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The precise assessment of vascular heterogeneity in brain tumors is vital for diagnosing, grading, predicting progression, and guiding treatment decisions. However, currently, there is a significant shortage of high-resolution imaging approaches. Herein, we propose a contrast-enhanced susceptibility-weighted imaging (CE-SWI) utilizing the minimalist dextran-modified Fe3O4nanoparticles (Dextran@Fe3O4NPs) for ultrahigh-resolution mapping of vasculature in brain tumors. The Dextran@Fe3O4NPs are prepared via a facile coprecipitation method under room temperature, and exhibit small hydrodynamic size (28 nm), good solubility, excellent biocompatibility, and high transverse relaxivity (r2*, 159.7 mM–1s–1) under 9.4 T magnetic field. The Dextran@Fe3O4NPs-enhanced SWI can increase the contrast-to-noise ratio (CNR) of cerebral vessels to 2.5 times that before injection and achieves ultrahigh-spatial-resolution visualization of microvessels as small as 0.1 mm in diameter. This advanced imaging capability not only allows for the detailed mapping of both enlarged peritumoral drainage vessels and the intratumoral microvessels, but also facilitates the sensitive imaging detection of vascular permeability deterioration in a C6 cells-bearing rat glioblastoma model. Our proposed Dextran@Fe3O4NPs-enhanced SWI provides a powerful imaging technique with great clinical translation potential for the precise theranostics of brain tumors.

Long‐term contrast‐enhanced angiography offers significant advantages in theranostics for diverse vascular diseases, particularly in terms of real‐time dynamic monitoring during acute vascular events; However, achieving vascular imaging with a duration of hours through a single administration of low‐dose contrast agent remains challenging. Herein, a hyaluronic acid‐templated gadolinium oxide (HA@Gd2O3) nanoprobe‐enhanced magnetic resonance angiography (MRA) is proposed to address this bottleneck issue for the first time. The HA@Gd2O3nanoprobe synthesized from a facile one‐pot biomineralization method owns ultrasmall size, good biocompatibility, optimal circulation half‐life (≈149 min), and a relatively high T1relaxivity (r1) under both clinical 3 T (8.215 mM−1s−1) and preclinical 9.4 T (4.023 mM−1s−1) equipment. The HA@Gd2O3nanoprobe‐enhanced MRA highlights major vessels readily with significantly improved contrast, extended imaging duration for at least 2 h, and ultrahigh resolution of 0.15 mm under 9.4 T, while only requiring half clinical dosage of Gd. This technique can enable rapid diagnosis and real‐time dynamic monitoring of vascular changes in a model of acute superior mesenteric vein thrombosis with only a single injection of nanoprobe. The HA@Gd2O3nanoprobe‐enhanced MRA provides a sophisticated approach for long‐term (hour scale) vascular imaging with ultrahigh resolution and high contrast through single administration of low‐dose contrast agent. An improved contrast‐enhanced magnetic resonance angiography (CE‐MRA) technique is proposed for long‐term vascular imaging through a single administration of low‐dose hyaluronic acid‐templated gadolinium oxide (HA@Gd2O3) nanoprobe for the first time. The HA@Gd2O3nanoprobe‐enhanced MRA achieves high‐resolution and high‐contrast vascular imaging with hour‐scale duration,thereby enabling real‐time dynamic monitoring of vascular conditions in acute vascular events.