Recent advances in three-dimensional ultrasound virtual cystoscopy in modeling and local staging for urothelial carcinoma with histopathological correlation: a cohort prospective study.

Background: Bladder urothelial carcinoma is an alarming urologic malignancy. Complex factors like modelling and local staging can affect treatment strategy. However, local staging, particularly the muscle invasion status, significantly influences decisions regarding treatment strategies. Therefore, this study aims to evaluate the novel advances of three-dimensional (3D) ultrasound (US) imaging to assess local staging in comparison with conventional cystoscopy. Methods: Forty-three patients with painless haematuria and conventional cystoscopy findings of bladder mass underwent 3D US virtual cystoscopy. All specimens from conventional cystoscopy were processed histologically. Results: Out of 43 participants, 18 (41.9%) patients proved to have invasive urothelial carcinoma by histopathology. The 3D US had a sensitivity of 97.5% and a specificity of 100%; however conventional cystoscopy was accurate in only 53.5% of the studied cases. Furthermore, in the case of malignant ulcers, mural extension into both the submucosal and the muscle layers was more readily appreciated in multiplanar images. Conclusion: 3D US updates are promising for use in bladder tumour modelling and local staging; however, they can be of value in evaluating mural and extramural tumour extent and have proven accuracy.

Biometric and morphological features on magnetic resonance imaging of fetal bladder in lower urinary tract obstruction: new perspectives for fetal cystoscopy.

OBJECTIVES: Incompatibility between currently available fetoscopes and the anatomical constraints of the distended fetal bladder, with the resulting curvature around the bladder neck, account for most technical difficulties during fetal cystoscopy in lower urinary tract obstruction (LUTO). The aim of this anatomical study was to assess by magnetic resonance imaging (MRI) the variation in three bladder angles (bladder-neck angle (BNA), vesicourethral angle (VUA) and angle between bladder dome and posterior urethra (DUA)), according to gestational age (GA), bladder volume and the presence of LUTO. METHODS: From our fetal medicine database, we retrieved for review 46 MRI examinations of male fetuses between 2015 and 2019, including 17 with LUTO, examined at a mean GA of 28.1 (range, 17.3-35.0) weeks and 29 age-matched controls, examined at 29.9 (range, 21.9-35.0) weeks. We measured bladder volume, bladder-wall thickness and the three bladder angles, and used the Mann-Whitney U-test to compare values between groups. Variations according to GA and bladder volume were determined using analysis of variance (ANOVA). A reliability study was performed using the Bland-Altman method and Lin's correlation coefficient was calculated. RESULTS: Both bladder volume and bladder-wall thickness were significantly greater in the LUTO group (P < 0.01). BNA was significantly larger in LUTO compared with control fetuses: the mean (range) was 127.1° (101.6-161.6°) vs 111.2° (88.5-157.3°) (P < 0.01). DUA averaged 117° and showed no difference between the groups (P = 0.92). No statistical comparison was performed on VUA since this was not measurable in most control fetuses. ANOVA showed no variation of any angle with bladder volume in both LUTO fetuses and control fetuses. BNA in LUTO fetuses was the only angle to vary with GA, being larger after, compared with at or before, 25 weeks (P = 0.04). The reliability study showed an acceptable bias for both intra- and interobserver reproducibility for all three angles. CONCLUSION: The findings that BNA is increased by approximately 15° in fetuses with LUTO and DUA averages 117° could aid in development of a customized fetal cystoscope and help to overcome the current technical challenges of fetal cystoscopy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Three-Dimensional Virtual Sonographic Cystoscopy for Detection of Ureterocele in Duplicated Collecting Systems in Children.

OBJECTIVES: Ureterocele is a sac-like dilatation of terminal ureter. Precise anatomic delineation is of utmost importance to proceed with the surgical plan, particularly in the ectopic subtype. However, the level of ureterocele extension is not always elucidated by the existing imaging modalities and even by conventional cystoscopy, which is considered as the gold standard for evaluation of ureterocele. This study aims to evaluate the accuracy of three-dimensional virtual sonographic cystoscopy (VSC) in the characterization of ureterocele in duplex collecting systems. METHODS: Sixteen children with a mean age of 5.1 (standard deviation 1.96) years with transabdominal ultrasonography-proven duplex system and ureterocele were included. They underwent VSC by a single pediatric radiologist. All of them subsequently had conventional cystoscopy, and the results were compared in terms of ureterocele features including anatomy, number, size, location, and extension. RESULTS: Three-dimensional VSC was well tolerated in all cases without any complication. Image quality was suboptimal in 2 of 16 patients. Out of the remaining 14 cases, VSC had a high accuracy in characterization of the ureterocele features (93%). Only the extension of one ureterocele was not precisely detected by VSC. CONCLUSIONS: The results of this study suggest three-dimensional sonography as a promising noninvasive diagnostic modality in the evaluation of ectopic ureterocele in children.

