title: Detection and characterization of hepatocellular carcinoma in rats with liver cirrhosis: diagnostic value of combined use of MR positive and negative contrast agents.
abstract: BACKGROUND
  Gadolinium-enhanced multi-phase dynamic imaging has improved the accuracy of the diagnosis of hypervascular hepatocellular carcinoma (HCC), but using gadolinium-enhanced dynamic imaging alone is problematic in evaluating hypovascular HCC. This work aimed at evaluating the combined use of superparamagnetic iron oxide (SPIO)-enhanced and gadolinium set in distinguishing HCCs from regenerative nodules (RNs) in a rat model induced by diethylnitrosamine (DEN).
  
  
  METHODS
  DEN-induced HCC model rats (n=40) and control rats (n=10) were studied. From weeks 16 to 19 after DEN administration, 4 animals were scanned every week. The hepatic changes were tested with a 1.5 Tesla magnet, and MR images of SPIO-enhanced and gadolinium set were obtained. According to the pathologic changes, the tumorigenesis was divided into HCC and RN (diameter of nodules > or =3 mm). Diagnostic accuracy of the combined SPIO-enhanced and gadolinium set and the gadolinium set alone was evaluated using receiver-operating characteristic curves. Sensitivity and specificity of the combined SPIO-enhanced and gadolinium set and the gadolinium set alone were calculated.
  
  
  RESULTS
  The listed tests were completed in 29 rats (21 treated and 8 controls). One hundred and six nodules (82 HCCs, 24 RNs) were analyzed. The Az value and sensitivity with the combined SPIO-enhanced and gadolinium set (Az 0.94, sensitivity 0.96) were higher than those with the gadolinium set alone (Az 0.92, sensitivity 0.89). Using the combined SPIO-enhanced and gadolinium set led to detection of 6 nodules which were negative in the gadolinium set alone and 3 nodules were correctly characterized.
  
  
  CONCLUSIONS
  Using the combined SPIO-enhanced and gadolinium set improved the detectability of HCCs and the SPIO-enhanced imaging compensated for the gadolinium set in differentiating HCCs from RNs in a rat model.
authors.affiliation: Department of Electronic Engineering, Dalian University of Technology, Dalian 116024, China.
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Guo
authors.forename: Tian-Shuang
authors.initials: TS
authors.lastname: Qiu
authors.forename: Jie
authors.initials: J
authors.lastname: Bian
authors.forename: Shu-Feng
authors.initials: SF
authors.lastname: Liu
authors.forename: Chang-Zheng
authors.initials: CZ
authors.lastname: Wang
mesh_terms: D000477:Alkylating Agents; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000150:complications / Q000473:pathology*; D003287:Contrast Media; D004052:Diethylnitrosamine; D004195:Disease Models, Animal; D005188:False Negative Reactions; D005189:False Positive Reactions; D005290:Ferric Compounds; D005682:Gadolinium; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000209:etiology / Q000473:pathology*; D008114:Liver Neoplasms, Experimental / Q000150:complications / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000477:Alkylating Agents; D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide; D004052:Diethylnitrosamine; D005682:Gadolinium