title: Feasibility of multianimal hyperpolarized (13) C MRS.
abstract: OBJECTIVE
  There is great potential for real-time investigation of metabolism with MRS and hyperpolarized (HP) (13) C agents. Unfortunately, HP technology has high associated costs and efficiency limitations that may constrain in vivo studies involving many animals. To improve the throughput of preclinical investigations, we evaluate the feasibility of performing HP MRS on multiple animals simultaneously.
  
  
  METHODS
  Simulations helped assess the viability of a dual-coil strategy for spatially localized multivolume MRS. A dual-mouse system was assembled and characterized with bench- and scanner-based experiments. Enzyme phantoms mixed with HP [1-(13) C] pyruvate emulated real-time metabolism and offered a controlled mechanism for evaluating system performance. Finally, a normal mouse and a mouse bearing a subcutaneous xenograft of colon cancer were simultaneously scanned in vivo using an agent containing HP [1-(13) C] pyruvate.
  
  
  RESULTS
  Geometric separation/rotation, active decoupling, and use of low input impedance preamplifiers permitted an encode-by-channel approach for spatially localized MRS. A precalibrated shim allowed straightforward metabolite differentiation in enzyme phantom and in vivo experiments at 7 Tesla, with performance similar to conventional acquisitions.
  
  
  CONCLUSIONS
  The initial feasibility of multi-animal HP (13) C MRS was established. Throughput scales with the number of simultaneously scanned animals, demonstrating the potential for significant improvements in study efficiency.
authors.affiliation: The Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Marc S
authors.initials: MS
authors.lastname: Ramirez
authors.forename: Jaehyuk
authors.initials: J
authors.lastname: Lee
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Walker
authors.forename: Yunyun
authors.initials: Y
authors.lastname: Chen
authors.forename: Charles V
authors.initials: CV
authors.lastname: Kingsley
authors.forename: Jorge
authors.initials: J
authors.lastname: De La Cerda
authors.forename: Kiersten L
authors.initials: KL
authors.lastname: Maldonado
authors.forename: Stephen Y
authors.initials: SY
authors.lastname: Lai
authors.forename: James A
authors.initials: JA
authors.lastname: Bankson
mesh_terms: D000818:Animals; D066241:Carbon-13 Magnetic Resonance Spectroscopy / Q000191:economics / Q000295:instrumentation* / Q000379:methods*; D003110:Colonic Neoplasms / Q000503:physiopathology*; D003362:Cost-Benefit Analysis; D004734:Energy Metabolism / Q000502:physiology*; D004867:Equipment Design; D005240:Feasibility Studies; D064593:Heterografts; D019344:Lactic Acid / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D019047:Phantoms, Imaging; D019289:Pyruvic Acid / Q000378:metabolism
chemical_list: D019344:Lactic Acid; D019289:Pyruvic Acid
keywords: 13C pyruvate; colon cancer; metabolism; multianimal; multiple-mouse; spectroscopy; throughput, hyperpolarized