anhuang Li

Layer-resolved colorectal tissues using nonlinear microscopy

In this work, multiphoton microscopy (MPM), based on the nonlinear optical processes two-photon excited fluorescence (TPEF) and second harmonic generation (SHG), was extended to evaluate the feasibility of using MPM to distinguish layers of the bowel wall. It was found that MPM has the ability to identify the four-layer microstructures of colorectal tissues including mucosa, submucosa, muscularis propria, and serosa as there are many intrinsic signal sources in each layer. Our results also showed the capability of using the quantitative analyses of MPM images for quantifying some feature parameters including the nuclear area, nuclear-to-cytoplasmic ratio, and optical redox ratio. This work demonstrates that MPM has the potential in noninvasively monitoring the development and progression of colorectal diseases and then guiding effective treatment.

A new method of assessing the surgical margin in rectal carcinoma—using nonlinear optical microscopy

Nowadays, surgical resection is still the most effective treatment strategy for rectal carcinoma and one of the most important factors affecting whether the operation is successful or not is the surgical margin determination, especially in the distal rectal carcinoma which should take the sphincter-preserving issue into consideration. However, until recently no reliable evaluation method has been developed for this purpose. There are some shortcomings in intraoperative negative surgical margin assessment such as either lack of enough detailed information of biological tissues or the fact that it is time-consuming. Multiphoton microscopy (MPM)—nonlinear optical microscopy, which is based on the nonlinear optical process two-photon excited fluorescence (TPEF) and second harmonic generation (SHG), has the ability to label freely and noninvasively visualize tissue micro-architecture at the sub-cellular level. The advantage of providing high contrast and high resolution biomedical image in real time makes MPM have a wide range of applications in life sciences. In this study, we introduced MPM to identify the boundary between normal and abnormal rectal tissues. MPM images clearly exhibit biological tissue microstructure and its morphological changes in the regions of our interest, which enable it to determine the surgical margin in rectal carcinoma. It can be foreseen that once MPM imaging system is used in clinical examination, it will greatly improve the accuracy of surgical resection.

Visualization of Tumor Response to Neoadjuvant Therapy for Rectal Carcinoma by Nonlinear Optical Imaging

The continuing development of nonlinear optical imaging techniques has opened many new windows in biological exploration. In this study, a nonlinear optical microscopy-multiphoton microscopy (MPM) was expanded to detect tumor response in rectal carcinoma after neoadjuvant therapy; especially normal tissue, pre- and post-therapeutic cancerous tissues were investigated in order to present more detailed information and make comparison. It was found that the MPM has ability not only to directly visualize histopathologic changes in rectal carcinoma, including stromal fibrosis, colloid response, residual tumors, blood vessel hyperplasia, and inflammatory reaction, which had been proven to have important influence on estimation of the prognosis and the effect of neoadjuvant treatment, but also to provide quantitative optical biomarkers including the intensity ratio of SHG over TPEF and collagen orientation index. These results show that the MPM will become a useful tool for clinicians to determine whether neoadjuvant therapy is effective or treatment strategy is approximate, and this study may provide the groundwork for further exploration into the application of MPM in a clinical setting.

Detection of morphologic alterations in rectal carcinoma following preoperative radiochemotherapy based on multiphoton microscopy imaging

BackgroundPreoperative radiochemotherapy improves outcomes in patients with locally advanced rectal carcinoma, and has been used increasingly in patient management. However, there is a strong clinical need to assess tumor response to neoadjuvant treatment, and a non-invasive technique that allows the precise identification of morphologic changes in tumors would be of considerable clinical interest.MethodsIn this study, we used multiphoton microscopy (MPM) to detect morphologic alterations in rectal adenocarcinomas in patients treated with preoperative radiochemotherapy.ResultsMPM was able to identify histopathologic alterations in rectal cancer following preoperative radiochemotherapy, and allowed the qualitative assessment of treatment efficacy and feasibility in relation to dose or strategy.ConclusionThese findings may provide the groundwork for evaluating tumor response to neoadjuvant treatment, thus allowing the tailoring of effective treatment doses and strategies.

A new improved WKB solution of the symmetrical multiple quantum wells planar waveguide

Based on the Helmholtzs equation and energy conservation law for the travelling wave field, the actual wave function for the TE travelling wave in the inhomogeneous dielectric is recommended, the original field distribution functions of the TE mode in symmetrical planar waveguide core layer and cladding layers are suggested. Moreover, the virgin phase shift for total reflection effect at the turning point is proposed, the eigen equation of a new improved WKB method for the symmetrical planar waveguide is given. As the concept of phase delay for optical wave in the dielectric and the new improved WKB method are engaged, the multiple quantum wells planar waveguide is considered as an equivalent of the triplex layer waveguide, a new method for analyzing the symmetrical multiple quantum wells planar waveguide is put forward. Several approximate formulas for computing the effective refractive index, the normalized frequency and mode field distribution are presented. Then, found on the maximal matching efficiency method for the mode field distributions, the expression of Gaussian approximation for the mode field distribution of single mode symmetrical multiple quantum wells planar waveguide is present. As an example, the normalized field distributions of GaAs/GaAlAs symmetrical multiple quantum wells planar waveguide is referred.

