Intrinsic Resting-State Functional Connectivity in the Human Spinal Cord at 3.0 T.
OBJECTIVE
To apply resting-state functional magnetic resonance (MR) imaging to map functional connectivity of the human spinal cord.


METHODS
Studies were performed in nine self-declared healthy volunteers with informed consent and institutional review board approval. Resting-state functional MR imaging was performed to map functional connectivity of the human cervical spinal cord from C1 to C4 at 1 × 1 × 3-mm resolution with a 3.0-T clinical MR imaging unit. Independent component analysis (ICA) was performed to derive resting-state functional MR imaging z-score maps rendered on two-dimensional and three-dimensional images. Seed-based analysis was performed for cross validation with ICA networks by using Pearson correlation.


RESULTS
Reproducibility analysis of resting-state functional MR imaging maps from four repeated trials in a single participant yielded a mean z score of 6 ± 1 (P < .0001). The centroid coordinates across the four trials deviated by 2 in-plane voxels ± 2 mm (standard deviation) and up to one adjacent image section ± 3 mm. ICA of group resting-state functional MR imaging data revealed prominent functional connectivity patterns within the spinal cord gray matter. There were statistically significant (z score > 3, P < .001) bilateral, unilateral, and intersegmental correlations in the ventral horns, dorsal horns, and central spinal cord gray matter. Three-dimensional surface rendering provided visualization of these components along the length of the spinal cord. Seed-based analysis showed that many ICA components exhibited strong and significant (P < .05) correlations, corroborating the ICA results. Resting-state functional MR imaging connectivity networks are qualitatively consistent with known neuroanatomic and functional structures in the spinal cord.


CONCLUSIONS
Resting-state functional MR imaging of the human cervical spinal cord with a 3.0-T clinical MR imaging unit and standard MR imaging protocols and hardware reveals prominent functional connectivity patterns within the spinal cord gray matter, consistent with known functional and anatomic layouts of the spinal cord.
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Oscar
O
San Emeterio Nateras
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Fang
F
Yu
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Eric R
ER
Muir
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Carlos
C
Bazan
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Crystal G
CG
Franklin
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Wei
W
Li
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Jinqi
J
Li
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Jack L
JL
Lancaster
From the Research Imaging Institute (O.S.E.N., E.R.M., C.G.F., W.L., J.L., J.L.L., T.Q.D.), Department of Radiology (O.S.E.N., C.B., J.L., J.L.L., T.Q.D.), and Department of Ophthalmology (E.R.M., W.L., T.Q.D.), University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229; and Graduate School in Biomedical Engineering, University of Texas, San Antonio, Tex (O.S.E.N., T.Q.D.).
Timothy Q
TQ
Duong
D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D013116:Spinal Cord / Q000502:physiology*