Narrow-band Imaging and Digital Flexible Ureteroscopy in the Detection of UUT-TCC
‘charge-coupled’ in its name. One row of information is transferred to the read-out register and the rows behind it are each shifted one row closer to the register. After being ‘read out’, the charge is released and the register is empty again for the next charge.
Narrow-band Imaging – A New Function Use in Upper Urinary Tract Transitional Cell Carcinoma Olympus has incorporated a new function for detecting suspicious tissue in the urinary tract: the FWL system. This is an alternative light-wavelength capture system that takes advantage of the altered blood vessel morphology of the urothelial mucosa.
NBI has created a promising technique for making an accurate observation of small tumours as well as establishing their exact limits, which are closely related to their vascularisation. These advances in tumour detection may have a substantial influence on conservative treatment of UUT-TCC, helping the urologist to perform a more complete vaporisation of small lesions that are not clearly visible with white light.
How it Works
NBI is an optical image enhancement technology that narrows the band width of the light output of the Olympus Exera II system to two bands: 415nm and 540nm. These narrow bands of light are strongly absorbed by haemoglobin and only penetrate the tissue surface, increasing the visibility of capillaries and other delicate tissue surface structures by enhancing the contrast between the two. As a result, under NBI, capillaries on the surface are displayed in brown and veins in the sub-surface are displayed in cyan on the operating monitor (see Figure 2).
This technology was recently compared with flexible cystoscopy in the detection of recurrent urothelial tumours of the bladder.2–4 The authors concluded that NBI has the potential to enhance the detection of recurrent urothelial tumours (p=0.01).
Herr and Donat showed that in 103 patients with tumour recurrences, 87% were detected by both white-light and NBI and another 17% only by NBI cystoscopy.2
NBI detected extra-papillary tumours or more
extensive carcinoma in situ in 56% of the patients found to have recurrences. The study by Bryan et al. produced similar results.3
Incorporation in Video-URS
Olympus now incorporates this NBI function in the video-URS. Today, no clinical data are available concerning NBI detection of UUT-TCC, but is expected to be useful in the diagnosis of early urothelial carcinoma and other hard-to-detect lesions, such as carcinoma in situ (see Figure 3). Figure 4 represents a comparative view of the NBI system and Hexvix system in the same patient. Between 2008 and 2009 Tenon University Hospital evaluated the NBI system in conjunction with the new URF-V for the conservative management of UUT-TCC. An endoscopic effect called ‘frog’s eggs effect’ (see Figure 5) was described. This effect was only obtained with urothelial tumour (due to capillaries into the tumour) and not with irritation of the urothelium, for example in relation with a JJ stent.
Tenon University Hospital Experience
Tenon University Hospital recently published its initial experience at the World Congress of Endourology in Munich, 2009. Between June 2008 and January 2009, NBI and white light scans using the new URF-V
EUROPEAN UROLOGICAL REVIEW
To the author’s knowledge, this is the first evaluation on NBI for UUT-TCC. NBI technology allowed the practitioners to diagnose and clearly visualise UUT-TCC and to identify the extended tumour limits.
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A: Endoscopic view with optical fibres flexible ureteroscope (Moiré effect); B: Endoscopic view with the new Olympus URF-V flexible ureteroscope.
Figure 2: Normal Urothelium AB
Figure 1: Comparative View (Same Patient with Calcium Oxalate Dehydrate Stone)
AB
A: Endoscopic view with white-light cystoscopy; B: Narrow-band imaging cystoscopy.
Olympus digital flexible ureteroscope were performed in 27 patients (20 male and seven female, with a mean age of 61). Fourteen patients (group one) were previously diagnosed and treated conservatively for UUT-TCC and underwent NBI as part of their follow-up. The 13 patients in group two underwent this practice to establish their diagnosis. Indications for procedures in this study were the following:
• UUT-TCC in 51.8%; • radiological abnormality of the upper urinary tract in 33.4%; and • haematuria in 14.8%.
Endoscopic Technique
The first stage consisted of careful full examination of the renal collecting system using URF-V in white-light mode, resulting in a map of the suspicious lesions. This was followed by NBI, which described a specific map of all distinctive lesions.
An abnormal appearance under NBI mode was defined as any area discordant in appearance versus white-light mode by either blood vessel concentration or appearance. Biopsies were taken from all the lesions detected by white light and even those lesions only visible by NBI. The biopsies were then sent to be interpreted by a dedicated pathologist blinded to all clinical information except the anatomic location of specimen. Holmium laser vaporisation was performed for all visible lesions by white-light or NBI mode.
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