title: Positive-contrast imaging in the rabbit hind-limb of transplanted cells bearing endocytosed superparamagnetic beads.
abstract: Positive-contrast methods can augment negative-contrast methods for CMR evaluation of transplanted cell fate in vivo. This study correlated positive-contrast signal characteristics in the rabbit hind-limb with xenograft cell number (rat fibroblasts bearing endocytosed 1 microm Bang's particles) at different stages of Gd-DTPA administration and 1 mm2 in-plane resolution (2 minute scans, 1.5 Tesla). Linear regressions modeled satisfactorily the cell number dependencies of signal-to-noise (SNR) and area-of-enhancement (R > 0.83), over approximately a 50-fold fluctuation in cell number to a lowest detected limit of 25k cells during Gd-DTPA administration. Gd-DTPA administration elevated the slopes of parameter regressions by four or more standard deviations.
authors.affiliation: Department of Cardiology, St. Michael's Hospital, Toronto, Ontario, Canada. warren.foltz@sw.ca
authors.forename: Warren D
authors.initials: WD
authors.lastname: Foltz
authors.forename: Charles H
authors.initials: CH
authors.lastname: Cunningham
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Mutsaers
authors.forename: Steven M
authors.initials: SM
authors.lastname: Conolly
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Stewart
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Dick
mesh_terms: D000818:Animals; D003287:Contrast Media; D005347:Fibroblasts / Q000637:transplantation*; D019786:Gadolinium DTPA; D006614:Hindlimb / Q000473:pathology*; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D011817:Rabbits; D051381:Rats; D012044:Regression Analysis; D014183:Transplantation, Heterologous
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA