The effect of position of patient on the passage of metrizamide (Amipaque), meglumine locarmate (Dimer X) and ioserinate (Myelografin) into the blood after lumbar myelography.

Lumbar myelography was carried out with the contrast media Amipaque, Dimer X and Myelografin in 10 patients each. Five of the patients treated with each contrast medium were kept in a sitting position after the examination, the others lay flat. Blood levels and excretion were measured up to 24 h. The results are interpreted as follows: 1. After lumbar injection of the contrast media there is a short phase of distribution in the subarachnoid space (lag time) and they then are transferred into the blood with a half-life of 3.9 +/- 2.4 h. The transport from the CSF is almost completed approximately after 24 h. The velocity of transport varies greatly between the individual patients. Watersoluble contrast media presumably flow passively with the CSF through the arachnoid villi into the venous blood. 2. The horizontal position of the patient reduces the lag time until the beginning of the actual transfer of the contrast medium. 3. The transfer of Dimer X begins somewhat later compared with Amipaque and Myelografin.