Rationale: Sensitive and accurate imaging of cancer is essential for early diagnosis and appropriate treatment. For generally employed magnetic resonance imaging (MRI) in clinic, comprehending how to enhance the contrast effect of T₁ imaging is crucial for improving the sensitivity of cancer diagnosis. However, there is no study ever to reveal the clear mechanism of how to enhance the effect of T₁ imaging and accurate relationships of influencing factors. Herein, this study aims to figure out key factors that affect the sensitivity of T₁ contrast-enhanced MRI (CE-MRI), thereby to realize sensitive detection of tumors with low dose of CAs./nMethods: Manganese oxide (MnO) nanoparticles (NPs) with various sizes and shapes were prepared by thermal decomposition. Factors impacting T₁ CE-MRI were investigated from geometric volume, surface area, crystal face to r₂/r₁ ratio. T₁ CE-MR imaging of liver, hepatic and subcutaneous tumors were conducted with MnO NPs of different shapes./nResults: The surface area and occupancy rate of manganese ions have positive impacts on the sensitivity of T₁ CE-MRI, while volume and r₂/r₁ ratio have negative effects. MnO octahedrons have a high r₁ value of 20.07 mM^-1s^-1 and exhibit an excellent enhanced effect in liver T₁ imaging. ZDS coating facilitates tumor accumulation and cellular uptake, hepatic and subcutaneous tumors could be detected with MnO octahedrons at an ultralow dose of 0.4 mg [Mn]/kg, about 1/10 of clinical dose./nConclusions: This work is the first quantitative study of key factors affecting the sensitivity of T₁ CE-MRI of MnO nanoparticles, which can serve as a guidance for rational design of high-performance positive MRI contrast agents. Moreover, these MnO octahedrons can detect hepatic and subcutaneous tumors with an ultralow dose, hold great potential for sensitive and accurate diagnosis of cancer with lower cost, less dosages and side effects in clinic.

中文翻译：

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使用超低剂量 MnO 八面体提高 T1 对比增强 MRI 的敏感性和敏感性诊断肿瘤

基本原理：灵敏而准确的癌症成像对于早期诊断和适当治疗至关重要。对于临床上普遍使用的磁共振成像（MRI），了解如何增强T ₁成像的对比效果对于提高癌症诊断的敏感性至关重要。然而，目前还没有研究揭示如何提高T ₁成像效果的明确机制以及影响因素的准确关系。在此，本研究旨在找出影响T ₁对比增强MRI（CE-MRI）灵敏度的关键因素，从而实现低剂量CAs对肿瘤的灵敏检测。/n方法：通过热分解制备了各种尺寸和形状的氧化锰 (MnO) 纳米粒子 (NPs)。从几何体积、表面积、晶面与r ₂ / r ₁比率研究影响T ₁ CE-MRI的因素。使用不同形状的 MnO NPs 对肝脏、肝脏和皮下肿瘤进行T ₁ CE-MR 成像。/n结果：锰离子的表面积和占有率对T ₁ CE-MRI的灵敏度有积极影响，而体积和r ₂ / r ₁比率有负面影响。MnO 八面体具有高r₁值为 20.07 mM ^-1 s ^-1并在肝脏T ₁成像中表现出优异的增强效果。ZDS 涂层促进肿瘤积累和细胞摄取，使用 MnO 八面体可以在 0.4 mg [Mn]/kg 的超低剂量下检测肝脏和皮下肿瘤，约为临床剂量的 1/10。/n结论：这项工作是第一个定量的影响T ₁灵敏度的关键因素研究MnO 纳米颗粒的 CE-MRI，可作为合理设计高性能正性 MRI 造影剂的指导。此外，这些MnO八面体可以以超低剂量检测肝脏和皮下肿瘤，在临床上以更低的成本、更少的剂量和更少的副作用对癌症进行灵敏准确的诊断具有巨大潜力。