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The registration of preoperative magnetic resonance (MR) images and intraoperative ultrasound (US) images is very important in the planning of brain tumor surgery and during surgery. Considering that the two-modality images have different intensity range and resolution, and the US images are degraded by lots of speckle noises, a self-similarity context (SSC) descriptor based on local neighborhood information was adopted to define the similarity measure. The ultrasound images were considered as the reference, the corners were extracted as the key points using three-dimensional differential operators, and the dense displacement sampling discrete optimization algorithm was adopted for registration. The whole registration process was divided into two stages including the affine registration and the elastic registration. In the affine registration stage, the image was decomposed using multi-resolution scheme, and in the elastic registration stage, the displacement vectors of key points were regularized using the minimum convolution and mean field reasoning strategies. The registration experiment was performed on the preoperative MR images and intraoperative US images of 22 patients. The overall error after affine registration was (1.57 ± 0.30) mm, and the average computation time of each pair of images was only 1.36 s; while the overall error after elastic registration was further reduced to (1.40 ± 0.28) mm, and the average registration time was 1.53 s. The experimental results show that the proposed method has prominent registration accuracy and high computational efficiency.
Subject(s)
Humans , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Ultrasonography/methods , Algorithms , Surgery, Computer-Assisted/methodsABSTRACT
Objective To investigate the diagnostic value of multimodal MRI for dual pathology (DP)in temporal lobe epilepsy (TLE).Methods The methods of voxel based morphometry (VBM)and voxel based analysis (VBA)had been employed to study the difference between 36 patients (20 cases left group and 16 cases right group)with TLE caused by DP and 36 healthy subjects on the grey matter (GM)volume,exponential apparent diffusion coefficient (eADC)and cerebral blood flow (CBF)value.The corresponding statistical study had also been conducted.Results There were significant statistical differences (FDR correction,P=0.001)between healthy subj ects and patients on the GM volume,eADC and CBF value.Those values decreased with diseased laterality and wider range in functional imaging.These overlaying abnormal brain regions were located in the temporal pole (superior temporal gyrus), temporal pole (middle temporal gyrus),middle temporal gyrus,inferior temporal gyrus,fusiform gyrus,hippocampus and parahippocampal gyrus which represented in all examination results.Conclusion The combined findings of multimodal MRI can improve the localization ability of seizure focus in TLE,which caused by DP,before surgery.
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BACKGROUND:Exploration on nonlinear acoustic response of the contrast agent microbubble contained in microvessel under ultrasound excitation is of great significance to maximizing ultrasonic energy deposition, promoting the development of quantitative imaging algorithm, revealing the damage mechanism or evaluating the targeted therapy, and overcoming the limitations of the traditional methods that are mainly used in large-size vessels, and measuring microvessel elasticity. OBJECTIVE:To build a microvessel containing an ultrasound microbubble, revealing the internal mechanism among ultrasound, microbubble, blood flow and microvessel. METHODS:Based on the finite element analysis and the lumped parameter model, three-dimensional microvessel containing microbubble model was built and simulated on Comsol Multiphysics 4.4 platform. RESULTS AND CONCLUSION:Microbubble exhibited slower radial motion compared with axial motion due to vascular wal limitation, but maximum displacement and stress were found near the microbubble center because of the oscil ation coupling of the microbubble with the vascular wal . Under the same ultrasound pressure, the excitation frequency increased, accompanied by decreased and stabilized microvessl constriction and dilation;under the same frequency, with the enhancement of ultrasound pressure, the local microbubble oscil ation lasted longer. With the increase of Young’s modulus of the microvessel wal , the frequency of microbubble oscil ation was reduced, while the amplitude increased. Al these findings indicate that the frequency of microbubble oscil ation increased with the reduction of microvessel size, while its amplitude decreased. The frequency of microbubble oscil ation increased with the enhancement of ultrasound excitation, while the amplitude decreased. On the contrary, ultrasound pressure affected the dynamic characteristics of microbubble and microvessel. In particular, it was the first to demonstrate that the elasticity of microvessel has approximate linear positive correlation with the amplitude of microbubble oscil ation, which reveals the relationship between microvessel elasticity and microbubble response so as to provide theoretical basis for indirect measurement of microvessel elasticity.
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The virtual surgical system is a surgical simulated software adopting image processing and 3-D visualization technology. It can help the surgeons to determine the operating position, simulate operation and plan for a optimal operation. VTK which exhibits high performance in visualization and ITK which has strong ability in image processing were integrated to solve the key problems such as image segmentation, image registration and fusion, 3-D reconstructing and virtual cropping. Experiments indicated that the integrated 3-D virtual surgical system can help surgeons to observe the surgical process and improve its reliability and quality.
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The contents and features of medical imaging technology and medical image processing course are introduced in this paper,relationship of the two courses and their different parts are mainly discussed.Contents and the multimedia courseware are then designed.
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Anisotropic diffusion has good effect on reducing noise and preserving edge, in fact it's an iterative process. An important question is to decide when the process should be stopped. The stopping time is chosen by minimal mean square error, signal-to-noise ratio and minimal correlation coefficient based on the information of the original (ideal) images and noises. The entropy and mutual information in information theory is adopted to develop a criterion on stopping diffusion process. The performance of the different criterions is proved by experiments, the specialty and the applying condition is also discussed.
Subject(s)
Humans , Anisotropy , Brain , Diagnostic Imaging , Diffusion , Radiographic Image Interpretation, Computer-Assisted , Methods , Tomography, X-Ray ComputedABSTRACT
It's required to display axial,coronal and sagittal images simultaneously of the volume data in medical 3-D visualization system.A rectangle with special color will be drawn to signify the current selected image,while the window gets the focus.This paper discusses how to draw rectangle outside the focused window by extending the class of capturing mouse and keyboard events.Results are given to verify the provided method.
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Medical Image has been increasingly applied in clinical diagnosis and treatment.It is very important to make use of large numbers of images in medical image management system in order to help clinician to analyze and diagnose.The traditional information retrieval techniques are not fit for retrieving large scale medical image databases.It is a very promising idea to introduce Content-based Image Retrieval(CBIR) technique into indexing medical image databases.The structure of the Content-based Medical Image Retrieval System(CBMIR) is introduced,and the key problems are mainly investigated,which included image segmentation,feature extraction,similarity searching and feedback mechanism.At last,the status and development of CBMIR are discussed.