title: Improved quantification of islet transplants by magnetic resonance imaging with Resovist.
abstract: OBJECTIVE
  We aimed to develop an accurate and reproducible method to quantify transplanted islets and monitor their functional status in vivo. To support this aim, we investigated the cytotoxic effect of Resovist on islet function and survival.
  
  
  METHODS
  The average pixel number for a single Resovist-labeled islet was measured. To determine Resovist cytotoxicity, DNA fragmentation, adenosine diphosphate-adenosine triphosphate ratio, ion channel activity, and in vivo islet function were evaluated. To quantitatively monitor the fate of islet transplant, we transplanted Resovist-labeled islets into syngeneic C57BL/6 mice for magnetic resonance imaging analysis.
  
  
  RESULTS
  The average pixel volume for a medium-sized islet (100-150 μm in diameter) was determined from the contrast signal void of magnetic resonance image. Toxicological analysis showed that Resovist did not affect islet at concentrations up to 40 times the labeling dose. In the quantitative analysis, the number of contrast spots did not correlated with the number of transplanted islets, whereas our newly adopted measure showed a significant correlation.
  
  
  CONCLUSIONS
  Islet transplant survival may be safely and accurately monitored using magnetic resonance imaging with the Resovist. We found in this study that pixel number may correlate more closely than the number of contrast spots with the number of islets transplanted.
authors.affiliation: Department of Molecular Medicine, Sungkyunkwan University, Seoul, Republic of Korea.
authors.forename: Ki-Soo
authors.initials: KS
authors.lastname: Park
authors.forename: Han-Shin
authors.initials: HS
authors.lastname: Lee
authors.forename: Young-Seok
authors.initials: YS
authors.lastname: Kim
authors.forename: Tong-Mook
authors.initials: TM
authors.lastname: Kang
authors.forename: Jung-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Joh
authors.forename: Sung-Joo
authors.initials: SJ
authors.lastname: Kim
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism; D000818:Animals; D020013:Calcium Signaling; D003287:Contrast Media / Q000633:toxicity; D003911:Dextrans / Q000633:toxicity; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D016381:Islets of Langerhans Transplantation / Q000473:pathology* / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data; D058185:Magnetite Nanoparticles / Q000633:toxicity; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019047:Phantoms, Imaging; D014185:Transplantation, Isogeneic
chemical_list: D000227:Adenine Nucleotides; D003287:Contrast Media; D003911:Dextrans; D007328:Insulin; D058185:Magnetite Nanoparticles; C065507:ferumoxides