I'm trying to create a fieldmap from data collected on a 3T GE MR750. I've managed to extract phase images from a sequence created by our radiographer, but they don't look quite right. Thick, dark horizontal lines through the coronal and sagittal planes (we collect the images in the axial plane). I think I've also got real and imaginary images, but they also have the dark horizontal lines.

Any advice on what's causing this would be much appreciated. Does anyone collecting phase maps have an image of what it should look like?

Cheers,

Rich