Administration of gadopentetate dimeglumine in MR imaging of intracranial tumors: dosage and field strength.

PURPOSE To investigate the efficacy of 0.025, 0.05 and 0.1 mmol/kg gadopentetate dimeglumine in MR imaging of patients with intracranial tumors at mid and high field strength.

METHODS In 88 patients, an open-label phase III multicenter dose-finding study was performed at 0.5, 1.0, and 1.5 T MR units. Before and after (5, 15, 25 minutes) intravenous administration of gadopentetate dimeglumine, imaging was performed with T1-weighted spin-echo sequences.

RESULTS With 0.1 mmol/kg yielding the highest values, tumor enhancement and numerical tumor/brain contrast showed dose-dependent 5-minute postcontrast values (P less than 0.05). Compared to 5-minute postcontrast values, there was no significant change at 15 and 25 minutes. Although the lowest values of enhancement were found at 0.5 T, differences in enhancement among the field strengths were not statistically significant. The numerical data were confirmed by visual assessment of tumor/brain contrast. Eighty to 90% of cases had diagnostically valuable enhancement at 0.1 mmol/kg, 50% at 0.05 mmol/kg, and 10% at 0.025 mmol/kg (P less than 0.05). There were no adverse events.

CONCLUSION Our results confirm that 0.1 mmol/kg gadopentetate dimeglumine is more effective at enhancing intracranial tumors than lower doses at mid and high field MR units.