Question Posted 04/01/14:
I am a PhD student at IUPUI and I process the resting state scans so that we can extract various rs-networks but during QC have noticed that there is an artifact that happens with some but not all of the scans. Its not motion but there seems to be a white or black band around the resting state volumes that we dont see when we process our scans using the same protocol. Our scans are acquired on a siemens 3T scanner. Would scanner type make a difference? I also notice that some of our scans which were acquired on a philips scanner have this same band around the brain image. Could you offer any clues as to why this occurs?
Response posted 11/24/14 by ADNI MRI Core:
Thanks you for your question to the ADNI MRI Core.

ADNI-GO/2 RSfMRI image data is known to have regions where SNR measurements over time are relatively poor. These regions are “pencil shaped” cylinders with the long axis in the S/I direction. The artifacts are assumed to be related to insufficient suppression of cardiac fluctuations aliased into the fMRI FOV as they almost always occur on the subjects left side. RSfMRI in ADNI-GO/2 is acquired only on Philips MRI scanners. Philips representatives indicate that scanner software patches will be implemented to fix this problem. However ADNI-GO/2 data is still being acquired on scanners running software that is known to create images with pencil artifacts.