Rongbiao Tang

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

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Publications (9)29.43 Total impact

  • Yan Xi, Yi Chen, Rongbiao Tang, Jianqi Sun, Jun Zhao
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    ABSTRACT: Spectral computed tomography (CT) has attracted considerable attention because of its energy-resolving capability in identifying and discriminating materials. The use of a narrow energy bin can improve energy resolution. However, a narrow energy bin has high noise ratio, which degrades the imaging quality of spectral CT. To address this problem, this study exploits the structure correlations of images in the energy domain and proposed two types of united iterative reconstruction (UIR) algorithms. One type uses the well-reconstructed broad-spectrum image, with all available photons, as a constraint, whereas the other type uses a pseudo narrow-energy image, which is estimated with the use of our proposed structure-coupling (SC) method, as a constraint. The SC method utilizes local structures to connect images that are reconstructed with broad-spectrum and narrow-energy CT datasets. Given a broad-spectrum image, the SC method can accurately estimate its corresponding narrow-energy image. Results show that UIR algorithms significantly outperform conventional iterative reconstruction algorithms for narrow-energy image reconstruction in spectral CT. Among the UIR algorithms, SC-UIR yields the best results.
    IEEE Transactions on Medical Imaging 07/2014; · 4.03 Impact Factor
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    ABSTRACT: The concept of the “neurovascular unit,” emphasizing the interactions between neural and vascular components in the brain, raised the notion that neural progenitor cell (NPC) transplantation therapy aimed at neural repair may be insufficient for the treatment of ischemic stroke. Here, we demonstrate that enhanced neurovascular recovery via cotransplantation of NPCs and embryonic stem cell-derived vascular progenitor cells (VPCs) in a rat stroke model is correlated with improved functional recovery after stroke. We found that cotransplantation promoted the survival, migration, differentiation, and maturation of neuronal and vascular cells derived from the cotransplanted progenitors. Furthermore, it triggered an increased generation of VEGF-, BDNF-, and IGF1-expressing neural cells derived from the grafted NPCs. Consistently, compared with transplantation of NPCs alone, cotransplantation more effectively improved the neurobehavioral deficits and attenuated the infarct volume. Thus, cotransplantation of NPCs and VPCs represents a more effective therapeutic strategy for the treatment of stroke than transplantation of NPCs alone.
    Stem cell reports. 01/2014; 3(1).
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    ABSTRACT: The objective of this study was to explore the potential of CO2 single contrast in-line phase contrast imaging (PCI) for pre-clinical small intestine investigation. The absorption and phase contrast images of CO2 gas production were attained and compared. A further increase in image contrast was observed in PCI. Compared with CO2-based absorption contrast imaging (ACI), CO2-based PCI significantly enhanced the detection of mucosal microstructures, such as pits and folds. The CO2-based PCI could provide sufficient image contrast for clearly showing the intestinal mucosa in living mice without using barium. We concluded that CO2-based PCI might be a novel and promising imaging method for future studies of gastrointestinal disorders.
    Scientific Reports 07/2013; 3:2313. · 5.08 Impact Factor
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    ABSTRACT: OBJECTIVES: To investigate the value of CT spectral imaging in differentiating hepatocellular carcinoma (HCC) from focal nodular hyperplasia (FNH) during the arterial phase (AP) and portal venous phase (PP). METHODS: Fifty-eight patients with 42 HCCs and 16 FNHs underwent spectral CT during AP and PP. The lesion-liver contrast-to-noise ratio (CNR) at different energy levels, normalised iodine concentrations (NIC) and the lesion-normal parenchyma iodine concentration ratio (LNR) were calculated. The two-sample t test compared quantitative parameters. Two readers qualitatively assessed lesion types according to imaging features. Sensitivity and specificity of the qualitative and quantitative studies were compared. RESULTS: In general, CNRs at low energy levels (40-70 keV) were higher than those at high energy levels (80-140 keV). NICs and LNRs for HCC differed significantly from those of FNH: mean NICs were 0.25 mg/mL ± 0.08 versus 0.42 mg/mL ± 0.12 in AP and 0.52 mg/mL ± 0.14 versus 0.86 mg/mL ± 0.18 in PP. Mean LNRs were 2.97 ± 0.50 versus 6.15 ± 0.62 in AP and 0.99 ± 0.12 versus 1.22 ± 0.26 in PP. NICs and LNRs for HCC were lower than those of FNH. LNR in AP had the highest sensitivity and specificity in differentiating HCC from FNH. CONCLUSIONS: CT spectral imaging may help to increase detectability of lesions and accuracy of differentiating HCC from FNH. KEY POINTS : • CT spectral imaging may help to detect hepatocellular carcinoma (HCC). • CT spectral imaging may help differentiate HCC from focal nodular hyperplasia. • Quantitative analysis of iodine concentration provides greater diagnostic confidence. • Treatment can be given with greater confidence.
    European Radiology 01/2013; · 4.34 Impact Factor
