PURPOSE: SPNs are increasingly diagnosed because of the widespread use of computer tomography. Its precise verification is crucial for further management. The method of non-invasive discrimination between normal lung parenchyma and pathological tissue would improve TBB biopsy hit rate. New approach for lung tissue examination by penetrating NIR spectroscopy has been validated in comparative randomized study. The aim was to prove superiority of adding NIR spectroscopy to diagnostic algorithm of SPN.
METHODS: Spectral measurements have been carried out using NIR spectroscope (200- 1100 nm). As the source of NIR mercury emitter was used. We designed instrument for measurement of penetrated NIR through lung tissue consisting of indicator and source fibers in insulated sleeve. Patient population consisted of 60 patients with CT/PET metabolically active solitary pulmonary node 2-5 cm in diameter. Patients have been randomized into the group of fluoroscopic TBB and NIR confirmed fluoroscopic TBB.
RESULTS: Intensity signal in wavelength interval 700-850 nm obtained during normal tissue measurement was 5-6 times lower than during measurement of cancer tissue in all cases. Hence normal tissue is characterized by significantly higher attenuation coefficient than cancer tissue. However resulting attenuation also strongly depends on path length of penetrating radiation. Such value is different at various locations and therefore we had to normalize spectra to its maximal value. Analysis showed spectral curve of normal tissue exhibits many local peaks which are induced by higher inhomogeneities compared to cancer tissue. From 33 cases in fluoroscopic group there have been 21 histologies confirming the diagnosis with 63,6% hit rate in our cohort. When NIR spectroscopy was used the hit rate went up to 85% with 23 of positive histologies in 27 patients.
CONCLUSION: From this data we conclude that addition of NIR spectroscopy for ideal biopsy area confirmation was successful in improving TBB hit rate.
CLINICAL IMPLICATIONS: Such device or its modifications could be for example easily included into the examination by electromagnetic navigation.
DISCLOSURE: Gorge Votruba, No Financial Disclosure Information; No Product/Research Disclosure Information