Spectral areas and ratios classifier algorithm for pancreatic tissue classification using optical spectroscopy

Needle-compatible miniaturized optoelectronic sensor for pancreatic cancer detection

Pancreatic cancer is one of the deadliest cancers, with a 5-year survival rate of <10%. The current approach to confirming a tissue diagnosis, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), requires a time-consuming, qualitative cytology analysis and may be limited because of sampling error. We designed and engineered a miniaturized optoelectronic sensor to assist in situ, real-time, and objective evaluation of human pancreatic tissues during EUS-FNA. A proof-of-concept prototype sensor, compatible with a 19-gauge hollow-needle commercially available for EUS-FNA, was constructed using microsized optoelectronic chips and microfabrication techniques to perform multisite tissue optical sensing. In our bench-top verification and pilot validation during surgery on freshly excised human pancreatic tissues (four patients), the fabricated sensors showed a comparable performance to our previous fiber-based system. The flexibility in source-detector configuration using microsized chips potentially allows for various light-based sensing techniques inside a confined channel such as a hollow needle or endoscopy.

Tissue Classification Using Optical Spectroscopy Accurately Differentiates Cancer and Chronic Pancreatitis

OBJECTIVES

Current pancreatic cancer diagnostics cannot reliably detect early disease or distinguish it from chronic pancreatitis. We test the hypothesis that optical spectroscopy can accurately differentiate cancer from chronic pancreatitis and normal pancreas. We developed and tested clinically compatible multimodal optical spectroscopy technology to measure reflectance and endogenous fluorescence from human pancreatic tissues.

METHODS

Freshly excised pancreatic tissue specimens (39 normal, 34 chronic pancreatitis, 32 adenocarcinoma) from 18 patients were optically interrogated, with site-specific histopathology representing the criterion standard. A multinomial logistic model using principal component analysis and generalized estimating equations provided statistically rigorous tissue classification.

RESULTS

Optical spectroscopy distinguished pancreatic cancer from normal pancreas and chronic pancreatitis (sensitivity, 91%; specificity, 82%; positive predictive value, 69%; negative predictive value, 95%; area under receiver operating characteristic curve, 0.89). Reflectance alone provided essentially the same classification accuracy as reflectance and fluorescence combined, suggesting that a rapid, low-cost, reduced-footprint, reflectance-based device could be deployed without notable loss of diagnostic power.

CONCLUSIONS

Our novel, clinically compatible, label-free optical diagnostic technology accurately characterizes pancreatic tissues. These data provide the scientific foundation demonstrating that optical spectroscopy can potentially improve diagnosis of pancreatic cancer and chronic pancreatitis.

[Prevention and treatment of post-traumatic pancreatic necrosis in patients with blunt abdominal trauma]

INTRODUCTION

High incidence of necrotic and suppurative complications is feature of acute post-traumatic pancreatitis. Severe trauma of the pancreas and post-traumatic pancreatitis lead to depressurization of ductal system that requires adequate drainage of damaged area and retroperitoneal fat.

MATERIAL AND METHODS

95 patients in group 1 received standardized treatment. The victims of the 2nd group (44 patients) were treated using immunoreactive therapy (roncoleukin) and octreotide (the dose depended on the severity of pancreatitis) at early stages. The efficacy of treatment was assessed based on clinical, laboratory and instrumental parameters.

RESULTS

Regardless severity of pancreatic injury overall mortality in groups 1 and 2 was 41% and 20.5% respectively. The main causes of adverse outcomes are severe destructive pancreatitis, postnecrotic suppurative complications.

CONCLUSION

Adequacy rather radicalism of surgery should be preferred for blunt pancreatic trauma management. Minimally invasive surgical techniques and new methods of biological hemostasis may be applied. Timely use of anti-enzymatic and immunoactive therapy reduces the risk of severe post-traumatic pancreatitis, suppurative complications and improves outcomes in patients with blunt pancreatic trauma.

In vivo optical spectroscopy for improved detection of pancreatic adenocarcinoma: a feasibility study

Pancreatic adenocarcinoma has a five-year survival rate of less than 6%. This low survival rate is attributed to the lack of accurate detection methods, which limits diagnosis to late-stage disease. Here, an in vivo pilot study assesses the feasibility of optical spectroscopy to improve clinical detection of pancreatic adenocarcinoma. During surgery on 6 patients, we collected spectrally-resolved reflectance and fluorescence in vivo. Site-matched in vivo and ex vivo data agreed qualitatively and quantitatively. Quantified differences between adenocarcinoma and normal tissues in vivo were consistent with previous results from a large ex vivo data set. Thus, optical spectroscopy is a promising method for the improved diagnosis of pancreatic cancer in vivo.

Laser-based non-invasive spectrophotometry – An overview of possible medical applications

The problem of the medical application of non-invasive (

The specially devised multifunctional laser diagnostic system “LAKK-M” was used as a diagnostic instrument in the majority of studies in MONIKI, allowing a combination of methods, such as non-invasive medical spectrophotometry in the form of laser fluorescence spectroscopy, laser Doppler flowmetry, tissue reflectance oximetry, etc. The system was used in both the experiments on laboratory animals, and for treatment of patients in different clinics of the institute.

