Air microbubbles as MR susceptibility contrast agent at 1.5 Tesla. |
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Authors: | Takashi Ueguchi Yuko Tanaka Seiki Hamada Risa Kawamoto Yuji Ogata Mitsuhiro Matsumoto Hironobu Nakamura Takeshi Johkoh |
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Institution: | Department of Radiology, Osaka University Hospital, Japan. ueguchi@hp-rad.med.osaka-u.ac.jp |
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Abstract: | Air microbubbles have been investigated recently at high magnetic field strength (2 Tesla or greater) as potential MR susceptibility contrast agents. We used a phantom to measure their susceptibility at 1.5 T to clarify their usefulness for this purpose. The phantom, filled with fresh Levovist suspension at 4 different doses (67 to 125 mg/mL), was continuously scanned with a gradient-echo technique at a temporal resolution of 10 s. The transverse relaxation increase (R2*) by microbubbles demonstrated a time course of exponential decay at each dose (time-constant, 39 to 57 s). The dependency of R2* on microbubble volume fraction was linear, with a slope of 89 s-1 per percentage microbubble volume fraction. Our study represents the first step towards applying microbubbles as susceptibility contrast agents at 1.5 T. |
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