed tomography urography (CTU) has replaced excretory urography (EU) and retrograde pyelography (RP) for imaging of upper tract urothelial carcinoma. While many studies have confirmed high sensitivity (88-100%) and specificity (93-100%) of CTU, an optimized CT protocol is of critical importance in screening, staging, and post-operative follow-up of patients (Chlapoutakis, Eur J Radiol 73(2):334-338, 2010; Caoli and Cohan, Abdom Radiol (NY) 41(6):1100-1107, 2016). The key element of the CT protocol is to have adequate distension of the collecting system with excreted contrast, to detect subtle lesions at an early stage. In this article, we discuss the background of upper urinary tract TTC, pathogenesis, CT protocol and the role of imaging in evaluation of this malignancy, staging, as well as different imaging appearances.

Rare case of an upper urinary tract carcinoma (UTUC) in renal pelvis and ureter associated to renal vein thrombosis: diagnostic imaging with CECT, MRI and CEUS

A 58-year-old woman complaining of dyspnea and mild flank pain was admitted to our radiology department after undergoing ultrasonography in another institution. She showed hydronephrosis and left kidney swelling. We performed a contrast-enhanced computed tomography (CECT) that confirmed the hydronephrosis and revealed a widely hypoperfused left kidney, a concentric thickening of the proximal ureter, and a slight and diffuse thickening of the renal pelvic wall, with a hyperdense content in the unenhanced CT phase and poor contrast enhancement in the post-contrast phases. A proximal ipsilateral renal vein thrombosis was associated. Non-contrast magnetic resonance imaging confirmed the CECT findings. At the same time, we performed a contrast-enhanced ultrasonography examination, which proved to be helpful for the characterization of the lesion and for patient management.

[Value of imaging in upper urinary tract tumors]

BACKGROUND

Staging of bladder cancer, hematuria as well as the evaluation of unclear findings of the kidneys and ureters are the most frequent indications for imaging of the upper urinary tract (UUT). Endourological assessment of the UUT is much more invasive compared to imaging of the bladder, raising the question of the optimal imaging technique. Several technical improvements regarding computed tomography (CT) as well as magnetic resonance imaging (MRI) were implemented in recent years.

OBJECTIVES

To compare the efficacy and limitations of the most important imaging techniques regarding the UUT.

MATERIALS AND METHODS

Systematic review of the literature and current German, European, and American guidelines regarding bladder cancer, urothelial carcinoma of the UUT and hematuria.

RESULTS

The CT-based urography has superseded excretory urography and is the first choice for imaging of the UUT. In case of contraindications, MRI is a feasible alternative. In all cases, a urography phase is indispensable.

CONCLUSIONS

Imaging of the UUT has to be used in a reasonable combination together with endourological methods and cytology. Optical coherence tomography, confocal laser endomicroscopy and scientific innovations such as radiomics might improve UUT imaging and differential diagnosis of UUT lesions in the future.