Narrow Band Imaging: Transforming the World of Endoscopy

04/11/2022

Narrow band imaging (NBI) is an advanced endoscopic imaging technique that employs green/blue wavelength light to vastly enhance visualization of mucosal structures and capillary patterns on the mucosal surface. The augmented imaging capacity of NBI enables specialists to diagnose and treat cancer more precisely and reliably. Since this technology can be harnessed for use in a number of anatomical settings, NBI represents a transformative tool that can improve the diagnostic capability of endoscopy throughout pre- intra- and postoperative stages.

While the patient benefits of NBI are clear, there is also a strong economic argument for its adoption by health care organizations (HCOs). With NBI being recommended in diagnostic regulatory guidelines worldwide 1 , this innovative technology is swiftly becoming the gold standard in endoscopic imaging.

Ear, Nose, Throat, Gastroenterology, Urology
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How does NBI work?

Unlike traditional white light imaging (WLI), which illuminates the mucosa with broad visible spectrum light, NBI technology utilizes specific wavelengths of blue (415 nm) and green (540 nm) light. Since these wavelengths fall within the peak absorption range of hemoglobin, this light is taken up by blood-containing tissues while reflecting off from surrounding mucosal tissue. This produces an image with striking contrast between the vasculature and mucosa. Because the light’s wavelength is directly proportional to the depth of its penetration, the blue light highlights the superficial mucosa while the green light penetrates deeper into the lower parts of the mucosa and submucosa. This makes for a far-improved visualization of the mucosal micro surface and microvascular patterns.

But how is improved visualization of blood vessels beneficial to endoscopy? In short, it makes for a far-improved diagnostic tool: Malignant mucosal lesions exhibit increased angiogenesis and therefore often present with a significantly increased number of blood vessels 2 . This is the primary feature that clinicians look for when performing an endoscopy, and with WLI it can be challenging to visualize these microvascular patterns. Therefore, detecting premalignant changes and/or malignant structures is challenging and such lesions can be missed with WLI alone. NBI overcomes this issue as the high-contrast visualization helps clinicians to identify mucosal lesions more easily and earlier on in their development. Not only does earlier detection leave greater scope and more options for treatment, it can also reduce recurrence of abnormal lesions such as dysplasia and cancer if an earlier diagnosis is made. It’s also very easy to switch between WLI and NBI as a filter located at the front of the endoscope lamp can be activated at the push of a button.

NBI and Patient Care

NBI is rapidly being adopted as a diagnostic tool, and this is supported by regulators including European Society for Gastrointestinal Endoscopy (ESGE), European Association of Urology (EAU) and European Laryngological Society (ELS) among others, who have integrated NBI into their diagnostic guidelines. Here we will look at the three clinical fields where NBI is making the greatest impact.

Gastroenterology
NBI technology has been adapted for gastroenterology, where NBI has proven to be a reliable tool for targeted biopsy in Barrett’s esophagus 3 , a condition that carries a high risk of developing into esophageal adenocarcinoma. When diagnosed at a late stage, prognosis is poor for patients with Barrett’s esophagus. With NBI, clinicians are able to identify neoplastic changes earlier to enable more treatment options and improved patient outcomes. Another esophageal disease, squamous cell carcinoma, is too being detected with greater reliability with the use on NBI 4 .  NBI is also aiding the assessment of colorectal lesions. With colorectal cancers, the detection and removal of polyps remains the most effective form of prevention, and using WLI these can often be missed 5 . NBI not only improves polyp detection rate, but the image quality also allows for highly accurate optical predictions of polyp histology – reducing the need for costly pathological analysis 6 .

Urology
NBI is reshaping urology diagnostics, where increased visualization of superficial structures is providing urologists with the best chance of obtaining optical diagnosis for non-muscle invasive bladder cancer (NMIBC) 7 and upper tract urinary cancer (UTUC) 8 . For example, whether used in initial screening or follow up procedures such as cystoscopy, the implementation of NBI is detecting NMIBC earlier and having a significant impact upon the reduction of recurrence
rates 9 .
In urology, NBI is proving useful beyond diagnosis: In the treatment of NMIBC, transurethral resection of bladder tumor is often required. With NBI, lesion limits can be visualized better, enabling the clinician to precisely mark and perform resection with visualization levels not previously possible.

Ear, Nose and Throat (ENT)
In ENT medicine, NBI can be used throughout a patient’s journey from diagnosis to follow-up procedures, and can be used in the operating room as well as during outpatient visits. NBI is suitable for numerous endoscopic procedures in ENT including as laryngoscopy, oral cavity examination, sinus surgery as well as for procedures in otology leading to the improved detection of carcinoma in situ and other diseases. In such settings, NBI’s advanced visualization allows for smaller margins, leaving less unwanted damage to healthy mucosa tissues, which is especially important when operating upon delicate structures like the vocal folds.
NBI allows ENT specialists to diagnose and treat early laryngeal cancer even more precisely and reliably 10 . With more early-stage detection coupled with more precise surgical excision of malignant lesions, it has been shown to significantly reduce recurrence rates.

NBI Benefits Patients and HCOs: Improving Outcomes while Reducing Costs

The benefits of NBI towards better patient outcomes is clear: Detecting malignant lesions earlier enables treatment options with better efficacy and improved patient prognosis. But this benefits not just the patient, but also the cost burden fronted by hospital organizations – if cancer is detected earlier, the cost of treatment can be reduced, e.g. if fewer rounds of chemotherapy or radiation treatment are required or if surgery can be avoided. NBI enables lower incidences of cancer recurrence, and this also cuts costs associated with multiple rounds of treatment.

Since fewer biopsies are required with NBI, the time of each endoscopy procedure will be reduced, plus overall fewer recurrent endoscopic procedures will be undertaken, also reducing costs. A reduction in the number of biopsies also reduces the workload within histology departments, and reduces costs associated with histological sample analysis. Overall, the versatility of NBI makes for a great cost-saving method for healthcare organizations (HCOs) due to less specialized equipment and expensive treatment plans being required. The graphic below shows an example of the cost per year of WLI versus NBI.

Summary

We have showcased how our NBI technology has revolutionized the world of endoscopy through improved diagnosis leading to better patient outcomes. This transformative technology has already been recognized by regulatory bodies such as NICE, and now with clear economic benefits of NBI becoming evident, it’s no wonder many healthcare providers are choosing Olympus NBI.

References

  1. 1.Non-muscle-invasive Bladder Cancer - Uroweb. [online] Uroweb - European Association of Urology. (2022).
  2. 2.The tumor microenvironment in esophageal cancer. Lin, E. W., Karakasheva, T. A., Hicks, P. D., Bass, A. J., & Rustgi, A. K. (2016). Oncogene, 35(41), 5337–5349.
  3. 3.Narrow-Band Imaging: Clinical Application in Gastrointestinal Endoscopy. Barbeiro, S., Libânio, D., Castro, R., Dinis-Ribeiro, M., & Pimentel-Nunes, P. (2018). Portuguese journal of gastroenterology, 26(1), 40–53.
  4. 4.Current Status of Mucosal Imaging with Narrow-Band Imaging in the Esophagus. Chiam, K. H., Shin, S. H., Choi, K. C., Leiria, F., Militz, M., & Singh, R. (2021). Gut and liver, 15(4), 492–499.
  5. 5.The role of narrow band imaging in colorectal polyp detection. Vișovan, I. I., Tanțău, M., Pascu, O., Ciobanu, L., & Tanțău, A. (2017). Bosnian journal of basic medical sciences, 17(2), 152–158.
  6. 6.Utility of the narrow-band imaging international colorectal endoscopic classification for optical diagnosis of colorectal polyp histology in clinical practice: a retrospective study. Hamada, Y., Tanaka, K., Katsurahara, M., Horiki, N., Yamada, R., Yamada, T., & Takei, Y. (2021). BMC gastroenterology, 21(1), 336.
  7. 7.Diagnosis of narrow-band imaging in non-muscle-invasive bladder cancer: a systematic review and meta-analysis. Li, K., Lin, T., Fan, X., Duan, Y., & Huang, J. (2013). International journal of urology 20(6), 602–609.
  8. 8.Narrow-band imaging digital flexible ureteroscopy in detection of upper urinary tract transitional-cell carcinoma: initial experience. Traxer, O., Geavlete, B., de Medina, S. G., Sibony, M., & Al-Qahtani, S. M. (2011). Journal of endourology, 25(1), 19–23
  9. 9.Narrow band imaging-assisted transurethral resection reduces the recurrence risk of non-muscle invasive bladder cancer: A systematic review and meta-analysis. Kang, W., Cui, Z., Chen, Q., Zhang, D., Zhang, H., & Jin, X. (2017). Oncotarget, 8(14), 23880–23890.
  10. 10.The Impact of Narrow-band Imaging on the Pre- and Intra- operative Assessments of Neoplastic and Preneoplastic Laryngeal Lesions. A Systematic Review. Saraniti, C., Chianetta, E., Greco, G., Mat Lazim, N., & Verro, B. (2021). International archives of otorhinolaryngology, 25(3), e471–e478.

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