title: T1rho imaging of murine brain tumors at 4 T.
abstract: OBJECTIVE
  The goal of this study was to evaluate the utility of T1rho weighting in magnetic resonance imaging of murine brain tumors.
  
  
  METHODS
  S91 Cloudman melanoma was implanted in mouse brains (n = 4). A T2-weighted spin-echo (SE) and a T1rho-weighted fast SE-based sequence were performed on a 4-T clinical imager. T2 and T1rho maps were computed. The tumor-to-normal-tissue contrast was compared between T2-weighted, T1rho-weighted, proton-density-weighted, and pre- and postcontrast T1-weighted SE images.
  
  
  RESULTS
  The tumor-tissue contrast of the T1rho-weighted images was similar to that of the T2-weighted images but less than that of the postcontrast T1-weighted images. The T1rho-weighted images provided better definition of tumor boundaries than T2-weighted images. At spin-locking powers of 0.5 and 1.5 kHz, the T1rho of the tumor was 64.0 msec +/- 0.46 and 68.65 msec +/- 0.59, respectively. There was no significant inter- or intra-animal variation in T1rho for tumor or normal brain cortex.
  
  
  CONCLUSIONS
  T1rho-weighted imaging performed at low spin-lock strengths qualitatively depicted tumor borders better than proton-density or T2-weighted imaging and could be useful in treatment planning when combined with other imaging sequences.
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, USA.
authors.forename: H
authors.initials: H
authors.lastname: Poptani
authors.forename: U
authors.initials: U
authors.lastname: Duvvuri
authors.forename: C G
authors.initials: CG
authors.lastname: Miller
authors.forename: A
authors.initials: A
authors.lastname: Mancuso
authors.forename: S
authors.initials: S
authors.lastname: Charagundla
authors.forename: N W
authors.initials: NW
authors.lastname: Fraser
authors.forename: J D
authors.initials: JD
authors.lastname: Glickson
authors.forename: J S
authors.initials: JS
authors.lastname: Leigh
authors.forename: R
authors.initials: R
authors.lastname: Reddy
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008546:Melanoma, Experimental / Q000000981:diagnostic imaging*; D051379:Mice; D008811:Mice, Inbred DBA; D011859:Radiography