Imaging the lumbosacral enlargement (LSE).

<p>The imaging volume was prescribed to cover from the superior margin of T11 to the inferior margin of the L1 vertebral bodies so that to ensure coverage of the LSE in all subjects. Example images are shown from superior, middle and inferior sections of the imaging volume.</p

Segmentation of the lumbosacral enlargement (LSE) using the active surface model (ASM) method.

<p>a) seed points are first positioned within the cord and b) the boundary of the cord is identified to obtain cross-sectional area (CSA) measurements of the LSE c) the grey matter (GM) boundary and CSA is also obtained using semi-automated and manual editing techniques.</p

Stacked plot diagram showing grey matter (GM) and white matter (WM) mean area fractions measured in a 15 mm section through the lumbosacral enlargement (LSE) in 10 healthy subjects.

<p>Stacked plot diagram showing grey matter (GM) and white matter (WM) mean area fractions measured in a 15 mm section through the lumbosacral enlargement (LSE) in 10 healthy subjects.</p

Planning of spectroscopy scans.

<p>Coronal (a) and sagittal (b) T2-weighted images of the upper cervical cord in a healthy subject showing voxel placement The NAA voxel (orange) is centred on the C2/3 intervertabral disc, avoiding surrounding CSF. The white voxel illustrates the chemical shift displacement of water. Keeping both the orange voxel (on resonance, 2.02 ppm) and white voxel (4.7 ppm) within the cord, ensures that metabolites between 2.02 and 4.7 ppm (tNAA, tCr, tCho, Glx, Ins) also arise from within the spinal cord and chemical shift displacement of each metabolite need not be an issue. Positioning of the rostrocaudal OVS slabs is shown in periphery of images a+b and positioning of the anterior-posterior OVS slabs is shown in c.</p

Scatter plots of relationship between age and (A) tNAA, (B) Glx, (C) tCho, (D) Ins and (E) Cr concentrations from the upper cervical cord.

<p>Regression lines are shown where there was a significant association (A, B). No significant association was seen between age and tCho, Ins or Cr (C–E).</p

Associations between age (predictor) and metabolite concentrations (response variable).

<p>Unstandardised and standardised regression coefficients calculated from the multivariate model are reported with 95% confidence intervals and p-values. The regression models adjusted for gender, linewidth and voxel volume.</p><p>Abbreviations: tNAA  = N-acetylaspartate + N-acetylaspartylglutamate, Cr  =  Creatine + phosphocreatine, tCho  =  Choline containing compounds, Ins  =  Myo-inositol, Glx  =  glutamate/glutamine.</p><p>Associations between age (predictor) and metabolite concentrations (response variable).</p

Cross-sectional area (CSA) and magnetisation transfer ratio (MTR) measurements in the lumbosacral enlargement (LSE) of 10 healthy subjects.

<p>Abbreviations:- LSE-CSA: Lumbosacral enlargement cross-sectional area; LSE-GM-CSA: Lumbosacral enlargement grey matter cross-sectional area; WM-MTR: White matter magnetisation transfer ratio, GM-MTR: Grey matter magnetisation transfer ratio; DSC: Dice similarity coefficient.</p><p>Cross-sectional area (CSA) and magnetisation transfer ratio (MTR) measurements in the lumbosacral enlargement (LSE) of 10 healthy subjects.</p

Grey and White Matter Magnetisation Transfer Ratio Measurements in the Lumbosacral Enlargement: A Pilot <i>In Vivo</i> Study at 3T

<div><p>Magnetisation transfer (MT) imaging of the central nervous system has provided further insight into the pathophysiology of neurological disease. However, the use of this method to study the lower spinal cord has been technically challenging, despite the important role of this region, not only for motor control of the lower limbs, but also for the neural control of lower urinary tract, sexual and bowel functions. In this study, the feasibility of obtaining reliable grey matter (GM) and white matter (WM) magnetisation transfer ratio (MTR) measurements within the lumbosacral enlargement (LSE) was investigated in ten healthy volunteers using a clinical 3T MRI system. The mean cross-sectional area of the LSE (LSE-CSA) and the mean GM area (LSE-GM-CSA) were first obtained by means of image segmentation and tissue-specific (i.e. WM and GM) MTR measurements within the LSE were subsequently obtained. The reproducibility of the segmentation method and MTR measurements was assessed from repeated measurements and their % coefficient of variation (%COV). Mean (± SD) LSE-CSA across 10 healthy subjects was 59.3 (± 8.4) mm² and LSE-GM-CSA was 17.0 (± 3.1) mm². The mean intra- and inter-rater % COV for measuring the LSE-CSA were 0.8% and 2.3%, respectively and for the LSE-GM-CSA were 3.8% and 5.4%, respectively. Mean (± SD) WM-MTR was 43.2 (± 4.4) and GM-MTR was 40.9 (± 4.3). The mean scan-rescan % COV for measuring WM-MTR was 4.6% and for GM-MTR was 3.8%. Using a paired t-test, a statistically significant difference was identified between WM-MTR and GM-MTR in the LSE (<i>p</i><0.0001). This pilot study has shown that it is possible to obtain reliable tissue-specific MTR measurements within the LSE using a clinical MR system at 3T. The MTR acquisition and analysis protocol presented in this study can be used in future investigations of intrinsic spinal cord diseases that affect the LSE.</p></div

Stacked plot diagram showing grey matter (GM) and white matter (WM) mean area fractions measured in a 15 mm section through the lumbosacral enlargement (LSE) in 10 healthy subjects.

<p>Stacked plot diagram showing grey matter (GM) and white matter (WM) mean area fractions measured in a 15 mm section through the lumbosacral enlargement (LSE) in 10 healthy subjects.</p

Prescription of the imaging volume between T11-L1 vertebral level to ensure coverage of the lumbosacral enlargement (LSE).

<p>Red arrow shows the position of the widest section of the LSE within the volume in this particular case.</p