SVM classifier of cervical histopathology images based on texture and morphological features.

BACKGROUND: Cervical histopathology image classification is a crucial indicator in cervical biopsy results. OBJECTIVE: The objective of this study is to identify histopathology images of cervical cancer at an early stage by extracting texture and morphological features for the Support Vector Machine (SVM) classifier. METHODS: We extract three different texture features and one morphological feature of cervical histopathology images: first-order histogram, K-means clustering, Gray Level Co-occurrence Matrix (GLCM) and nucleus feature. The original dataset used in our experiment is obtained from 20 patients diagnosed with cervical cancer, including 135 whole slide images (WSIs). Given an entire WSI, the patches on its tissue region are extracted randomly. RESULTS: We finally obtain 3,000 patches, including 1,000 normal, 1,000 hysteromyoma and 1,000 cancer images. Among them, 80% of the entire data set is randomly selected as training set and the remaining 20% as test set. The accuracy of SVM classification using first-order histogram, K-means clustering, GLAM and nucleus feature for extracting features are respectively 87.4%, 90.6%, 91.6% and 93.5%. CONCLUSIONS: The classification accuracy of the SVM combining the four features is 96.8%, and the proposed nucleus feature plays a key role in the SVM classification of cervical histopathology images.

Effects of different-intensity laser acupuncture at two adjacent same-meridian acupoints on nitric oxide and soluble guanylate cyclase releases in human.

OBJECTIVES: The aim of this study was to detect the influences of LA at nonacupoint and two adjacent acupoints of pericardium meridian on the releases of NO and sGC in 20 healthy subjects. METHODS: Different intensities (12, 24, 48 mW) of infrared laser were used for irradiating Jianshi (PC5), Ximen (PC4) acupoints and nonacupoint for 20, 40 minutes, respectively. Semi-circular tubes were taped to the skin surface and filled with NO-scavenging compound for 20 minutes to capture NO and sGC, which were measured using spectrophotometry in a blinded fashion. RESULTS: As the increase in the intensity of LA stimulation, the levels of NO releases over acupoints all were significantly increased, NO releases in nonacupoints following the same treatment only changed slightly, sGC amounts were observably enhanced over acupoints, but did not any change in nonacupoint area. Different intensities of LA treatments can sensitively affect the NO and sGC releases over acupoints. This indicated that LA-induced releases of the NO and sGC were specific to acupoints. CONCLUSIONS: This is the first evidence reporting that LA induced significant elevations of NO-sGC releases over acupoints, and the enhanced signal molecules contribute to local circulation, which improves the beneficial effects of the therapy.

Changes in Nitric Oxide Releases of the Contralateral Acupoint during and after Laser Acupuncture at Bilateral Same-Name Acupoints in Human.

OBJECTIVE: The purpose of the study was to examine the effects of laser acupuncture (LA) at right Neiguan (RPC6)/left Neiguan (LPC6) acupoints on the releases of nitric oxide (NO) in the treated and contralateral/nontreated PC6, compared to the nonacupoint control area. METHODS: 24 mW LA at RPC6, LPC6, and nonacupoint in 22 healthy subjects for 40 min: sterilized dialysis tube was taped to the nontreated PC6/nonacupoint during the treatment and immediately taped to the treated and nontreated PC6/nonacupoint after LA removal. NO-scavenging compound was injected into the tube for 40 min to absorb the molecular which was tested by spectrophotometry in a blinded fashion. RESULTS: LA-induced NO releases over PC6 acupoints for the nontreated and treated sides all significantly increased after LA removal, but for the nontreated acupoints they did not change during LA stimulation. LA at RPC6 induced the more release of the NO at contralateral side than stimulating LPC6, but not on nonacupoints. The results suggest that LA-induced NO release over contralateral acupoint and NO release resulting from the lateralized specificity all are different and specific to the acupoint within different time course. CONCLUSIONS: LA-evoked NO release over acupoints could improve the neurogenic, endothelial activity of the vessel wall to further facilitate microcirculation.

A Correlation Study between Two Adjacent Same-Meridian Acupoints after Laser-Needle Acupuncture with Optical Coherence Tomography and Diffuse Reflectance Spectra.

