SU‐E‐I‐68: Preliminary Evaluation of Potential MRI Contrast Materials for the Purpose of MR‐Ultrasound Fusion Application in the Abdomen

Abstract

Purpose: To evaluate a variety of materials that might serve as fiducial markers for abdominal MRI‐ultrasound fusion applications. Methods: Two experiments were performed: (1) in a phantom, a broad set of candidate materials were evaluated based on visibility in spin echo T1 and T2, and gradient echo T1 and T2* MRI pulse sequences; (2) the leading candidates were evaluated using standard clinical abdominal pulse sequences, both in a phantom and volunteer. Experiment 1 evaluated: two commercial fiducial MRI markers (IZI Medical Products and Beekley Medical); vitamin E and fish oil capsules; water; and copper sulfate solution. Experiment 2 evaluated fish oil capsules and copper sulfate solution. In experiment 2, ultrasound coupling gel was also evaluated. Liquids were poured in wells drilled in a plexiglass base. All scanning was performed with a clinical 1.5T GE Signa Excite scanner. For each pulse sequence, maximum intensity projection images (MIPs) were formed, after removing the phantom signals. Visibility was evaluated by rank ordering signal magnitude in the MIPs. Results: In experiment 1, copper sulfate solution and fish oil were superior to the other materials. In experiment 2, ultrasound gel and copper sulfate solution were clearly superior to the other materials, and were easily seen in the all of the phantom and volunteer images. Conclusion: Based on these preliminary experiments, ultrasound gel and copper sulfate solution appear to be the most promising fiducial marker materials for MRI‐ultrasound fusion applications in the abdomen.