A rat EEG model for evaluating contrast media neurotoxicity.

Area of Science:

• Neuroscience
• Radiology
• Toxicology

Background:

• X-ray contrast media are essential in medical imaging.
• Assessing the neurotoxicity of these agents is crucial for patient safety.
• Intracisternal administration in animal models provides a direct route to evaluate central nervous system effects.

Purpose of the Study:

• To evaluate the electroencephalographic (EEG) effects and neurotoxicity of intracisternally administered x-ray contrast media in rats.
• To compare the neurotoxic potential of meglumine iothalamate (IOT), metrizamide (MET), iogulamide (IOG), and ioversol (IOV).

Main Methods:

• Rats were anesthetized and artificially ventilated.
• Electrodes were placed to record EEG, and arterial blood pressure (BP) was monitored.
• Contrast agents were injected via the cisterna magna at varying doses (30-240 mgI/kg).
• EEG, BP, blood gases, and pH were monitored post-injection.

Main Results:

• Normal saline control caused no significant changes.
• Meglumine iothalamate (30 mgI/kg) induced epileptogenic activity and death in 75% of animals.
• Metrizamide showed minimal effects at 30 mgI/kg but caused severe EEG changes and 33% mortality at higher doses.
• Ioversol produced mild to moderate EEG abnormalities at 120 and 240 mgI/kg.

Conclusions:

• Intracisternal administration of certain x-ray contrast media can induce significant neurotoxicity in rats.
• Meglumine iothalamate and metrizamide exhibit considerable epileptogenic potential and lethality.
• Ioversol appears to have a lower neurotoxic profile compared to IOT and MET at the tested doses.