Fluorescence investigations to classify malignant laryngeal lesions in vivo

Discrimination of vocal folds lesions by multiclass classification using autofluorescence spectroscopy: An ex vivo study

BACKGROUND

Autofluorescence spectroscopy is effective for noninvasive detection but underutilized in tissue with various pathology analyses. This study evaluates whether AFS can be used to discriminate between different types of laryngeal lesions in view of assisting in vocal fold surgery and preoperative investigations.

METHODS

A total of 1308 spectra were recorded from 29 vocal fold samples obtained from 23 patients. Multiclass analysis was performed on the spectral data, categorizing lesions into normal, benign, dysplastic, or carcinoma.

RESULTS

Through an appropriate selection of spectral components and a cascading classification approach based on artificial neural networks, a classification rate of 97% was achieved for each lesion class, compared to 52% using autofluorescence intensity.

CONCLUSIONS

The ex vivo study demonstrates the effectiveness of AFS combined with multivariate analysis for accurate classification of vocal fold lesions. Comprehensive analysis of spectral data significantly improves classification accuracy, such as distinguishing malignant from precancerous or benign lesions.

Diagnostic value of autofluorescence laryngoscope in early laryngeal carcinoma and precancerous lesions: A systematic review and meta-analysis

OBJECTIVE

We aim to evaluate the diagnostic value of autofluorescence laryngoscope (AFL) in early laryngeal carcinoma and precancerous lesions. aWe also assess the value of AFL in diagnosis of early laryngeal carcinoma and precancerous lesions in comparison with that of white light laryngoscope (WL).

METHODS

The databases consisting of PubMed, Cochrane Library, Web of science and CNKI were systematically searched to find pertinent literatures of AFL in diagnosing early laryngeal carcinoma and precancerous lesions. We made a quality evaluation of every study we included using the modified Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). The pooled sensitivities, specificities were calculated using Meta-Disc 1.4. And we estimated the summary receiver operating characteristic curves (SROC) and area under the curves (AUC).

RESULTS

We finally included 23 studies. The results of AFL in diagnosing early laryngeal carcinoma and precancerous lesions showed higher sensitivity of 0.91 (95%CI: 0.89-0.93; χ²=43.78, p = 0.0025) and specificity of 0.80 (95%CI: 0.77-0.82; χ²=130.64, p = 0.000), and the weighted AUC of AFL was 0.948 ± 0.013 (95%CI: 0.921-0.974) and the diagnostic accuracy (Q*) was 0.887 ± 0.018. The sensitivity and specificity of WL were 0.74 (95%CI: 0.70-0.77; χ²=52.40, p = 0.000) and 0.89 (95%CI: 0.87-0.90; χ²=299.22, p = 0.000), and the weighted AUC of WL was 0.835 ± 0.029 (95%CI: 0.777-0.892) and the diagnostic accuracy (Q*) was 0.767 ± 0.027.

CONCLUSION

The meta-analysis and systematic review suggested that AFL had high diagnostic value in early laryngeal carcinoma and precancerous lesions, and its diagnostic value was higher than that of WL. These results indicated that AFL can provide good guidance for the early detection of laryngeal carcinoma and precancerous lesions.

[Advances in endoscopic diagnosis of dysplasia and carcinoma of the larynx]

To improve the preoperative and intraoperative diagnosis of laryngeal cancer and its precursors, various endoscopic imaging techniques have been developed in recent years. These techniques differ markedly in their specific applications and goals. Precisely distinguishing among normal mucosa, dysplasia and invasive carcinoma with these procedures is necessary. Furthermore, the exact identification of tumor margins should be possible. The long-term goal is the development of optical biopsy. Since so far there have only been small studies regarding the evaluation of the presented methods, it is necessary to establish multi-center trials with large sample sizes to accurately estimate the value of these endoscopic imaging techniques.

Fluorescence lifetime techniques in medical applications

This article presents an overview of time-resolved (lifetime) fluorescence techniques used in biomedical diagnostics. In particular, we review the development of time-resolved fluorescence spectroscopy (TRFS) and fluorescence lifetime imaging (FLIM) instrumentation and associated methodologies which allow in vivo characterization and diagnosis of biological tissues. Emphasis is placed on the translational research potential of these techniques and on evaluating whether intrinsic fluorescence signals provide useful contrast for the diagnosis of human diseases including cancer (gastrointestinal tract, lung, head and neck, and brain), skin and eye diseases, and atherosclerotic cardiovascular disease.

