Effect of external magnetic field on realistic bifurcated right coronary artery hemodynamics

Abstract

Diagnostic technology based on magnetic fields is commonly used in medicine for diagnosis and therapy. However, the exposure to strong electromagnetic fields has adverse outcomes in patients. Thus, the objective of the current study is to investigate the effect of applying external uniform magnetic fields on the blood flow in both healthy and diseased cases of right coronary artery and determine the safe values of the applied magnetic field strengths. The diseased cases include a 40% stenosed artery along with two blood disorder cases with a hematocrit level of 20% and 60%. A comprehensive three-dimensional steady non-Newtonian flow model is developed using the Casson model to investigate the effect of the magnetic field on both shear rate and hematocrits. The model is numerically simulated at different values of magnetic field strengths and its orientation. The results indicated that the magnetic field in the Y-direction has a dominant effect compared to other directions. Moreover, the maximum increase in the main branch mass flow rate fraction is about 6.2%. Another interesting finding is that the wall shear stress is slightly affected by the magnetic field strength. For the stenosed case, it is found that the high magnetic field strengths can reduce the formulation of the vortices and hence reduce the risk of thrombosis, which agrees with published works. Additionally, the obtained results confirm that using a magnetic field up to 11.7 T, which is used in magnetic resonance imaging devices, is safe, and has a slight effect on blood flow parameters such as the wall shear stress.

Lightweight and drift-free magnetically actuated millirobots via asymmetric laser-induced graphene

“…To validate the ability of the fabricated GH millirobots to conduct therapeutic drug delivery, we conducted in vivo manipulation of a GH millirobot in a rat’s stomach. A GH millirobot, which was manipulated using a rotating magnetic field with a strength of 12 mT (far below the safety level with respect to human exposure 52 , 53 ), was imaged in real-time by using a digital subtraction angiography (DSA) device. To ensure unambiguous identification and tracking, the path of the GH millirobot’s movement had to be sufficiently long for the imaging system (which had resolution of ~200 μm); therefore, a rat was selected because of its adequately sized stomach.…”