Gd-DTPA: an alternative contrast medium for CT

OBJECTIVE: The purpose of this study was to demonstrate that gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) could be used as a contrast medium in CT as an alternative to iodine-based compounds. MATERIALS AND METHODS: Solutions of different concentrations of Gd-DTPA and iopromide were scanned in a tissue equivalent phantom and it was shown that Gd-DTPA caused 2.5 times the attenuation of an equimolar solution of iopromide. From these in vitro studies an in vivo dose of 0.5 mmol/kg Gd-DTPA was calculated to be equivalent to 50 ml iopromide 300. RESULTS: Pre- and postenhancement CT was performed in a volunteer using Gd-DTPA intravenously, and adequate enhancement occurred in intracranial vessels. CONCLUSION: Gd-DTPA can be used to provide enhancement during CT and might be of value in iodine-sensitive patients.