Abstract:ObjectiveTo detect the characteristics of fMRI for lumbar spinal cord by stimulating anterolateral legs based on a fast spin echo sequence,and compare the differences of the activation signal between transverse and sagittal plane to determine the feasibility and repeatability of the functional magnetic resonance imaging (fMRI) for lumbar spinal cord.MethodsGE1.5T Signa MR syetem was employed to transmit and receive RF pulse by using an eight-channel CTL coil.Twelve volunteers were stimulated by an electrical stimulator (intermittent pulse,frequency 20HZ) on the anterolateral leg skin to detect fMRI activation signal.Spinal fMRI was acquired by a single-shot fast spin echo (SSFSE) sequence based on signal enhancement by the extra vascular water proton (SEEP) effect.Scanning parameters were as follows (sag/axial):TR=6000ms,TE=6.8/6.6ms,thickness=4/7mm,space=0.5mm,FOV=24cm×24cm,parent=256×256,NEX=1,and ETL=64.Block design was used as the activation pattern,such as R1-S1-R2-S2-R3-S3-R4.The imaging data were analyzed with SPM8 and Marsbar.ResultsActivation signal of the lumbar spinal cord was found in all volunteers except for the data of two volunteers were taking off for their movements out of range.Time-intensity changes curves were correlated with periods of rest and active in both axial and sagittal views through the spinal cord.In the sagittal view,the activation was mainly located at the T12(10/10),and the signal intensity percentage varied from 0.0% to 2.0%.Few signal was also found at T11(2/10) and L1(3/10).In the axial view,the activation signal mainly focus on the ipsilateral dorsal horn (7/10),and few signal was also found at the contra-lateral dorsal horn (5/10) and bilateral ventral horn (3/10).At T12 vertebral level,there was no statistically significant difference in the average activation signal pixels and signal intensity changes between sagittl and transverse plane(Z=-1.825,Z=-1.376;P>0.05).ConclusionsThere are feasibilites of fMRI of lumbar spinal cord based on SEEP effect using 1.5T MR scanner,and the characterized activation signal was focused on the T12 with a high repeatability.Moreover,activation signal of axial lumber is consistent with that of sagittal lumber.
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