Fig 6.

Effect of patient rotation on the image. A, An unsubtracted image from a DSM study obtained with the patient in the true right lateral decubitus position and the image intensifier horizontal shows the contrast outlining the exiting nerve roots and filling small nerve sheath diverticula. B, An unsubtracted image from a DSM study from the same patient in the oblique left lateral decubitus position and the image intensifier horizontal shows partial obscuration of the contrast in the nerve sheaths due to an overlying contrast column within the thecal sac. Note the differences in the position of the spinous processes indicating the patient obliquity.