This study is to investigate the correlations among Sanjian (LI3), Hegu (LI4), and Yangxi (LI5) acupoints and their corresponding nonacupoints on the Yangming Large Intestine Meridian of Hand before and after laser irradiation using optical coherence tomography (OCT) and diffuse reflectance spectra. The experiment was conducted on 10 healthy people. A 658 nm laser with 50 mW output power was used for irradiating LI4, LI5 acupoints and their corresponding nonacupoints. As to LI4 acupoint with laser irradiation for duration of 15 or 45 minutes, the OCT backscattered light intensities of LI4 and LI5 acupoints increased significantly, and the reflectance intensities (RIs) of the LI3, LI4, and LI5 acupoints decreased significantly. As to LI5 acupoint with laser irradiation for duration of 15 or 45 minutes, the changes of OCT backscattered light intensities of the corresponding irradiated acupoint and LI4 acupoint increased significantly, and the RIs decreased significantly. However, the OCT backscattered light intensities and RIs for their nonacupoints were almost not changed. The results show that an association exists between two adjacent same-meridian acupoints on the same meridian after laser-needle acupuncture to some extent.

Effects of titanium dioxide nanoparticles coupled with diode laser on optical properties of in vitro normal and cancerous human lung tissues studied with optical coherence tomography and diffuse reflectance spectra.

The objective is to investigate the effects of two different sized (60 and 100 nm) titanium dioxide (TiO2) nanoparticles (NPs) penetration and accumulation in in vitro human normal lung (NL) tissue, lung squamous cell carcinoma (LSCC) tissue, and 650-nm diode laser-pretreated tissue on their optical properties studied with optical coherence tomography monitoring and diffuse reflectance (DR) spectra measurement. As with TiO2 NPs penetrating into the tissues, the intensities of DR of the samples increase, and then the enhancements of DR and the attenuation coefficients of the tissues were quantitatively calculated. The results suggest that 650-nm diode laser pretreatment increased the amounts of TiO2 NPs penetration and accumulation in NL and LSCC tissues, and the tissue optical properties were significantly influenced by accumulation of TiO2 NPs.

Influence of nanoparticles accumulation on optical properties of human normal and cancerous liver tissue in vitro estimated by OCT.

In this work, the potential use of nanoparticles as contrast agents by using spectral domain optical coherence tomography (SD-OCT) in liver tissue was demonstrated. Gold nanoparticles (average size of 25 and 70 nm), were studied in human normal and cancerous liver tissues in vitro, respectively. Each sample was monitored with SD-OCT functional imaging for 240 min. Continuous OCT monitoring showed that, after application of gold nanoparticles, the OCT signal intensities of normal liver and cancerous liver tissue both increase with time, and the larger nanoparticles tend to produce a greater signal enhancement in the same type of tissue. The results show that the values of attenuation coefficients have significant differences between normal liver tissue and cancerous liver tissue. In addition, 25 nm gold nanoparticles allow higher penetration depth than 70 nm gold nanoparticles in liver tissues.

In vitro assessment of effects of hyperglycemia on the optical properties of blood during coagulation using optical coherence tomography.

No published reports have demonstrated the capability of the optical coherence tomography technique for quantifying the optical coherence tomography signal slope, 1/e light penetration depth, and attenuation coefficient of hyperglycemic blood by an in vitro assessment. The purpose of this study was to investigate the effects of hyperglycemia on optical properties during in vitro blood coagulation by optical coherence tomography. Normal whole blood acted as the control group. After 1-h coagulation, the average optical coherence tomography signal slope decreased approximately 23.3 and 16.7%, and the 1/e light penetration depths increased approximately 21.5 and 19.2% for the control and hyperglycemic groups, respectively. It could be seen from the 1/e light penetration depth evolution curves that the blood coagulation time was about (425 ± 19) s for normal whole blood and (367 ± 15) s for the hyperglycemic blood. The coagulation time decreased 13.6% for the hyperglycemic blood compared with that for normal whole blood. There was statistically significant difference in blood coagulation time between the hyperglycemic and normal whole blood (p < 0.05). The results suggested that hyperglycemia has a procoagulant effect. Our experiment was the first reported study of monitoring hyperglycemic blood coagulation using OCT. We conclude that OCT is potential technique to quantify and follow the liquid-gel transition of hyperglycemic blood coagulation.

