This study presents a hyperspectral optical imaging system for the diagnosis of infantile hemangiomas. Pilot studies were conducted in the clinic on infants. As the main results, the parameters of blood flow and saturation of the areas with hemangiomas were calculated using a previously developed neural network approach. The results indicate the possibility of using this system to monitor the effectiveness of hemangiomas therapy.
This work shows the application of LSCI for mapping the cerebral vessels of a laboratory animal, and also presents the time-frequency processing of the registered signal. Thus, we expand the capabilities of the existing LSCI approach and demonstrate spatial mapping of blood flow fluctuations.
At the moment, percutaneous needle biopsy (PNB) remains the gold standard for diagnosing liver cancer. However, the relatively high probability of false-negative results can still be an issue with the method. The introduction of real-time feedback for the precise navigation of the biopsy tool is an up-and-coming technology to immensely reduce the mistakes in taking relevant tissue samples. This work presents the technical details of the developed optical biopsy system, which implements fluorescence lifetime and diffuse reflectance measurements. Also, we demonstrate the most recent results of measurements by the system equipped with a novel needle optical probe, compatible with the 17.5G biopsy needle standard. At the first stage, measurements were verified in the murine model with inoculated hepatocellular carcinoma (HCC). With that model, we demonstrate that the registered set of independent diagnostic parameters allows us to reliably distinguish the HCC tissue, liver tissue in the control and the metabolically changed liver tissues of animals with the developed HCC tumour. At the second stage, the optical biopsy system was tested during the routing procedure of the transcutaneous biopsy in humans with suspected cancerous processes in the liver. Our results demonstrate that the developed technique can reliably discriminate malignant tumours of different nature (primary HCC and adenocarcinoma metastasis) from liver tissues. We conclude that, being supported by machine learning approaches, the presented technique can significantly decrease the rate of false-negative results for transcutaneous biopsy.
This article describes the results of experimental studies using optical methods for in vitro estimation of the composition of bile obtained from patients with different etiologies of obstructive jaundice. Experimental studies were carried out using spectrophotometry and Raman spectroscopy methods to study and compare optical properties of bile from patients with obstructive jaundice caused either by choledocholithiasis or malignant tumors. The results show that the selected methods are suitable for studying the composition and optical properties of bile and can provide additional diagnostic information. Averaged Raman spectra, as well as absorption spectra of bile, corresponding to different etiologies of jaundice origin were demonstrated.
The aim of this work is to develop practical tools to recognize the average flow rate of physiological fluids in capillaries. This tool is represented by classification models in an artificial neural networks form. The flow rate data were obtained experimentally. Intralipid was used as the test liquid. Laser speckle contrast imaging was used to obtain images of liquid flow in a glass capillary. The experiment was carried out with an average flow rate of 0-2 mm/s with various concentrations of intralipid. The results of training of fully connected and convolutional neural networks for processing the received data are presented. The accuracy of determining the average flow rate of intralipid with different concentrations was comparable to the previously obtained results for a fixed concentration and amounted to approximately 97.5%.
This article presents a liquid phantom technology that simulates the fluorescent properties of protoporphyrin IX (PPIX). A technology was developed for the isolation of PPIX from dark egg shells with a final concentration close to the real values in human tissues. A comparative analysis of the transmittance coefficient of the manufactured phantom as well as the fluorescence spectra measured through the combined use of a CCD spectrometer and a hyperspectral camera is presented as results.
In this paper we demonstrate results of combined measurements by diffuse reflectance and fluorescence lifetime measuring techniques for real time liver cancer differentiation using a needle optical probe.
The article describes the development of the optical phantom mimicking flavin adenine dinucleotide (FAD) and skin collagen fluorescence. The results of experimental studies using fluorescence imaging and fluorescence spectroscopy methods are demonstrated. The method of optical phantom production for quick calibration of fluorescence imaging devices for further application in clinical practice is proposed.
