title: Air microbubbles as MR susceptibility contrast agent at 1.5 Tesla.
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.
authors.affiliation: Department of Radiology, Osaka University Hospital, Japan. ueguchi@hp-rad.med.osaka-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Ueguchi
authors.forename: Yuko
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Seiki
authors.initials: S
authors.lastname: Hamada
authors.forename: Risa
authors.initials: R
authors.lastname: Kawamoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ogata
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Hironobu
authors.initials: H
authors.lastname: Nakamura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Johkoh
mesh_terms: D000388:Air; D003287:Contrast Media; D008279:Magnetic Resonance Imaging / Q000379:methods*; D045423:Microbubbles; D019047:Phantoms, Imaging; D011134:Polysaccharides
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508