J Korean Soc Magn Reson Med.  2006 Jun;10(1):26-31.

Comparative Study of Functional Magnetic Resonance Imaging by Global Scaling Analysis

• Yoo DS

Abstract

PURPOSE: To evaluate the effect of global scaling analysis on brain activation for sensory and motor func-tional MR imaging study.
MATERIALS AND METHODS
Four normal subjects without abnormal neurological history were included. Arm extension-flexion movement was used for motor function and 1 KHz pure tone stimulation was used for auditory function. Functional magnetic resonance imaging was performed at 3T MRI (GE, Milwaukee, USA) using BOLD-EPI technique and SPM2 was employed for data analysis. On data analysis, the brain activation images were obtained with and without global scaling by fixing other parameters such as motion correction and realignment.
RESULTS
The difference in brain activation between no scaling and global scaling was not large in case of right upper extremity movement (p<0.000001). For auditory test, brain activation with global scaling showed larger activation than that of without global scaling (p<0.05).
CONCLUSION
A caution must be taken into account when analyzing functional imaging data with global s-caling especially for functional study of small local BOLD signal change.

Keyword

fMRI; Brain; Global scaling; Data analysis

MeSH Terms

Arm
Brain
Magnetic Resonance Imaging*
Statistics as Topic
Upper Extremity