To determine optimal lighting conditions for contrast imaging of surgical objects, optical characteristics of biological tissues and spectral characteristics of smart light "LED light" source based on RGBW LED are compared. The spectral characteristics of tissues and organs have been investigated. Optimal lighting conditions for contrast imaging of biological tissues during surgery were studied. The optimal colour of light for working with individual organs against the background of the whole organism is selected. Perspective of light fixture application with the possibility of dynamic colour control is shown.
The paper describes the results of experimental studies using custom developed optical biopsy system for diagnostics in vivo during the procedure of fine needle aspiration biopsy. Experimental studies were conducted in laboratory mice with inoculated hepatocellular carcinoma. The measurements were carried out using fluorescence spectroscopy and diffuse reflectance spectroscopy methods to reveal metabolic and morphological changes in tissues. The results show that the developed approach is sensitive for cancer detection. Quantified differences in the maximum of fluorescence spectra and diffuse reflectance spectra between tumor and normal tissues were demonstrated and approved with morphological analysis.
The possibility of using a multi-modal approach in the clinical practice of a dermatologist for psoriasis, which includes 3 optical non-invasive technologies: laser Doppler flowmetry, video capillaroscopy, and laser speckle-contrast imaging, is demonstrated. The dynamics of changes in the main microhemodynamic parameters of the microcirculatory bed of patients with psoriasis during conservative therapy was studied, and the effectiveness of treatment of patients suffering from psoriasis was evaluated.
The paper describes the methodology and technical implementation of a multimodal approach for optical diagnostics in hepatopancreatobiliary organs focal and diffuse neoplasms. Fine needle aspiration biopsy technique and following cytological examination show its effectiveness and safety but its performing takes several days. However, the problem of real-time analysis of pathological changes in tissues remains relevant. The solution suggested is implementing of optical biopsy methods (namely fluorescence spectroscopy and diffuse reflectance spectroscopy) in the form of fiber-optic probe compatible with standard biopsy fine needles. The special device was designed for this purpose to conduct optical measurements and compare the results with ones obtained by conventional biopsy. The proposed methodology seems promising for developing new diagnostic criteria for clinical practice.
Presently, in the modern laser Doppler flowmetry (LDF) the distribution of blood perfusion and its changes along the Doppler shift frequencies are simply ignored and/or not properly addressed. Utilizing the registered power spectrum of photocurrent, we introduce an LDF signal processing approach suitable for expanding of diagnostic capabilities of the technique. In particular, we demonstrate that it is possible to determine how the oscillations of blood ow (cardiac, breathe, myogenic, etc.) are distributed along the Doppler shift frequency. Wavelet analysis is utilized to extract the oscillations corresponded to the particular frequency sub-bands of blood perfusion. The main purpose of this study is to identify influence of local pressure by fiber optic probe on cardiac oscillations and their distribution along frequency of Doppler shift.
At present, fluorescence spectroscopy (FS) and diffuse reflectance spectroscopy (DRS) are widespread methods highly used in medical practice. The combined application of these methods is a promising tool to improve the predictive force of classifiers for tissue type recognition as well as to compensate the attenuation of the fluorescence radiation by blood for the accurate evaluation of the biomarkers content in living tissue. Several techniques are known to normalize the resulting fluorescence spectrum in order to exclude the attenuation effect. In this study, an approach based on the dividing of the experimentally obtained FS spectrum by DRS spectrum has been applied for experiments with occlusion test. The implemented multimodal approach for the in vivo optical measurements in combination with occlusion test for minimisation of blood influence has shown good repeatability of obtained experimental fluorescence spectra. The results are of particular interest for the further development of methods for compensating the influence of chromophores in optical spectroscopy.
