Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention

Shanghai, China

Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention

Shanghai, China

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Xie X.,Fudan University | Wang Y.,Fudan University | Wang Y.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention
PLoS ONE | Year: 2015

Background: Coronary blood flow can always be matched to the metabolic demand of the myocardium due to the regulation of vasoactive segments. Myocardial compressive forces play an important role in determining coronary blood flow but its impact on flow regulation is still unknown. The purpose of this study was to develop a coronary specified flow regulation model, which can integrate myocardial compressive forces and other identified regulation factors, to further investigate the coronary blood flow regulation behavior. Method: A theoretical coronary flow regulation model including the myogenic, shear-dependent and metabolic responses was developed. Myocardial compressive forces were included in the modified wall tension model. Shear-dependent response was estimated by using the experimental data from coronary circulation. Capillary density and basal oxygen consumption were specified to corresponding to those in coronary circulation. Zero flow pressure was also modeled by using a simplified capillary model. Result: Pressure-flow relations predicted by the proposed model are consistent with previous experimental data. The predicted diameter changes in small arteries are in good agreement with experiment observations in adenosine infusion and inhibition of NO synthesis conditions. Results demonstrate that the myocardial compressive forces acting on the vessel wall would extend the auto-regulatory range by decreasing themyogenic tone at the given perfusion pressure. Conclusions: Myocardial compressive forces had great impact on coronary auto-regulation effect. The proposed model was proved to be consistent with experiment observations and can be employed to investigate the coronary blood flow regulation effect in physiological and pathophysiological conditions. © 2015 Xie, Wang. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Xie X.,Fudan University | Wang Y.,Fudan University | Wang Y.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention
Microcirculation | Year: 2015

Objective: Auto-regulatory reserve of coronary blood flow is nonuniformly distributed across the ventricular wall. MCF are thought to play an important role in determining the transmural distribution of myocardium blood flow. Here, impacts of MCF on coronary flow regulation are analyzed using a theoretical model. Methods: Coronary microvessels at various depths in the ventricular wall are represented by parallel segments. Nine vessel regions are connected in series to represent one parallel segment, which includes four vasoactive regions regulated by the wall tension, the shear stress and the metabolic demand. The nonuniform distribution of MCF is modeled and its effects on coronary flow regulation are taken into consideration by using a modified tension model and a vessel collapse model. Flow regulation behaviors in both normal and obstructed coronary circulation are simulated. Results: Model-predicted auto-regulatory curve is shifted to the high pressure region by including the effect of MCF. Model-predicted flow distributions in obstructed coronary circulation show that severe stenosis in coronary artery would first impede myocardial blood flow in subendocardial layer. Conclusions: The model results indicate that MCF plays an important role in coronary flow regulation and also in determining the transmural distribution of myocardium blood flow. © 2015 John Wiley & Sons Ltd.


Deng W.,Fudan University | Deng W.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention | Li F.,Fudan University | Li F.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention | And 4 more authors.
Stereotactic and Functional Neurosurgery | Year: 2014

Background/Aims: Augmented reality (AR) technology solves the problem of view switching in traditional image-guided neurosurgery systems by integrating computer-generated objects into the actual scene. However, the state-of-the-art AR solution using head-mounted displays has not been widely accepted in clinical applications because it causes some inconvenience for the surgeon during surgery. Methods: In this paper, we present a Tablet-AR system that transmits navigation information to a movable tablet PC via a wireless local area network and overlays this information on the tablet screen, which simultaneously displays the actual scene captured by its back-facing camera. With this system, the surgeon can directly observe the intracranial anatomical structure of the patient with the overlaid virtual projection images to guide the surgery. Results: The alignment errors in the skull specimen study and clinical experiment were 4.6 pixels (approx. 1.6 mm) and 6 pixels (approx. 2.1 mm), respectively. The system was also used for navigation in 2 actual clinical cases of neurosurgery, which demonstrated its feasibility in a clinical application. Conclusions: The easy-to-use Tablet-AR system presented in this study is accurate and feasible in clinical applications and has the potential to become a routine device in AR neuronavigation. © 2013 S. Karger AG, Basel.


