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The purpose of this paper was to confirm prior findings in demonstrating imaging superiority of 0.1 mmol/kg of body weight of Gadobenate Dimeglumine (Multihance) over 0.1 mmol/kg of body weight of Gadoterate meglumine (Dotarem), in a properly sized and powerful clinical study. Secondly, the authors aimed to evaluate whether a half dose, of 0.05 mmol/kg Multihance provides similar diagnostic information to the full dose of 0.1 mmol/kg Dotarem when these agents are administered in otherwise identical MR imaging examinations.
The study utilizes a rigorous double-blind randomized intraindividual crossover study design. For the purposes of their study, superior imaging performance refers to significantly greater lesion enhancement and diagnostic information. The authors ascribe this to the higher relaxivity properties of Multihance in vivo, which results in greater signal intensity enhancement on T1 weighted images.
177 patients who were referred for contrast enhanced MR imaging for known or suspected brain tumors were prospectively enrolled in the study and randomly assigned to either study Arm 1 or study Arm 2. Study Arm 1 had 70 patients, who received the full dose of Multihance and the full dose of Dotarem, in otherwise identical examinations. 107 patients were randomly assigned to Arm 2 and received a half dose of Multihance and a full dose of Dotarem.
Three independent Neuroradiologists evaluated the images. Qualitative and quantitative assessment of the images for each patient in each study arm was performed with images presented in a global matched pairs fashion. All images from examination 1 were simultaneously displayed with the images from examination 2, so as to provide a side-by-side comparison.
Each study was qualitatively assessed for diagnostic information in terms of overall diagnostic preference and based on the quality of the following criteria: lesion border delineation, the definition of the extent of disease, visualization of lesion internal morphology, and lesion contrast as compared with the surrounding normal tissue.
Quantitative assessment was performed by measuring signal intensity utilizing regions of interest positioned on up to three enhancing lesion per patient. Each ROI that was placed on the selected post injection image from one examination simultaneously appeared on the corresponding image from the other examination. The signal intensity values were calculated utilizing the percentage of enhancement of the lesions in the post contrast minus pre contrast lesion-to-background ratio on the T1 pre contrast images. Interreader agreement for the diagnostic findings was presented as a percentage agreement for three readers and assessed using generalized kappa statistics, stratified into quintiles.
Qualitative image assessment was evaluated based on global diagnostic preference, lesion border delineation, disease extent, internal morphology, and qualitative assessment of contrast enhancement. The results of Arm 1 of the study demonstrate that there is a highly significant superiority for Multihance over Dotarem by all three readers for all qualitative assessments in patients receiving the full contrast dose of each agent. Additionally, in Arm 2 of the study, there was no statistically significant difference by any reader for any qualitative parameter among patients receiving the half dose of Multihance compared with full dose of Dotarem.
For the quantitative evaluation: the mean percentage signal enhancement of lesions on the T1 weighted spin echo images was significantly higher for Multihance compared with Dotarem for the full dose of each agent; whereas no meaningful differences were noted between the half dose of Multihance compared with full dose of Dotarem. Similar results were obtained for determination of the lesion to background ratio with the full dose of Multihance and the full dose of Dotarem, and again no significant statistical difference between the half dose of Multihance compared with full dose of Dotarem. All three readers noted significantly higher post contrast lesion to background ratio values for the full dose of Multihance versus the full dose of Dotarem. There was no statistically significant difference between the half dose of Multihance versus the full dose of Dotarem for lesion contrast enhancement relative to background ratio
In summary, Vaneckova et al demonstrate that there is superior imaging performance for Gadobenate Dimeglumine (Multihance) in comparison to Gadoterate Meglumine (Dotarem) for both qualitative and quantitative enhancement when these agents are administered at equivalent doses of 0.1 mmol per kilogram of body weight. In terms of diagnostic preference, all three readers within the study also preferred Multihance over Dotarem in the qualitative assessment. Furthermore, in quantitative assessment, higher lesion to background ratios were observed in the full dose of Multihance over Dotarem. For all three neuroradiologists, there was no statistically significant difference in preference for either the half dose Multihance in comparison to the full dose of Dotarem. Similarly, there was no statistically significant difference between quantitative enhancement characteristics between the half dose of Multihance compared with the full dose of Dotarem
