title: In Vivo UTE-MRI Reveals Positive Effects of Raloxifene on Skeletal-Bound Water in Skeletally Mature Beagle Dogs.
abstract: Raloxifene positively affects mechanical properties of the bone matrix in part through modification of skeletal-bound water. The goal of this study was to determine if raloxifene-induced alterations in skeletal hydration could be measured in vivo using ultra-short echotime magnetic resonance imaging (UTE-MRI). Twelve skeletally mature female beagle dogs (n = 6/group) were treated for 6 months with oral doses of saline vehicle (VEH, 1 mL/kg/d) or raloxifene (RAL, 0.5 mg/kg/d). After 6 months of treatment, all animals underwent in vivo UTE-MRI of the proximal tibial cortical bone. UTE-MRI signal intensity versus echotime curves were analyzed by fitting a double exponential to determine the short and long relaxation times of water with the bone (dependent estimations of bound and free water, respectively). Raloxifene-treated animals had significantly higher bound water (+14%; p = 0.05) and lower free water (-20%) compared with vehicle-treated animals. These data provide the first evidence that drug-induced changes in skeletal hydration can be noninvasively assessed using UTE-MRI.
authors: Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Matthew R
authors: MR
authors: Allen
authors: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Paul R
authors: PR
authors: Territo
authors: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Chen
authors: C
authors: Lin
authors: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Scott
authors: S
authors: Persohn
authors: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Lei
authors: L
authors: Jiang
authors: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Amanda A
authors: AA
authors: Riley
authors: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Brian P
authors: BP
authors: McCarthy
authors: Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Christopher L
authors: CL
authors: Newman
authors: Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: David B
authors: DB
authors: Burr
authors: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Gary D
authors: GD
authors: Hutchins
mesh_terms: D000818:Animals; D004285:Dogs; D005260:Female; D008279:Magnetic Resonance Imaging; D011859:Radiography; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D013977:Tibia / Q000000981:diagnostic imaging* / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
chemical_list: D014867:Water; D020849:Raloxifene Hydrochloride
keywords: CORTICAL BONE; HYDRATION; NONINVASIVE IMAGING; SERMS