In cases where there is significant field distortion (such as in this case where the patient is in a stereotactic head frame), the resulting images will be distorted as well.

Correction for Field Distortion

Post-processing methods for correcting field distortion attempt to "warp" the perfusion image onto an anatomic template image (e.g. a T2 FSE). These attempts do not produce high quality output, as the basic information is lacking.

Addressing the problem up front (altering the head frame components or using a less susceptible pulse sequence) is generally necessary. In the following case, we switched from a GE-EPI to SE-EPI.

rCBV from GE-EPI	rCBV from SE-EPI