Excretion of aqueous myelographic contrast media in animals undergoing a repeat myelogram.

The rate of elimination of contrast media may be a factor in side effects and complications of aqueous myelography. The authors studied the effect of a previous myelogram and arachnoiditis on the elimination of aqueous contrast media from the subarachnoid space. Serum and cisternal CSF iodine concentrations were measured after experimental myelography in subhuman primates. The transfer of the aqueous contrast media from CSF to serum was slowed and the circulation with the cerebrospinal fluid into the intracranial cisterns was increased by a previous myelogram or arachnoiditis.

The effect of dehydration on the elimination of aqueous contrast media from the subarachnoid space.

The frequency of side effects and complications from aqueous myelography is increased by dehydration. To study the effect of dehydration on the elimination of water-soluble contrast medium from the lumbar subarachnoid space, we measured iodine concentrations in the cerebrospinal fluid, serum, and urine for 24 hours after myelography in "hydrated" and "dehydrated" monkeys. Dehydrated animals were fasted for 12 hours prior to and 24 hours after myelography; hydrated animals received oral fluids ad libitum and 300 ml of intravenous fluids. Dehydrated animals had a lower concentration of contrast medium in the blood than hydrated animals. Dehydration slows the elimination of aqueous contrast medium from the lumbar subarachnoid space.

Elimination of aqueous myelographic contrast media from the subarachnoid space.

Elimination of aqueous contrast media from the lumbar subarachnoid space was measured. Iodine concentrations in serum and cisterna magna cerebrospinal fluid were studied in animals undergoing myelography with metrizamide, iocarmate, Iopamidol, or P-297. We found that all four contrast media were eliminated rapidly into the serum and urine, and transported slowly into the basal cisterns.

Blood brain-barrier disruption of nonionic iodinated contrast medium following coil embolization of a ruptured intracerebral aneurysm.

Few reports of temporary disruption of the blood-brain barrier (BBB) following neurointerventional procedures, presumably caused by nonionic radiographic contrast medium (CM), exist in the literature. We described such a case in a 72-year-old man presenting with acute subarachnoid hemorrhage, who underwent coil embolization of a ruptured anterior communicating artery complex aneurysm. At the time of his follow-up CT examination, a large amount of iodine was found in the cerebrospinal fluid (CSF). Because of this experience, the iodine concentration in the CSF of five other patients who also underwent an intracranial endovascular procedure was measured. It was concluded that this increased iodine might have been caused by temporary leakage or breakdown of the BBB. Even if the total amount of CM may not be excessive, the disproportionately high concentration injected into a single vascular territory may pose a unique set of variables increasing the risk of BBB disruption.

Lumbar myelography with metrizamide in rabbits. An investigation of contrast media penetration and resorption.

Neurotoxicity from subarachnoid contrast media is probably related to their specific pharmacologic effects and to their penetration into the central nervous system. The lack of a barrier between the cerebrospinal fluid and the extracellular fluid of the brain and cord allows water-soluble contrast media to diffuse into the neural tissue. The aim of this investigation was to develop a method that allows one to quantify the neural tissue penetration for a given contrast medium in relation to the cerebrospinal fluid concentration and contact time and apply this to the use of metrizamide. The result shows a good correlation between iodine concentration in the lumbar cerebrospinal fluid and that in the lumbar cord suggestive of a simple diffusion. When time of sacrifice (contact time) is added as a covariant there is also some indication of retention of metrizamide in the neural tissue. The investigation also demonstrates that the resorption of the contrast medium in the rabbit in this experimental model is mainly in the lumbo-sacral region.

Attenuation changes of the ventricular CSF after intravenous injection of contrast material.

The CT attenuation change of the intraventricular CSF after i. v. administration of contrast material has been studied in 20 patients. A very small increase of attenuation was observed in the entire material. The method does not seem to be appropriate at present for the study of small attenuation changes in the CSF reflecting the passage of contrast material.