Transfer Ratio Measurements in the Lumbosacral Enlargement: A Pilot In Vivo Study at 3T

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 reli-able grey matter (GM) and white matter (WM) magnetisation transfer ratio (MTR) measure-ments 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) MTRmeasurements within the LSE were subse-quently obtained. The reproducibility of the segmentation method and MTRmeasurements 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-CS