What is a key factor influencing the Peripheral Nerve Stimulation (PNS) during MRI scanning?

The key factor influencing Peripheral Nerve Stimulation (PNS) during MRI scanning is the rise time of the gradient pulses. Rise time refers to the duration it takes for the gradient magnetic field to change from zero to its maximum value. Short rise times can lead to rapid changes in the magnetic field, which increases the likelihood of inducing electrical currents in the body. These induced currents can stimulate peripheral nerves, potentially resulting in PNS sensations such as tingling or discomfort.

While maximum gradient and field strength do play roles in the overall operation of MRI systems, they are not as directly influential on PNS as rise time. Similarly, tissue type may affect how nerve stimulation is perceived, but it is the gradient pulse characteristics, particularly the rise time, that have the most significant impact on the incidence of PNS during scanning. In practice, keeping rise times longer can help mitigate the risk of PNS while ensuring effective imaging.