title: Differentiation of hepatocellular carcinoma and hepatic metastasis from cysts and hemangiomas with calculated T2 relaxation times and the T1/T2 relaxation times ratio.
abstract: OBJECTIVE
  To determine the diagnostic capability of the T1 and T2 relaxation times and the T1/T2 relaxation times ratio generated with the mixed turbo spin echo (mixed-TSE) pulse sequence, in order to discriminate between hepatocellular carcinoma (HCC)/metastases and hemangiomas/cysts.
  
  
  METHODS
  A retrospective review of 36 MR examinations implementing the mixed-TSE pulse sequence demonstrated 70 focal hepatic lesions. Quantitative MR algorithms were used to generate T1 and T2 relaxation times, and the T1/T2 relaxation times ratio for each lesion. A two-sample t-test compared mean T1 and T2 relaxation times, and the T1/T2 relaxation times ratio, by lesion type: carcinoma/metastases and hemangiomas/cysts. Sensitivity and specificity for discriminating carcinoma/metastases from hemangiomas/cysts with T2 relaxation time thresholds of 112 and 125 msec, as well as a ratio of T1/T2 relaxation times of 5.8, were calculated.
  
  
  RESULTS
  Using a T2 relaxation time threshold of 112 msec, 92% sensitivity and 100% specificity discriminating cysts/hemangiomas from HCC/liver metastasis was demonstrated. With a threshold of 125 msec, 96% sensitivity and 98% specificity was demonstrated. There was no correlation between calculated T1 relaxation times and type of lesion. Using a T1/T2 relaxation times ratio of 5.8, 100% sensitivity and specificity were demonstrated.
  
  
  CONCLUSIONS
  Although there is high sensitivity and specificity associated with the use of T2 relaxation times alone to discriminate carcinoma/metastases from hemangiomas/cysts, using the T1/T2 relaxation times ratio threshold of 5.8 allowed proper classification of all lesions.
authors.affiliation: Boston University Medical Center, Department of Radiology, Boston, Massachusetts 02118, USA. sfarraher@yahoo.com
authors.forename: Steven W
authors.initials: SW
authors.lastname: Farraher
authors.forename: Hernán
authors.initials: H
authors.lastname: Jara
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Chang
authors.forename: Al
authors.initials: A
authors.lastname: Ozonoff
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Soto
mesh_terms: D000465:Algorithms; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000556:secondary*; D003560:Cysts / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006391:Hemangioma / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity