title: Evaluation of image quality of DWIBS versus DWI sequences in thoracic MRI at 3T.
abstract: OBJECTIVE
  To compare diffusion weighted imaging with background suppression (DWIBS) sequence with classic spectral diffusion sequence (DWI) with and without respiratory gating in mediastinal lymph node analysis at 3T.
  
  
  METHODS
  26 patients scheduled for mediastinoscopic lymph node analysis, prospectively undergone a thoracic 3T MRI with DWIBS (FatSat=STIR; TR/TE=6674.1/44.7ms; IR=260 ms) and DWI sequences (FatSat=SPIR; TR/TE=1291/59.6 ms) (b=0-400-800 s/mm2) with and without (free breathing) respiratory gating. Images at b=800 were analyzed by two radiologists. They performed qualitative analysis of fat-sat homogeneity and motion artifacts, rated from 0 to 4, and quantitative evaluation by studying signal to background (STB) of lymph nodes.
  
  
  RESULTS
  Quality of fat suppression was significantly higher for DWIBS than for DWI both for free-breathing (score 3.48±0.65 vs. 1.76±0.96, p<0.0001) and respiratory-gated scans (3.17±0.77 vs. 1.72±0.73, p=0.0001). Similarly, artifacts were reduced with DWIBS (3.16±0.47 vs. 1.76±0.59, p<0.0001; 3.0±0.73 vs. 2.04±0.53, p=0.0001). Quantitative analysis showed higher STB with DWIBS (3.26±1.83 vs. 0.98±0.44, p<0.0001; 3.56±, 2.09 vs. 0.92±0.59, p<0.0001). Gating did not improve image quality and STB on DWIBS (p>0.05).
  
  
  CONCLUSIONS
  In thoracic MRI, ungated DWIBS sequence improves fat-sat homogeneity, reduces motion artifacts and increases STB of lymph nodes. Respiratory gating does not improve DWIBS image quality.
authors.affiliation: Department of Radiology, Centre hospitalier de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France. Electronic address: caroline.mesmann@chu-lyon.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Mesmann
authors.affiliation: Department of Radiology, Hopital Cardiologique Louis Pradel, Hospices Civils de Lyon, Lyon, France.
authors.forename: Monica
authors.initials: M
authors.lastname: Sigovan
authors.affiliation: Department of Radiology, Hopital Cardiologique Louis Pradel, Hospices Civils de Lyon, Lyon, France.
authors.forename: Lise-Prune
authors.initials: LP
authors.lastname: Berner
authors.affiliation: Department of Radiology, Centre hospitalier de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France.
authors.forename: Adva
authors.initials: A
authors.lastname: Abergel
authors.affiliation: Department of Thoracic Surgery, Hopital Cardiologique Louis Pradel, Hospices Civils de Lyon, Lyon, France.
authors.forename: François
authors.initials: F
authors.lastname: Tronc
authors.affiliation: Department of Radiology, Hopital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France; Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Berthezène
authors.affiliation: Department of Radiology, Hopital Cardiologique Louis Pradel, Hospices Civils de Lyon, Lyon, France; Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, France.
authors.forename: P
authors.initials: P
authors.lastname: Douek
authors.affiliation: Department of Radiology, Centre hospitalier de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France; Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, France.
authors.forename: Loic
authors.initials: L
authors.lastname: Boussel
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000328:Adult; D000368:Aged; D016477:Artifacts; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008198:Lymph Nodes / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008482:Mediastinum / Q000473:pathology*; D008875:Middle Aged; D009038:Motion; D011446:Prospective Studies; D011871:Radiology; D012119:Respiration; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water
keywords: DWIBS; Diffusion; Lymph node; MR imaging; Mediastinal