Wen-Jeng Lee

Relations of Epicardial Adipose Tissue Measured by Multidetector Computed Tomography to Components of the Metabolic Syndrome Are Region-Specific and Independent of Anthropometric Indexes and Intraabdominal Visceral Fat

CONTEXT Epicardial adipose tissue (EAT) is a metabolically active visceral fat depot. Its distribution is asymmetrical and primarily concentrated in the grooves. To date, it remains unclear which measurement of EAT best reflects its metabolic risk. OBJECTIVE We aimed to examine the correlations between various multidetector computed tomographic measurements of EAT, metabolic syndrome components, and plasma levels of high-sensitivity C-reactive protein and adipokines. DESIGN, SETTING, AND PARTICIPANTS This study included 148 consecutive patients undergoing multidetector computed tomography prior to diagnostic coronary angiography. Thickness in the grooved segments, cross-sectional areas, and total volume of EAT were measured. The cross-sectional areas of sc and visceral abdominal fat depots were additionally measured in 70 randomly selected patients. RESULTS Thickness of EAT in the left atrioventricular groove was the only EAT measurement significantly correlated with all three metabolic syndrome components (blood pressure, lipid, and glucose components) and plasma levels of resistin and high-sensitivity C-reactive protein after age and gender adjustments. The association between left atrioventricular groove thickness and increasing number of metabolic syndrome components remained significant after additional adjustments for body mass index, waist circumference, and intraabdominal visceral fat area. By using the receiver operating characteristic analysis, the optimal cutoff point for left atrioventricular groove thickness to predict the presence of at least two metabolic syndrome components was 12.4 mm. CONCLUSIONS A simple measurement of EAT thickness in the left atrioventricular groove may provide a more accurate assessment of metabolic risk associated with EAT, which could not be accounted for by anthropometric indexes and intraabdominal visceral fat.

Association of epicardial adipose tissue with coronary atherosclerosis is region-specific and independent of conventional risk factors and intra-abdominal adiposity

OBJECTIVE To elucidate which measurement of epicardial adipose tissue (EAT) best reflects its atherogenic risk, we examined the associations between different EAT measurements and various atherosclerotic parameters of the entire coronary tree and individual coronary arteries. METHODS This study included 224 consecutive patients underwent multidetector computed tomography before diagnostic coronary angiography. Regional thickness, cross-sectional areas, and total volume of EAT were measured. Four atherosclerotic parameters, including severity score, extent score, calcium volume score, and number of coronary arteries with ≥50% luminal stenosis, of the entire coronary tree and individual coronary arteries were assessed. RESULTS Both total EAT volume and thickness of EAT in the left atrioventricular groove were unanimously associated with the presence of coronary atherosclerosis dichotomously defined by the 4 scoring systems. However, only EAT thickness in the left atrioventricular groove, but not total EAT volume, was significantly associated with all 4 parameters of coronary atherosclerosis in a dose-dependent manner, even after adjustments for conventional risk factors, body-mass index, waist circumference, C-reactive protein, and intra-abdominal visceral fat area. Using the receiver-operating-characteristic analysis, 12.2mm was the optimal cutoff point for left atrioventricular groove thickness to predict the presence of significant coronary stenosis (≥50% diameter stenosis). Among the three coronary arteries, left atrioventricular groove thickness was most strongly correlated with ≥50% diameter stenosis in the embedded left circumflex artery by multivariate regression model. CONCLUSIONS Thickness of EAT in the left atrioventricular groove provides a more accurate assessment of its atherogenic risk and is therefore a better coronary risk factor than total EAT volume.

In vivo optical biopsy of hamster oral cavity with epi-third-harmonic-generation microscopy

The first in vivo optical virtual biopsy based on epi-third-harmonic-generation (THG) microscopy is successfully demonstrated using Syrian hamster oral mucosa as a model system. Without complex physical biopsy procedures, epi-THG microscopy can provide high spatial resolution dynamic images of oral mucosa and sub-mucosa in all three dimensions. The demonstrated intra-vital epi-THG microscopy provide high resolution observation of blood flow in the capillary and could be a promising tool to image angiogenesis, which is an important feature for many human diseases including malignancies. The system setup of epi-THG microscopy can be easily integrated with other nonlinear optical microscopy such as second-harmonic generation and multi-photon fluorescence microscopy by using the same laser system to provide better integrated molecular and structural information for future clinical diagnosis. By adding 6% acetic acid solution on the mucosa, THG contrast on the borders of nuclei was found to be greatly enhanced due to the alterations of their linear and nonlinear THG susceptibilities. With a virtual-transition-based technology without using fluorescence, the optical epi-THG biopsy we demonstrated shows promise for future noninvasive in vivo diseases examinations.

