论文标题
高敏感且高吞吐量的磁共振温度计使用超顺磁性纳米颗粒
Highly sensitive and high throughput magnetic resonance thermometry using superparamagnetic nanoparticles
论文作者
论文摘要
磁共振成像（MRI）在癌性肿瘤的热消融过程中可实现非侵入性3D温度。尽管T1或T2对比度MRI对温度相对不敏感，但具有更高温度敏感性的技术（例如化学位移或扩散成像）受到运动伪像和长时间扫描时间的影响。我们描述了一种高度敏感和高吞吐量MR温度计的方法，该方法不容易受到运动伪影的影响。我们使用超顺磁性铁氧化铁纳米颗粒（SPION）来破坏水质子的T2。运动变窄导致T2与扩散常数之间的比例，仅取决于特定环境中的温度。我们的结果表明，对于纯水，核磁共振（NMR）线宽和T2遵循与水的自扩散常数相同的温度依赖性。因此，T2映射是在SPIONS存在下的扩散映射，而T2是温度计。对于纯水，在9.4 T MRI扫描仪中的64 x 64图像（体素尺寸= 0.5 mm x 0.5 mm x 3 mm）的T2映射导致温度分辨率为0.5 k，扫描时间为2分钟。这表明一种高度敏感且高吞吐量的MR温度计技术可能可用于监测热疗法期间的生物组织或诊断。
Magnetic resonance imaging (MRI) enables non-invasive 3D thermometry during thermal ablation of cancerous tumors. While T1 or T2 contrast MRI are relatively insensitive to temperature, techniques with greater temperature sensitivity such as chemical shift or diffusion imaging suffer from motional artifacts and long scan times. We describe an approach for highly sensitive and high throughput MR thermometry that is not susceptible to motional artifacts. We use superparamagnetic iron oxide nanoparticles (SPIONs) to spoil T2 of water protons. Motional narrowing results in proportionality between T2 and the diffusion constant, dependent only on the temperature in a specific environment. Our results show, for pure water, the nuclear magnetic resonance (NMR) linewidth and T2 follow the same temperature dependence as the self-diffusion constant of water. Thus, T2 mapping is a diffusion mapping in the presence of SPIONs, and T2 is a thermometer. For pure water, a T2 mapping of a 64 x 64 image (voxel size = 0.5 mm x 0.5 mm x 3 mm) in a 9.4 T MRI scanner resulted in a temperature resolution of 0.5 K for a scan time of 2 minutes. This indicates a highly sensitive and high throughput MR thermometry technique potentially useful for monitoring of biological tissues during thermal therapies or for diagnosis.
