title: Stability of real-time MR temperature mapping in healthy and diseased human liver.
abstract: OBJECTIVE
  To determine the stability and quality of MR temperature mapping using the proton resonance frequency (PRF) method in the liver of hepatic tumor patients.
  
  
  METHODS
  The standard deviation (SD) of a series of temperature maps was determined in 30 patients (21 patients with cirrhotic livers with carcinoma, and nine patients with noncirrhotic livers with metastasis or angioma) and in five volunteers at normal body temperature under free breathing. A respiratory-gated segmented echo-planar imaging (EPI) sequence (three slices in one expiration phase) was performed with sensitivity encoding (SENSE) acceleration on a 1.5 T scanner. Motion-corrupted images were identified by calculation of the cross-correlation coefficient, and discarded.
  
  
  RESULTS
  A T2* range of 10-33 msec was found, with especially low values in advanced cirrhotic livers. The mean temperature SD in patients was 2.3 degrees C (range = 1.5-5.0 degrees C). The stability in healthy livers was slightly better than that in cirrhotic livers, and it was higher in the right liver than in the left liver. The gating failed in 4% of the images when the respiratory cycle was irregular, leading to motion artifacts and errors in the temperature maps.
  
  
  CONCLUSIONS
  The achieved temperature stability and image quality makes real-time quantitative monitoring of thermal ablation of liver tumors feasible on a clinical scanner.
authors.affiliation: Laboratory for Molecular and Functional Imaging: From Physiology to Therapy, CNRS/Université Victor Segalen Bordeaux 2, Bordeaux, France.
authors.forename: Claudia
authors.initials: C
authors.lastname: Weidensteiner
authors.forename: Noureddine
authors.initials: N
authors.lastname: Kerioui
authors.forename: Bruno
authors.initials: B
authors.lastname: Quesson
authors.forename: Baudoin Denis
authors.initials: BD
authors.lastname: de Senneville
authors.forename: Hervé
authors.initials: H
authors.lastname: Trillaud
authors.forename: Chrit T W
authors.initials: CT
authors.lastname: Moonen
mesh_terms: D016477:Artifacts; D001831:Body Temperature; D006528:Carcinoma, Hepatocellular / Q000503:physiopathology*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008099:Liver / Q000502:physiology / Q000503:physiopathology* / Q000601:surgery; D008103:Liver Cirrhosis / Q000503:physiopathology*; D008113:Liver Neoplasms / Q000503:physiopathology* / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012815:Signal Processing, Computer-Assisted