Pulmonary Endogenous Fluorescence Allows the Distinction of Primary Lung Cancer from the Perilesional Lung Parenchyma

Toward handheld optically guided biopsy combining diffuse reflectance spectroscopy and autofluorescence

Significance

We aim to validate the technologies essential for a handheld, optically guided biopsy device designed to enhance the diagnostic yield and accuracy of percutaneous liver biopsy procedures.

Aim

We aim to combine diffuse reflectance spectroscopy (DRS) and autofluorescence (AF) spectroscopy in a fiber-optic needle probe using mini spectrometers for the classification of tumor and healthy tissues.

Approach

A fiber-optic needle probe combining DRS and AF spectroscopy, incorporating mini spectrometers to facilitate future integration into a biopsy actuator, was designed and built. This custom probe was used to measure healthy liver tissues and colorectal metastases in excised liver segments. A linear discriminant analysis was applied to the DRS and AF data to distinguish tumors from healthy tissues.

Results

The miniaturized combined DRS and AF spectroscopy system could accurately distinguish tumors from healthy liver with a sensitivity of 95% and a specificity of 96% from a sample size of N = 10 patients and 52 measurements.

Conclusions

We demonstrate the feasibility of miniaturizing a combined DRS and AF spectroscopy system for the classification of tumor and healthy tissues. This validation supports the feasibility and further development of a handheld, optically guided biopsy device.

Autofluorescence imaging within the liver: a promising tool for the detection and characterization of primary liver tumors

OBJECTIVES

To assess the performance of 405 nm-induced autofluorescence for the characterization of primary liver nodules on ex vivo resected specimens.

MATERIALS AND METHODS

Forty resected liver specimens bearing 53 primary liver nodules were included in this IRB-approved prospective study. Intratissular spectroscopic measurements were performed using a 25-G fibered-needle on all ex vivo specimens: 5 autofluorescence measurements were performed in both nodules and adjacent parenchyma. The spectra derivatives of the 635 and 670 nm autofluorescence peaks observed in nodules and in adjacent liver parenchyma were compared (Kruskal-Wallis and Mann-Whitney when appropriate).

RESULTS

A total of 42 potentially evolutive primary liver nodules-34 hepatocellular carcinomas, 4 intrahepatic cholangiocarcinomas, 4 hepatocellular adenomas-and 11 benign nodules-5 focal nodular hyperplasias, 6 regenerative nodules-were included. Both 635 and 670 nm Δderivatives were significantly higher in benign as compared to potentially evolutive (PEV) nodules (respectively 32.9 ± 4.5 vs 15.3 ± 1.4; p < 0.0001 and 5.7 ± 0.6 vs 2.5 ± 0.1; p < 0.0001) with respective sensitivity and specificity of 78% and 91% for distinguishing PEV from benign nodules.

CONCLUSION

405 nm-induced autofluorescence enables the discrimination of benign from PEV primary liver nodules, suggesting that autofluorescence imaging could be used to optimize US targeted liver biopsies.

KEY POINTS

• 405 nm-induced autofluorescence can distinguish liver tumors from the adjacent liver parenchyma. • The analysis of autofluorescence imaging observed within primary liver tumors can discriminate benign tumors from those requiring follow-up or targeted liver biopsy. • In current practice, autofluorescence imaging could be embedded within biopsy needle, to enable, in addition to ultrasound guidance, optimal targeting of liver nodules which could optimize tissue sampling.

Optical percutaneous needle biopsy of the liver: a pilot animal and clinical study

This paper presents the results of the experiments which were performed using the optical biopsy system specially developed for in vivo tissue classification during the percutaneous needle biopsy (PNB) of the liver. The proposed system includes an optical probe of small diameter acceptable for use in the PNB of the liver. The results of the feasibility studies and actual tests on laboratory mice with inoculated hepatocellular carcinoma and in clinical conditions on patients with liver tumors are presented and discussed. Monte Carlo simulations were carried out to assess the diagnostic volume and to trace the sensing depth. Fluorescence and diffuse reflectance spectroscopy measurements were used to monitor metabolic and morphological changes in tissues. The tissue oxygen saturation was evaluated using a recently developed approach to neural network fitting of diffuse reflectance spectra. The Support Vector Machine Classification was applied to identify intact liver and tumor tissues. Analysis of the obtained results shows the high sensitivity and specificity of the proposed multimodal method. This approach allows to obtain information before the tissue sample is taken, which makes it possible to significantly reduce the number of false-negative biopsies.

Preclinical ex vivo evaluation of the diagnostic performance of a new device for in situ label-free fluorescence spectral analysis of breast masses

OBJECTIVES

To assess the diagnostic performance of a new device for in situ label-free fluorescence spectral analysis of breast masses in freshly removed surgical specimens, in preparation for its clinical development.

METHODS

Sixty-four breast masses from consenting patients who had undergone either a lumpectomy or a mastectomy were included. Label-free fluorescence spectral acquisitions were obtained with a 25G fibre-containing needle inserted into the mass. Data from benign and malignant masses were compared to establish the most discriminating thresholds and measurement algorithms. Accuracy was verified using the bootstrap method.

RESULTS

The final histological examination revealed 44 invasive carcinomas and 20 benign lesions. The maximum intensity of fluorescence signal was discriminant between benign and malignant masses (p < .0001) whatever their sizes. Statistical analysis indicated that choosing five random measurements per mass was the best compromise to obtain high sensitivity and high negative predictive value with the fewest measurements. Thus, malignant tumours were identified with a mean sensitivity, specificity, negative and positive predictive value of 98.8%, 85.4%, 97.2% and 93.5%, respectively.

CONCLUSION

This new in situ tissue autofluorescence evaluation device allows accurate discrimination between benign and malignant breast masses and deserves clinical development.

KEY POINTS

• A new device allows in situ label-free fluorescence analysis of ex vivo breast masses • Maximum fluorescence intensity discriminates benign from malignant masses (p < .0001) • Five random measurements allow a high negative predictive value (97.2%).