Continuous noninvasive monitoring of changes in human skin optical properties during oral intake of different sugars with optical coherence tomography.

The objective of this study was to evaluate the effects of blood glucose concentration (BGC) on in vivo human skin optical properties after oral intake of different sugars. In vivo optical properties of human skin were measured with a spectral domain optical coherence tomography (SD-OCT). Experimental results show that increase of BGC causes a decrease in the skin attenuation coefficient. And the maximum decrements in mean attenuation coefficient of skin tissue after drinking glucose, sucrose and fructose solution are 47.0%, 36.4% and 16.5% compared with that after drinking water, respectively (p < 0.05). The results also show that blood glucose levels of the forearm skin tissue are delayed compared with finger-stick blood glucose, and there are significant differences in the time delays after oral intake of different sugars. The time delay between mean attenuation coefficient and BGC after drinking glucose solution is evidently larger than that after drinking sucrose solution, and that after drinking sucrose solution is larger than that after drinking fructose solution. Our pilot studies indicate that OCT technique is capable of non-invasive, real-time, and sensitive monitoring of skin optical properties in human subjects during oral intake of different sugars.

Evaluation of ultrasound and glucose synergy effect on the optical clearing and light penetration for human colon tissue using SD-OCT.

Topical application optical clearing agents (OCAs) can effectively enhance the tissue optical clearing on the human colon tissue, which has been demonstrated in our previous studies. Nevertheless, the strong light scattering still limits the diffusion rate of OCAs and penetration depth of light into the tissue. In this study, in order to further increase the diffusion of the OCA of glucose into tissue, we employ a method to improve the glucose permeability and light penetration with ultrasound (sonophoretic delivery, SP) and glucose (G) synergy on human normal and cancerous colon tissues in vitro, which was measured and quantified with spectral-domain optical coherence tomography (SD-OCT) technology. To evaluate the effect of ultrasound mediation, the percentages of OCT signal enhancement (PSE) and 1/e light-penetration depth were calculated for G alone and ultrasound-G treatments. The PSE was calculated at approximately 313 µm from the sample tissue surface. For normal and cancerous colon tissues the PSE were about 91.1 ± 10.6% and 65.3% ± 12.3% with 30% G/SP, but for the 30% G alone treatment it was about 78.6 ± 11.2% and 54.5% ± 9.3%, respectively. The max value of 1/e light-penetration depth for normal colon tissue was 0.47 ± 0.02 mm with 30% G alone and 0.60 ± 0.05 mm (p < 0.05)with 30% G/SP synergy. However, for the cancerous colon tissue the max value was 0.45 ± 0.01 mm and 0.57 ± 0.03 mm (p < 0.05), respectively. The obtained permeability coefficients showed a significant enhancement with ultrasound mediation. The mean permeability coefficients of 30% G/SP in normal and cancerous colon tissues were (6.3 ± 0.16) × 10(-6) cm/s and (12.1 ± 0.34) × 10(-6) cm/s (p < 0.05), respectively. These preliminary experiments showed that ultrasound can effectively enhance the tissue optical clearing and glucose diffusion rate as well as increase the light-penetration depth into biotissues.

Noninvasive blood glucose monitoring during oral intake of different sugars with optical coherence tomography in human subjects.

The potential of OCT applied to noninvasive blood glucose monitoring has attracted significant efforts. In this work we investigated the feasibility of OCT in monitoring blood glucose during oral intake of different sugars in humans. Five groups of experiments were performed, in which different sugars were used. The OCT signal slope (OCTSS) changed with variation of blood glucose concentration (BGC). A good correlation between OCTSS and BGC was observed in these experiments. The averaged correlation coefficients R between OCTSS and BGC are 0.900, 0.836, 0.895 and 0.884, corresponding to oral administration of glucose, fructose, sucrose and mixed sugar, respectively. Our studies demonstrated the capability and accuracy of the OCT system in monitoring BGC noninvasively and it could become a powerful tool in daily blood glucose monitoring for patients.

[Comparative study of time-correlated temperature and back-scattered light intensity for human Hegu acupoint and non-acupoint tissue irradiated by near-infrared laser].