Computed tomography virtual cystoscopy for follow-up of patients with superficial bladder tumours in comparison to conventional cystoscopy: An exploratory study.

OBJECTIVE: To evaluate and analyse the efficacy of computed tomography (CT) virtual cystoscopy in comparison to conventional cystoscopy for the follow-up of patients with non-muscle-invasive bladder cancer. PATIENTS AND METHODS: The study was done over 3 years, from April 2010 to June 2013, and included 30 patients who all had non-muscle-invasive transitional cell carcinoma (Ta, T1). The patients all underwent complete transurethral resection of the tumour and presented for first follow-up check cystoscopy. The examination was performed using a 16-slice multi-detector (MD) CT scanner. The results were compared for sensitivity and specificity in relation to the site, size, and shape of the tumour. RESULTS: In all, 20 lesions were detected by CT virtual cystoscopy in 18 patients, whilst the remaining 12 were lesion free. Conventional cystoscopy, detected 23 lesions in 19 patients. The sensitivity of the virtual images was 87%; its specificity in identifying lesions was 100%, with a positive predictive value of 100% and negative predictive value of 78.5%. CONCLUSION: CT virtual cystoscopy is a promising technique for detecting bladder tumours and some other bladder lesions. However, the detection rate for recurrent NMIBC does not appear to be adequate to replace conventional cystoscopy.

3D detection and extraction of bladder tumors via MR virtual cystoscopy.

PURPOSE: This paper proposes a pipeline for the detection and extraction of 3D regions of bladder tumors via MR virtual cystoscopy. METHODS: After the acquisition of volumetric bladder images with a high-resolution T2-weighted 3D sequence, the inner and outer surfaces of the bladder wall were segmented simultaneously by a coupled directional level-set method. Based on the Laplacian method, a potential field was built up between two surfaces so that the thickness of each voxel within the bladder wall was estimated. To detect bladder abnormalities, four volume-based morphological features, including bent rate, shape index, wall thickness, and a novel morphological feature, which reflects bent rate difference between the inner and outer surfaces, were extracted. The combination of these four features was used to detect seeds on the inner surface by using selected filtering criterion. Then all points on streamlines started from detected seeds formed 3D candidate regions. Finally the fuzzy c-means clustering with spatial information (sFCM) was used to extract tumors from surrounding bladder wall tissues in candidate regions. RESULTS: The proposed pipeline was evaluated by a database of MR bladder images acquired from ten patients with bladder cancer. To find an optimal feature combination for tumor detection, the performance of different combinations of these features was evaluated with different filtering criteria. With the combination of all four features, the computer-aided detection pipeline shows a high performance of 100 % sensitivity with 2.3 FPs/case. Comparing with tumor regions delineated by radiological experts, the average overlap ratio of tumor regions extracted by sFCM is 86.3 %. CONCLUSIONS: The experimental result demonstrates the feasibility of the proposed pipeline on the detection and extraction of bladder tumors. It may provide an effective way to achieve the goal of evaluating the whole bladder for tumor detection and local staging.

A unified EM approach to bladder wall segmentation with coupled level-set constraints.

Magnetic resonance (MR) imaging-based virtual cystoscopy (VCys), as a non-invasive, safe and cost-effective technique, has shown its promising virtue for early diagnosis and recurrence management of bladder carcinoma. One primary goal of VCys is to identify bladder lesions with abnormal bladder wall thickness, and consequently a precise segmentation of the inner and outer borders of the wall is required. In this paper, we propose a unified expectation-maximization (EM) approach to the maximum-a posteriori (MAP) solution of bladder wall segmentation, by integrating a novel adaptive Markov random field (AMRF) model and the coupled level-set (CLS) information into the prior term. The proposed approach is applied to the segmentation of T(1)-weighted MR images, where the wall is enhanced while the urine and surrounding soft tissues are suppressed. By introducing scale-adaptive neighborhoods as well as adaptive weights into the conventional MRF model, the AMRF model takes into account the local information more accurately. In order to mitigate the influence of image artifacts adjacent to the bladder wall and to preserve the continuity of the wall surface, we apply geometrical constraints on the wall using our previously developed CLS method. This paper not only evaluates the robustness of the presented approach against the known ground truth of simulated digital phantoms, but further compares its performance with our previous CLS approach via both volunteer and patient studies. Statistical analysis on experts' scores of the segmented borders from both approaches demonstrates that our new scheme is more effective in extracting the bladder wall. Based on the wall thickness calibrated from the segmented single-layer borders, a three-dimensional virtual bladder model can be constructed and the wall thickness can be mapped onto the model, where the bladder lesions will be eventually detected via experts' visualization and/or computer-aided detection.

