Frencken Adriaan L, Blasiak Barbara, Tomanek Boguslaw, Kruk Danuta, van Veggel Frank C J M
Department of Chemistry, University of Victoria, Victoria, BC V8W 2Y2, Canada.
Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, BC V8W 2Y2, Canada.
Materials (Basel). 2025 May 14;18(10):2290. doi: 10.3390/ma18102290.
Magnetic resonance imaging (MRI) is widely used as a medical imaging technique due to its non-invasive nature, high spatial contrast, and virtually unlimited depth of penetration. Different modalities can be used for contrast in MRI, including (spin-lattice) and or * (spin-spin) proton relaxation times, and specific contrast agents (CAs) have been developed that locally enhance the contrasts in MRI images. We present a method combining - and -specific CAs in a single imaging technique, referred to as correlation MRI. This technique allows different CAs to be used simultaneously to visualize contrast between multiple types of tissue in the same image when applied as targeted CAs. An obstacle for the quantitative use of correlation MRI is that and relaxivity changes generated by CAs are not independent of each other. Here, we measured relaxivities in mixtures with various concentrations of Cas, including Magnevist (Gd-based, primarily a T CA) and Feridex (Fe- and Fe-based, primarily a T CA), and compared them to theoretically predicted values. It was found that, at clinically relevant concentrations, relaxivities of the mixtures deviate from linearly added values. We finally propose a three-dimensional calibration curve to quantitatively determine the concentration in mixtures of CAs, based on the measured relaxivities.
磁共振成像（MRI）因其非侵入性、高空间对比度和几乎无限的穿透深度，被广泛用作一种医学成像技术。MRI中可使用不同的模态来形成对比，包括（自旋晶格）和或*（自旋 - 自旋）质子弛豫时间，并且已经开发出了特定的造影剂（CAs），可在局部增强MRI图像中的对比度。我们提出了一种在单一成像技术中结合 - 和 - 特异性CAs的方法，称为相关MRI。当用作靶向造影剂时，该技术允许同时使用不同的造影剂来在同一图像中可视化多种类型组织之间的对比度。相关MRI定量使用的一个障碍是造影剂产生的 和 弛豫率变化并非相互独立。在此，我们测量了含有不同浓度造影剂混合物的弛豫率，这些造影剂包括马根维显（基于钆，主要是一种T造影剂）和菲立磁（基于铁和铁，主要是一种T造影剂），并将它们与理论预测值进行比较。结果发现，在临床相关浓度下，混合物的弛豫率偏离线性相加值。我们最终基于测量的弛豫率提出了一条三维校准曲线，以定量确定造影剂混合物中的浓度。
