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Multiple imaging modalities are employed independent of one another while managing complex cardiac arrhythmias. To combine electrical, anatomical, and functional imaging in a single catheter system, we developed a balloon catheter that carried 64 electrodes on its surface and an intracardiac echocardiography (ICE) catheter through a central lumen. The catheter system was inserted, and the balloon was inflated inside the left ventricle (LV) of eight dogs with 6-wk-old infarction, created by occlusion in the left anterior descending coronary artery. Anatomy was constructed by ICE imaging (9 MHz) through the balloon. Single-beat noncontact mapping (NCM) was performed via the multielectrode array to reconstruct unipolar endocardial electrograms during sinus rhythm. Standard contact mapping (CM) of the endocardium was also carried out for reference. Myocardial infarction in anterior LV extending from the middle to apical regions was localized both by ICE and NCM and validated by CM and pathology. The overall difference in the activation times between NCM and CM was 3 [+ or -] 1 ms. Unipolar voltage in infarcted middle anterior LV was smaller than the voltage in normal middle inferior LV both by NCM (11 [+ or -] 4 vs. 16 [+ or -] 3 mV; P = 0.002) and CM (11 [+ or -] 3 vs. 20 [+ or -] 4 mV; P < 0.001). Unipolar voltage was also inversely related to infarct transmurality, both by NCM (r = -0.87; P = 0.005) and CM (r = -0.94; P < 0.001). The infarct area by ICE (7.7 [+ or -] 2.9 [cm.sup.2]) was in agreement with CM (bipolar voltage, electrophysiology; myocardial infarction; noncontact mapping

A novel method combined differential evolution algorithm and modified Newton--Raphson method is proposed in this paper to solve the electrical impedance tomography (EIT) inverse problem. This method is applied to the two-dimensional impedance reconstruction of brain section based on a four-layer concentric circle model and real head geometric model. Our simulations demonstrate that the novel combination method is robust and time saving in obtaining high-quality reconstruction in EIT problems for brain imaging studied in this paper. Index Terms--DE--MNR combination, differential evolution (DE) algorithm, electrical impedance tomography (EIT) inverse problem, modified Newton--Raphson (MNR) method.

An efficient improvement, based on the idea of homotopy, is proposed to improve and ensure the convergence of the modified Newton-Raphson algorithm through the continuous mapping of solution space, and the behavior of solution is restrained towards the global convergence after several initial solution mappings. Comparisons of new algorithm with MNR are presented, and the advantage of new algorithm is demonstrated for the problem of electrical impedance tomography. Index terms - Modified Newton-Raphson algorithm, regularization, homotopy, electrical impedance tomography.

This paper presents an optimal design method by means of mean field annealing (MFA). The mean field theory (MFT) is introduced, and a certain MFA application extension based on Peierls inequality is explained in detail, the critical temperature that is important for classes of problem while applying MFA is discussed. With MFA, the optimal size design of electromagnetic device is carried out. The results are compared with two existing algorithms, the modified simulated annealing (MSA) and one-variable stochastic simulated annealing based MFA (S-MFA), in both operating cost and final quantities. To modify the final results to reach the global optimum, Hooke-Jeeves Pattern Search method is adopted. Favorable results show the effectiveness of the proposed scheme.

Presents methods for computing electroencephalography (EEG) and magnetoencephalography (MEG) for constructing a real head model from magnetic resonance imaging (MRI) data. Construction of real head model; Forward computations for EEG and MEG; Results and discussion.

Details a study which proposed a method for biomedical electromagnetic inverse problems based on the technique of maximum mutual information. Theoretical development; Inverse problem of MEG; Conclusion.

In this paper, the Fourier transform based minimum mean square error (FT-based MMSE) method is used to calculate the regional cerebral blood volume (rCBV) in magnetic resonance (MR) perfusion imaging, and the method is improved to handle the existing noise in the imaging process. In the experiments with signal-to-noise ratio (SNR) of 50 dB, the rCBV values were compared with the results using MMSE method. The effects of different SNRs on the estimation of rCBV were analyzed. The experimental results showed that MMSE was a simple way to filter the measurement noise, and could calculate rCBV accurately. Compared with other existing methods, the present method is not sensitive to environment, and furthermore, it is suitable to deal with the perfusion images acquired from the environment with larger SNR.

The Infrared images have been applied in clinical diagnoses, but the images are noisy and blurred. Therefore the smooth processing that can keep edges is needed. Traditional smoothing methods have the common defect that they smooth not only the noise region but also the edges. AMSS (affine morphological scale space) algorithm can be used to better save the edge information, it has the Partial Differential Equation that is of morphological affine invariability and contrast invariability. The smooth processing method based on AMSS is introduced to handle the infrared image in this paper, and the better performance is obtained.

