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Dear Freesurfers,

while acquiring our fMRI data we stumbled upon an artifact in our structural data none of us has ever seen before. I wanted to ask, if maybe you have seen something like this and have an idea about its origin?

We followed your suggesed morphometry protocol (without multiecho, based on a standard MRAGE siemens protocol --> https://secure-web.cisco.com/10ieaIo5lzXeZK3jmi_ma4CitDtsCtqHlLkGJmLgjS_IhlL... ). Our structural acquisition parameters were: 192 slices, voxel size = 1 x 1 x 1 mm, TR = 1600 ms, TE = 2360 ms, TI = 1200 ms, flip angle = 9 °, FOV = 256 mm, bandwidth = 250 Hz/ Px, echo spacing = 6.78 ms. We were using a 3 Tesla Magnetom Vida scanner with a 64-channel head coil.

There's a picture of the artifact attached.

Thanks a lot, we'd be really curious to know, whether you've seen somehting like this before!

Best, Marilena Wilding MORPHOMETRY PROTOCOLS (January 2009) MPRAGEhttps://secure-web.cisco.com/10ieaIo5lzXeZK3jmi_ma4CitDtsCtqHlLkGJmLgjS_IhlLz3hoaJA3kEpfK-VgPE7pIrVLGHT0uLXXvNQPew7twvnwXLgv8Yf5sojnnhAS-wCPHy8MsrpF0niQtBegMz-qkGWVpxPb9o8qJj1vR5G5RHLfgyWrYaWq8QhpWvZs7SHk0e_afBI86WjSbw1FnwGJW-4tDB2pYQr47caCdrkJu1N1mSWstvIlSZV3ig6UmVmi3DJrmGUcxZHV_6NWtKvqvPaJneZ6B-fWYJYEVm7QyRBQ-scQiEJpTz15LmAoB-t_-GEhdwQVUSNTp_Qr2WaU4f1Q00kkWwUAIXFqQRkg/https%3A%2F%2Fsurfer.nmr.mgh.harvard.edu%2Ffswiki%2FFreeSurferWiki%3Faction%3DAttachFile%26do%3Dget%26target%3DFreeSurfer_Suggested_Morphometry_Protocols.pdf Acquisition time: 8:28 Voxel size: 1.0 x 1.0 x 1.0 mm3 Geometry: FoV 256 mm (256 x 256 matrix), 176 sagittal slices, slice thickness 1 mm, phase encoding anterior-posterior (readout superior-inferior) (3D encoding) Timing: TR 20 ms, TE 1.85+n2.0 ms (n = 0,..,7), bandwidth 651 Hz/px for all echoes (bipolar readout trajectory) RF: non-selective excitation at 30° and 5° (then 20°, then 3°) surfer.nmr.mgh.harvard.edu