Characteristics and differences of temperature and back-scattered light intensity in different depths of 0.2, 0.4, 0.6, 0.8 and 1 mm for both human Hegu acupoint and non-acupoint tissue irradiated by 808 nm diode laser at the different power of 15, 25 and 35 mW were studied. The temperature and the back-scattered light intensity in different depths of 0.2, 0.4, 0.6, 0.8 and 1 mm for human Hegu acupoint and non-acupoint tissue were measured by using the infrared thermography and optical coherence tomography. The result shows few differences in the temperature and the back-scattered light intensity of human Hegu acupoint and non-acupoint tissue before irradiation. The temperature and back-scattered light intensity of Hegu acupoint and the non-acupoint after irradiation were significantly higher, and the temperature and back-scattered light intensity of Hegu acupoint significantly were higher than the non-acupoint areas. At 0-40 min after the irradiation, the temperature and back-scattered light intensity of Hegu acupoint and the non-acupoint area will fluctuate and gradually decrease with the passage of time. From the results above, it is clearly seen that Hegu acupoint is different from non-acupoint both in the back-scattered light intensity and temperature after irradiation, and Hegu acupoint is more sensitive to laser irradiation than non-acupoint tissue.

Effects of optical clearing agents on noninvasive blood glucose monitoring with optical coherence tomography: a pilot study.

Recently, the capability of optical coherence tomography (OCT) has been demonstrated for noninvasive blood glucose monitoring. In this work, we investigate the administration of chemical agents onto human skin tissue to increase the transparency of the surface of the skin, as a means of improving the capability of OCT imaging for clinically relevant applications. Eight groups of experiments were proposed, in which different optical clearing agents (OCA) were used. The results indicate that, when properly used, some OCAs perform well in promoting the capability of OCT for noninvasive blood glucose monitoring. Among the four kinds of OCA we used, 50% v/v glycerol solute turns out to be the best enhancer. Compared with the results of the experiments in which no OCA was used, when 50% glycerol was applied onto the human skin topically, the correlation coefficient between the OCT signal slope (OCTSS) and blood glucose concentration (BGC) was improved by 7.1% on average, and the lag time between changes in the OCTSS and BGC was cut by 8 min on average. The results of 10 w/v mannitol were also good, but not as pronounced.

Ex vivo determination of glucose permeability and optical attenuation coefficient in normal and adenomatous human colon tissues using spectral domain optical coherence tomography.

Recent reports have suggested that spectral domain optical coherence tomography (SD-OCT) is a useful tool for quantifying the permeability of hyperosmotic agents in various tissues. We report our preliminary results on quantification of glucose diffusion and assessment of the optical attenuation change due to the diffusion of glucose in normal and adenomatous human colon tissues in vitro by using a SD-OCT and then calculated the permeability coefficients (PC) and optical attenuation coefficients (AC). The PC of a 30% aqueous solution of glucose was 3.37±0.23×10⁻6 cm/s in normal tissue and 5.65±0.16×10⁻6 cm/s in cancerous colon tissue. Optical AC in a normal colon ranged from 3.48±0.37 to 2.68±0.82 mm⁻¹ and was significantly lower than those seen in the cancerous tissue (8.48±0.95 to 3.16±0.69 mm⁻¹, p<0.05). The results suggest that quantitative measurements of using PC and AC from OCT images could be a potentially powerful method for colon cancer detection.

Synergistic effect of hyperosmotic agents and sonophoresis on breast tissue optical properties and permeability studied with spectral domain optical coherence tomography.

Hyperosmotic agents have shown great potential in tissue optical clearing. However, the low efficiency of the permeation in biological tissues seriously restricts its application in reality. The synergy of sonophoresis as a penetration enhancer and hyperosmotic agents, 20% glucose (G) and 20% mannitol (M), in optical clearing has been investigated by analyzing the variation of the attenuation coefficients and the permeability coefficients. In the sonophoresis experiments, ultrasound (US) was applied for 10 min before applying hyperosmotic agents. Along with the administration of hyperosmotic agents, the samples were monitored with optical coherence tomography (OCT) functional imaging for the next 2 h. The attenuation coefficients of each group were obtained from the 2-D OCT images based on Beer's Law. The original attenuation coefficient is 12.38 ± 0.73 cm-1 in normal breast tissue. After 45 min treatment, it changes to be 5.91 ± 0.82 cm-1 and 4.14 ± 0.67 cm-1 for 20% G and 20% G/US, respectively. The attenuation coefficient of breast cancer tissue is 18.17 ± 1.45 cm-1 at the beginning, and it becomes 8.70 ± 0.87 cm-1 for 20% G and 6.80 ± 0.92 cm-1 for 20% G/US after 30 min. Meanwhile, the permeability coefficients of hyperosmotic agents were much enlarged by the treatment of ultrasound in both breast normal tissue and breast cancer tissue. A significant difference in permeability coefficients between health tissue and tumor tissue was also observed in the experiment (p<0.01).

Assessment of the effects of ultrasound-mediated glucose on permeability of normal, benign, and cancerous human lung tissues with the Fourier-domain optical coherence tomography.

The objective of this study was to evaluate the effects of ultrasound-mediated analyte diffusion on permeability of normal, benign, and cancerous human lung tissue in vitro and to find more effective sonophoretic (SP) delivery in combination with the optical clearing agents (OCAs) method to distinguish normal and diseased lung tissues. The permeability coefficients of SP in combination with OCAs diffusion in lung tissue were measured with Fourier-domain optical coherence tomography (FD-OCT). 30% glucose and SP with a frequency of 1 MHz and an intensity of 0.80 W/cm2 over a 3 cm probe was simultaneously applied for 15 min. Experimental results show that the mean permeability coefficients of 30% glucose/SP were found to be (2.01±0.21)×10(-5) cm/s from normal lung (NL) tissue, (2.75±0.28)×10(-5) cm/s from lung benign granulomatosis (LBG) tissue, (4.53±0.49)×10(-5) cm/s from lung adenocarcinoma tumor (LAT) tissue, and (5.81±0.62)×10(-5) cm/s from lung squamous cell carcinoma (LSCC) tissue, respectively. The permeability coefficients of 30% glucose/SP increase approximately 36.8%, 125.4%, and 189.1% for the LBG, LAT, and LSCC tissue compared with that for the NL tissue, respectively. There were statistically significant differences in permeability coefficients of 30% glucose/SP between LBG and NL tissue (p<0.05), between LAT and NL tissue (p<0.05), and between LSCC and NL tissue (p<0.05). The results suggest that the OCT functional imaging technique to combine an ultrasound-OCAs combination method could become a powerful tool in early diagnosis and monitoring of changed microstructure of pathologic human lung tissue.

Investigation of the permeability and optical clearing ability of different analytes in human normal and cancerous breast tissues by spectral domain OCT.

The potential of OCT applied for early breast cancer detection attracted significant efforts. The permeability coefficients and the percentages of OCT signal enhancement for normal and cancerous breast tissues have been investigated from the experiments of 20% glucose, 40% glucose, and 20% mannitol in vitro. Obtained results indicate that the permeability coefficient in breast cancer tissue is prominently larger than that in normal breast tissue, while the optical clearing effect is just the reverse to that for each agent. The results suggest that OCT has the ability to distinguish cancer tissue from different aspect.

Quantification of glucose diffusion in human lung tissues by using Fourier domain optical coherence tomography.

In this study, we report permeability coefficients of 30% glucose diffusion by the optical coherence tomography signal slope (OCTSS) method in four kinds of human lung tissue in vitro: normal lung tissue, benign granulomatosis lung tissue, squamous cell carcinoma and adenocarcinoma tumor. To quantify the permeability coefficient of the agent, the monitored region was 80 µm thickness at a tissue depth of ca 230 µm from the surface. The permeability coefficients of 30% glucose from 10 independent experiments were averaged and found to be (1.35 ± 0.13) × 10(-5) cm s(-1) from the normal lung tissue, (1.78 ± 0.21) × 10(-5) cm s(-1) from the benign granulomatosis lung tissue, (2.88 ± 0.19) × 10(-5) cm s(-1) from the adenocarcinoma tumor and (3.53 ± 0.25) × 10(-5) cm s(-1) from the squamous cell carcinoma, respectively. It could be clearly seen that the permeability coefficients of 30% glucose increase ca 32%, 113% and 162% in the benign granulomatosis, adenocarcinoma tumor and squamous cell carcinoma of human lung tissue compared with that from the normal lung tissue, respectively. Therefore, we inferred from this pilot study that the OCT imaging is a feasible method to distinguish normal and cancer lung tissue.