Computed tomography-virtual cystoscopy in the evaluation of a bladder mass: Could it replace standard conventional cystoscopy?

OBJECTIVE: To determine the role of computed tomography-virtual cystoscopy (CT-VC) in the detection and evaluation of bladder cancer, compared to standard conventional cystoscopy (CC). PATIENTS AND METHODS: Twenty-five patients with a clinical presentation of a bladder mass(es) were selected from an outpatient urology clinic between May 2011 and August 2012. All patients were then assessed using multi-slice CT of the bladder, CT-VC and CC. The results were then compared amongst axial CT images, multiplanar reconstruction (MPR) images, CT-VC and CC, and compared with the pathological results. RESULTS: Forty lesions were found at CC in the 25 patients. MPR images had a greater sensitivity for detecting small masses of ⩽5 mm, and for identifying the location of the masses, especially basal (100%), than had axial images. The diagnostic results varied significantly (P = 0.031 and 0.039) between CC and axial images. The difference was slightly significant (P = 0.063) for MPR images and was not significant (P = 0.99) for virtual images. CONCLUSIONS: Compared to CC, CT-VC was much less invasive, but it was not possible to take a biopsy and provide tissue for histopathology, and it could not depict flat lesions or mucosal colour changes. Therefore, CT-VC could be considered for bladder mapping before CC, in the follow-up of patients with superficial transitional cell carcinoma after transurethral resection of the tumour, in combination with urine cytology, and for patients in whom CC is difficult or contraindicated.

Virtual cystoscopy (pneumo-cystoscopy)-Its utility in the prospective evaluation of bladder tumor.

AIM: To evaluate the role of virtual cystoscopy (VC) comparing it with cystopanendoscopy (CPE) for detecting bladder tumor(s). MATERIAL AND METHODS: Ethical clearance was obtained from the Institutional ethics committee. After an informed consent 30 patients fulfilling the inclusion criteria were enrolled in the prospective non-randomized clinical study and were evaluated as per protocol with VC performed by a qualified radiologist who was blinded to the findings of CPE performed by a qualified urologist. The results so obtained were analyzed using appropriate statistical tools. RESULTS: The mean age of the patients was 56 years. Sensitivity of VC in detecting bladder lesions was 92%. However, when axial images were also interpreted along with VC, the sensitivity increased to 96% for detecting bladder lesions. The specificity of VC with axial CT was 40% in respect of detecting bladder lesions. VC with axial CT was 85.7% sensitive in identifying multiple bladder tumors. There were no complications on account of performing VC. Minor problems were encountered with VC and CPE in 16.7% and 13.3% patients respectively. CONCLUSIONS: VC with axial CT is 96% sensitive in detecting bladder lesions and 85.7% sensitive in detecting the multiplicity of the tumors. VC may be a useful complementary diagnostic tool for the workup of select patients with suspected bladder lesions. However, larger randomized controlled studies are needed to better define the precise clinical and diagnostic role of VC in routine practice. SETTINGS AND DESIGN: Prospective Clinical Comparative Non Randomized Clinical Study.

A Review on Virtual Cystoscopy Techniques / 中国医学物理学杂志

Objective: Bladder cancer is the ninth cause of cancer deaths and has high recurrence rate after resection of the tumors. Cystoscopy is the current most accurate method for investigating the bladder abnormalities. However, it is expensive, uncomfortable and invasive. It is possible to induce bleeding, urinary-tract infection and even puncture of bladder. Advances in medical imaging and computer technologies make virtual cystoscopy a potential alternative. Methods: Computed tomography (CT) and magnetic resonance imaging (MR/) are the preferred imaging modalities for virtual cystoseopy to get clear structural images or (and) functional images of the bladder. The boundary of bladder is segmented manually or automatically, and then the bladder is reconstructed and displayed by surface rendering. Useful features are extracted from the images and expressed o nthe reconstructed bladder to provide more valuable diagnosis information for doctors. Results: Comparing with conventional cystuscopy, virtual cystuscopy is noninvasive, more convenient, flexible and can provide more useful diagnosis information as well. Conclusions: Virtual cystoscopy is a promising method of detection and reexamination of bladder cancer. So far, more researches are needed for the virtual cystoscopy before clinical application. It clinical and commercial value are under investigation.