Fast MRI imaging lets doctors steer magnetic microrobots in real time

Researchers at Huazhong University of Science and Technology in China have developed an innovative magnetic resonance imaging (MRI) technique that enables real-time, artifact-free navigation of magnetic microrobots inside the body. Their multi-frequency dual-echo (MFDE) MRI sequence dramatically reduces the repetition time from about 1,000 milliseconds to just 30 milliseconds, allowing near real-time imaging with high spatial accuracy. This advancement addresses previous challenges in MRI-driven robotic control, such as slow imaging speeds, tracking inaccuracies, and interference between imaging gradients and robot motion. The MFDE method uses dual echoes generated by two adjacent 180-degree radio-frequency pulses and alternates positive and negative offset frequency excitations to maintain image quality despite rapid scanning. The system was validated through experiments including guiding a magnetic microrobot through a complex 3D maze, navigating phantom endovascular models mimicking tortuous vessels, and in vivo navigation within a rat’s large intestine. These demonstrations highlight the potential of this technology for minimally invasive medical