Uso de contraste em imagens via ressonância magnética

Abstract

In recent years, the use of magnetic resonance imaging (MRI) has grown significantly, primarily due to its effectiveness in diagnosing various pathologies. This examination employs a strong magnetic field and radiofrequency pulses to generate high-resolution images. In a specialized computer, the electrical signal captured by coils is converted into a digital signal, producing the images displayed on the monitor. It is a non-invasive method that does not require the use of ionizing radiation. The introduction of a new class of metallopharmaceutical compounds, known as contrast agents, has significantly impacted image quality and the development of MRI techniques. Considering the high number of procedures performed and the importance of understanding how these agents work, this thesis presents a bibliographic review on the subject. The contrast in each image depends on several variables, making it essential to understand the mechanisms influencing this contrast. To comprehend the role of contrast agents in 𝑇1 e and 𝑇2 relaxation times, it is important to analyze two types of parameters: intrinsic contrasts, which are inherent characteristics of organic tissues and remain unchanged, and extrinsic contrast parameters, which can be adjusted. With a focus on gadolinium-based contrast, its paramagnetic properties enhance the signal in images, allowing for the highlighting of areas with greater vascularization, such as tumors and inflammations. Typically administered intravenously, gadolinium alters the relaxation time of nearby water molecules, resulting in more detailed images with higher contrast. Therefore, it can be concluded that contrast agents are fundamental in MRI techniques, as they provide a strong signal in various tissues, thereby improving image contrast.