Within the last decade, extensive scientific data has been obtained which has opened up the possibility of using non-invasive medical spectrophotometry

Methods of complex non-invasive medical spectrophotometry appear to be an efficient tool in practical medicine for differential diagnostics of a number of diseases and pathologies, as well as for monitoring and prediction of the treatment outcome. At the same time, they also create an important perspective for gaining novel and fundamental knowledge about the blood microcirculation system which was not available earlier due to the absence of the diagnostic technology allowing information to be obtained

Characterizing human pancreatic cancer precursor using quantitative tissue optical spectroscopy

In a pilot study, multimodal optical spectroscopy coupled with quantitative tissue-optics models distinguished intraductal papillary mucinous neoplasm (IPMN), a common precursor to pancreatic cancer, from normal tissues in freshly excised human pancreas. A photon-tissue interaction (PTI) model extracted parameters associated with cellular nuclear size and refractive index (from reflectance spectra) and extracellular collagen content (from fluorescence spectra). The results suggest that tissue optical spectroscopy has the potential to characterize pre-cancerous neoplasms in human pancreatic tissues.

Nonlinear optical microscopy for histology of fresh normal and cancerous pancreatic tissues

BACKGROUND

Pancreatic cancer is a lethal disease with a 5-year survival rate of only 1-5%. The acceleration of intraoperative histological examination would be beneficial for better management of pancreatic cancer, suggesting an improved survival. Nonlinear optical methods based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) of intrinsic optical biomarkers show the ability to visualize the morphology of fresh tissues associated with histology, which is promising for real-time intraoperative evaluation of pancreatic cancer.

METHODOLOGY/PRINCIPAL FINDINGS

In order to investigate whether the nonlinear optical imaging methods have the ability to characterize pancreatic histology at cellular resolution, we studied different types of pancreatic tissues by using label-free TPEF and SHG. Compared with other routine methods for the preparation of specimens, fresh tissues without processing were found to be most suitable for nonlinear optical imaging of pancreatic tissues. The detailed morphology of the normal rat pancreas was observed and related with the standard histological images. Comparatively speaking, the preliminary images of a small number of chemical-induced pancreatic cancer tissues showed visible neoplastic differences in the morphology of cells and extracellular matrix. The subcutaneous pancreatic tumor xenografts were further observed using the nonlinear optical microscopy, showing that most cells are leucocytes at 5 days after implantation, the tumor cells begin to proliferate at 10 days after implantation, and the extracellular collagen fibers become disordered as the xenografts grow.

CONCLUSIONS/SIGNIFICANCE

In this study, nonlinear optical imaging was used to characterize the morphological details of fresh pancreatic tissues for the first time. We demonstrate that it is possible to provide real-time histological evaluation of pancreatic cancer by the nonlinear optical methods, which present an opportunity for the characterization of the progress of spontaneous pancreatic cancer and further application in a non-invasive manner.

Models of light propagation in human tissue applied to cancer diagnostics

Optical methods such as reflectance and fluorescence spectroscopy are being investigated for their potential to aid cancer detection in a quantitative, minimally invasive manner. Mathematical models of reflectance and fluorescence provide an important link between measured optical data and biomedically-relevant tissue parameters that can be extracted from these data to characterize the presence or absence of disease. The most commonly-used mathematical models in biomedical optics are the diffusion approximation (DA) to the radiative transfer equation, Monte Carlo (MC) computational models of light transport, and semi-empirical models. This paper presents a review of the applications of these models to reflectance and endogenous fluorescence sensing for cancer diagnostics in human tissues. Specific examples are given for cervical, breast, and pancreatic tissues. A comparison of the DA and MC methods in two biologically-relevant regimes of optical parameter space will also be discussed.

Photon-tissue interaction model enables quantitative optical analysis of human pancreatic tissues

A photon-tissue interaction (PTI) model was developed and employed to analyze 96 pairs of reflectance and fluorescence spectra from freshly excised human pancreatic tissues. For each pair of spectra, the PTI model extracted a cellular nuclear size parameter from the measured reflectance, and the relative contributions of extracellular and intracellular fluorophores to the intrinsic fluorescence. The results suggest that reflectance and fluorescence spectroscopies have the potential to quantitatively distinguish among pancreatic tissue types, including normal pancreatic tissue, pancreatitis, and pancreatic adenocarcinoma.

Instrumentation to rapidly acquire fluorescence wavelength-time matrices of biological tissues

A fiber-optic system was developed to rapidly acquire tissue fluorescence wavelength-time matrices (WTMs) with high signal-to-noise ratio (SNR). The essential system components (473 nm microchip laser operating at 3 kHz repetition frequency, fiber-probe assemblies, emission monochromator, photomultiplier tube, and digitizer) were assembled into a compact and clinically-compatible unit. Data were acquired from fluorescence standards and tissue-simulating phantoms to test system performance. Fluorescence decay waveforms with SNR > 100 at the decay curve peak were obtained in less than 30 ms. With optimized data transfer and monochromator stepping functions, it should be feasible to acquire a full WTM at 5 nm emission wavelength intervals over a 200 nm range in under 2 seconds.