The improvement of cardiac multispiral computed tomography protocol for planning interventional arrhythmia management

Purpose. The study aimed at the comparison of computed tomography (СT) contrast enhancement (CE) protocols for optimal visualization of cardiac chambers, evaluation of their impact on results of non-invasive superficial cardiac mapping.Methods. The study included 93 patients with heart rhythm disorders in whom catheter ablation of arrhythmia was planned. Noninvasive cardiac mapping for arrhythmia localization was performed and included multichannel ECG-registration and CT with intravenous СE (1st group - monophasic (50 patients), 2nd group - split-bolus (18 patients), 3rd group - with pre-bolus (25 patients). Qualitative and quantitative (measurement of mean blood attenuation in four chambers, calculation of ventricular-myocardial [VM] contrast-to-noise ratio VM-LV и VM-RV for the left ventricle [LV] and right ventricle [RV], respectively) parameters were compared between the groups. Fusion of ECG and CT data was carried out a semi-automatic mode with a non-invasive imaging complex.Results. Regardless of CE technique, sufficient and homogeneous contrast attenuation was obtained for the left atrium (LA) and LV (mean blood attenuation in LA more than 278 HU, LV 250 HU, VM-LV 0,582). In most cases, the enhancement of the right heart was insufficient with the monophasic protocol; the average CT density was lower than 200 HU, VM-RV 0,256. The split-bolus protocol improved visualization of the right atrium (RA) and RV (blood density in RA 258HU, RV 227HU, VMRV 0,541); however, there was a heterogeneity of the RA cavity due to artifacts from the superior vena cava (VC) and unenhanced blood from the inferior VC. Pre-bolus administration increased the contrast ratio between RA myocardium and blood due to the improvement of blood CT density in the inferior VC (blood density 294 HU). The quality of RV CE was similar to 2nd group (blood density 264 HU, VM-RV 0,565).Conclusion. The split-bolus and with pre-bolus CE protocols improve visualization of the RV, supporting the high-level enhancement of the left heart. The protocol with a pre-bolus is preferable for exact differentiation of the right atrial endocardial contour.

The improvement of cardiac multispiral computed tomography protocol for planning interventional arrhythmia management

Purpose. Comparison of computer tomography (СT) contrast enhancement (CE) protocols for optimal visualization of cardiac chamber, definition it’s influence on results of non-invasive superficial cardiac mapping.Materials and methods. The study included 93 patients with heart rhythm disorders who planned catheter ablation of arrhythmia. Noninvasive cardiac mapping was made for topical diagnostics. It includes multichannel ECG-registration and CT with intravenous СE (1st group monophasic (50 patients), 2nd group split-bolus (18 patients), 3rd group with pre-bolus (25 patients). Qualitative and quantitative (measurement of mean blood attenuation in four chambers, calculation of ventricular-myocardial contrast-to-noise ratio VM-LV и VM-RV for left ventricle (LV) and right ventricle (RV), respectively) parameters were compared between groups. Fusion of ECG and CT data was made semi-automatic with diagnostic complex «Amycard 01К».Results. Regardless of CE technique was noted sufficient and homogeneous contrast attenuation of left atrium (LA) and LV (mean blood attenuation in LA more than 278 HU, LV 250 HU, VM-LV 0,582). Enhancement of right heart was insufficient with monophasic protocol, in most cases the average CT density was lower than 200 HU, VM-RV 0,256. Split-bolus protocol improves visualization of right atrium (RA) and RV (blood density in RA 258HU, RV 227HU, VM-RV 0,541), however there was heterogeneity of RA cavity because of artifacts from superior vena cava (VC) and unenhanced blood from inferior inferior VC. Using of pre-bolus increases contrast ratio between RA myocardium and blood due to increasing CT density of blood in inferior VC (blood density 294 HU). Quality of right ventricle CE was similar to 2nd group (blood density 264 HU, VM-RV 0,565).Conclusion. CE protocols split-bolus and with pre-bolus improve visualization of right ventricle, supporting the high level enhancement of left heart. Protocol with pre-bolus is preferable for exact differentiation of right atrial endocardial contour.

Hemodynamics Numerical Simulation of Stenosis Bifurcation

The main purpose of this research is to analyze blood flow in various scenarios such as 20%, 50% and 80% blockage in blood vessel due to aortic atherosclerosis. Valuable Information for clinical diagnosis of cardiovascular diseases can be obtained by analyzing the behavior of blood flow and its variations. An idealized numerical model of the human bifurcated aorta is created then simulations of steady blood flow were performed on this model and various parameters have been considered. The model parameters include the blood flow velocity, pressure, wall shear stress (WSS) of vessels, constant blood density and constant viscosity. The data computed from software indicates behavior of blood flow according to changes in physical properties of blood vessel. These results are mostly similar to physiological and pathological results of vessels observed in clinical practice. This study will eventually help to find the Fluid Structure Interaction (FSI) of blood flow and blood vessel which will be bring a favorable change in cardiovascular diseases treatments.

Numerical Simulation of Pulsating Flow over Blood Vessel Robot

In order to study the influence of pulsating blood flow to robot and blood vessel, UDF programming of the inlet velocity is defined as the boundary condition, and the model simulate the turbulent blood flow. Moreover, in this situation, this paper analyzes the influence caused by blood parameters for the biggest surface pressure on robot. The results are showed that the variation of pressure and velocity is different on different position at 0.08s and 0.27s, and the surface pressure of the robot become greater by the increase of blood density or viscosity.