Optical biopsy of fixed human skin with backward-collected optical harmonics signals

Harmonics-based optical microscopy has been widely applied in biomedical researches due to its noninvasiveness to the studied biomaterials. Due to momentum conservation consideration, most previous studies collect harmonics generation signals in a forward geometry, especially for third harmonic generation signals. However, the adopted forward transmission type geometry is not feasible for future clinical diagnosis. In this paper, first virtual biopsy based on backward propagating optical higher harmonics, combining second harmonic and third harmonic, is demonstrated in the fixed human skin specimens. In our study, third harmonic generation can provide morphologic information including the distribution of basal cells while second harmonic generation can provide distribution of collagen fibers in dermis. Therefore, this technique is ideal for future noninvasive in vivo skin disease examination without dye.

Three‐Dimensional Reconstruction and Modeling of Middle Ear Biomechanics by High‐Resolution Computed Tomography and Finite Element Analysis

Objective: To present a systematic and practical approach that uses high‐resolution computed tomography to derive models of the middle ear for finite element analysis.

Microsatellite instability in gastric carcinoma with special references to histopathology and cancer stages

To study the molecular mechanism of gastric carcinogenesis, the frequencies of microsatellite instability were evaluated with seven dinucleotide repeat loci in 59 patients with gastric carcinoma. Microsatellite instability at two or more loci was found in 41.5% (17/41) of advanced gastric carcinoma, 21.4% (3/14) of early gastric carcinoma, but not in remnant gastric carcinoma (0/4), with an overall frequency of 33.9% (20/59). Diffuse gastric carcinoma had a similar prevalence (32.1%, 9/28) to intestinal gastric carcinoma (40.7%, 11/27). The frequency of microsatellite instability in gastric carcinoma was not significantly different with respect to age, sex and Helicobacter pylori infection. Microsatellite instability tended to occur more frequently in cancers of the cardia (62.5%, 5/8) compared with cancers of other stomach regions (31.9%, 15/47), but the difference was not statistically significant. These data suggest that microsatellite instability occurs in early gastric carcinoma and its occurrence increases during tumour progression. Furthermore, its frequency was independent of age, gender, histological types and Helicobacter pylori infection.

In vivo and ex vivo imaging of intra-tissue elastic fibers using third-harmonic-generation microscopy

Elastin is an essential and widespread structural protein in charge of the integrity on tissues and organs. In this study, we demonstrate that elastin is a major origin of the third-harmonic-generation (THG) contrast under Cr:forsterite laser excitation operating at 1230nm, with selective visualization inside many tissues such as lung tissues and arteries. In vivo imaging of the nude mouse elastic cartilage beneath the hypodermis by epi- THG microscopy keeps the high resolution and contrast in all three dimensions. Combined with second-harmonic-generation microscopy, THG microscopy exhibits the ability to show the extraordinary proliferation of elastic fibers for the ophthalmic disease of pterygium and the capability of distinguishable visualization from collagen.

All-terahertz fiber-scanning near-field microscopy

We demonstrate a room-temperature-operated all-terahertz (THz) fiber-scanning near-field imaging system. The upright-type THz near-field microscope has a compact size, capable of being integrated with an optical microscope. This transmission illumination near-field system could be a promising tool to distinguish breast cancer from the normal tissue without pathologic staining.

High-sensitivity in vivo THz transmission imaging of early human breast cancer in a subcutaneous xenograft mouse model.

We performed in vivo THz transmission imaging study on a subcutaneous xenograft mouse model for early human breast cancer detection. With a THz-fiber-scanning transmission imaging system, we continuously monitored the growth of human breast cancer in mice. Our in vivo study not only indicates that THz transmission imaging can distinguish cancer from the surrounding fatty tissue, but also with a high sensitivity. Our in vivo study on the subcutaneous xenograft mouse model will encourage broad and further investigations for future early cancer screening by using THz imaging system.

Molecular third-harmonic-generation microscopy through resonance enhancement with absorbing dye

This paper reports a facile and effortless method to realize three-dimensional (3D) molecular third-harmonic-generation (THG) microscopy through the technique of resonance enhancement with absorbing dye. Hematoxylin, a popular absorbing stain, is applied as an example to verify the multiphoton resonant enhancement based on the 1230 nm excitation light and can selectively enhance THG yield at cell nuclear sites in the studied specimens, serving as a cell nucleus contrast agent. It is concluded that combining THG microscopy with the mature staining technique can readily achieve 3D molecular imaging without using fluorescence.