Abstract Ultra-high-field (UHF) magnetic resonance imaging (MRI) can open up new avenues in clinical diagnostic imaging. Its sensitivity can be further improved using contrast agents (CAs). Therefore, developing low-molecular-weight MR CAs that are efficient under UHF is crucial to ensure taking full advantage of MR imaging at UHF. Moreover, designing highly stable UHF liver-specific CA has been challenging. Here, using dysprosium (Dy3+), which relaxes water protons via a Curie relaxation that increases T2 relaxation substantially with the magnetic field strength, we report a new macrocyclic liver specific Dy3+ complex (Dy[DO3A-EOB]). We observed a 7.06 times higher r2/r1 ratio of Dy[DO3A-EOB] at 9.4 T than that of 1.5 T, which suggests a superior negative-enhancing MR CA at UHF. In vivo MR imaging results further demonstrated that Dy[DO3A-EOB] showed a much strong negative enhancement at UHF (9.4 T) than under a low field (1.5 T). It was also found that, in addition to the ligand structure, the metal itself plays an important role in determining the liver uptake pattern of the CA. Therefore, we successfully demonstrated the first example of a small-molecular-weight liver-specific Dy3+ complex acting as a T2 CA with high sensitivity at UHF for diagnosis of liver diseases.

中文翻译：

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用于超高场磁共振成像的高性能肝胆镝造影剂

摘要 超高场 (UHF) 磁共振成像 (MRI) 可为临床诊断成像开辟新途径。使用造影剂 (CA) 可以进一步提高其灵敏度。因此，开发在 UHF 下有效的低分子量 MR CA 对于确保充分利用 UHF MR 成像至关重要。此外，设计高度稳定的 UHF 肝脏特异性 CA 一直具有挑战性。在这里，我们使用镝 (Dy3+)，它通过居里弛豫使水质子弛豫，随着磁场强度显着增加 T2 弛豫，我们报告了一种新的大环肝脏特异性 Dy3+ 复合物（Dy[DO3A-EOB]）。我们观察到 9.4 T 时 Dy[DO3A-EOB] 的 r2/r1 比是 1.5 T 时的 7.06 倍，这表明 UHF 下具有优越的负增强 MR CA。体内 MR 成像结果进一步表明，Dy[DO3A-EOB] 在 UHF (9.4 T) 下比在低场 (1.5 T) 下显示出强得多的负增强。还发现，除了配体结构之外，金属本身在决定 CA 的肝脏摄取模式方面也起着重要作用。因此，我们成功展示了小分子量肝脏特异性 Dy3+ 复合物作为 T2 CA 的第一个例子，在 UHF 下具有高灵敏度，用于诊断肝脏疾病。