The paper presents the results of in vivo experimental measurements of the endogenous fluorescence and blood perfusion in common bile duct tissues in obstructive jaundice patients during minimally invasive surgical operations. Nowadays the type of interventions become more widespread for treating hepatopancreatobiliary pathologies. An effective feedback which can be established by one or more optical diagnostic channels integrated into the standard instruments for minimally invasive manipulations would be of particular value to practical surgeons. To collect reference data, an experimental study has been conducted using a fiber optical probe with fluorescence spectroscopy and laser Doppler flowmetry channels. For every measurement, the areas of interest were different areas of common bile duct obstructed by a malignant tumor. Obtained results demonstrated significant variety registered intensities of fluorescence spectra and values of blood perfusion. Tested fiber optical endoscopic system showed sensitivity to the tissue state in the investigated area, so the two modal approach seems to be promising for further research and implementation in clinical practice.
Fine needle aspiration biopsy technique and following histological examination show its effectiveness and safety but its performing takes several time. However, the problem of real-time analysis of pathological changes in tissues remains relevant. We demonstrate optical fine-needle biopsy method, combining a fine needle (17.5G) and a fiber-optic probe (1 mm diameter) for minimally invasive interrogation of tissue in vivo. During rat tumor experiment, we collected spectrally-resolved diffuse reflectance and fluorescence. Quantified differences between tumor and normal tissues were demonstrated and approved with morphological analysis. The proposed methodology seems promising for developing new diagnostic criteria for clinical practice.
At present, minimally invasive interventions become more widespread for treating hepatopancreatoduodenal area pathologies. However, new methods and approaches are necessary for obtaining more diagnostic information in real time. Several methods within the framework of “optical biopsy” concept are considered. The features and areas of application of each method are reviewed to find out which of them can be used in further studies to assess the possibility of intraoperative use in minimally invasive abdominal surgery. Preliminary measurements with fluorescence spectroscopy method have been performed at excitation wavelengths 365 nm and 450 nm. Areas of interest were common bile duct, gallbladder and liver abscess. In our opinion, the obtained results can be a basis for further research and provide a deeper understanding of pathological processes of abdominal cavity organs tissues.
Local hemodynamic parameters were studied by means of laser Doppler flowmetry in 15 patients with psoriasis in the stationary stage, who have plaques on the inner surface of the forearm.
LDF signals recorded at the site of psoriatic lesions of the tissue as well as in the intact tissue at a distance of 1-2 cm from the affected area were analysed. LDF signals were postprocessed by continuous wavelet transform using the Morlet wavelet.
Laser Doppler flowmetry (LDF) was utilized for blood ow measurements. Wavelet analysis was used to identify spectral characteristics of the LDF signal in patients with rheumatic diseases and diabetes mellitus. Baseline measurements were applied for both pathological groups. Blood flow oscillations analyses were performed by means of the wavelet transform.
Higher baseline perfusion was observed in both pathological groups in comparison to controls. Differences in the spectral properties between the groups studied were revealed. The results obtained demonstrated that spectral properties of the LDF signal collected in basal conditions may be the signature of microvasculature functional state.
According to the International Diabetes Federation, the challenge of early stage diagnosis and treatment effectiveness monitoring in diabetes is currently one of the highest priorities in modern healthcare. The potential of combined measurements of skin fluorescence and blood perfusion by the laser Doppler flowmetry method in diagnostics of low limb diabetes complications was evaluated. Using Monte Carlo probabilistic modeling, the diagnostic volume and depth of the diagnosis were evaluated. The experimental study involved 76 patients with type 2 diabetes mellitus. These patients were divided into two groups depending on the degree of complications. The control group consisted of 48 healthy volunteers. The local thermal stimulation was selected as a stimulus on the blood microcirculation system. The experimental studies have shown that diabetic patients have elevated values of normalized fluorescence amplitudes, as well as a lower perfusion response to local heating. In the group of people with diabetes with trophic ulcers, these parameters also significantly differ from the control and diabetes only groups. Thus, the intensity of skin fluorescence and level of tissue blood perfusion can act as markers for various degrees of complications from the beginning of diabetes to the formation of trophic ulcers.
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