Iohexol compared to metrizamide in cervical and thoracic myelography. A randomized double blind parallel study

Area of Science:

• Radiology
• Neurology
• Medical Imaging

Background:

• Cervical myelography is a diagnostic imaging technique used to visualize the spinal cord and nerve roots in the neck region.
• Contrast media are essential for enhancing image quality during myelography.
• Iohexol (Omnipaque) and metrizamide (Amipaque) are non-ionic contrast agents evaluated for their safety and efficacy in myelography.

Purpose of the Study:

• To compare the safety and efficacy of iohexol (Omnipaque) versus metrizamide (Amipaque) in patients undergoing cervical myelography.
• To assess image quality, subjective side effects, and electroencephalogram (EEG) changes associated with each contrast agent.

Main Methods:

• A randomized, double-blind study involving 50 patients undergoing cervical myelography.
• Patients received either iohexol (n=29) or metrizamide (n=21) via lumbar or C1-C2 puncture.
• Contrast media concentrations were 300 mg I/ml for iohexol and 240 mg I/ml for metrizamide.

Main Results:

• Image quality was comparable between iohexol and metrizamide, with excellent or good results in all examinations.
• Subjective side effects, particularly headache, were significantly more frequent with metrizamide (67%) than with iohexol (34%).
• EEG changes occurred in 47% of patients receiving metrizamide compared to 24% receiving iohexol; three patients on metrizamide experienced spike activity and mental reactions.

Conclusions:

• Iohexol (Omnipaque) exhibited a more favorable safety profile than metrizamide (Amipaque) in cervical myelography, with fewer adverse events and EEG alterations.
• The study indicates that iohexol is better suited for cervical myelography compared to metrizamide, offering comparable image quality with improved patient tolerance.