Applications of Micro-CT in Imaging Heart Diseases of the Murine Models

Review Article

Austin J Nucl Med Radiother. 2016; 3(1): 1017.

Applications of Micro-CT in Imaging Heart Diseases of the Murine Models

Wang Y¹, Yu C¹, Gao S¹, Lin Li¹, Chen W²* and Zhu Y³*

¹Tianjin University of Traditional Chinese Medicine, China

²Department of Molecular Imaging and Nuclear Medicine, Tianjin Medical University Cancer Institute and Hospital, China

³Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, China

*Corresponding author: Yan Zhu, Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China 300193

Wei Chen, Molecular Imaging & Nuclear Medicine Department, Tianjin Medical University Cancer Hospital, China

Received: March 11, 2016; Accepted: May 24, 2016; Published: May 27, 2016

Abstract

Objective: This non-systematic review discusses the feasibility and advancements on the application of micro-Computed Tomography (micro-CT) in the experimental scope of murine cardiac models.

Methods: Medline and Elsevier were searched for inclusion of relevant studies. A total of 69 articles were downloaded by using ‘micro-CT’, ‘murine’, and ‘heart’ as the keywords including synonyms like ‘mouse’, ‘rat’, ‘rodent’, and 47 of them were retained after review. No limitations in time were considered.

Results: The major application of micro-CT in murine heart research included the following disease models: Atherosclerosis (AS), Myocardial Infarction (MI), Coronary Artery Disease (CAD), Congenital Heart Defects (CHD) and Ischemia/Reperfusion (I/R). Experimental advancements in recent years of micro-CT are listed, while limitations and challenges of micro-CT are briefly discussed. Future trends of the imaging technology are also mentioned in the following part.

Conclusion: A number of years of preclinical practices have proven the feasibility and efficacy of micro-CT. However, new studies based on multimodality are still in demand to help strengthen our understanding of the mechanisms that give rise to the progression of cardiac diseases.

Keywords: Micro-CT; Small animal modeling; In vivo; Ex vivo; Heart disease

Abbreviations

Micro-CT: Micro-Computed Tomography; AS: Atherosclerosis; MI: Myocardial Infarction; CAD: Coronary Artery Disease; CHD: Congenital Heart Defects; I/R: Ischemia/Reperfusion; CNT: Carbon Nano Tube; Micro-CTA: Micro-Computed Tomography Angiography; DM: Diabetes Mellitus; ApoE: ApolipoproteinE; LF: Left Ventricle; CO: Cardiac Output; SV: Stroke Volume; MRI: Magnetic Resonance Imaging; DOB: Dobutamine; Micro-PET: Micro Positron Emission Tomography; Micro-SPECT: Micro Single- Photon Emission Computed Tomography.

Introduction

Over the past 20 years, technical advances in picture acquisition and imaging capabilities have vastly increased the quality and quantity of anatomical and physiopathologic data. Micro-Computed tomography (Micro-CT) is a relatively new modality that rapidly improves high spatial resolution imaging of subtle structures. Due to its high density resolution, relatively low cost and scanning efficiency, micro-CT imaging has been improved over the last decades and has shown its utility in many preclinical practices. Micro-CT, suitable for either ex vivo or in vivo imaging, has evolved from custom-made to commercially available scanner. The purpose of this paper is to provide an overview of applications of micro-CT on murine models with a focus on the diagnostic accuracy and preclinical value in heart disease. Experimental advancements in recent years of micro- CT are listed, while limitations and challenges of micro-CT are briefly discussed. Future trends of the imaging technology are also mentioned in the following section.

CT imaging in clinical use

CT scanner has rapidly evolved from single slice to multi-slice which started from 4-slice systems in 1998 to the latest 256-slice and even 320-slice CT systems [1]. Becker H-C [2] from reviewing the literature and clinical results concluded that cardiac CT could accurately diagnose heart disease or other sources of chest pain, markedly decrease health care expenditure, and reliably predict clinical outcomes with appropriate patient selection.

Cardiac imaging with coronary CT angiography provide indications about: (1) evaluation of coronary arteries for atherosclerosis or anomalies; (2) evaluation of noncoronary pathology including the great vessels, chambers, myocardium, valves, or pericardium; (3) evaluation of cardiac chamber function, including ejection fraction and chamber volumes; (4) evaluation of low-to-intermediate risk symptomatic patients presenting with symptoms of stable angina or acute chest pain; and (5) discordant or inconclusive stress tests [3]. In a recent study [4], it was reported that the sensitivity and specificity of 320-slice Computed Tomography Angiography (CTA) were 100% and 87% to detect significant Coronary Artery Disease (CAD) in patients with acute chest pain in the Emergency Department.

For the cardiac surgeons, the main benefits of Multi-Detector-Row CT (MDCT) lie in the combination of large scan-volume coverage, high spatial resolution, decent identification of calcifications, and the record other thoracic structures simultaneously. Preoperative applications may include the assessment of heart valves, noninvasive evaluation of large thoracic vessels, staging of cardiac tumors, and programming of minimally invasive surgical procedures. After surgery, MDCT examinations particularly facilitate an early identification of severe postoperative complications [5]. MDCT may also be used to assess coronary artery bypass graft patency and to detect transplant-related complications in heart transplant recipients at an early stage. For instance, CT is the modality of choice in patients with aortic stenosis arranged for planning of aortic valve implantation. A multicenter trial of 1038 European patients enrolled at 32 centers (SOURCE-registry) showed overall survival of 76.1% after one year [6,7]. A two-year follow-up of patients in the placement of aortic transcatheter valves (PARTNER) trial supported it as an alternative to surgery in high risk patients with the death rate of 33.9% [8].

Applications of micro-CT in murine heart

Apart from integrative murine modeling of normal physiological function, micro-CT has been successfully used for detecting diseases of bone fracture [9,10], lung fibrosis [11], nonalcoholic fatty liver disease [12] and cardiac injury [13], and understanding mechanisms of pathological conditions. This paper summarized the applications of micro-CT in murine with a focus on the heart. Calcifications, atherosclerosis plagues, shape of vessel and cardiac structure were detected with or without contrast material. Cardiac functional metrics can be computed by 4D cardiac micro-CT data sets. All of the concerned articles were listed in (Table 1) chronologically.