Electrical impedance tomography (EIT) detects tissue composition inside a medium by determining its resistive properties, and uses various electrode configurations to pass a small electric current and measure corresponding potential. We investigated the feasibility of reconstructing scarred tissue inside the heart wall by employing EIT on the basis of a catheter carrying a plurality of electrodes and placed inside the blood-filled heart cavity. We built a computer model of the biological medium, and reconstructed the resistivity distribution using the finite element method and Tikhonov regularization. The results established the successful implementation of the numeric methods and the possibility of localizing and quantifying scarred myocardium. Novel application of EIT from inside the heart cavity could be useful during catheterization and may complement other diagnostic modalities. Further research is necessary to assess the impact of several factors on the accuracy of the reconstruction and include number of electrodes, catheter location, and scar size.

With the ability of imaging the temperature distribution of body, infrared imaging is promising in diagnostication and prognostication of diseases. However the poor quality of the raw original infrared images prevented applications and one of the essential problems is the low contrast appearance of the imagined object. In this paper, the image enhancement technique based on the Retinex theory is studied, which is a process that automatically retrieve the visual realism to images. The algorithms, including Frackle-McCann algorithm, McCann99 algorithm, single-scale Retinex algorithm, multi-scale Retinex algorithm and multi-scale Retinex algorithm with color restoration, are experienced to the enhancement of infrared images. The entropy measurements along with the visual inspection were compared and results shown the algorithms based on Retinex theory have the ability in enhancing the infrared image. Out of the algorithms compared, MSRCR demonstrated the best performance.

The improved Differential Evolution (DE)algorithm is proposed in this paper to solve the resistivity parameters estimation problem based on 2D real head model. Our simulations demonstrate that the improved DE algorithm is robust in obtaining high quality reconstruction, and the convergence is much faster than the usual DE algorithm.Furthermore, the selection of the amplification parameters is much easier.

Introduction: The study tested the feasibility of differentiating radiofrequency ablation lesions from normal myocardium and quantifying their dimensions by myocardial contrast echocardiography (MCE)., Methods and Results: In 11 normal dogs, we created 14 focal and 4 linear lesions at different left ventricular sites.MCE was performed both before and after ablation by using an intracardiac echocardiography catheter (9 MHz)and infusing contrast microbubbles through the left coronary artery. An independent observer examined the lesion pathology. We found that intracardiac echocardiography alone could not delineate lesion dimensions. However, after ablation, MCE localized the lesions as well-defined, low-contrast areas within the normally opacified myocardium. Lesion dimensions byMCE immediately after ablation and 30 minutes later were similar. In 12 focal lesions, the average maximum depth (5.55 +/- 1.38 mm) and average maximum diameter(10.38 +/- 2.09 mm) by MCE were in excellent agreement with the pathologic depth (5.20 +/- 1.45 mm) and diameter(10.61 +/- 1.67 mm). Two focal lesions could not be detected by MCE and later were found to be superficial. Three-dimensional MCE correctly reconstructed the extent and shape of linear lesions compared to pathology (length: 18.7+/- 5.7 vs 18.5 +/- 5.6 mm; maximum longitudinal cross-sectional area: 81.2 +/- 9.6 vs 76.0 +/-10.3 mm(2))., Conclusion: MCE accurately localized and quantified radiofrequency ablation lesions in the normal leftv entricle. This new application of MCE may advance'ablation for managing ventricular arrhythmias that involve intramural or epicardial regions by providing instantaneous anatomic feedback on the effects of ablation during catheterization.

The modified Newton-Raphson (MNR) method is used to solve the inverse resistivity problem in this paper. Using Tikhonov regularization method, comparisons among the L-curve method, the zero-crossing (ZC) method and the generalized cross validation (GCV) method are carried out for determining the regularization parameters of MNR method. By these criterions the appropriate regularization parameters are self-determined and adjusted with the reconstruction iterations. Our simulation experiments on 2D circle model showed that the GCV method can provide the best reconstruction quality with the fastest speed in inverse resistivity problem using MNR method.

Differential evolution (DE) method is used in This work to solve the EEG source localization problem based on equal current dipole model. The single dipole sources with four-shell concentric sphere model are reconstructed. Our simulations demonstrate that DE algorithm is robust in obtaining high quality reconstruction for EEG problems with single current dipole sources.

Three EIT approaches for static imaging of head are investigated in this paper. The modified Newton-Raphson (MNR) method and the differential evolution (DE) algorithm are applied to the impedance reconstruction of 2D section of head based on real head model. Comparisons are carried out on the results obtained using simulated data, and a DE-MNR combination method is proposed, which demonstrated high impedance reconstruction quality with fast convergence in the 2D EIT simulation for static imaging of head.