Open Access

Narrow band imaging (NBI) during medical thoracoscopy: first impressions

  • Nicolas Schönfeld1Email author,
  • Carsten Schwarz1,
  • Jens Kollmeier1,
  • Torsten Blum1,
  • Torsten T Bauer1 and
  • Sebastian Ott1
Journal of Occupational Medicine and Toxicology20094:24

DOI: 10.1186/1745-6673-4-24

Received: 5 July 2009

Accepted: 26 August 2009

Published: 26 August 2009

Abstract

Background

This is the first ever evaluation of narrow band imaging (NBI), an innovative endoscopic imaging procedure, for the visualisation of pleural processes.

Methods

The pleural cavity was examined in 26 patients with pleural effusions using both white light and narrow band imaging during thoracoscopy under local anaesthesia.

Results

In the great majority of the patients narrow band imaging depicted the blood vessels more clearly than white light, but failed to reveal any differences in number, shape or size. Only in a single case with pleura thickened by chronic inflammation and metastatic spread of lung cancer did narrow band imaging show vessels that were not detectable under white light.

Conclusion

It is not yet possible to assess to what extent the evidence provided by NBI is superior to that achieved with white light. Further studies are required, particularly in the early stages of pleural processes.

Thoracoscopy is the standard diagnostic procedure for investigating exudative pleural effusions and leads to a conclusive diagnosis for 95% of patients when carried out under local anaesthesia [1]. Thoracoscopy can also be employed for staging primary thoracic malignancies, i.e. malignant pleural mesotheliomas or primary malignant pulmonary tumours with possible pleural dissemination. Despite the high diagnostic yield of thoracoscopy under local anaesthesia, some patients still remain without a conclusive diagnosis or have to undergo a surgical procedure under general anaesthesia. Apart from the conventional white light, other imaging procedures that are said to yield more information, especially at to the presence of a pleural tumour, have already been investigated, but the evidence has remained limited [24].

Narrow band imaging (NBI) is a new, alternative light-wavelength capture system that takes advantage of altered blood vessel morphology. Wavelengths of light in the visible spectrum are filtered from the illumination source, with the exception of narrow bands in the blue and green spectrum centered at 415 nm and 540 nm, coinciding with the peak absorption spectrum of oxyhemoglobin, making blood vessels more pronounced when viewed in NBI mode [5]. We present the first ever results with NBI in a series of patients with pleural processes.

Methods

Medical thoracoscopy was performed under local anaesthesia and conscious sedation, using a prototype OLYMPUS XLTF-160 pleuravideoscope in single hole technique [6]. Following removal of the pleural fluid, the pleural cavity was inspected at first under white light and then under NBI as described elsewhere for bronchoscopy [5, 7]. Afterwards, biopsies were taken from macroscopically altered sites. We used the OLYMPUS EVIS EXERA II video system (CV-180 videoprocessor and CLV-180 light source) manufactured by Olympus Medical Systems Corp., Japan. The findings were analysed retrospectively.

Results

The results are summarised in Table 1. A total of 15 women (median age 66 years) and 11 men (median age 64 years) with pleural effusions were examined. Biopsies of the parietal pleura or diaphragm were taken for all but one of these patients. Only in patient #26 NBI showed more vessels than white light (fig. 1 and 2). In all other patients, there was either no difference, or blood vessels merely appeared more prominent (example in fig. 3 and 4).
Figure 1

Pleural cavity of patient #26 (lung cancer (adenocarcinoma), chronic inflammatory changes), white light.

Figure 2

Pleural cavity of patient #26, NBI.

Figure 3

Pleural cavity of patient #2 (small cell lung cancer, large polyps), white light.

Figure 4

Pleural cavity of patient #2, NBI.

Table 1

Results of thoracoscopy in all patients (n = 26)

Pat.

