Chest
Volume 147, Issue 5, May 2015, Pages 1395-1400
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Original Research: Disorders of the Pleura
A Pilot Study of Autofluorescence in the Diagnosis of Pleural Disease

https://doi.org/10.1378/chest.14-1351Get rights and content

BACKGROUND

Conventional medical thoracoscopy (MT), routinely performed in patients with pleural disease, does not always lead to a conclusive diagnosis. The endoscopic appearance of pleural diseases under white light could be misleading. Autofluorescence has been shown to be an interesting and effective diagnostic tool. The objective of this study was to evaluate the diagnostic value of autofluorescence imaging during MT.

METHODS

Patients with undiagnosed pleural effusion admitted to our clinical center between August 2013 and February 2014 were enrolled. MT was performed first with white light and then by autofluorescence. Endoscopic results of different diseases were recorded, and biopsy specimens were obtained for pathologic analysis. We calculated the diagnostic sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the two methods by comparing them with the pathologic results.

RESULTS

Thirty-seven eligible patients were studied, including 21 with malignancy, nine with tuberculous pleurisy, three with infective pleurisy, and four with no diagnosed condition. Autofluorescence revealed additional malignant lesions, which were missed under white light in five patients. The diagnostic sensitivity and NPV of autofluorescence were 100% (95% CI, 98.5%-100%) and 100% (95% CI, 93.9%-100%), respectively. Autofluorescence was superior to white light, with a sensitivity of 92.8% (95% CI, 89.3%-95.3%) and NPV of 76.8% (95% CI, 67.0%-84.4%). For the specificity and PPV, no significant difference was found.

CONCLUSIONS

The advantage of autofluorescence is its high sensitivity and NPV. It is useful to detect microlesions and delineate the pathologic margins. Autofluorescence can benefit patients with its better visualization.

Section snippets

Patients

Eligible patients presented with an undiagnosed exudative pleural effusion after at least one thoracocentesis and were admitted to Beijing Chaoyang Hospital between August 2013 and February 2014. Patient age ranged from 18 to 90 years. Patients with multiple pleural adhesions, transudatory pleural effusions, respiratory failure, coagulation disorders, anesthetic allergy, pregnancy, or any other MT contraindications were excluded. All patients received thoracic ultrasonography, chest CT scans,

Equipment

The AFI videobronchoscope BF-F260 (the AFI system) was used as the fluorescence method during MT, whereas the flexirigid medical thoracoscope Olympus LTF-240 was used as a means of conventional white light mode control. The AFI system consists of three parts: an autofluorescence endoscope (BF-F260), a videoprocessor unit (EVIS LUCERA SPECTRUM [CV-260SL]; Olympus), and a xenon light source. An integrated filter enabled the selection of white light and excitation from the xenon light. The

Thoracoscopic Procedure

MT was performed in an endoscopy suite. For minimizing the visual bias, each procedure was completed by two pulmonologists working together. The patients were positioned on the nonaffected side, and a sterile field was prepared. The patients were given local anesthesia, staying conscious during the procedure. An entrance trocar was inserted into the thoracic cavity for inspection. After evacuating pleural effusions, the pleural cavity was first thoroughly inspected by conventional thoracoscope

Outcome Evaluation

The specimens were categorized as AFI positive or negative and WLT positive or negative. The pathologist was blinded to the categorization and assessed each specimen separately. The pathologic reports were classified as malignancy, TB, infection, nonspecific inflammation, and normal. In this study, true positive was defined as abnormal endoscopic findings along with pathologic examination identifying as malignancy, TB, or infection. False positive was defined as abnormal endoscopic findings

Results

Thirty-seven patients aged 22 to 85 years with undiagnosed exudative pleural effusions were enrolled, including 17 men and 20 women. Twenty patients had right-sided effusions, 16 had left-sided effusions, and one had bilateral effusions. Thirty-three patients received diagnoses, including 21 with malignancy, nine with tuberculous pleurisy, and three with infective pleurisy. Four patients did not receive a diagnosis because their pleural biopsy specimens indicated nonspecific inflammatory

Complications

No severe complications occurred in any patients studied. Minor postoperative complications included localized pain in two of the 37 patients (5.4%) and subcutaneous emphysema in another two patients (5.4%). No complication from the autofluorescence occurred. Furthermore, 5 to 10 min were required for additional fluorescence examination. This method proved to be as safe as the conventional thoracoscopy.

Discussion

Application of fluorescence in the diagnosis of pleural diseases was first reported in 2002 by Prosst et al,4 who developed an animal pleural carcinosis model of human adenocarcinoma and measured photosensitizer (5-aminolevulinic acid [5-ALA]) accumulations in the tumor by applying indirect spectrometry; it was 11 times higher than the normal tissues. Fluorescence detected 30% more pleural malignant lesions than conventional thoracoscopy. Another group showed similar findings in a pig model,5

Conclusions

To our knowledge, we are the first group to report on the application of the autofluorescence diagnostic method during MT. The advantages of autofluorescence lie in its extremely high sensitivity and NPV. Autofluorescence combined with white light is helpful in identifying microlesions and delineating pathologic margins. AFI also contributes to the precise staging of advanced lung cancer with pleural effusions. For patients with AFI-negative results, physicians should be careful when evaluating

Acknowledgments

Author contributions: F. W. and Z. T. had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data collection and analysis. F. W. and Z. W. contributed to the data collection and analysis; F. W., Z. W., L. X., X. W., and Y. W. contributed to the MT procedure; F. W. contributed to the writing of the manuscript; Z. W. and Z. T. contributed to the review and editing of the manuscript; and L. X., X. W., and Y. W. contributed to

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Dr F. Wang is currently at the Department of Respiratory Medicine, Fuxing Hospital, Capital Medical University, Beijing, China.

Drs F. Wang and Z. Wang contributed equally to this manuscript.

FUNDING/SUPPORT: This study was supported by Beijing Municipal Science & Technology Commission [No. Z131107002213107].

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.

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