[Design and development of the multi-dimensional ultrasonic reconstruction and visualization system].

The design and development of multi-dimensional ultrasonic reconstruction and visualization system (MURVS) have been described in the present paper. This system is basically composed of four modules: the data input/output module, image segmentation and arrangement module, multi-dimensional reconstruction module, and the dynamic visualization module. At first, some algorithms used in the system are introduced by the authors, including the AVI segmentation algorithm, three-dimensional interpolation algorithm, and volume rendering algorithms. Then the key questions of techniques to be discussed are: how to design the main modules, how to solve the dynamic visualization problem, and how to implement the system. The experiments indicate that MURVS is able to reconstruct all three-dimensional data fields in one cardiac cycle of a patient within 4 seconds, and dynamically display the motion of the heart. It allows the medical professionals to select different parameters when observing the reconstructed results. This is very helpful for medical professionals to reach more accurate diagnoses of their patients' diseases.

[Quantitative functional evaluation on right ventricle with auto-segmentation and three-dimensional reconstruction].

The authors first segment the right ventricle regions from the echocardiographics by introducig a seeded region growth algorithm. Then they reconstrunct the three dimensional data field of right ventricle by using rotary scanning interpolation algorithm. And then, the authors propose a layer-by-layer, row-by-row, and voxel-by-voxel approach based on the interpolation results to estimate the volume of right ventricle. Finally, some right ventricle functional parameters such as EDV (End-diastolic volume), ESV (End-systolic volume), and RVEF (Right ventricular ejection fraction) are computed according to the volume results. The volume variation curves of several patients during a cardiac cycle have been successfully plotted out. The obtained results are compared with those from Tomtec medial image workstation. The comparison indicates the proposed approach is practical and meaningful.

Intracardiac echocardiography-guided his bundle pacing and atrioventricular nodal ablation.

BACKGROUND: His bundle pacing (HBP) results in rapid synchronous ventricular activation, but has been associated with long procedure times and compromised pacing and sensing performance. This study sought to reduce procedure time and radiation exposure, and improve electrical performance through more accurate lead placement. METHODS: Intracardiac echocardiography (ICE) was used to guide ablation and lead implantation at the His bundle, right atrial appendage (RAA), and right ventricular apex (RVA), and to assess cardiac function. Custom bipolar screw-in leads with steerable delivery sheaths and an ablation catheter were navigated using ICE (local detailed imaging) and fluoroscopy (global imaging) in anesthetized closed-chest canines (N = 6). RESULTS: HBP (N = 1) or His + ventricular septal pacing (N = 5) was achieved in all canines. The QRS width was 59.7 +/- 5.3 ms for canines in sinus rhythm (SR) and 82.8 +/- 16.6 ms for canines with HBP (P = 0.0086). The QRS width for RVA pacing was 106.3 +/- 18.4 ms (P = 0.042 vs HBP; P = 0.00013 vs SR). HBP thresholds were 3.0 +/- 1.0 volts at 0.5 ms (N = 5 due to a late exit block in one canine). The average procedure duration for His lead placement was 40 +/- 28 minutes (range of 3-81 minutes) and the total procedural X-ray exposure was 12 +/- 12 minutes (range of 2-30 minutes). Hemodynamic performance was similar for HBP and RAA pacing. CONCLUSIONS: Feasibility of ICE guidance for His pacing and precision ablation of the atrioventricular (AV) node has been shown. This anatomic approach improved accuracy, limited X-ray exposure, and might allow His pacing in patients with preexisting AV nodal block.

[Computer-aided diagnosis of fatty liver based on ultrasonic images].

This study aims to provide a computer-aided method for the diagnosis of fatty liver by B-scan ultrasonic imaging. Fatty liver is referred to the infiltration of triglycerides and other fats of the liver cells, which affected the texture of liver tissue. In this paper, some features including mean intensity ratio, as well as angular second moment, entropy and inverse differential moment of gray level co-occurrence matrix were extracted from B-scan ultrasonic liver images. Feature vectors which indicated two classes of images were created with the four features. Then we used kappa-means clustering algorithm, self-organized feature mapping (SOFM) artificial neural network and back-propagation (BP) artificial neural network to classify these vectors. The accuracy rate of kappa-means clustering algorithm was 100% for normal liver and 63.6% for fatty liver. The results of SOFM neural network showed that the accuracy rate was 84.8% for normal liver and 90.9% for fatty liver. The accuracy rate of neural network was 100% both for normal liver and fatty liver. This technology could detect the characteristics of B-scan images of normal liver and fatty liver more accurately. It could greatly improve the accuracy of the diagnosis of fatty liver.

