Accuracy of visual assessment in the detection and quantification of myocardial scar by delayed enhancement magnetic resonance imaging.

BACKGROUND: Delayed-enhancement magnetic resonance imaging (DE-MRI) is now a standard for the detection of myocardial scar and viability. Standard analysis needs expensive software. OBJECTIVE: To determine the accuracy of visual assessment in the detection and quantification of myocardial scar by DE-MRI technique. MATERIAL AND METHOD: The authors enrolled 32 patients with coronary artery disease (CAD) as documented by coronary angiography (CAG) and left ventricular dysfunction. All patients underwent cardiac magnetic resonance imaging for the assessment of global and regional myocardial function and DE-MRI. The presence and amount of scar in each myocardial segment was assessed by standard method. Visual assessment was performed by two methods: 1) visual drawing of the boundary of the hyperenhancement region and calculation of percentages of scar in an individual segment; 2) visual estimation of grading of hyperenhancement area from 0 (no scar) to 4 (> 75% scar). The agreement for scar detection and correlation of scar quantification for individual segments were evaluated. RESULTS: Thirty-one of 32 patients in the present study had myocardial scar. One thousand four hundred and thirty two myocardial segments were analyzed. Visual detection of myocardial scar has an excellent level of agreement with standard method of scar (Kappa = 0.963 and 0.952, p<0.001 for visual method I and II). Visual method I and II has an accuracy of 98.2% and 97.6% respectively in the detection of myocardial scar compared to standard method. Percentages of myocardial scar in each myocardial segment by visual method I correlate very well with standard method (Intraclass Correlation Coefficient = 0.885). Visual grading of amount of myocardial scar also has an excellent correlation with standard method (Spearman rank correlation coefficient = 0.934). CONCLUSION: Visual assessment of myocardial scar is accurate for the detection and quantification of scar.

Accuracy of magnetic resonance imaging in the diagnosis of coronary artery disease.

BACKGROUND: Coronary magnetic resonance angiography is a noninvasive method to visualize coronary arteries. The objective of this study was to determine the accuracy of coronary magnetic resonance imaging in the detection of coronary artery stenosis. METHOD: The authors studied 61 patients who were scheduled for their first diagnostic X-ray coronary angiography. Magnetic resonance imaging of the coronary arteries under free-breathing was performed prior to the catheterization schedule. The results were compared. RESULTS: Forty-one out of 61 patients (67.2%) had significant coronary stenosis of at least one major coronary artery. Sixteen (26.2%) had triple vessel disease. A total of 391 of 427 segments had interpretable image quality (91.6%). The diagnostic accuracy of the left main artery, left anterior descending artery, left circumflex artery, and right coronary artery was 96.7 per cent, 90 per cent, 80 per cent and 85.2 per cent respectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the detection of any significant coronary disease were 97.6 per cent, 75 per cent, 91.2 per cent, 90.9 per cent and 92.3 per cent respectively. CONCLUSIONS: Coronary magnetic resonance imaging is an accurate non-invasive imaging technique in the detection of coronary artery stenosis.