Comparison of visual scoring and quantitative planimetry methods for estimation of global infarct size on delayed enhanced cardiac MRI and validation with myocardial enzymes.
OBJECTIVE
Although delayed enhanced CMR has become a reference method for infarct size quantification, there is no ideal method to quantify total infarct size in a routine clinical practice. In a prospective study we compared the performance and post-processing time of a global visual scoring method to standard quantitative planimetry and we compared both methods to the peak values of myocardial biomarkers.


METHODS
This study had local ethics committee approval; all patients gave written informed consent. One hundred and three patients admitted with reperfused AMI to our intensive care unit had a complete CMR study with gadolinium-contrast injection 4±2 days after admission. A global visual score was defined on a 17-segment model and compared with the quantitative planimetric evaluation of hyperenhancement. The peak values of serum Troponin I (TnI) and creatine kinase (CK) release were measured in each patient.


RESULTS
The mean percentage of total left ventricular myocardium with hyperenhancement determined by the quantitative planimetry method was (20.1±14.6) with a range of 1-68%. There was an excellent correlation between quantitative planimetry and visual global scoring for the hyperenhancement extent's measurement (r=0.94; y=1.093x+0.87; SEE=1.2; P<0.001) The Bland-Altman plot showed a good concordance between the two approaches (mean of the differences=1.9% with a standard deviation of 4.7). Mean post-processing time for quantitative planimetry was significantly longer than visual scoring post-processing time (23.7±5.7min vs 5.0±1.1min respectively, P<0.001). Correlation between peak CK and quantitative planimetry was r=0.82 (P<0.001) and r=0.83 (P<0.001) with visual global scoring. Correlation between peak Troponin I and quantitative planimetry was r=0.86 (P<0.001) and r=0.85 (P<0.001) with visual global scoring.


CONCLUSIONS
A visual approach based on a 17-segment model allows a rapid and accurate assessment of the myocardial global delayed enhancement. This scoring method could be used on a daily practice and useful for the management strategy of post-MI patients.
Mewton
Nathan
N
Hôpital Cardiovasculaire Louis Pradel, 28, Avenue Doyen Lépine, 69677 Bron cedex, Hospices Civils de Lyon, France. nmewton@gmail.com
Revel
Didier
D
Bonnefoy
Eric
E
Ovize
Michel
M
Croisille
Pierre
P
D015415:Biomarkers / Q000097:blood; D003287:Contrast Media; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006571:Heterocyclic Compounds; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000473:pathology*; D015588:Observer Variation; D009942:Organometallic Compounds; D011446:Prospective Studies; D019210:Troponin I / Q000097:blood
D015415:Biomarkers; D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D019210:Troponin I; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate; D003402:Creatine Kinase