Label-free detection of fibrillar collagen deposition associated with vascular elements in glioblastoma multiforme by using multiphoton microscopy.

Glioblastoma multiforme (GBM‐WHO grade IV) is the most common and the most aggressive form of brain tumors in adults with the median survival of 10–12 months. The diagnostic detection of extracellular matrix (ECM) component in the tumour microenvironment is of prognostic value. In this paper, the fibrillar collagen deposition associated with vascular elements in GBM were investigated in the fresh specimens and unstained histological slices by using multiphoton microscopy (MPM) based on two‐photon excited fluorescence (TPEF) and second harmonic generation (SHG). Our study revealed the existence of fibrillar collagen deposition in the adventitia of remodelled large blood vessels and in glomeruloid vascular structures in GBM. The degree of fibrillar collagen deposition can be quantitatively evaluated by measuring the adventitial thickness of blood vessels or calculating the ratio of SHG pixel to the whole pixel of glomeruloid vascular structure in MPM images. These results indicated that MPM can not only be employed to perform a retrospective study in unstained histological slices but also has the potential to apply for in vivo brain imaging to understand correlations between malignancy of gliomas and fibrillar collagen deposition.

Imaging normal and cancerous human gastric muscular layer in transverse and longitudinal sections by multiphoton microscopy

Multiphoton microscopy (MPM) based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) has been widely used for imaging microstructure of biological tissues. In this article, we used MPM to investigate the microstructure changes of normal and cancerous human gastric muscular layer in transverse and longitudinal sections. The results displayed different patterns of microstructure changes of smooth muscular tissue, cell morphology and interstitial fibers in transverse and longitudinal sections, being similar to standard histopathological images but without the need for tissue processing. Our study demonstrated that MPM can bring more detailed complementary information on tissue architecture through observing transverse and longitudinal sections of tissues, which are the important pathological information when the pathologists diagnose the gastrointestinal lesions. These observations indicate that MPM could be an important potential tool to provide real-time pathological diagnosis for gastric cancer in the future. SCANNING 38:357-364, 2016.

Identification of normal and cancerous human colorectal muscularis propria by multiphoton microscopy in different sections

Multiphoton microscopy (MPM) based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) as a potential diagnostic tool is attractive. MPM can effectively provide information about morphological and biochemical changes in biological tissues at the molecular level. In this paper, we attempt to identify normal and cancerous human colorectal muscularis propria by multiphoton microscopy in different sections (both in transverse and longitudinal sections). The results show that MPM can display different microstructure changes in the transverse and longitudinal sections of colorectal muscularis propria. MPM also can quantitatively describe the alteration of collagen content between normal and cancerous muscle layers. These are important pathological findings that MPM images can bring more detailed complementary information about tissue architecture and cell morphology through observing the transverse and longitudinal sections of colorectal muscularis propria. This work demonstrates that MPM can be better for identifying the microstructural characteristics of normal and cancerous human colorectal muscularis propria in different sections.

Crosstalk between Two Nonparallel MQW Waveguides in Y Branch Optical Switch

Based on the mutual coupling coefficient between two identical structure parallel rectangular waveguides and the scalar integral method for analyzing the mutual coupling factor between two nonparallel waveguides, the coupling characteristic between two nonparallel straight rectangular single mode waveguides is discussed, and a computing instance is introduced for showing the crosstalk characteristic between two nonparallel output rectangular waveguides in the Y branch optical switch. These works provide some theoretical support for ascertaining the fundamental parameters of a Y branch MQW waveguides optical switches.

Crosstalk between two nonparallel waveguides in AWG demultiplexer

Based on the mutual coupling coefficient what derived from the method of field distribution analysis, the expressions of coupling factor and coupling efficiency between two identical structure nonparallel straight rectangular waveguides are suggested, and computing instances are introduced for showing the crosstalk between adjacent rectangular waveguides in the star coupler of an AWG demultiplexer. Then, an approximation expression for computing the maximal crosstalk between adjacent arrayed waveguides of an AWG demultiplexer is recommended. As the crosstalk between adjacent arrayed waveguides of an AWG demultiplexer is in need of a limit, the expression for estimating the space between the end face centers of adjacent arrayed waveguides in an AWG demultiplexer is advanced also, and a computing instance is introduced for showing the crosstalk between adjacent arrayed waveguides in an AWG demultiplexer. Finally, based on the Gaussian approximation for the mode field distribution of optical waveguide, the theoretical model of the spectral response efficiency of an AWG demultiplexer is engaged, a computing instance is presented for showing the spectral response characteristic and crosstalk characteristic of an bilateral symmetry structure AWG demultiplexer. These works provides some help for ascertaining the basic parameters of an AWG demultiplexer.