[A method based on image processing and analyzing technology for estimating the activity of mesenchymal stem cells].

Cell culture is one of the usual methods for studying living cell and tissue, the method presented in this paper is based on image processing and analyzing technology for activity estimation of mesenchymal stem cells (MSCs). The existing activity estimation methods are costly, complex and invasive. In this method, thresholding is used to preprocess image and to separate out the growth hallow. Then the area is calculated by counting the pixels of the growth hallow. The changes of the activity estimated by this method are similar to those by corresponding cellular experiments. Compared with the existing methods in biology, medicine or medical cellular science, this method is easier, faster, cost-effective and non-invasive. The proposed method has been proved to be efficient by primary experiments of MSCs.

[Estimation of fetal weight on the basis of neural network].

The ultrasonic estimation of fetal weight at delivery is of important prognostic significance in obstetrical practice. The convertional regression formulas used for estimating fetal weight have the disadvantage of less reliability. In this study, we used the back propagation neural network (BP) to estimate Fetal Weight. Some input variables were adopted in constructing the BP model: biparietal diameter (BPD), cerebellum transverse diameter (TCD), abdominal circumference (AC), liver length (LL), femur length (FL), fetal thigh soft tissue thickness (FSTT), and gestational age (GA). The fetal weights of 109 singleton fetuses were estimated. In the training group and validation group, coincidence rates were 89.77% and 76.19% respectively. The results show that the estimation based on neural network is more accurate than that by regression method. GA, its unit is not week but day in our formulas, is very valuable in combination with other ultrasonic parameters on estimation.

Automatic segmentation of echocardiography based on a morphological reconstruction algorithm.

OBJECTIVE: To improve the precision of the traditional segmentation of echocardiogram, by suppressing the influence from inherent speckle noises in medical ultrasonic images. METHOD: An automatic segmentation method based on reconstructed morphology was proposed in this paper. First, the opening and closing operations by reconstruction were imposed to the ultrasonic image. Second, the top-hat operation was used to extract the bright and/or dark features and to find out the boundaries corresponding to these features, whereby implemented the automatic segmentation. RESULT: The segmented echocardiogram had less artificial boundaries resulted from speckle noise, and could accurately be extracted the artery and ventricle. CONCLUSION: The presented method can detect both dark and bright objects accurately, and the boundary has a fine continuity. In addition, the algorithm is also applicable to the extraction of sole bright/dark features, accordingly to reduce the complexity and time needed and to improve the accuracy.

[A feasibility study on use of surface and interface properties for evaluating hemocompatibility of carbonaceous biomaterials].

In order to evaluate diamond like carbon film (DLC), DLC containing Si, graphite, diamond film (DF), low temperature isotropic carbon film (LTIC) and SiC, we investigated the correlations between surface energy parameters and hemocompatibility indices such as kinetic clotting time, hemolysis and platelet consumption. An analysis of T-type correlation degree in the Grey system theory was performed. The results showed: (1) all of correlation degrees between kinetic clotting time and polar surface energy parameters were positive, but for critical surface tension, the correlation degree was negative; among five of surface energy parameters, interface tension had the highest relation degree (0.63) with kinetic clotting time, and critical surface tension (-0.43) took the second place; (2) on the contrary, all of correlation degrees between hemolysis and polar surface energy parameters were negative, but for critical surface tension, the correlation degree was positive; and that which had closer correlations with hemolysis were still interface tension (-0.43) and critical surface tension (0.29); (3) critical surface tension had the highest relation degree (0.68) with platelet consumption, and surface tension (0.32) took the second place; (4) kinetic clotting time possessed higher negative correlation degrees with hemolysis (-0.57) and platelet consumption (-0.36). These data indicate that kinetic clotting time depended on a balance between the polarity of surface and the limited humidifying of water on the surface, and that platelet consumption was based on good humidification and power polarity of surface, while hemolysis was promoted by the aid of chromatic dispersion action stemming from the surface and fully humidifying of water on the surface. There was "seesaw effect" between kinetic clotting time and hemolysis or platelet consumption, hence the hemocompatibility of carbonaceous biomaterials could be equivalently evaluated by using kinetic clotting time as an index. It has been confirmed: (1) successive occurrences, including adhesion, deformation and collection of platelets on the material surfaces as results of protein adsorption, are the major mechanism of blood coagulation of carbonaceous materials; (2) the hemocompatibility of carbonaceous biomaterials can be evaluated by using critical surface tension as an index. These findings may underpin the hemocompatibility evaluation of carbonaceous biomaterials based on surface properties.

