What is the slew rate if the rise time is 0.3 ms, pulse duration is 0.75 seconds, and maximum gradient is 45 mT/m?

To determine the slew rate, it's important to understand its definition. The slew rate is the rate at which the gradient can change with respect to time, and it is calculated by dividing the change in the gradient (maximum gradient) by the rise time.

Given that the rise time is 0.3 ms (which is 0.0003 seconds) and the maximum gradient is 45 mT/m (which is equivalent to 0.045 T/m), we can use the formula for slew rate:

Slew rate = Maximum gradient / Rise time.

Substituting the values we have:

Slew rate = 0.045 T/m / 0.0003 seconds = 150 T/m/s.

This calculation accurately reflects how quickly the gradient field can be applied in the context of an MRI machine, which is crucial for image quality and safety.

Therefore, the correct answer aligns with this calculation, giving a slew rate of 150 T/m/s. Understanding the importance of slew rate in MRI systems helps ensure proper operation and patient safety, as faster slew rates can lead to artifacts and increased risk of peripheral nerve stimulation.