What is the slew rate given these parameters? Rise time 300 microseconds, pulse duration 0.75 seconds, maximum gradient 45 mT/m

To calculate the slew rate, you need to understand the relationship between rise time and the maximum gradient. The slew rate is defined as the maximum change in gradient strength per unit time, which can be derived from the formula:

Slew Rate = Maximum Gradient / Rise Time

Here, the maximum gradient is given as 45 mT/m (which is 0.045 T/m), and the rise time is 300 microseconds (or 300 x 10^-6 seconds).

First, convert the units of maximum gradient into an appropriate form for calculation:

Slew Rate = 0.045 T/m / (300 x 10^-6 s)

To perform the calculation, convert 300 microseconds to seconds:

300 microseconds = 300 x 10^-6 s = 0.0003 s.

Now calculate the slew rate:

Slew Rate = 0.045 T/m / 0.0003 s = 150 T/m/s.

This result indicates the rate at which the gradient field can change, and the calculation reveals that the correct answer is indeed 150 T/m/s. This value is critical in MRI, as it determines how quickly the gradients can be ramped up and down, influencing the speed