Phosphocreatine (PCr) plays a vital role in neuron and myocyte energy homeostasis. Currently, there are no routine diagnostic tests to noninvasively map PCr distribution with clinically relevant spatial resolution and scan time. Here, we demonstrate that artificial neural network-based chemical exchange saturation transfer (ANNCEST) can be used to rapidly quantify PCr concentration with robust immunity to commonly seen MRI interferences. High-quality PCr mapping of human skeletal muscle, as well as the information of exchange rate, magnetic field and radio-frequency transmission inhomogeneities, can be obtained within 1.5 min on a 3 T standard MRI scanner using ANNCEST. For further validation, we apply ANNCEST to measure the PCr concentrations in exercised skeletal muscle. The ANNCEST outcomes strongly correlate with those from³¹P magnetic resonance spectroscopy (R = 0.813,p < 0.001,ttest). These results suggest that ANNCEST has potential as a cost-effective and widely available method for measuring PCr and diagnosing related diseases.

D -glucose–enhanced MRI detects altered CSF flow and glucose utilization in early Alzheimer’s disease when plaque formation begins.

Stimuli-responsive nanoprobes that integrate multi-modal imaging capacities are highly desirable for precise tumor visualization. Herein, novel porous gold nanocluster-decorated manganese monoxide nanocomposites (MnO@Au NCs) were synthesized via a facile approach. The porous gold nanocluster layer was germinated on the surface of the as-prepared MnO@DMSA NPs through simple reduction of chloroauric acid in the presence of hydroxylamine hydrochloride. The MnO@Au NCs could be effectively internalized by tumor cells and slowly release Mn²⁺ ions within the acidic tumor microenvironment, improving the visualization of the tumor morphology. Benefitting from the porous architecture, the enhanced accessibility of Mn centers to proximal water molecules greatly augmented T₁-weighted MRI contrast capacity. Compared with the conventional Mn-based contrast agents, the porous Au nanoclusters on MnO@Au NCs could delay the release of Mn²⁺ ions and thus effectively prolong the diagnostic time window. The broad near-infrared absorption of MnO@Au NCs features a high photoacoustic imaging depth than that of conventional gold nanospheres. Moreover, the Au nanoclusters exhibited desirable X-ray computed tomography contrast and rapid clearance from the living body. The as-prepared MnO@Au NCs hold great potential for accurate tumor imaging.