Disc bulge before and after compression changed with a difference of 0.1 ± 0.06 mm (4.5%) across all 220 disc positions in 55 patients - Resize the spinal canal before and after compression at the 16 narrowest position on the MRI: Compressed MRI changes the size of the geographic archipelago, the DCSA at the narrowest position compared to the uncompressed MRI, at the same time the change is statistically significant with p <0.001.