title: Comparison between nonspecific and necrosis-avid gadolinium contrast agents in vascular disrupting agent-induced necrosis of rodent tumors at 3.0T.
abstract: OBJECTIVE
  : To compare a commercial contrast agent (CA) Dotarem and a necrosis-avid CA (NACA) for their ability to evaluate the therapeutic necrosis with a vascular disrupting agent (VDA) on magnetic resonance imaging in rodent liver tumors to determine which could better correlate with the histopathologic outcome.
  
  
  METHODS
  : After the VDA treatment, 16 rats with 32 liver rhabdomyosarcomas were randomized into Dotarem and NACA groups (n = 8 per group) for both interindividual and intraindividual comparisons. T2-weighted imaging, T1-weighted imaging (T1WI), contrast-enhanced T1-weighted imaging (CE-T1WI), and diffusion-weighted imaging were performed at baseline, after VDA treatment and CA injections. The enhancing efficacy of CAs at immediate and delayed enhancement on CE-T1WI in viable tumor and necrosis was compared. Tumor necrosis ratios calculated from NACA and Dotarem were compared and correlated with gold-standard histopathology.
  
  
  RESULTS
  : On the immediate CE-T1WI, viable tumor was enhanced by either CA. On the delayed CE-T1WI at 30 minutes, both CAs failed to demarcate viable tumor from necrosis. At 24 hours post-NACA, the necrosis was clearly distinguished from viable tumor and thus derived necrosis ratio matched that from histopathology (P = 0.99); necrosis ratio from Dotarem was significantly lower than that from NACA and histopathology (P < 0.05, both), with a higher correlation of NACA than that of Dotarem with histopathology (r = 0.99 vs. r = 0.82).
  
  
  CONCLUSIONS
  : NACA better evaluated VDA-induced tumor necrosis than nonspecific CA on T1WI in tumor models of rat liver. NACA showed a closer correlation with histopathology than nonspecific CA for the delineation of true necrosis. Delayed enhancement on T1WI with nonspecific CA is not suitable for the assessment of VDA-induced tumor necrosis.
authors.affiliation: Department of Radiology, University Hospitals, University of Leuven, Belgium.
authors.forename: Huaijun
authors.initials: H
authors.lastname: Wang
authors.forename: Marlein
authors.initials: M
authors.lastname: Miranda Cona
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Junjie
authors.initials: J
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Yu
authors.forename: Yuanbo
authors.initials: Y
authors.lastname: Feng
authors.forename: Ronald
authors.initials: R
authors.lastname: Peeters
authors.forename: Frederik
authors.initials: F
authors.lastname: De Keyzer
authors.forename: Guy
authors.initials: G
authors.lastname: Marchal
authors.forename: Yicheng
authors.initials: Y
authors.lastname: Ni
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor; D003287:Contrast Media / Q000009:adverse effects*; D004195:Disease Models, Animal; D019786:Gadolinium DTPA / Q000009:adverse effects*; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009336:Necrosis / Q000139:chemically induced*; D051381:Rats; D012206:Rhabdomyolysis / Q000175:diagnosis* / Q000473:pathology; D012307:Risk Factors; D013223:Statistics as Topic; D014652:Vascular Diseases / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D003287:Contrast Media; D019786:Gadolinium DTPA