[Dynamic three-dimensional reconstruction of tissue Doppler ultrasound heart images].

Traditional 3D ultrasound reconstruction system can just depict 3D anatomical structure, so it is very difficult to give an accurate assessment of the functionality of the heart. In this study, a dynamic 3D reconstruction method of tissue Doppler ultrasound heart images is set up based on the combination of 3D reconstruction and tissue Doppler imaging technique. Dynamic 3D acceleration field of heart movement is reconstructed to supply a new approach of accurate assessment of functionality of the heart. The key problem of vector interpolation and fusion imaging in the process of acceleration vector field reconstruction is solved. The 3D acceleration field of heart movement and anatomical structure is reconstructed separately from the original tissue Doppler acceleration images and showed in the same field. The experimental results testified that the 3D space relationship of acceleration and anatomical structure is correct and this method can supply more information for the assessment of heart functionality.

[A medical ultrasonic image filtering method based on anisotropic diffusion].

OBJECTIVE: To remove the speckle noise in ultrasonic images by using anisotropic diffusion method. METHOD: Based on anisotropic diffusion, a partial differential equation, of which the initial data was the input images, was transformed into differential forms and solved with iterations. The speckle scale function of the equation was modified to make better use in filtering medical ultrasonic images. RESULT: By comparing the results with other three filters, the anisotropic diffusion method could smooth the speckles very well and the edge of the image was also clear. CONCLUSION: Anisotropic diffusion can remove the speckle noise effectively and has great potential in filtering medical ultrasonic images.

[Energy mechanism of effects of carbon phase components on hemocompatibility for DLC].

The correlations between surface energy parameters and carbon phase components in six diamond like carbon film (DLC) samples made in different ways and processing conditions were further investigated using the analysis of T-type correlation degree in the Grey system theory based on our earlier studies such as the determination of carbon phase and surface energy parameters, the analyses of carbon phase components, surface energy parameters and adhesive characteristic of platelets for DLC. The results showed: (1) as a whole critical surface tension has the closest relation with carbon phase components, chromatic dispersion branch of surface tension takes the second place, but for the other four parameters, the correlation is weak; (2) DLC phase has larger negative correlation (degrees -0.57, -0.33) with critical surface tension and chromatic dispersion branch of surface tension, while its correlation degrees with the other four parameters related to polarity are all positive values smaller than 0.20; (3) C-H phase and C-O phase have larger positive correlation (degrees 0.48, 0.25) with critical surface tension. We have come to three conclusions (1) DLC phase plays a dominant part in hemocompatibilioty of DLC by powerfully decreasing humidification and limitedly increasing polarity; (2) the energy mechanism of platelet deformation enhanced by C-H phase and C-O phase involves increasing the critical surface tension of DLC; (3) the hemocompatibility of DLC can be evaluated by using the critical surface tension as index and using the content of DLC phase and additional content limitation of C-H phase and C-O phase as standard. This study has provided a theoretical basis for evaluating the hemocompatibility of DLC based on surface properties.

[Analysis of Grey correlation between surface energy and adhesive characteristic of platelet for DLC].

In this study, the diamond like carbon (DLC) samples made from different processes and processing conditions, were subjected to the test of platelet adhesion. The surface energy parameters such as surface tension, critical surface tension, interface tension, adhesive power, and polar branch and chromatic dispersion branch of surface tension based on determining balanced contact angle of ethanol, water and different ratios of ethanol/water solution on surfaces of the samples were calculated, respectively. Then the effects of these parameters on the amounts and deformation index of the platelets adhering to the samples were assessed by analyzing the T-type correlation degree in the Grey system. The results showed: (1) all degrees of correlation between surface energy parameters and adhesion amounts of platelet are positive, but for deformation index, the correlation degrees are negative except for critical surface tension; (2) the adhesion amounts of platelet increase with the rising polar branch of surface tension, while the deformation index increases with rising chromatic dispersion branch of surface tension; (3) Both adhesion amounts and deformation index of platelet are positively correlated with critical surface tension to a higher degrees; (4) the effects of polar branch of surface tension on adhesion amounts and deformation index of platelet keep pace with the surface tension, interface tension and adhesive power. Thus two important conclusions have been obtained: (1) the adhesive characteristic of platelets to the surface of DLC is closely related with the surface energy of DLC; the hemocompatibility of DLC is decided by the balance between the polarity of DLC surface and the limited humidifying water on the surface; there is a blood compatible range delimited by critical surface tension; (2) adhesion and deformation of platelets on surface of DLC have different energy mechanism: polar surface is advantageous to the adhesion, while the deformation is achieved with the aid of chromatic dispersion action stem from the surface.

