PT  - JOURNAL ARTICLE
AU  - F Z Yetkin
AU  - V M Haughton
AU  - R W Cox
AU  - J Hyde
AU  - R M Birn
AU  - E C Wong
AU  - R Prost
TI  - Effect of motion outside the field of view on functional MR.
DP  - 1996 Jun 01
TA  - American Journal of Neuroradiology
PG  - 1005--1009
VI  - 17
IP  - 6
4099  - http://www.ajnr.org/content/17/6/1005.short
4100  - http://www.ajnr.org/content/17/6/1005.full
SO  - Am. J. Neuroradiol.1996 Jun 01; 17
AB  - PURPOSE To evaluate the effect of objects moving outside the field of view on functional MR imaging.METHODS Echo-Planar image sequences were acquired in the sagittal plane of a stationary phantom or of the head of a volunteer subject while a second phantom was moved periodically outside the field of view. The signal intensity changes in each pixel within the field of view were measured.RESULTS Movement of the phantom outside the field of view produced signal intensity changes in the field of view that equaled or exceeded typical functional activation without the latency that characterizes activation. The greatest changes occurred at the bottom and top edges in the phantom and at the interfaces in the head.CONCLUSION If temporally correlated with the performance of a task, movement of objects or tissues outside the field of view may produce artifactual changes in signal intensity. The artifactual signal intensity changes were characterized by their location, greater magnitude, and more rapid rise to maximum than seen with typical "activation."