title: T1-Weighted Contrast-Enhanced Magnetic Resonance Imaging of the Small Bowel: Comparison Between 1.5 and 7 T.
abstract: OBJECTIVE
  T1-weighted (T1w) contrast-enhanced magnetic resonance imaging (MRI) of the small bowel at 1.5 T magnetic field strength has become a standard technique in investigating diseases of the small bowel. High-field MRI potentially offers improved soft tissue contrast and spatial resolution, providing increased image detail. The purpose of this study was to evaluate the feasibility of contrast-enhanced small bowel MRI at 7 T and to compare results with 1.5 T.
  
  
  METHODS
  Twelve healthy volunteers underwent small bowel MRI on a 1.5 T and 7 T MRI system. A coronal fat-saturated T1w spoiled gradient-echo sequence (3-dimensional [3D] FLASH) was applied precontrast and at 20 seconds, 75 seconds, and 120 seconds after intravenous contrast administration. Furthermore, late-phase coronal and axial fat-saturated T1w 2-dimensional (2D) FLASH data sets were acquired. Visual evaluation of tissue contrast and image detail of the small bowel wall and mesentery as well as contrast ratios were compared between 1.5 T and 7 T in an intraindividual comparison. In addition, subjective ratings of image impairment by artifacts were assessed at both field strengths.
  
  
  RESULTS
  Magnetic resonance imaging of the small bowel at 7 T revealed equal tissue contrast and image detail compared with 1.5 T. Higher contrast and improved image detail of mesentery structures at 7 T were found in nonenhanced 3D FLASH. Quantitatively measured contrast between the bowel wall and bowel lumen showed significantly lower contrast at 7 T in nonenhanced 3D FLASH and in late-phase 2D FLASH. Image quality was more impaired at 7 T compared with 1.5 T, mainly due to increased susceptibility artifacts and B1 inhomogeneities.
  
  
  CONCLUSIONS
  T1-weighted contrast-enhanced MRI of the small bowel at 7 T represents a promising MR technique for establishing ultra-high magnetic field strengths in clinical applications. Despite increased artifacts at 7 T, depiction of the small bowel was achieved with comparable quality to the current state-of-the-art field strength of 1.5 T. Assessment of potential diagnostic benefits should be the focus of future high-field MRI studies.
authors.affiliation: From the *Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, and †Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen; ‡Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg; and §High Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Hahnemann
authors.forename: Oliver
authors.initials: O
authors.lastname: Kraff
authors.forename: Stephan
authors.initials: S
authors.lastname: Orzada
authors.forename: Lale
authors.initials: L
authors.lastname: Umutlu
authors.forename: Sonja
authors.initials: S
authors.lastname: Kinner
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ladd
authors.forename: Harald H
authors.initials: HH
authors.lastname: Quick
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Lauenstein
mesh_terms: D000328:Adult; D016477:Artifacts; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007421:Intestine, Small / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D003287:Contrast Media