Xu T.,Fudan University | Lu S.,Fudan University | Zhang H.,Fudan University | Zhang H.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention
Journal of Cellular and Molecular Medicine | Year: 2016

Telocytes (TCs) are a novel type of interstitial cells present in a wide variety of organs and tissues (www.telocytes.com). Telocytes are identified morphologically by a small cell body and specific long prolongations (telopodes) alternating thin segments (podomers) with dilations (podoms). The presence of TCs in rat meninges has been identified in previous research. We here present further evidence that TCs existed in canine dura mater, closed to capillary and surrounded by a great deal of collagen fibres under transmission electron microscope. 2016 John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.


Li H.,Fudan University | Li H.,University of California at Los Angeles | Zhang H.,Fudan University | Zhang H.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention | And 3 more authors.
Journal of Cellular and Molecular Medicine | Year: 2014

Telocytes (TCs) are a novel type of interstitial cell of whom presence has been recently documented in many tissues and organs. However, whether TCs exists in bone marrow is still not reported. This study aims to find out TCs in mice bone marrow by using scanning electron microscope (SEM) and transmission electron microscope (TEM). SEM images showed that in mice bone marrow most of TCs have small spherical cell body (usually 4-6 μm diameter) with thin long telopodes (Tps; usually one to three). The longest Tp observed was about 70 μm, with an uneven calibre. Direct intercellular contacts exist between TCs. TEM shows mitochondria within dilations of Tps. Also, by TEM, we show the close spatial relations of Tps with blood vessels. In conclusion, this study provides ultrastructural evidence regarding the existence of TCs in mice bone marrow, in situ. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.


Zhang Z.,Fudan University | Liu D.,Fudan University | Deng M.,Chongqing University | Ta D.,Fudan University | And 2 more authors.
Ultrasound in Medicine and Biology | Year: 2014

The experimental observation of cumulative second-harmonic generation of fundamental Lamb waves in long bones is reported. Based on the modal expansion approach to waveguide excitation and the dispersion characteristics of Lamb waves in long bones, the mechanism underlying the generation and accumulation of second harmonics by propagation of the fundamental Lamb waves was investigated. An experimental setup was established to detect the second-harmonic signals of Lamb wave propagation in long bones invitro. Through analysis of the group velocities of the received signals, the appropriate fundamental Lamb wave modes and the duration of the second-harmonic signals could be identified. The integrated amplitude of the time-domain second-harmonic signal was introduced and used to characterize the efficiency of second-harmonic generation by fundamental Lamb wave propagation. The results indicate that the second-harmonic signal generated by fundamental Lamb waves propagating in long bones can be observed clearly, and the effect was cumulative with propagation distance when the fundamental Lamb wave mode and the double-frequency Lamb wave mode had the same phase velocities. The present results may be important in the development of a new method to evaluate the status of long bones using the cumulative second harmonic of ultrasonic Lamb waves. © 2014 World Federation for Ultrasound in Medicine & Biology.


Yan S.,Fudan University | Wu X.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention | Wang W.,Fudan University
International Journal of Hyperthermia | Year: 2016

Purpose In pulmonary veins (PVs) isolation (PVI), radiofrequency (RF) energy is often used to create a linear lesion for blocking the accessory conduction pathways around PVs. By using transient finite element analysis, this study compared the effectiveness of phase-shift mode (PsM) ablation with bipolar mode (BiM) and unipolar mode (UiM) in creating a continuous lesion and lesion depth in a 5-mm thick atrial wall. Materials and methods Computer models were developed to study the temperature distributions and lesion dimensions in atrial walls created through PsM, BiM, and UiM. Four phase-shift angles – 45°, 90°, 135°, and 180° – were considered in PsM ablation (hereafter, PsM-45°, PsM-90°, PsM-135°, and PsM-180°, respectively). Results At 60 s/30 V peak value of RF voltage, UiM and PsM-45° did not create an effective lesion, whereas BiM created a lesion of maximum depth and width approximately 1.01 and 1.62 mm, respectively. PsM-135° and PsM-180° not only created transmural lesions in 5-mm thick atrial walls but also created continuous lesions between electrodes spaced 4 mm apart; similarly, PsM-90° created a continuous lesion with a maximum depth and width of nearly 4.09 and 6.12 mm. Conclusions Compared with UiM and BiM, PsM-90°, PsM-135° and PsM-180° created continuous and larger lesions in a single ablation procedure and at 60 s/30 V peak value of RF voltage. Therefore, the proposed PsM ablation method is suitable for PVI and linear isolation at the left atrial roof for treating atrial fibrillation. © 2016 Taylor & Francis


