Indian Journal of Urology
: 2009  |  Volume : 25  |  Issue : 4  |  Page : 560--561

Fibered confocal microscopy: A novel adjunct to improvise cystoscopy

Ankush Gupta, Apul Goel, Bhupendra P Singh 
 Department of Urology, King George Medical University, Lucknow 226 003, Uttar Pradesh, India

Correspondence Address:
Apul Goel
Department of Urology, King George Medical University, Lucknow 226 003, Uttar Pradesh

How to cite this article:
Gupta A, Goel A, Singh BP. Fibered confocal microscopy: A novel adjunct to improvise cystoscopy.Indian J Urol 2009;25:560-561

How to cite this URL:
Gupta A, Goel A, Singh BP. Fibered confocal microscopy: A novel adjunct to improvise cystoscopy. Indian J Urol [serial online] 2009 [cited 2021 Nov 30 ];25:560-561
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In this experimental study, the authors have applied the principles of confocal microscopy in assessing bladder tumors ex vivo. The bladders of 4 patients were examined in the laboratory immediately after cystectomy. The contrast applied was 0.05% fluorescein sodium, either directly by spraying over the suspicious areas in an opened bladder or instilled via a Foley catheter in intact bladders. The contact time for contrast was 5 minutes followed by washout with phosphate buffered saline. Both normal and suspicious regions of the bladder mucosa were imaged with Cellvizio® fibered confocal microscope (Mauna Kea Technologies, Paris, France). The images produced were 60 µm deep, with a lateral resolution of 1 µm and a field of view of 240 µm in diameter. The specimens were then subjected to routine hematoxylin and eosin staining for histopathologic examination. The images of confocal microscopy were evaluated against the histopathology sections. Pathologically, 2 patients had high-grade invasive transitional cell carcinoma, 1 patient had high-grade invasive primary bladder adenocarcinoma, and another patient had multifocal CIS. The confocal microscopy images were able to differentiate between normal bladder mucosa and malignant urothelial changes. The difference was noted primarily in the cellular architecture patterns and vascular density. [1]


Cystoscopy is limited by its inability to detect the presence of carcinoma in situ (CIS), assess the depth of invasion, grade of lesion, etc. Several technological advances have been made to improve upon the acquisition of this information such as optical coherence tomography for intravesical real-time imaging and staging of bladder cancer. [2] Fibered confocal microscopy is another adjunctive development to augment the conventional cystoscopy. The principles of confocal microscopy were laid down by Marvin Minsky in 1957. In a conventional fluorescence microscopy, the entire specimen is flooded with incident light. All parts of the specimen in the optical path are excited and the fluorescence is detected by an appropriate camera or detection device. The basic concept behind confocal imaging is the use of point illumination by lasers and a pinhole detector to eliminate out-of-focus information. [3] Only the light within the focal plane is detected, which furnishes better quality of images as compared with conventional fluorescence microscopy. Further technological advances and miniaturization have enabled the use of fibered confocal microscope along with flexible endoscopes and cystscopes. Clinically, it has been used in the evaluation of various eye diseases and is particularly useful for imaging, qualitative analysis, and quantification of endothelial cells of the cornea. [4] Preliminary studies in gastrointestinal endoscopy and bronchoscopy also have been encouraging and the images obtained have shown excellent correlation with histopathologic sections. [5] The application of confocal microscopy to the urinary tract has been previously employed in vivo only in rat bladders. This is the first report of its use in a human urinary bladder. Similar to the differences noted in gastrointestinal endoscopy, variations were noted in the normal and malignant bladder mucosa, which was confirmed on histopathology. Currently, there are no recommendations for image interpretation. There are some pitfalls of the technology such as the need for the probe to be in direct contact with the mucosal surface, which precludes scanning of the entire bladder. Furthermore, the limited depth of penetration is insufficient for determining the muscle invasive nature of malignant disease, a major factor for further therapeutic management. Since the images closely correlate with histopathological sections, it will require considerable experience for a urologist to reliably interpret them. Currently, the staining of tissue has been done with fluorescein sodium applied topically. The development of intravenous fluorescent molecular contrasts with high specificity for colonic epithelium has been reported. Similar markers of urothelium can further improvise detection and diagnosis. An in vivo application to bladders is likely to produce better results of fluorescent imaging due to intact vascular supply, which had been eliminated in this ex vivo study. This technology, after further refinements, may be helpful in obtaining an optical biopsy, which means real time histopathologic information of a bladder pathology. Though in its infancy, the technology appears to be a promising adjunct to conventional cystoscopy and other novel imaging techniques for urothelial assessment.


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