School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.
Math Biosci Eng. 2022 Jul 20;19(10):10213-10251. doi: 10.3934/mbe.2022479.
Abdominal aortic aneurysms are serious and difficult to detect, conditions can be deadly if they rupture. In this study, the heat transfer and flow physics of Abdominal Aortic Aneurysm (AAA) were discussed and associated with cardiac cycle to illustrate the cardiac thermal pulse (CTP) of AAA. A CTP and infrared thermography (IRT) evaluation-based on AAA and abdomen skin surface detection method was proposed, respectively. Infrared thermography (IRT) is a promising imaging technique that may detect AAA quicker and cheaper than other imaging techniques (as biomarker). From CFD rigid-wall and FSI Analysis, the transient bioheat transfer effect resulted in a distinct thermal signature (circular thermal elevation) on the temperature profile of midriff skin surface, at both regular body temperature and supine position, under normal clinical temperature. However, it is important to note that thermography is not a perfect technology, and it does have some limitations, such as lack of clinical trials. There is still work to be done to improve this imaging technique and make it a more viable and accurate method for detecting abdominal aortic aneurysms. However, thermography is currently one of the most convenient technologies in this field, and it has the potential to detect abdominal aortic aneurysms earlier than other techniques. CTP, on the other hand, was used to examine the thermal physics of AAA. In CFD rigid-wall Analysis, AAA had a CTP that only responded to systolic phase at regular body temperature. In contrast, a healthy abdominal aorta displayed a CTP that responded to the full cardiac cycle, including diastolic phase at all simulated cases. Besides, the findings from FSI Analysis suggest the influence of numerical simulation techniques on the prediction of thermal physics behaviours of AAA and abdominal skin surface. Lastly, this study correlated the relationship between natural convective heat transfer coefficient with AAA and provided reference for potential clinical diagnostic using IRT in clinical implications.
腹主动脉瘤是严重且难以检测的疾病,如果破裂可能是致命的。本研究讨论了腹主动脉瘤(AAA)的传热和流动物理学,并将其与心脏周期相关联,以说明 AAA 的心脏热脉冲(CTP)。提出了一种基于 AAA 和腹部皮肤表面检测的 CTP 和红外热成像(IRT)评估方法。与其他成像技术(作为生物标志物)相比,红外热成像(IRT)是一种很有前途的成像技术,可能更快、更便宜地检测 AAA。从计算流体动力学刚性壁和 FSI 分析可以看出,瞬态生物传热效应导致中腹部皮肤表面的温度曲线呈现出明显的热特征(圆形热升高),在正常体温和仰卧位下,在正常临床温度下。然而,需要注意的是,热成像并不是一种完美的技术,它确实存在一些局限性,例如缺乏临床试验。仍然需要做一些工作来改进这种成像技术,使其成为一种更可行和准确的检测腹主动脉瘤的方法。然而,热成像目前是该领域最方便的技术之一,它有可能比其他技术更早地检测出腹主动脉瘤。CTP 用于检查 AAA 的热物理。在计算流体动力学刚性壁分析中,AAA 在正常体温下仅对收缩期有 CTP 响应。相比之下,健康的腹主动脉在所有模拟病例中都有 CTP 响应,包括舒张期。此外,FSI 分析的结果表明,数值模拟技术对 AAA 和腹部皮肤表面热物理行为预测的影响。最后,本研究还关联了自然对流换热系数与 AAA 的关系,为潜在的临床诊断提供了参考,在临床意义上可以使用 IRT。