Lower tract neoplasm: Update of imaging evaluation

A pilot study of [18F]F-fluciclovine positron emission tomography/computed tomography for staging muscle invasive bladder cancer preceding radical cystectomy

AIM

To assess the ability of [18F]F-fluciclovine-PET/CT to stage muscle invasive bladder cancer (MIBC) before radical cystectomy.

METHODS

This single-site prospective pilot study enrolled patients with MIBC and T2-T4, N0 disease on CT/MRI slated to undergo radical cystectomy (RC). Dynamic and static [18F]F-fluciclovine-PET/CT images were acquired. Clinical readers assessed for confirmation of the primary bladder lesion on imaging and the presence of pelvic nodal metastases. Findings were compared to pathology at RC. Kinetic parameters from dynamic PET/CT were compared across bladder lesions of different clinical stages.

RESULTS

The study enrolled sixteen patients (median age: 73 years, range: 57-88 years, 11 males, 5 females), twelve receiving neoadjuvant chemotherapy before RC. There was high specificity amongst all three readers for detecting lymph node metastases (overall specificity: 0.91, 95%CI: 0.81-1.00) with good overall agreement rate with pathology (0.67, 95%CI: 0.44-0.83). The overall PPV for all readers for identifying node-positive disease was 0.4 (95%CI: 0-1.00), and the overall sensitivity was 0.13 (95%CI: 0-0.44). The overall PPV for detecting the primary tumor was 0.69 (95%CI: 0.47-0.88), and the sensitivity was 0.89 (95%CI: 0.78-1.00), with NPV and specificity being 0.70 (95%CI: 0.33, 1.00) and 0.39 (95%CI: 0.33, 0.50), respectively. Compartmental analysis of the primary bladder tumor revealed that k1 and vb parameters significantly differentiated between low (pT0-pT1) and high (pT2-pT4) risk disease (p < 0.05). Immunohistochemical assessment showed no significant correlation of tumor [18F]F-fluciclovine uptake nor kinetic parameter with amino acid transporter expression.

CONCLUSIONS

[18F]F-fluciclovine demonstrates good specificity and agreement rate for MIBC staging, with sensitivity like CT/MRI. Kinetic parameters such as k1 was able to delineate higher-stage ( ≥ = pT2) primary lesions. Heterogeneous amino acid transporter expression can be seen across lesions. Further studies are warranted to understand [18F]F-fluciclovine PET/CT use in the context of other imaging modalities in this disease.

CLINICAL TRIAL REGISTRATION

NCT04018053 Registered 2/26/2020.

Imaging the Female Urethra: US and MRI in Cystic and Solid Pathologic Conditions

The female urethra can be affected by numerous pathologic conditions, many of which are infrequent and often underdiagnosed, particularly before the introduction of MRI. Diagnosing urethral pathologic conditions is challenging due to ambiguous signs and symptoms, nonspecific physical examinations, atypical presentations (such as benign conditions mimicking malignant disorders), and large lesions. Various imaging techniques, including transperineal or transvaginal US and MRI, are essential for accurate anatomic and tissue characterization. Female urethral pathologic conditions can be categorized into cystic lesions (with urethral diverticulum as the most common), benign and malignant solid urethral lesions, and iatrogenic lesions. Defining the location of the pathologic finding is the first step in radiologic diagnosis. By analyzing tissue characteristics (cystic versus noncystic), shape, morphology, and location (including urethral dependence and relationship to the pubic symphysis), an accurate diagnosis can often be achieved. Identifying whether a lesion is urethral-dependent helps distinguish between urethral and other conditions, such as Bartholin gland and Gartner duct cysts. Radiologists must recognize these features to determine the most appropriate diagnostic and therapeutic strategies. ©RSNA, 2025 Supplemental material is available for this article.

ACR Appropriateness Criteria® Pretreatment Staging of Urothelial Cancer: 2024 Update

Urothelial cancer is the second most common cancer, and cause of cancer death, related to the genitourinary tract. The goals of imaging for pretreatment staging of urothelial cancer are to evaluate for both local and distant spread of the cancer and assessing for synchronous sites of urothelial cancer in the upper tracts and bladder. For pretreatment staging of urothelial carcinoma, patients can be stratified into one of three groups: 1) nonmuscle invasive bladder cancer; 2) muscle invasive bladder cancer; and 3) upper urinary tract urothelial carcinoma. This document is a review of the current literature for urothelial cancer and resulting recommendations for pretreatment staging imaging. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Evaluation of grade and invasiveness of bladder urothelial carcinoma using infrared imaging and machine learning