Li H.,Fudan University | Li H.,University of California at Los Angeles | Lu S.,Fudan University | Liu H.,Taishan Medical University | And 3 more authors.
Journal of Cellular and Molecular Medicine | Year: 2014

Here, we here present scanning electron microscope data for the existent telocytes (TCs) on the endothelial surface of the wall of pig coronary arteries, internal thoracic arteries and carotid arteries. These cells have a small (8.39 ± 1.97 μm/4.95 ± 0.91 μm) cell body of different shapes (from round to triangular, depending on the number of cellular prolongations) with very long (of about 30 μm) and thin cellular processes called telopodes (Tps), which have uneven calibre. The number of Tps ranges between 2 and 6. Tps typically present the alternation of podoms and podomers, and also have a dichotomic branching pattern. These data could influence the current attempts for elucidating the role(s) of TCs. © 2014 The Authors.


Zhang C.,Fudan University | Wang M.,Fudan University | Song Z.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention
IEEE Transactions on Biomedical Engineering | Year: 2011

In image-guided neurosurgery, brain tissue displacement and deformation during neurosurgical procedures are a major source of error. In this paper, we implement and evaluate a linear-elastic-model-based framework for correction of brain shift using clinical data from five brain tumor patients. The framework uses a linear elastic model to simulate brain-shift behavior. The model is driven by cortical surface deformations, which are tracked using a surface-tracking algorithm combined with a laser-range scanner. The framework performance was evaluated using displacements of anatomical landmarks, tumor contours and self-defined evaluation parameters. The results show that tumor deformations predicted by the present framework agreed well with the ones observed intraoperatively, especially in the parts of the larger deformations. On average, a brain shift of 3.9 mm and a tumor margin shift of 4.2 mm were corrected to 1.2 and 1.3 mm, respectively. The entire correction process was performed in less than 5 min. The data from this study suggest that the technique is a suitable candidate for intraoperative brain-deformation correction. © 2011 IEEE.


Ma L.,Fudan University | Ma L.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention | Song Z.J.,Fudan University | Song Z.J.,Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention
Clinical Neurology and Neurosurgery | Year: 2013

Objective To ascertain whether diffusion tensor imaging (DTI) metrics including tensor shape measures such as planar and spherical isotropy coefficients (CP and CS) can be used to distinguish high-grade from low-grade gliomas. Methods Twenty-five patients with histologically proved brain gliomas (10 low-grade and 15 high-grade) were included in this study. Contrast-enhanced T1-weighted images, non-diffusion weighted b = 0 (b0) images, fractional anisotropy (FA), apparent diffusion coefficient (ADC), CS and CP maps were co-registered and each lesion was divided into two regions of interest (ROI): enhancing and immediate peritumoral edema (edema adjacent to tumor). Univariate and multivariate logistic regression analyses were applied to determine the best classification model. Results There was a statistically significant difference in the multivariate logistic regression analysis. The best logistic regression model for classification combined three parameters (CS, FA and CP) from the immediate peritumoral part (p = 0.02), resulting in 86% sensitivity, 80% specificity and area under the curve of 0.81. Conclusion Our study revealed that combined DTI metrics can function in effect as a non-invasive measure to distinguish between low-grade and high-grade gliomas. © 2013 Elsevier B.V.

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