What is the slew rate for a sequence with a rise time of 0.2 ms, maximum gradient of 40 mT/m, and cycle time of 0.5 seconds?

To calculate the slew rate, which is the change in gradient strength per unit time, you can use the formula:

Slew Rate = Maximum Gradient / Rise Time.

In this scenario, the maximum gradient is given as 40 mT/m (which is equivalent to 0.04 T/m) and the rise time is 0.2 ms (which is equivalent to 0.0002 seconds).

Using the formula, we can plug in the values:

Slew Rate = 0.04 T/m / 0.0002 s = 200 T/m/s.

This calculation confirms that the correct answer is indeed 200 T/m/s, making it a vital metric in MRI operations. A higher slew rate indicates a quicker transition in gradient strength, which can enhance spatial resolution and reduce the time for scans. Understanding the relationship between the rise time, maximum gradient, and slew rate is crucial for optimizing MRI sequences and ensuring patient safety.