Gender

Age

Macroscopical findings

Histological diagnosis

1

female

81

chronic inflammation, pleural thickening (visceral and parietal)

chronic pleuritis (underlying disease: chronic renal failure)

2

male

74

multiple polyps (parietal)

small cell lung cancer

3

male

69

small nodes (parietal), adhesions

squamous-cell lung cancer

4

female

62

Adhesions, small nodes (parietal)

malignant mesothelioma

5

female

58

small confluent nodes (parietal)

breast cancer

6

male

59

pleural thickening (parietal)

lung cancer (adenocarcinoma)

7

female

81

large nodes (parietal and visceral), adhesions

malignant mesothelioma

8

male

47

large nodes (parietal), adhesions

malignant mesothelioma

9

female

65

small confluent nodes (parietal)

breast cancer

10

female

63

solitary node/polyp (parietal)

ovarian cancer

11

female

68

acute inflammation, adhesions, lymphangiectasis

breast cancer

12

male

64

small confluent nodes, polyps (parietal)

malignant mesothelioma

13

male

85

large nodes, polyps (parietal and visceral)

malignant mesothelioma

14

male

82

pleural plaques (parietal), adhesions

squamous-cell lung cancer

15

male

64

pleural plaques (parietal), small confluent nodes

malignant mesothelioma

16

female

88

multiple large nodes (parietal and visceral)

lung cancer (adenocarcinoma)

17

female

37

acute inflammation, adhesions, pleural thickening

tuberculous pleurisy

18

female

46

no abnormalities

inflammatory changes (underlying diease: squamous-cell lung cancer, effusion e vacuo)

19

female

63

subacute inflammation, pleural thickening

malignant mesothelioma

20

female

63

large nodes, polyps (parietal and visceral)

lung cancer (adenocarcinoma)

21

female

82

large confluent nodes, polyps (parietal and visceral)

malignant mesothelioma

22

male

64

multiple small nodes, polyps (parietal and visceral)

malignant mesothelioma

23

male

72

pleural thickening, solitary polyps

squamous-cell lung cancer

24

male

66

pleural thickening, adhesions

small cell lung cancer

25

female

80

large solitary nodes (parietal)

breast cancer

26

female

67

large solitary nodes (parietal) and chronic inflammatory changes

lung cancer (adenocarcinoma)

Discussion

Our first examinations of the pleural cavity with NBI have indicated that in cases with diffuse spread of malignant tumour no substantial improvement in diagnoses is to be expected. Whereas the blood vessels in the region of the tumour tissue that was already identifiable macroscopically were more clearly depicted, the number of changes rendered visible was no greater than with white light. This was also true for mesothelioma patients. In the two cases of non-specific pleuritis, in which the pleura did not appear to be essentially thickened, the visualisation of the blood vessels was similar under both white light and NBI.

As was to be expected, NBI also failed to demonstrate any blood vessels in the deeper layers of pleural plaques typical of asbestos-related disease. However, a different situation was found in a single patient with pleura showing chronic inflammatory changes, besides tumour polyps. In this case distinctly more deeper blood vessels were identifiable than under white light. To what extent this observation is indicative of an actual diagnostic advantage cannot, however, be ascertained on the basis of this initial series.

Other groups having used different procedures such as fluorescence techniques reported to have found more exact indications of spreading of malignant pleural mesotheliomas [3, 4]. However, the numbers of patients participating in these studies were so small that it has not as yet been possible to produce reliable evidence. It is possible that the same applies to NBI, in so far as in some cases mesotheliomas are associated with the development of a considerable amount of fibrotic tissue [8] and may thus not be identifiable histologically in biopsies taken under medical thoracoscopy. In such cases imaging of vascular structures in deeper layers of a thickened pleura could give some indication of from where the biopsy should best be taken. However, until considerably larger numbers of patients have been examined with NBI this remains speculation.

A second interesting question that could be investigated in future clinical studies with NBI in pleural processes is whether NBI were to be used intra-operatively to inspect the pleura before planned resection of lung cancer [9]. This would facilitate detection of any previously unobserved pleural dissemination at other locations. It is already common in surgery for small effusions associated with primary pulmonary malignomas to begin the operation under thoracoscopy and only to perform thoracotomy and continue with the resection if there are no signs of pleural dissemination. If possible, studies of this kind should not – as is so often done with innovative techniques – be carried out at only a single centre, but be performed as prospective, multicentre studies. It would thus be possible to arrive at a more objective assessment of such innovative techniques.

Abbreviations

NBI: 

narrow band imaging.

Declarations

Authors’ Affiliations

(1)
Lungenklinik Heckeshorn, HELIOS Klinikum Emil von Behring

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Copyright

© Schönfeld et al; licensee BioMed Central Ltd. 2009

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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