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    ABSTRACT: It is crucial to understand the distribution of embolic agents inside target liver during and after the hepatic portal vein embolization (PVE) procedure. For a long time, the problem has not been well solved due to the radiolucency of embolic agents and the resolution limitation of conventional radiography. In this study, we first reported use of fluorescent carboxyl microspheres (FCM) as radiolucent embolic agents for embolizing hepatic portal veins. The fluorescent characteristic of FCM could help to determine their approximate location easily. Additionally, the microspheres were found to be fairly good embolizing agents for PVE. After the livers were excised and fixed, they were imaged by in-line phase contrast imaging (PCI), which greatly improved the detection of the radiolucent embolic agents as compared to absorption contrast imaging (ACI). The preliminary study has for the first time shown that PCI has great potential in the pre-clinical investigation of PVE with radiolucent embolic agents.
    PLoS ONE 01/2013; 8(12):e80919. · 3.53 Impact Factor
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    ABSTRACT: The primary goal of this study was to evaluate the feasibility of using anti-vascular endothelial growth factor receptor 2 (VEGFR2)-conjugated poly(lactic-co-glycolic acid) (PLGA) microspheres as an x-ray phase contrast agent to assess the VEGFR2 expression in cell cultures. The cell lines, mouse LLC (Lewis lung carcinoma) and HUVEC (human umbilical vein endothelial cell), were selected for cell adhesion studies. The bound PLGA microspheres were found to better adhere to LLC cells or HUVECs than unbound ones. Absorption and phase contrast images of PLGA microspheres were acquired and compared in vitro. Phase contrast imaging (PCI) greatly improves the detection of the microspheres as compared to absorption contrast imaging. The cells incubated with PLGA microspheres were imaged by PCI, which provided clear 3D visualization of the beads, indicating the feasibility of using PLGA microspheres as a contrast agent for phase contrast CT. In addition, the microspheres could be clearly distinguished from the wall of the vessel on phase contrast CT images. Therefore, the approach holds promise for assessing the VEGFR2 expression on endothelial cells of tumor-associated vessels. We conclude that PLGA microsphere-based PCI of the VEGFR2 expression might be a novel, promising biomarker for future studies of tumor angiogenesis.
    Physics in Medicine and Biology 04/2012; 57(10):3051-63. · 2.70 Impact Factor
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    ABSTRACT: Super-paramagnetic microbeads are widely used for cell isolation. Evaluation of the binding affinity of microbeads to cells using optical microscopy has been limited by its small scope. Here, magnetic property of microbeads was first investigated by using synchrotron radiation (SR) in-line x-ray phase contrast imaging (PCI). The cell line mouse LLC (Lewis lung carcinoma) was selected for cell adhesion studies. Targeted microbeads were prepared by attaching anti-VEGFR2 (vascular endothelial growth factor receptor-2) antibody to the shell of the microbeads. The bound microbeads were found to better adhere to LLC cells than unbound ones. PCI dynamically and clearly showed the magnetization and demagnetization of microbeads in PE-50 tube. The cells incubated with different types of microbeads were imaged by PCI, which provided clear and real-time visualization of the cell isolation. Therefore, PCI might be considered as a novel and efficient tool for further cell isolation studies.
    PLoS ONE 01/2012; 7(9):e45597. · 3.53 Impact Factor
  • Yan Xi, Rongbiao Tang, Yujie Wang, Jun Zhao
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    ABSTRACT: In the present study, we investigated the potential of gas-filled microbubbles as contrast agents for in-line x-ray phase-contrast imaging (PCI) in biomedical applications. When imaging parameters are optimized, the microbubbles function as microlenses that focus the incoming x-rays to form bright spots, which can significantly enhance the image contrast. Since microbubbles have been shown to be safe contrast agents in clinical ultrasonography, this contrast-enhancement procedure for PCI may have promising utility in biomedical applications, especially when the dose of radiation is a serious concern. In this study, we performed both numerical simulations and ex vivo experiments to investigate the formation of the contrast and the effectiveness of microbubbles as contrast agents in PCI.
    Applied Physics Letters 07/2011; 99(1):011101-011101-3. · 3.52 Impact Factor
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    ABSTRACT: The purpose of the study was to evaluate the feasibility of microbubbles as phase contrast imaging (PCI) agents for angiography applications. The hypothesis was that the introduction of microbubbles into tissue produces a significant change in the refractive index and highlights the lumen of the vessel in PCI. The absorption and phase contrast images of commercially available microbubbles were obtained and compared in vitro. A further increase in contrast was observed in PCI. Microbubbles highlighted the lumen of the renal microvessels, acting as a positive contrast medium in ex vivo imaging. In addition, home-made microbubbles with larger diameters were introduced for image contrast enhancement in living tumor-bearing mice, demonstrating the feasibility of microbubble-based x-ray phase-contrast imaging for tumor vasculature in vivo.
    Physics in Medicine and Biology 06/2011; 56(12):3503-12. · 2.70 Impact Factor