Time-Varying Gradient Magnetic Fields - Video Lesson

Hey, everybody. This is another lesson in our series on MRI safety. This video focuses on time varying gradient magnetic fields. In it, we will explore peripheral nerve stimulation, the risks associated with it, the impacts of time varying gradients on implanted devices, and the risks of acoustic noise in MRI. So let's get started. First, let's talk about peripheral nerve stimulation. This occurs because of the MRI's rapidly changing magnetic fields from positive to negative. These changes induce electrical currents in the conductive tissues of the body. These currents can stimulate nerves causing sensations ranging from a slight tingling to involuntary muscle contractions. These contractions can lengthen scan times due to patient motion and, in severe cases, could cause patient injury. Current safety limits for peripheral nerve stimulation are until the patient experiences discomfort. If a patient complains of