Computational study of the effects of arterial bifurcation on the temperature distribution during cryosurgery

Abstract

BackgroundThermally significant blood flows into locally cooled diseased tissues and warm them during cryosurgery so that the iceball is often hard to cover the whole diseased volume. This paper is aimed at investigating the effects of large arterial bifurcation on the temperature distribution during cryosurgery through simulation method.MethodsA parametric geometry model is introduced to construct a close-to-real arterial bifurcation. The three-dimensional transient conjugate heat transfer between bifurcated artery and solid tissues with phase change during cryosurgery is performed by finite volume method.ResultsThe discussion was then made on the effects of the relative position between cryoprobe and artery bifurcation, the inlet velocity of root artery and the layout of multiple cryoprobes on the temperature distribution and iceball evolution. The results show that the thermal interaction between blood flow and iceball growth near bifurcation is considerable complex. The thermal effects of bifurcation could modulate the iceball morphology, severely weaken its freezing volume and prevent the blood vessel from being frozen.ConclusionThe present work is expected to be valuable in optimizing cryosurgery scheme of the situation that the bifurcated artery is embedded into the disease tissue.

A Computational Study on the Effect of Bifurcation Lesions with Different Structures on Blood Velocity and Temperature

“…The density of blood is set to 1050 kg/m 3 , and the viscosity of blood is 0.0035 Pa•s. The time-independent blood flow field is solved though using the SIMPLE algorithm, and the stable temperature field through the second-order upwind algorithm is obtained [17]. The mesh quality significantly affects the simulation results, while the excessively small mesh size would lead to high computing resources needed.…”

“…The initial blood temperature assumes as 37°C. The thermal conductivity of blood is set to 0.55 W/m•K [17]. Fig.…”

“…Wang et al [16] have found that fractal vascular trees have an important effect on tissue temperature and intracellular ice formation during the combined cryosurgery and hyperthermia for cancer therapy. In addition, Zheng et al [17] have studied the thermal effects of bifurcation on the iceball morphology during cryosurgery. Recently, Zhang et al [18] investigated the impact of a bifurcation structure on the heat transfer and temperature distribution of pulsatile blood flow.…”

Recent progress in cryoablation cancer therapy and nanoparticles mediated cryoablation

“…Like the heat sink effect, warm blood flows into locally cooled tissues and raises temperature during cryoablation so it becomes difficult to cover the entire region of diseased tissues with the ice ball. Computational studies of the effects of arterial bifurcation (branching) on the temperature distribution during cryosurgery have shown that the convective heat transfer from bifurcated vessels can limit ice ball formation, cause irregular ice ball shape near the arterial bifurcation and prevent the blood vessels from being frozen 15 . Hence, areas of tissue that have high vascularity may see less benefit from cryoablation, although artery walls may benefit from lower susceptibility to ice-induced damage.…”