title: Robust spatially resolved pressure measurements using MRI with novel buoyant advection-free preparations of stable microbubbles in polysaccharide gels.
abstract: MRI of fluids containing lipid coated microbubbles has been shown to be an effective tool for measuring the local fluid pressure. However, the intrinsically buoyant nature of these microbubbles precludes lengthy measurements due to their vertical migration under gravity and pressure-induced coalescence. A novel preparation is presented which is shown to minimize both these effects for at least 25 min. By using a 2% polysaccharide gel base with a small concentration of glycerol and 1,2-distearoyl-sn-glycero-3-phosphocholine coated gas microbubbles, MR measurements are made for pressures between 0.95 and 1.44 bar. The signal drifts due to migration and amalgamation are shown to be minimized for such an experiment whilst yielding very high NMR sensitivities up to 38% signal change per bar.
authors.affiliation: Department of Physics, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Morris
authors.forename: Martin
authors.initials: M
authors.lastname: Bencsik
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Nestle
authors.forename: Petrik
authors.initials: P
authors.lastname: Galvosas
authors.forename: David
authors.initials: D
authors.lastname: Fairhurst
authors.forename: Anil
authors.initials: A
authors.lastname: Vangala
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Perrie
authors.forename: Glen
authors.initials: G
authors.lastname: McHale
mesh_terms: D005782:Gels / Q000032:analysis / Q000737:chemistry; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008365:Manometry / Q000379:methods*; D045423:Microbubbles; D011134:Polysaccharides / Q000032:analysis* / Q000737:chemistry*; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D005782:Gels; D011134:Polysaccharides