Contrast material-enhanced visualization of the ablation medium for magnetic resonance-monitored ethanol injection therapy: imaging and safety aspects.
OBJECTIVE
This study was performed to test whether the dissociation rate of free Gd3+ ions from gadoterate meglumine is significantly increased when the contrast agent is dissolved in ethanol and whether the magnetic resonance (MR) signal of gadolinium/ethanol solutions is enhanced to a degree that promises reliable detection during MR imaging-guided intralesional administration, such as for the treatment of low-flow venous malformations.


METHODS
The apparent gadoterate meglumine-induced enhancement of the longitudinal proton relaxation rate of sterile ethanol/water solutions, stored at a temperature of 24 degrees C +/- 5 degrees C in the dark, was monitored for 2 weeks. The content of dissociated Gd3+ ions was determined after 6 and 8.5 months of storage. The signal difference between contrast agent/ethanol solutions and muscle tissue was assessed with imaging at 0.5 T and 1.5 T.


RESULTS
Commercialized gadoterate meglumine diluted with 94% ethanol was not shown to have released toxic Gd3+ during storage times that exceed its physiologic circulation and excretion times after intravenous injection by a factor of more than 100. A maximum dissociation rate of 0.05% per month was estimated from the detection limit of the analysis. The apparent molar relaxivity of the contrast agent in the mixtures varied by less than 0.1 L/mmol per second with no temporal trend. Gradient-echo ethanol/muscle contrast increased with Gd concentrations to maximums of 15 mmol/L (at 0.5 T) and 25 mmol/L (at 1.5 T).


CONCLUSIONS
Neither limited solubility nor release of Gd3+ ions could be identified as a general safety hazard associated with the application of gadoterate meglumine/ethanol solutions at Gd concentrations of 0.5-25 mmol/L, and such ablation mixtures could be efficiently and reliably visualized.
Nanz
Daniel
D
Division of Cardiology and Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland. daniel.nanz@usz.ch
Andreisek
Gustav
G
Fröhlich
Johannes M
JM
Weishaupt
Dominik
D
Treiber
Karl
K
Ess
Sonja
S
Pfammatter
Thomas
T
D001165:Arteriovenous Malformations / Q000175:diagnosis / Q000628:therapy; D003287:Contrast Media / Q000008:administration & dosage / Q000009:adverse effects / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D015552:Injections, Intralesional; D008279:Magnetic Resonance Imaging / Q000379:methods; D008536:Meglumine / Q000009:adverse effects / Q000737:chemistry*; D009942:Organometallic Compounds / Q000009:adverse effects / Q000737:chemistry*; D011522:Protons; D012995:Solubility; D013997:Time Factors; D014867:Water / Q000737:chemistry
D003287:Contrast Media; D009942:Organometallic Compounds; D011522:Protons; D014867:Water; D000431:Ethanol; D008536:Meglumine; D005682:Gadolinium; C072417:gadoterate meglumine