Urothelial bladder carcinoma (BC) is primarily diagnosed with a subjective examination of biopsies by histopathologists, but accurate diagnosis remains time-consuming and of low diagnostic accuracy, especially for low grade non-invasive BC. We propose a novel approach for high-throughput BC evaluation by combining infrared (IR) microscopy of bladder sections with machine learning (partial least squares-discriminant analysis) to provide an automated prediction of the presence of cancer, invasiveness and grade. Cystoscopic biopsies from 50 patients with clinical suspicion of BC were histologically examined to assign grades and stages. Adjacent tissue cross-sections were IR imaged to provide hyperspectral datasets and cluster analysis segregated IR images to extract the average spectra of epithelial and subepithelial tissues. Discriminant models, which were validated using repeated random sampling double cross-validation, showed sensitivities (AUROC) ca. 85% (0.85) for the identification of cancer in epithelium and subepithelium. The diagnosis of non-invasive and invasive cases showed sensitivity values around 80% (0.84-0.85) and 76% (0.73-0.80), respectively, while the identification of low and high grade BC showed higher sensitivity values 87-88% (0.91-0.92). Finally, models for the discrimination between cancers with different invasiveness and grades showed more modest AUROC values (0.67-0.72). This proves the high potential of IR imaging in the development of ancillary platforms to screen bladder biopsies.

FTIR Spectroscopic Imaging Supports Urine Cytology for Classification of Low- and High-Grade Bladder Carcinoma

Simple Summary

Human urine cytological samples were investigated using Fourier transform infrared spectroscopic imaging in terms of recognition of bladder cancer. The clustering of IR spectra of whole cytological smears revealed very good spectral correlation with normal urothelial cell features. Next, the combination of spectral information derived from unsupervised hierarchical cluster analysis and partial least square discriminant analysis (PLS-DA) classified normal vs. low- and high-grade bladder urothelial carcinoma with sensitivity and specificity of 90–97%.

Abstract

Bladder urothelial carcinoma (BC) is a common, recurrent, life-threatening, and unpredictable disease which is difficult to diagnose. These features make it one of the costliest malignancies. Although many possible diagnostic methods are available, molecular heterogeneity and difficulties in cytological or histological examination induce an urgent need to improve diagnostic techniques. Herein, we applied Fourier transform infrared spectroscopy in imaging mode (FTIR) to investigate patients’ cytology samples assigned to normal (N), low-grade (LG) and high-grade (HG) BC. With unsupervised hierarchical cluster analysis (UHCA) and hematoxylin-eosin (HE) staining, we observed a correlation between N cell types and morphology. High-glycogen superficial (umbrella) and low-glycogen piriform urothelial cells, both with normal morphology, were observed. Based on the spectra derived from UHCA, principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were performed, indicating a variation of protein content between the patient groups. Moreover, BC spectral cytology identified a low number of high-glycogen cells for which a shift of the carbohydrate/phosphate bands was also observed. Despite high cellular heterogeneity, PLS-DA was able to classify the spectra obtained. The voided urine FTIR cytology is one of the options that might be helpful in BC diagnosis, as high sensitivity and specificity up to 97% were determined.

Eligibility and Radiologic Assessment for Adjuvant Clinical Trials in Kidney Cancer

Purpose

To harmonize the eligibility criteria and radiologic disease assessment definitions in clinical trials of adjuvant therapy for renal cell carcinoma (RCC).

Method

On November 28, 2017, US-based experts in RCC clinical trials, including medical oncologists, urologic oncologists, regulators, biostatisticians, radiologists, and patient advocates, convened at a public workshop to discuss eligibility for trial entry and radiologic criteria for assessing disease recurrence in adjuvant trials in RCC. Multiple virtual meetings were conducted to address the issues identified at the workshop.

Results

The key workshop conclusions for adjuvant RCC therapy clinical trials were as follows. First, patients with non-clear cell RCC could be routinely included, preferably in an independent cohort. Second, patients with T3-4, N+M0, and microscopic R1 RCC tumors may gain the greatest advantages from adjuvant therapy. Third, trials of agents not excreted by the kidney should not exclude patients with severe renal insufficiency. Fourth, therapy can begin 4 to 16 weeks after the surgical procedure. Fifth, patients undergoing radical or partial nephrectomy should be equally eligible. Sixth, patients with microscopically positive soft tissue or vascular margins without gross residual or radiologic disease may be included in trials. Seventh, all suspicious regional lymph nodes should be fully resected. Eighth, computed tomography should be performed within 4 weeks before trial enrollment; for patients with renal insufficiency who cannot undergo computed tomography with contrast, noncontrast chest computed tomography and magnetic resonance imaging of the abdomen and pelvis with gadolinium should be performed. Ninth, when feasible, biopsy should be undertaken to identify any malignant disease. Tenth, when biopsy is not feasible, a uniform approach should be used to evaluate indeterminate radiologic findings to identify what constitutes no evidence of disease at trial entry and what constitutes radiologic evidence of disease. Eleventh, a uniform approach for establishing the date of recurrence should be included in any trial design. Twelfth, patient perspectives on the use of placebo, conditions for unblinding, and research biopsies should be considered carefully during the conduct of an adjuvant trial.