Fluorescence spectroscopy measurements in ultrasonic navigated resection of malignant brain tumors

BACKGROUND AND OBJECTIVE

Glioblastoma multiforme is a highly malignant primary brain tumor. It has no border but at best a marginal zone, however, invisible to the surgeon. An optical touch pointer (OTP) enabling differentiation of healthy and tumor tissue by means of fiber-optic fluorescence spectroscopy has been developed. In combination with an ultrasonic navigation system, the OTP may be used for demarcation of resectable tumor tissue. The aim of the study was to evaluate the clinical performance of OTP during surgery of malignant brain tumors.

STUDY DESIGN/MATERIALS AND METHODS

Nine patients were operated on with the standard surgical procedure, including white light microscopy and navigation. A total of 5 mg/kg bodyweight of 5-amino-levulin acid was orally administrated before surgery. The OTP was calibrated into the ultrasound-based navigation system and measurements were performed in tumor core and along the tumor border. The ratio between the protoporphyrin IX fluorescence at 635 nm and the autofluorescence was used for quantifications of data. Biopsies (n = 20), ultrasound images (n = 30), and visual inspection (n = 180) were compared to the fluorescence ratio.

RESULTS/CONCLUSION

Healthy and tumor tissue could be identified and differentiated with the OTP (P < 0.001). The fluorescence ratio in average was 0 outside the tumor and low in the gliotic edema zone around the tumor. It increased in the marginal zone and was highest in the solid tumor tissue. In the necrotic tissue, in the center of the tumor, the ratio in average was 0. The OTP can be used in combination with ultrasound-based navigation and may help to determine whether to resect otherwise not identifiable tissue.

Use of 5-ALA fluorescence guided endoscopic biopsy of a deep-seated primary malignant brain tumor

The introduction of fluorescence-guided resection of primary malignant brain tumors was a milestone in neurosurgery. Deep-seated malignant brain tumors are often not approachable for microsurgical resection. For diagnosis and therapy, new strategies are recommended. The combination of endoscopy and 5-aminolevulinic acid–induced protoporphyrin IX (5-ALA-induced Pp IX) fluorescence–guided procedures supported by neuronavigation seems an interesting option. Here the authors report on a combined approach for 5-ALA fluorescence–guided biopsy in which they use an endoscopy system based on an Xe lamp (excitation approximately λ = 407 nm; dichroic filter system λ = 380–430 nm) to treat a malignant tumor of the thalamus and perform a ventriculostomy and septostomy. The excitation filter and emission filter are adapted to ensure that the remaining visible blue remission is sufficient to superimpose on or suppress the excited red fluorescence of the endogenous fluorochromes. The authors report that the lesion was easily detectable in the fluorescence mode and that biopsy led to histological diagnosis.

Optical and molecular techniques to identify tumor margins within the larynx

Failure to remove tumor cells from the larynx significantly increases the risk of local recurrence following surgical excision. Healthy tissue must be preserved to optimize long-term vocal and swallowing function. It is essential to accurately distinguish between healthy mucosa, dysplasia, and invasive carcinoma. Optical and molecular examining technologies have been developed to improve tumor margin identification in vivo. We aimed to review the efficacy of these technologies. Published articles were identified using MEDLINE, EMBASE, and Cochrane central register of controlled trials (CENTRAL). Randomized clinical trials are required to establish the benefit to patients and cost to the health service of using 5-aminolevulinic acid (ALA)-induced fluorescent imaging, contact endoscopy, and optical coherence tomography (OCT). Furthermore, primary research is required to validate other techniques, such as confocal endomicroscopy and Raman spectroscopy, and to develop their clinical applications in the larynx.

Contact endoscopy as a novel technique in the detection and diagnosis of mucosal lesions in the head and neck: a brief review

Background. There are a variety of described noninvasive optical detection techniques for evaluation of head and neck mucosal lesions. Contact endoscopy is a promising method of in vivo microscopic examination whereby a rigid telescope is placed on a previously dye-stained mucosa allowing evaluation of the superficial cell layers of the epithelium. This technique produces real-time, magnified images of cellular architecture of surface mucosa comparable to histology without the need for biopsy. In this review, we will briefly summarize the efficacy of CE in the detection of precancerous and cancerous mucosal lesions and its potential as a novel technique in early diagnosis, monitoring, and preoperative assessment of mucosal lesions of the head and neck. Methods. PUBMED, MEDLINE, and COCHRANE search revealed five prospective articles on contact endoscopy for the diagnosis of mucosal lesions in the head and neck. Results. The literature search yielded five prospective studies examining contact endoscopy for the diagnosis of benign versus malignant head and neck mucosal lesions. These reported a sensitivity and specificity of 77-100%, specificity of 66-100% and an accuracy of 72-92%. Conclusion. Contact endoscopy is a promising optical technology that may be a useful adjunct in the evaluation and diagnosis of benign and malignant head and neck mucosal lesions. Future prospective randomized double-blind studies of this detection method are required.