Purpose To substantially shorten the acquisition time required for quantitative three‐dimensional (3D) chemical exchange saturation transfer (CEST) and semisolid magnetization transfer (MT) imaging and allow for rapid chemical exchange parameter map reconstruction. Methods Three‐dimensional CEST and MT magnetic resonance fingerprinting (MRF) datasets of L‐arginine phantoms, whole‐brains, and calf muscles from healthy volunteers, cancer patients, and cardiac patients were acquired using 3T clinical scanners at three different sites, using three different scanner models and coils. A saturation transfer‐oriented generative adversarial network (GAN‐ST) supervised framework was then designed and trained to learn the mapping from a reduced input data space to the quantitative exchange parameter space, while preserving perceptual and quantitative content. Results The GAN‐ST 3D acquisition time was 42–52 s, 70% shorter than CEST‐MRF. The quantitative reconstruction of the entire brain took 0.8 s. An excellent agreement was observed between the ground truth and GAN‐based L‐arginine concentration and pH values (Pearson's r > 0.95, ICC > 0.88, NRMSE < 3%). GAN‐ST images from a brain‐tumor subject yielded a semi‐solid volume fraction and exchange rate NRMSE of 3.8prefix±1.3%$$ 3.8\pm 1.3\% $$ and 4.6prefix±1.3%$$ 4.6\pm 1.3\% $$, respectively, and SSIM of 96.3prefix±1.6%$$ 96.3\pm 1.6\% $$ and 95.0prefix±2.4%$$ 95.0\pm 2.4\% $$, respectively. The mapping of the calf‐muscle exchange parameters in a cardiac patient, yielded NRMSE < 7% and SSIM > 94% for the semi‐solid exchange parameters. In regions with large susceptibility artifacts, GAN‐ST has demonstrated improved performance and reduced noise compared to MRF. Conclusion GAN‐ST can substantially reduce the acquisition time for quantitative semi‐solid MT/CEST mapping, while retaining performance even when facing pathologies and scanner models that were not available during training.

Wirelessly powered microdevices are being miniaturized to improve safety, longevity, and spatial resolution in a wide range of biomedical applications. Some wireless microdevices have reached a point where they can be injected whole into the central nervous system. However, the state-of-the-art floating microdevices have not yet been tested in chronic brain applications, and there is a growing concern that the implants might migrate through neural tissue over time. Using a 9.4T MRI scanner, we attempt to address the migration question by tracking ultra-small devices injected in different areas of the brain (cortico-subcortical) of rats over 5 months. We demonstrate that injectable microdevices smaller than 0.01 mm3 remain anchored in the brain at the targeted injection site over this time period. Based on CD68 (microglia) and GFAP (astrocytes) immunoreactivity to the microdevice, we hypothesize that glial scar formation is preventing the migration of chronically implanted microdevices in the brain over time.