Abstract 3670: Spectroscopy imaging platform differentiates pathology diagnoses in breast surgical specimens
Authors: Laughney Ashley M. , Krishnaswamy Venkataramanan , Paulsen Keith D. , Pogue Brian W. , Rizzo Elizabeth J. , Barth Richard J. , Wells Wendy A. 
Published: August 2012

Abstract
Optical spectroscopy probes increasingly have been employed for diagnostic sensing during breast conserving surgery to aid surgeons in complete resection while minimizing damage to healthy tissues; however, traditional fiber probe-based systems rely on the assumption that ultra-structural changes associated with malignancy yield disease-specific contrast in a single, volume-averaged measure. A scanning-beam spectroscopy platform was designed to efficiently realize the imaging extension of probe-based spectroscopy methods and to selectively sample the scattering response of breast surgical specimens. The imaging system employs dark-field illumination and confocal detection to rapidly sample broadband spectra at 100μm lateral resolution over a 1cm2 field of view. Optical scattering is exquisitely sensitive to the morphological features observed in pathology, the diagnostic gold standard, and has not been studied sufficiently in thick tissues in a waveband that avoids absorption. In this study, 29 fresh breast tissue specimens procured during conservative surgery were imaged and returned to pathology for standard histological processing. A protocol was developed for accurate co-registration between the imaged field and histology. Over 300,00 broadband spectra were sampled and parameterized according to an empirical approximation to Mie theory. Further, the gray-level co-occurrence matrix representation of texture features was used to mathematically represent intensity-level spatial dependence in the scattering images. Spatially, the intra and inter-patient scattering response is quite heterogeneous; but imaging accounts for this natural variance so that diagnostic classification improved. The average scattering power per 100x100 pixel field of view was sufficient to discriminate between benign and malignant pathologies with a positive and negative predictive value of 1.00 and 0.90 respectively, using a simple, threshold-based classification. As compared to classification on a per-spectrum basis, which yielded positive and negative predictive values of just 0.71 and 0.75 respectively. Further, textural features yielded discriminated between invasive and in situ carcinomas with p&lt;0.05, suggesting potential to discriminate between these surgically undifferentiable pathologies. The scanning spectroscopy platform was designed to strike a balance between sensitivity to tissue ultra-structure and imaging the macroscopic fields encountered during surgery. It allows for high throughput imaging of light scattering from the surface of breast surgical specimens, and the sheer number of spectra collected dramatically improves diagnostic classification.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3670. doi:1538-7445.AM2012-3670