Backward emission angle of microscopic second-harmonic generation from crystallized type I collagen fiber.

A theoretical model that deals with SHG from crystallized type I collagen fiber formed by a bundle of fibrils is established. By introducing a density distribution function of dipoles within fibrils assembly into the dipole theory and combining with structural order (m,l) parameters revealed by quasi-phase-matching (QPM) theory, our established theoretical model comprehensively characterizes both biophysical features of collagen dipoles and the crystalline characteristics of collagen fiber. This new model quantitatively reveals the 3-D distribution of second-harmonic generation (SHG) emission angle (θ,ϕ) in accordance with the emission power. Results show that fibrils diameter d(1) and structural order m, which describes the structural characteristics of collagen fiber along the incident light propagation direction has significant influence on backward∕forward SHG emission. The decrease of fibrils diameter d(1) induces an increase of the peak SHG emission angle θ(max). As d(1) decreases to a threshold value, in our case it is around d(1) = 150 nm when (m,l) = (1,0), θ(max) > 90 deg, indicating that backward SHG emission appears. The SHG may have two symmetrical emission distribution lobes or may have only one or two unsymmetrical emission lobes with unequal emission power, depending on the functional area of (m,l) on d(1).

Microscopic second harmonic generation (SHG) from tilt-placed collagen fibrils.

We report a theoretical study of second-harmonic generation (SHG) from the collagen fibrils which have a tilt angle Φ between their axes with the plane of the polarization angle α of the linearly polarized focused light. The effects of Φ as well as α on SHG emission have been investigated. Our results show that the total strength of SHG electrical field (E(2ω)) and power (P(2ω)) reach their maximal values as Φ locates at a certain angle, here it is around 27° under all demonstrated α. When Φ < 27°, E(2ω) and P(2ω) gradually increase to their maximal value, while when Φ > 27°, they quickly drops. Specially, E(2ω) and P(2ω) are almost undetectable when Φ ≥ 45°. Also, Φ influences the distribution pattern of E(2ω), P(2ω) and their parallel (E(2ω,p), P(2ω,p)) and perpendicular (E(2ω,s), P(2ω,s)) components, such as the number of emission lobes and shape. α has unevenly impact on E(2ω) and P(2ω), the far deviation of α from x axis induce much great decrease of E(2ω) and P(2ω). α = 45° has special influence on the distribution pattern of E(2ω,s), E(2ω), P(2ω,s) as well as P(2ω) compared to those of α = 0° and 90°.

[In vivo reflectance spectroscopy study of different clearing agents on human skin optical clearing].

The changes of skin tissue reflectance spectroscopy before and after being treated with the optical clearing agents of three different types of optical clearing within the wavelength rang of 400-1 000 nm, and the degree of changes in reflectance spectroscopy of each group skin during 0-60 min at 580 nm in vivo were real-time dynamically researched. The reflectance spectroscopy of skin tissue before and after being dealt by the optical clearing agents of glycerol, glucose and propylene glycol was measured using a USB-4000 fiber spectrophotometer at 0, 10, 20, 30, 40, 50 and 60 min. The results showed that the reflectance spectral intensity was distinctly decreased, but the reflectance was significantly increased gradually with the time prolonged. However, different optical clearing agents have different clearing progress. The relative decrease of reflectance of palm skin tissue before and after being dealt by the optical agents of 40% glycerol, 40% glucose and 40% propylene glycol during 10, 20, 30, 40, 50 and 60 min at the wavelength 580 nm is 5%, 7%, 9%, 10%, 11% and 12%, 9%, 13%, 16%, 19%, 21% and 22%, and 14%, 22%, 29%, 32%, 34% and 35%, respectively. The significant improvement in light transmittance and enhancement of light penetration through tissue was demonstrated for all solutions. The effect and processes of optical clearing of skin tissue is not only closely related to the choosing of the clearing agent type, but also related to the treatment time with the skin tissue. The clearing progress of different type optical clearing agent showed the order of 40% propylene glycol, 40% glucose and 40% glycerol.