title: Comparison of delayed myocardial enhancement in the early and late phase after contrast injection: is it possible to reduce the examination time for myocardial viability study?
abstract: OBJECTIVE
  We studied whether we can obtain a myocardial viability study immediately after contrast injection to reduce the whole cardiac MR examination time.
  
  
  METHODS
  We examined 36 patients with cardiovascular abnormality on comprehensive cardiac MRI. T1-weighted images with inversion recovery (IR) were obtained 5 min after stress perfusion with 0.05 mmol/kg of gadodiamide and 15 min after the resting perfusion with the same dose. (The latter images were obtained 25 min after the initial administration.) We evaluated the existence, the number of sectors, and the degree of enhancement at each time. The contrast ratio was also calculated. The number of the enhanced sectors and the contrast ratio were statistically compared using Student's t test.
  
  
  RESULTS
  All 17 cases of delayed myocardial enhancement at 25 min after contrast injection showed some enhancement at 5 min after contrast injection. However, the number of enhanced sectors was larger at 25 min after the initial injection in 11 cases, and it was statistically significant (P=.017). The degree of enhancement was stronger at 25 min in 14 cases. However, the contrast ratio at 5 and 25 min after contrast injection was not significantly different (P=.245).
  
  
  CONCLUSIONS
  Myocardial viability study immediately after contrast injection is too early to evaluate the extent of myocardial injury.
authors.affiliation: Department of Radiology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan. ytanaka@md.tsukuba.ac.jp
authors.forename: Yumiko Oishi
authors.initials: YO
authors.lastname: Tanaka
authors.forename: Sadanori
authors.initials: S
authors.lastname: Ohtsuka
authors.forename: Masashi
authors.initials: M
authors.lastname: Shindo
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Oyake
authors.forename: Manabu
authors.initials: M
authors.lastname: Minami
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006331:Heart Diseases / Q000473:pathology*; D006801:Humans; D007275:Injections, Intravenous; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA