Yanping Bai

Correlations Between B-Mode Ultrasonic Image Texture Features and Tissue Temperature in Microwave Ablation

Objective. The purpose of this study was to find the correlations between B‐mode ultrasonic tissue texture features and tissue temperature in microwave ablation. Methods. A total of 20 in vitro porcine liver samples were used for microwave ablation experiments. B‐mode ultrasonic images under various temperatures were acquired. The texture features of the differential images based on the gray level histogram, including the mean of the gray scale (MGS), standard deviation of the gray scale, and entropy of the gray scale (ENT), and those based on the gray level co‐occurrence matrix, including the contrast (CON), angular second moment (ASM), inverse difference moment (IDM), and correlation, were extracted. Correlations between the features and liver sample temperature were analyzed. In addition, water bath heating experiments were also performed on 15 in vitro porcine liver samples for analysis validation. Results. The correlation coefficients across the MGS, ENT, and ASM in 4 directions (0°, 45°, 90°, and 135°), the CON and IDM in 3 directions (45°, 90°, and 135°), and a temperature range of 15°C to 90°C were high and greater than 0.9 during microwave ablation. All texture features of the differential B‐mode ultrasonic images changed with rising temperature from 25°C to 60°C during water bath heating. Conclusions. Changes in image features reflect changes in tissue temperature during microwave ablation.

Ultrasound monitoring of temperature and coagulation change during tumor treatment with microwave ablation

Microwave ablation therapy has become an important method for tumor treatment in recent years. The temperature and the coagulation region need real-time noninvasive monitoring to ensure the safety and effectiveness during the treatment. The authors reviewed the ultrasonic monitoring methods for tumor microwave ablation therapy both at home and abroad. In addition, the authors also prospected this technique in the future.

Anatomic Differences in Early Blindness: A Deformation‐Based Morphometry MRI Study

This study aims to investigate the regional changes in the early onset of blindness using the deformation‐based morphometry (DBM) method.

The ECG Tele-Monitor Based on Embedded Web Server

This paper indicates a method on tele-monitoring ECG signals using the embedded web server and dynamic web page technology. The software is developed on ARM9 based on embedded Linux RTOS. Boa web server is used to realize embedded web server function and the dynamic web page is realized by CGI to display ECG parameters on the web page. The experiment result indicates that ECG tele-monitoring system can be implemented by using the embedded web server and dynamic web page technology. It is a simple, low cost tele- monitoring method and is easy to be popularized.

Application Study of Using Ultrasonic Integral Backscatter to Monitor Microwave Coagulation Therapy

Microwave (MW) ablation is a minimally invasive therapeutic strategy for the local treatment of solid malignancies that has received much attention over the past few years. It is very important to detect and evaluate lesions generated by MW during treatment procedures. This study describes one new ultrasonic imaging technique to characterize lesions based on estimation of relative changes in tissue properties derived from backscattered RF data. A single microwave heating antenna was used to produce coagulation in vitro pig liver tissues. The RF signals were recorded as outputs from a modified diagnostic ultrasound system. The integrated backscatter values, which can be used as an indicator of the microstructure and backscattering property of tissues, were calculated in water-bath experiment and MW treatment. The rule of change in integrated backscatter values with temperature has been analyzed by statistics through water-bath experiment. The integrated backscatter ratio values were subsequently used to form images revealing the lesion areas. It is possible using ultrasonic integral backscatter to monitor microwave coagulation. The result shows that this approach can be used to identify the normal and coagulated tissue caused by temperature rise and provide the information of tissue damage.

Features of Ultrasonic Radio Frequency Signal in Microwave Ablation Experiments

The main purpose of this paper was to validate whether the method using features of ultrasonic radio frequency signal (URFS) is effective for non-invasive monitoring in microwave ablation. A total of 15 fresh in vitro porcine livers were experimented. Features of amplitude integral, energy, sum of absolute value of difference (SAD) integral, time-shift and attenuation coefficient of URFS were extracted. Changing rules of these features and the relationships between time-shift, attenuation coefficient and tissue temperature were analyzed. Experimental results showed that maximums of amplitude integral, energy and SAD integral occur at the temperature within 50-60?C. In addition, there was a linear relationship between time-shift and tissue temperature within 60ºC and the ultrasonic attenuation coefficient increased with the temperature rising. Therefore, features of URFS can reflect the change of tissue property and may be used in the non-invasive monitoring of microwave ablation in the future.

Deformation-Based Morphometric study on Blind men's brain structures

Many studies have shown the functional relevance of cross-modal plasticity in blind men. However, few researches have focused on whether such functional plasticity is associated with macroscopic changes of structural anatomy in brain regions. Fortunately, deformation based morphometry (DBM) provides an important tool for the computational anatomy research. In this study we detected the changes of regional volume in brain structures between the blind men and normal controls with DBM method. Information of the difference is derived from the deformation field acquired during HAMMER non-rigid registration. The experimental results show that the regions expanded in the blind men’s brain are located at Brodmann 19,31 while the contracted regions located at Brodmann 17,18. This research is very helpful to discover the relationship between structural anatomy and functional data of blind men at a macroscopic level from neuroimaging perspective.

Morphometric studies of first-episode schizophrenia's brain structures

Many studies have already demonstrated structural brain differences among different patient populations using the morphometric analysis techniques. Voxel-based morphometry (VBM) and deformation-based morphometry (DBM) are the two widely used methods. This paper mainly compared the difference of the two methods and analyzed the reason why many differences exist in the experimental results focused on the same disease. The first-episode schizophrenias brain structures were analyzed using both VBM and DBM. The results based on the two methods exactly evaluated our analysis and provided pathological evidence for the first-episode schizophrenia.

Coagulated region recognition of microwave ablation based on texture analysis of B-mode ultrasound image

Microwave ablation (MA) is popular as a minimally invasive, painless and effective oncological treatment. The paper presents an approach of characterizing the thermal coagulation during microwave ablation using B-mode ultrasound image textures and pattern recognition technique. During the MA treatment, the series of B-mode ultrasound images were obtained. Textures of different ROIs such as gray level histogram and gray level co-occurrence matrices from the obtained ultrasound images were extracted separately. And then these textures were classified by support vectors machine (SVM). The experimental results have shown that the textures of coagulated and non-coagulated region have significant differences. The classification accuracy of SVM by 19 parameters is 0.9528. The method described in this paper is an effective way to realize thermal coagulation monitoring using texture features of B-mode ultrasound images.

Comparison of VBM and DBM Methods by Study of Blind Men's Brain Structures

Many studies have already demonstrated structural brain differences among different patient populations using the morphometric analysis techniques. Voxel-based morphometry (VBM) and deformation-based morphometry (DBM) are the two widely used methods. This paper mainly compared the difference of the two methods and analyzed the reason why many researches exist differences in the experimental results focused on the same disease. The blind mens brain structures were analyzed using both VBM and DBM. The results based on the two methods exactly evaluated our analysis and provided evidence for the functional relevance of cross-modal plasticity studies.