Conclusions and Relevance

The discussions suggested that a uniform approach to eligibility criteria and radiologic disease assessment will lead to more consistently interpretable trial results in the adjuvant RCC therapy setting.

Imaging of urachal anomalies

Urachal anomalies are classified into four types depending on the level of persistence of the embryonic urachal remnants between the urinary bladder and the umbilicus: patent urachus, umbilical-urachal sinus, urachal cyst, and vesico-urachal diverticulum. Due to the increasing use of cross-sectional imaging, urachal anomalies are frequently detected as incidental findings. Imaging plays a pivotal role in the initial diagnosis, evaluation of complications, treatment follow-up, and long-term surveillance of patients with urachal anomalies. Different urachal anomalies demonstrate characteristic imaging features that aid in a timely diagnosis and guide treatment. A patent urachus is visualized as an elongated tubular structure between the umbilicus and the urinary bladder. While umbilical-urachal sinus appears as focal dilatation at the umbilical end of the urachal remnant, the vesico-urachal diverticulum presents as a focal outpouching of the urinary bladder at anterosuperior aspect. Urachal cysts are identified as midline fluid-filled sacs most frequently located near the dome of the urinary bladder. Untreated urachal anomalies could progress into potential complications, including infection and malignancy. Knowledge regarding imaging features of urachal anomalies helps in timely diagnosis, treatment, follow-up, and early detection of complications.

Eligibility and Radiologic Assessment in Adjuvant Clinical Trials in Bladder Cancer

Objective

To harmonize eligibility criteria and radiographic disease assessments in clinical trials of adjuvant therapy for muscle-invasive bladder cancer (MIBC).

Methods

National experts in bladder cancer clinical trial research, including medical and urologic oncologists, radiologists, biostatisticians, and patient advocates, convened at a public workshop on November 28, 2017, to discuss eligibility, radiographic entry criteria, and assessment of disease recurrence in adjuvant clinical trials in patients with MIBC.

Results

The key workshop conclusions for adjuvant MIBC clinical trials included the following points: (1) patients with urothelial carcinoma with divergent histologic differentiation should be allowed to enroll; (2) neoadjuvant chemotherapy is defined as at least 3 cycles of neoadjuvant cisplatin-based combination chemotherapy; (3) patients with muscle-invasive, upper-tract urothelial carcinoma should be included in adjuvant trials of MIBC; (4) patients with severe renal insufficiency can enroll into trials using agents that are not renally excreted; (5) patients with microscopic surgical margins can be included; (6) patients should undergo a standard bilateral lymph node dissection prior to enrollment; (7) computed tomographic (CT) imaging should be performed within 4 weeks prior to enrollment. For patients with renal insufficiency who cannot undergo CT imaging with contrast, noncontrast chest CT and magnetic resonance imaging of the abdomen and pelvis with gadolinium should be done; (8) biopsy of indeterminate lesions to evaluate for malignant disease should be done when feasible; (9) a uniform approach to evaluate indeterminate radiographic lesions when biopsy is not feasible should be included in any trial design; (10) a uniform approach to determining the date of recurrence is important in interpreting adjuvant trial results; and (11) new high-grade, upper-tract primary tumors and new MIBC tumors should be considered recurrence events.

Conclusions and Relevance

A uniform approach to eligibility criteria, definitions of no evidence of disease, and definitions of disease recurrence may lead to more consistent interpretations of adjuvant trial results in MIBC.

Multimodality imaging of the male urethra: trauma, infection, neoplasm, and common surgical repairs

OBJECTIVE

The aim of this article is to describe the indications and proper technique for RUG and MRI, their respective image findings in various disease states, and the common surgical techniques and imaging strategies employed for stricture correction.

RESULTS

Because of its length and passage through numerous anatomic structures, the adult male urethra can undergo a wide array of acquired maladies, including traumatic injury, infection, and neoplasm. For the urologist, imaging plays a crucial role in the diagnosis of these conditions, as well as complications such as stricture and fistula formation. While retrograde urethrography (RUG) and voiding cystourethrography (VCUG) have traditionally been the cornerstone of urethral imaging, MRI has become a useful adjunct particularly for the staging of suspected urethral neoplasm, visualization of complex posterior urethral fistulas, and problem solving for indeterminate findings at RUG.

CONCLUSIONS

Familiarity with common urethral pathology, as well as its appearance on conventional urethrography and MRI, is crucial for the radiologist in order to guide the treating urologist in patient management.

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.