title: Focal hepatic lesions: detection and characterization with combination gadolinium- and superparamagnetic iron oxide-enhanced MR imaging.
abstract: OBJECTIVE
  To compare gadolinium- and superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging for detection and characterization of focal hepatic lesions when different contrast agent administration sequences are used.
  
  
  METHODS
  Unenhanced, dynamic gadolinium-enhanced, and SPIO-enhanced hepatic MR images were obtained in 134 patients. SPIO-enhanced MR imaging was performed immediately after gadolinium-enhanced dynamic MR imaging in 50 patients, 1 day after gadolinium-enhanced dynamic MR imaging in 40 patients, and before gadolinium-enhanced dynamic MR imaging in 44 patients. Two radiologists independently reviewed the gadolinium image set (unenhanced and gadolinium-enhanced dynamic MR images) and the SPIO image set (unenhanced and SPIO-enhanced MR images) in random order. Lesion detection sensitivity and lesion characterization accuracy were compared by analyzing the area under the receiver operating characteristic curve (Az).
  
  
  RESULTS
  Overall lesion detection accuracy for pooled data was significantly higher with the SPIO set (Az = 0.903) than with the gadolinium set (Az = 0.857) (P <.05). When hypovascular lesions were excluded, the detection rate was similar with the two sets. When hepatocellular carcinomas were excluded, the detection rate was significantly higher with the SPIO set (P <.01). Readers were more accurate in differentiating benign from malignant lesions with the gadolinium set (Az = 0.915) than with the SPIO set (Az = 0.847) (P <.01). Detection accuracy tended to be better with the images obtained after the second contrast agent was used.
  
  
  CONCLUSIONS
  Hypovascular lesion detection was better with SPIO-enhanced MR images than with gadolinium-enhanced MR images. Detection and characterization of hypervascular lesions were improved with gadolinium-enhanced MR images.
authors.affiliation: Department of Diagnostic Radiology, Research Institute of Radiological Science, Severance Hospital, and Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seodaemun-ku, Shinchon-dong 134, Seoul 120-752, Republic of Korea.
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Joo Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Jae-Joon
authors.initials: JJ
authors.lastname: Chung
authors.forename: Mi Suk
authors.initials: MS
authors.lastname: Park
authors.forename: Joon Seok
authors.initials: JS
authors.lastname: Lim
authors.forename: Young Taik
authors.initials: YT
authors.lastname: Oh
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007501:Iron; D008113:Liver Neoplasms / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010087:Oxides; D012680:Sensitivity and Specificity
chemical_list: D010087:Oxides; D005682:Gadolinium; D007501:Iron