When imaging a hemorrhagic infarct in the brain, which pulse sequence would demonstrate the magnetic susceptibility effects better?

The gradient echo pulse sequence is particularly effective for demonstrating magnetic susceptibility effects, especially in cases of hemorrhagic infarcts. This is due to the way gradient echo sequences are sensitive to magnetic field inhomogeneities, which can be caused by the presence of blood products or other materials that alter the local magnetic environment.

In the case of a hemorrhagic infarct, the accumulated blood can create variations in the magnetic field, leading to differences in local magnetization that gradient echo sequences can highlight. This sensitivity allows for the detection of subtle changes in signal intensity at the site of the hemorrhage, which helps in identifying the extent and characteristics of the infarct more clearly.

By contrast, other techniques like spin echo and fast spin echo pulse sequences rely on 180-degree refocusing pulses that can reduce the effects of magnetic susceptibility, making them less effective in this scenario. Inversion recovery techniques are primarily used for suppressing specific signals rather than enhancing the visibility of lesions caused by susceptibility effects. Thus, gradient echo sequences are preferable for visualizing the complex interactions occurring due to the presence of blood in the brain during a hemorrhagic event.