The Lumbar Spine as a Dynamic Structure Depicted in Upright MRI

Spinal canal stenosis is a dynamic phenomenon that becomes apparent during spinal loading. Current diagnostic procedures have considerable short comings in diagnosing the disease to full extend, as they are performed in supine situation. Upright MRI imaging might overcome this diagnostic gap.This study investigated the lumbar neuroforamenal diameter, spinal canal diameter, vertebral body translation, and vertebral body angles in 3 different body positions using upright MRI imaging.Fifteen subjects were enrolled in this study. A dynamic MRI in 3 different body positions (at 0 degrees supine, 80 degrees upright, and 80 degrees upright+hyperlordosis posture) was taken using a 0.25T open-configuration scanner equipped with a rotatable examination bed allowing a true standing MRI.The mean diameter of the neuroforamen at L5/S1 in 0 degrees position was 8.4mm on the right and 8.8mm on the left, in 80 degrees position 7.3mm on the right and 7.2mm on the left, and in 80 degrees position with hyperlordosis 6.6mm (P<0.05) on the right and 6.1mm on the left (P<0.001).The mean area of the neuroforamen at L5/S1 in 0 degrees position was 103.5mm(2) on the right and 105.0mm(2) on the left, in 80 degrees position 92.5mm(2) on the right and 94.8mm(2) on the left, and in 80 degrees position with hyperlordosis 81.9mm(2) on the right and 90.2mm(2) on the left.The mean volume of the spinal canal at the L5/S1 level in 0 degrees position was 9770mm(3), in 80 degrees position 10600mm(3), and in 80 degrees position with hyperlordosis 9414mm(3).The mean intervertebral translation at level L5/S1 was 8.3mm in 0 degrees position, 9.9mm in 80 degrees position, and 10.1mm in the 80 degrees position with hyperlordosis.The lordosis angle at level L5/S1 was 49.4 degrees in 0 degrees position, 55.8 degrees in 80 degrees position, and 64.7mm in the 80 degrees position with hyperlordosis.Spinal canal stenosis is subject to a dynamic process, that can be displayed in upright MRI imaging. The range of anomalies is clinically relevant and dynamic positioning of the patient during MRI can provide essential diagnostic information which are not attainable with other methods.