Ectopic osteoinduction and early degradation of recombinant human bone morphogenetic protein-2-loaded porous beta-tricalcium phosphate in mice.

The present study investigated the ectopic osteoinduction and early degradation of recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded porous beta-tricalcium phosphate (beta-TCP) in mice. The porous beta-TCP with 50 microg of rhBMP-2 (n = 25) and porous beta-TCP (control group, n = 25) were implanted into muscle pouches in the right and left thigh of 28-day-old mice (n = 25), respectively. At every time point (3, 7, 14, 21 and 28 days after implantation), five mice were euthanized and the histological examinations of implantation sites were performed. In addition, the alkaline phosphatase (ALP) activity was also quantitatively analyzed. For the rhBMP-2-loaded group, blood vessel formation and immature cartilage was observed within the porous beta-TCP 3 days after implantation. Mature cartilage was observed 7 days after implantation of rhBMP-2-loaded porous beta-TCP. Newly formed woven bone, lamellar bone as well as marrow were observed 14 and 21 days after implantation of the rhBMP-2-loaded porous beta-TCP. Lamellar bone and marrow were observed 28 days after implantation of the rhBMP-2-loaded porous beta-TCP. For the control group, no bone or cartilage was observed at all time points. However, multinucleated giant cells and fibrous tissues were observed in the control group at 7 and 28 days after implantation, respectively. At 21 and 28 days after implantation, porous beta-TCP was observed to fragment indicating early degradation of the porous beta-TCP in both groups. In addition, ALP was observed to be significantly higher in the rhBMP-2-loaded beta-TCP as compared to the control beta-TCP. It was concluded from this study that the rhBMP-2-loaded porous beta-TCP induced blood vessel and ectopic bone formation.

[Recommendations for mitral regurgtitation with Doppler echocardiography].

Mitral regurgitation is one of the most serious heart diseases. With the development of up-to-date medical techniques, the ratio of successful operations in valvular repair and valvular replacement has been largely improved. Examinations before operation become extremely crucial. Accurate method is required in assessing the degree of mitral regurgitation to set down the corresponding treatment method. This paper reviews the evaluation methods of mitral valvular regurgitation provided in these years and presents comments on the application areas as well as the merits and disadvantages of those methods. Finally, the prospect of the method based on three-dimensional Doppler ultrasonographic imaging on mitral regurgitation is discussed.

[Analysis of correlation degree between phase components and adsorptive amounts of serum proteins for DLC film].

In the present paper, the influence of carbon phase components of three kinds of diamond like carbon (DLC) films, viz. DLC, DLC rich in graphite and DLC rich in diamond films, on adsorption of human serum albumin (HSA), human serum fibrinogen (HFG) and immunoglobin (IgG) was quantitatively analyzed by use of T-type correlation degree in the grey system theory. Through the analysis, the rational explanation for adsorptive amounts variations of the serum proteins with phase components in the experiment is reached and some essential conclusions have been obtained: (1) The effect of graphite phase and C-H phase on HSA adsorption are greater than that of other phase components; with the increase of these two phase coumponents, the adsorptive amounts of HSA decrease; (2) The powerful influence on HFG adsorption stems from DLC phase and C-O phase; with the decrease of DLC phase or the increase of C-O phase, the adsorptive amounts of HFG increase; (3) All of the carbon phase components have only limited influence on IgG adsorption in positive or negative fashion with a little difference in degree; (4) DLC phase has both effects of enhancing adsorption for HSA and weakening adsorption for HFG and IgG, thus its influence on the hemocompatibility of DLC films is much more important than that of other phase components.

[Effects of the variation in components of DLC on protein adsorption].

Diamond-like carbon(DLC) was prepared by means of plasma source ion implantation-ion beam enhanced deposition. Through the heat treatment upon DLC in air and in depressed Ar gas, the DLC rich in graphite, DLC rich in diamond, and other kinds of DLC used in the study were obtained respectively. For the three kinds of DLC, the components of carbonaceous phase were analysed by X-ray photoelectron spectroscopy (XPS), the adsorptive amounts of human serum albumin (HSA), human serum fibrinogen (HFG) and human serum immunoglobin (IgG) on their surfaces in the condition of constant temperature were determined by radio isotope 125I labelling method. Results showed the graphite phase and diamond phase in DLC increased by two times or so respectively after the aforementioned different heat treatment. In pace with the increase of these foreign phases, the adsorptive amounts of HFG and IgG on DLC greatly increase but the adsorptive amounts of HSA on DLC decrease; furthermore, there is a change from non-selective adsorption of three human serum proteins into selective adsorptions of HFG and IgG prior to HSA. These results indicate that the foreign phases in DLC such as graphite, diamond, C-H phase and C-O phase have a great effect on protein adsorption on DLC and hence a negative effect on the hemocompatibility of DLC. The mechanisms for the increase of graphite phase and diamond phase in the process of heat treatment were also discussed in this paper.

[Fast volume rendering of echocardiogram with shear-warp algorithm].

Shear-warp is a volume rendering technology based on object-order. It has the characteristics of high speed and high image quality by comparison with the conventional visualization technology. The authors introduced the principle of this algorithm and applied it to the visualization of 3-D data obtained by interpolating rotary scanning echocardiogram. The 3-D reconstruction of the echocardiogram was efficiently completed with high image quality. This algorithm has a prospective application in medical image visualization.

[Probe into the platelets adhesion to carbonaceous biomaterials].

In order to clarify the mechanism of blood coagulation for carbonaceous biomaterials, the plasma rich in platelet was obtaining through the centrifugation of fresh human blood containing anticoagulant. Adhesive tests of platelets to surfaces of DLC, diamond film(DF) and graphite was carried out at 37 degrees C. Then, morphology observation, counting and deformation index calculation of the platelets adhering to surfaces of the three kinds of materials were analyzed by SEM. It has been shown that there is no any platelet on the surface of DLC, but on DF and graphite, a lot of platelets are observed with serious deformation of type III-V. The adhesive amounts of platelet on the surface of graphite are more than those on DF, but deformation index of platelets on the surface of DF is more than that on graphite. Three major conclusions have been obtained through comparative analyses with our previous researches and related literatures: (1) Adhesion, deformation and collection of platelets occurred in succession on material surfaces resulting from protein adsorption are the major mechanism of blood coagulation of carbonaceous materials; (2) Deformation degree of platelets is more important hemocompatibility index than consumption ratio of platelets for carbonaceous materials; (3) The purer the DLC, the better is the hemocompatibility. These conclusions possess important directive function for improving and designing carbonaceous materials used in artificial mechanical heart valves.

[Axis registration and image interpolation of rotary scanning echocardiogram].

The object of this study was to work at accurate axis registration and interpolation methods for multi-dimension reconstruction of rotary scanning ultrasonic medical images. At first, time-field curves of the images' axes were analyzed according to their characteristic points and the axial direction registration was realized. Similar matrix was used to find registration pixels line near the axes of two images. Auto-correlation function and Fourier spectrum were used to evaluate the effects of axes registration. Second, an interpolation method was studied for the special space distribution of rotary scanning images. Results of experiments indicate that the axes registration and interpolation methods were suitable to rotary scanning medical images. The quality of reconstruction can be greatly improved by registration-based interpolation methods.

[Research of myocardial velocity characteristics of paced canine heart based on ultrasonic Doppler tissue imaging].

OBJECTIVE: To quantitatively analyze the characteristics of regional myocardial velocities of paced heart over His bundle, and explore the myocardial velocity pattern. METHOD: 5 dogs were paced at 120 times/min over His bundle. We defined the His bundle adjacent region and the top region of interventricular septum (IVS) as our regions of interest (ROI). Images of Doppler tissue velocity in ROI and corresponding electrocardiograms were observed and recorded by a 2-D Color Doppler tissue imaging (DTI) system. Quantitative velocities of myocardial DTI images were mapped by a neural network from the image sequences. Finally the velocity characteristics of the myocardium around His bundle and IVS were analyzed. RESULT: We obtained myocardial time-velocity curves in the ROI, and some results based on those curves: In the His bundle adjacent region intervals of myocardial systole and diastole were (209.75 +/- 19.41) ms and (294.50 +/- 17.87) ms, respectively. Myocardial systole velocity (S), early diastole velocity (E) and late diastole velocity (A) were (5.43 +/- 1.53) cm/s, (3.95 +/- 1.18) cm/s and (1.72 +/- 0.77) cm/s, respectively, E/A was 2.06 +/- 0.95; In IVS region intervals of myocardial systole and diastole were (191.33 +/- 17.23) ms and (294.70 +/- 17.91) ms, respectively. S, E and A were (3.17 +/- 1.34) cm/s, (2.17 +/- 0.64) cm/s and (1.48 +/- 0.52) cm/s, respectively. E/A was 1.305 +/- 0.287. CONCLUSION: The primary characteristics of myocardial velocities paced over His bundle were: 1) Myocardial velocities in His bundle adjacent region were higher than those in IVS. 2) E/A was greater than one.