title: Three-dimensional Look-Locker MRI for evaluation of postcontrast myocardial and blood T1 values: comparison with two-dimensional Look-Locker and late gadolinium enhancement MRI.
abstract: BACKGROUND
  Two-dimensional (2D) Look-Locker MRI technique can identify myocardial fibrosis, but cannot cover the whole left ventricle during a single scan.
  
  
  OBJECTIVE
  To develop breath-hold three-dimensional (3D) Look-Locker MRI for the evaluation of postcontrast myocardial and blood T1 values and myocardial scarring in the left ventricle.
  
  
  METHODS
  A phantom and 24 patients with myocardial diseases underwent gadolinium-enhanced 2D and 3D Look-Locker MRI using a 1.5-T unit. We compared the T1 value of the phantom and the values of the myocardium and blood in the patients between the two Look-Locker MRI sequences. In the patient study, the scan ordering of the two Look-Locker MRI was selected randomly. We also assessed the ability of the 3D imaging to detect myocardial scarring that was confirmed by late gadolinium enhancement MRI.
  
  
  RESULTS
  The phantom study showed a good agreement for the T1 value between 2D and 3D Look-Locker MRI. There were no significant differences in the myocardial T1 values after contrast between 2D and 3D Look-Locker MRI or in the T1 values between the two imaging slices on the 3D Look-Locker MRI (P > 0.10). A better agreement for the myocardial T1 values was found when the 3D Look-Locker imaging was performed first. The T1 values for blood were affected by the scan order (P < 0.05). The 3D Look-Locker MRI showed myocardial scarring with a shorter T1 value (290.4 ± 62.7 ms) than those for unscarred myocardium (360.8 ± 30.3 ms).
  
  
  CONCLUSIONS
  Three-dimensional Look-Locker MRI may precisely estimate the postcontrast myocardial and blood T1 values for the entire left ventricle during a single scan.
authors.affiliation: Department of Radiology, Nippon Medical School, Tokyo, Japan. yas-amano@nifty.com
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Amano
authors.forename: Masaki
authors.initials: M
authors.lastname: Tachi
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kumita
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006331:Heart Diseases / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA