Maximum DB/dt & Switching Noise in 1.5T MRI Scanners for Safety Evaluation of Active Implantable Medical Device

Neha Bharat Butala¹, Ramez Emile Necola Shehada¹, Peter Nabil Costandi¹, Ali Dianaty¹, Kevin Jurkowski¹

Active implantable medical devices (AIMD) in patients undergoing MRI, present a risk of tissue stimulation at gradient dB/dt rates lower than the imposed limits for direct stimulation. Additionally, the gradient amplifier noise, ripple could interfere with AIMD, compromising safety. The dB/dt and associated ripple were investigated in 1.5T MRI scanners. A total of 126 measurements were performed using Faraday coils in various scanners and bore locations, while running different clinical sequences. The magnitude and location of maximum dB/dt and ripple was identified. This information may be valuable for assessment of unintended gradient stimulation hazard to demonstrate MR compatibility of AIMD.