title: Effects of gadolinium contrast agent on aortic blood flow and myocardial strain measurements by phase-contrast cardiovascular magnetic resonance.
abstract: BACKGROUND
  Quantitative blood flow and aspects of regional myocardial function such as myocardial displacement and strain can be measured using phase-contrast cardiovascular magnetic resonance (PC-CMR). Since a gadolinium-based contrast agent is often used to measure myocardial infarct size, we sought to determine whether the contrast agent affects measurements of aortic flow and myocardial displacement and strain. Phase-contrast data pre and post contrast agent was acquired during free breathing using 1.5T PC-CMR.
  
  
  RESULTS
  For aortic flow and regional myocardial function 12 and 17 patients were analysed, respectively. The difference pre and post contrast agent was 0.03±0.16 l/min for cardiac output, and 0.1±0.5 mm for myocardial displacement. Linear regression for myocardial displacement (MD) after and before contrast agent (CA) showed MDpostCA=0.95MDpreCA+0.05 (r=0.95, p<0.001). For regional myocardial function, the contrast-to-noise ratios for left ventricular myocardial wall versus left ventricular lumen were pre and post contrast agent administration 7.4±3.3 and 4.4±8.9, respectively (p<0.001). The contrast-to-noise ratios for left ventricular myocardial wall versus surrounding tissue were pre and post contrast agent administration -16.9±22 and -0.2±6.3, respectively (p<0.0001).
  
  
  CONCLUSIONS
  Quantitative measurements of aortic flow yield equal results both in the absence and presence of gadolinium contrast agent. The total examination time may thereby be reduced when assessing both viability and quantitative flow using PC-CMR, by assessing aortic flow post contrast agent administration. Phase-contrast information for myocardial displacement is also assessable both in the absence and presence of contrast agent. However, delineation of the myocardium may be difficult or impossible post contrast agent due to the lower image contrast. Acquisition of myocardial displacement should therefore be performed pre contrast agent using current PC-CMR sequences.
authors.affiliation: Department of Clinical Physiology, Lund University, and Department of Imaging and Function, Skåne University Hospital, Lund, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Hedström
authors.forename: Karin Markenroth
authors.initials: KM
authors.lastname: Bloch
authors.forename: Erik
authors.initials: E
authors.lastname: Bergvall
authors.forename: Freddy
authors.initials: F
authors.lastname: Ståhlberg
authors.forename: Håkan
authors.initials: H
authors.lastname: Arheden
mesh_terms: D000328:Adult; D000368:Aged; D001011:Aorta / Q000187:drug effects* / Q000503:physiopathology; D001783:Blood Flow Velocity; D003287:Contrast Media; D005260:Female; D006571:Heterocyclic Compounds; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012039:Regional Blood Flow; D013548:Sweden; D016277:Ventricular Function, Left / Q000187:drug effects*
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate