title: Comparison of T2 and T2*-weighted MR molecular imaging of a mouse model of glioma.
abstract: BACKGROUND
  Standard MRI has been used for high-grade gliomas detection, albeit with limited success as it does not provide sufficient specificity and sensitivity to detect complex tumor structure. Therefore targeted contrast agents based on iron oxide, that shorten mostly T2 relaxation time, have been recently applied. However pulse sequences for molecular imaging in animal models of gliomas have not been yet fully studied. The aim of this study was therefore to compare contrast-to-noise ratio (CNR) and explain its origin using spin-echo (SE), gradient echo (GE), GE with flow compensation (GEFC) as well as susceptibility weighted imaging (SWI) in T2 and T2* contrast-enhanced molecular MRI of glioma.
  
  
  METHODS
  A mouse model was used. U87MGdEGFRvIII cells (U87MG), derived from a human tumor, were injected intracerebrally. A 9.4 T MRI system was used and MR imaging was performed on the 10 day after the inoculation of the tumor. The CNR was measured prior, 20 min, 2 hrs and 24 hrs post intravenous tail administration of glioma targeted paramagnetic nanoparticles (NPs) using SE, SWI, GE and GEFC pulse sequences.
  
  
  RESULTS
  The results showed significant differences in CNR among all pulse sequences prior injection. GEFC provided higher CNR post contrast agent injection when compared to GE and SE. Post injection CNR was the highest with SWI and significantly different from any other pulse sequence.
  
  
  CONCLUSIONS
  Molecular MR imaging using targeted contrast agents can enhance the detection of glioma cells at 9.4 T if the optimal pulse sequence is used. Hence, the use of flow compensated pulse sequences, beside SWI, should to be considered in the molecular imaging studies.
authors.forename: Barbara
authors.initials: B
authors.lastname: Blasiak
authors.forename: Samuel
authors.initials: S
authors.lastname: Barnes
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Foniok
authors.forename: David
authors.initials: D
authors.lastname: Rushforth
authors.forename: John
authors.initials: J
authors.lastname: Matyas
authors.forename: Dragana
authors.initials: D
authors.lastname: Ponjevic
authors.forename: Wladyslaw P
authors.initials: WP
authors.lastname: Weglarz
authors.forename: Randy
authors.initials: R
authors.lastname: Tyson
authors.forename: Umar
authors.initials: U
authors.lastname: Iqbal
authors.forename: Abedelnasser
authors.initials: A
authors.lastname: Abulrob
authors.forename: Garnette R
authors.initials: GR
authors.lastname: Sutherland
authors.forename: Andre
authors.initials: A
authors.lastname: Obenaus
authors.forename: Boguslaw
authors.initials: B
authors.lastname: Tomanek
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003287:Contrast Media; D005910:Glioma / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental; D011673:Pulsatile Flow
chemical_list: D003287:Contrast Media; D058185:Magnetite Nanoparticles