title: High-resolution magnetic resonance imaging quantitatively detects individual pancreatic islets.
abstract: OBJECTIVE
  We studied whether manganese-enhanced high-field magnetic resonance (MR) imaging (MEHFMRI) could quantitatively detect individual islets in situ and in vivo and evaluate changes in a model of experimental diabetes.
  
  
  METHODS
  Whole pancreata from untreated (n = 3), MnCl(2) and glucose-injected mice (n = 6), and mice injected with either streptozotocin (STZ; n = 4) or citrate buffer (n = 4) were imaged ex vivo for unambiguous evaluation of islets. Exteriorized pancreata of MnCl(2) and glucose-injected mice (n = 6) were imaged in vivo to directly visualize the gland and minimize movements. In all cases, MR images were acquired in a 14.1 Tesla scanner and correlated with the corresponding (immuno)histological sections.
  
  
  RESULTS
  In ex vivo experiments, MEHFMRI distinguished different pancreatic tissues and evaluated the relative abundance of islets in the pancreata of normoglycemic mice. MEHFMRI also detected a significant decrease in the numerical and volume density of islets in STZ-injected mice. However, in the latter measurements the loss of β-cells was undervalued under the conditions tested. The experiments on the externalized pancreata confirmed that MEHFMRI could visualize native individual islets in living, anesthetized mice.
  
  
  CONCLUSIONS
  Data show that MEHFMRI quantitatively visualizes individual islets in the intact mouse pancreas, both ex vivo and in vivo.
authors.affiliation: Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland. smaragda.lamprianou@unige.ch
authors.forename: Smaragda
authors.initials: S
authors.lastname: Lamprianou
authors.forename: Riikka
authors.initials: R
authors.lastname: Immonen
authors.forename: Christine
authors.initials: C
authors.lastname: Nabuurs
authors.forename: Asllan
authors.initials: A
authors.lastname: Gjinovci
authors.forename: Laurent
authors.initials: L
authors.lastname: Vinet
authors.forename: Xavier C R
authors.initials: XC
authors.lastname: Montet
authors.forename: Rolf
authors.initials: R
authors.lastname: Gruetter
authors.forename: Paolo
authors.initials: P
authors.lastname: Meda
mesh_terms: D000465:Algorithms; D000818:Animals; D002712:Chlorides / Q000008:administration & dosage; D003287:Contrast Media / Q000008:administration & dosage; D003922:Diabetes Mellitus, Type 1 / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology*; D005934:Glucagon / Q000378:metabolism; D050416:Glucagon-Secreting Cells / Q000378:metabolism / Q000473:pathology; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism; D007089:Image Enhancement / Q000379:methods*; D007150:Immunohistochemistry; D007262:Infusions, Intravenous; D007274:Injections, Intraperitoneal; D007328:Insulin / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000378:metabolism / Q000473:pathology; D007515:Islets of Langerhans / Q000378:metabolism / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D017895:Manganese Compounds / Q000008:administration & dosage; D051379:Mice; D008810:Mice, Inbred C57BL; D009929:Organ Size; D013311:Streptozocin / Q000633:toxicity
chemical_list: D002712:Chlorides; D003287:Contrast Media; D007328:Insulin; D017895:Manganese Compounds; D013311:Streptozocin; D005934:Glucagon; D005947:Glucose; C025340:manganese chloride