Manso Jimeno Marina, Vaughan John Thomas, Geethanath Sairam
Department of Biomedical Engineering, Columbia University in the City of New York, New York, New York, USA.
Columbia Magnetic Resonance Research Center, Columbia University in the City of New York, New York, New York, USA.
NMR Biomed. 2023 Mar 13:e4921. doi: 10.1002/nbm.4921.
Presently, magnetic resonance imaging (MRI) magnets must deliver excellent magnetic field (B ) uniformity to achieve optimum image quality. Long magnets can satisfy the homogeneity requirements but require considerable superconducting material. These designs result in large, heavy, and costly systems that aggravate as field strength increases. Furthermore, the tight temperature tolerance of niobium titanium magnets adds instability to the system and requires operation at liquid helium temperature. These issues are crucial factors in the disparity of MR density and field strength use across the globe. Low-income settings show reduced access to MRI, especially to high field strengths. This article summarizes the proposed modifications to MRI superconducting magnet design and their impact on accessibility, including compact, reduced liquid helium, and specialty systems. Reducing the amount of superconductor inevitably entails shrinking the magnet size, resulting in higher field inhomogeneity. This work also reviews the state-of-the-art imaging and reconstruction methods to overcome this issue. Finally, we summarize the current and future challenges and opportunities in the design of accessible MRI.
目前，磁共振成像（MRI）磁体必须提供优异的磁场（B）均匀性，以实现最佳图像质量。长磁体能够满足均匀性要求，但需要大量超导材料。这些设计导致系统体积庞大、重量沉重且成本高昂，并且随着场强增加问题会愈发严重。此外，铌钛磁体对温度的严格耐受性给系统增加了不稳定性，需要在液氦温度下运行。这些问题是全球范围内MRI密度和场强使用存在差异的关键因素。低收入地区使用MRI的机会较少，尤其是高场强MRI。本文总结了对MRI超导磁体设计的拟议修改及其对可及性的影响，包括紧凑型、减少液氦用量以及特殊系统。减少超导体用量必然会缩小磁体尺寸，导致更高的场不均匀性。这项工作还回顾了用于克服此问题的最新成像和重建方法。最后，我们总结了可及性MRI设计中当前和未来的挑战与机遇。
