Myocardial infarct sizing by late gadolinium-enhanced MRI: Comparison of manual, full-width at half-maximum, and n-standard deviation methods.

PURPOSE: To compare three widely used methods for myocardial infarct (MI) sizing on late gadolinium-enhanced (LGE) magnetic resonance (MR) images: manual delineation and two semiautomated techniques (full-width at half-maximum [FWHM] and n-standard deviation [SD]). MATERIALS AND METHODS: 3T phase-sensitive inversion-recovery (PSIR) LGE images of 114 patients after an acute MI (2-4 days and 6 months) were analyzed by two independent observers to determine both total and core infarct sizes (TIS/CIS). Manual delineation served as the reference for determination of optimal thresholds for semiautomated methods after thresholding at multiple values. Reproducibility and accuracy were expressed as overall bias ± 95% limits of agreement. RESULTS: Mean infarct sizes by manual methods were 39.0%/24.4% for the acute MI group (TIS/CIS) and 29.7%/17.3% for the chronic MI group. The optimal thresholds (ie, providing the closest mean value to the manual method) were FWHM30% and 3SD for the TIS measurement and FWHM45% and 6SD for the CIS measurement (paired t-test; all P > 0.05). The best reproducibility was obtained using FWHM. For TIS measurement in the acute MI group, intra-/interobserver agreements, from Bland-Altman analysis, with FWHM30%, 3SD, and manual were -0.02 ± 7.74%/-0.74 ± 5.52%, 0.31 ± 9.78%/2.96 ± 16.62% and -2.12 ± 8.86%/0.18 ± 16.12, respectively; in the chronic MI group, the corresponding values were 0.23 ± 3.5%/-2.28 ± 15.06, -0.29 ± 10.46%/3.12 ± 13.06% and 1.68 ± 6.52%/-2.88 ± 9.62%, respectively. A similar trend for reproducibility was obtained for CIS measurement. However, semiautomated methods produced inconsistent results (variabilities of 24-46%) compared to manual delineation. CONCLUSION: The FWHM technique was the most reproducible method for infarct sizing both in acute and chronic MI. However, both FWHM and n-SD methods showed limited accuracy compared to manual delineation. J. Magn. Reson. Imaging 2016;44:1206-1217.

Electrophysiological study generally is negative in patients <40 years suspected of supraventricular tachycardia but also complaining of chest pain and/or syncope.

BACKGROUND: The diagnosis of paroxysmal supraventricular tachycardia (SVT) frequently is a dilemma. Electrophysiological study (EPS) is the only means to evaluate the nature of symptoms when noninvasive studies remain negative. Our objectives were to determine the clinical factors of negativity or positivity of (EPS) in patients suspected of SVT. METHODS: EPS was performed in 2650 patients complaining of tachycardia and suspected of SVT. Transesophageal EPS consisted of programmed atrial stimulation in control state and after isoproterenol. Patients were followed from 1 month to 18 years (2.93 ± 4 years). RESULTS: SVT was induced in 1944 patients, age 48 ± 19.5. EPS remained negative in 706 patients, age 34 ± 17 (p<0.0001). Age <40 years, feeling of dizziness/syncope or chest pain associated with tachycardia, the absence of heart disease or short PR interval was more frequent in patients with negative EPS (respectively 64, 42, 26, 96, 88.5%) than in patients with induced SVT (34, 14, 4, 88, 59%) (p<0.0001).The positive predictive value for the prediction of a negative EPS of age <40, chest pain, syncope or their association was 63.5, 42, 26.5, 11% and negative predictive value was 66, 86, 94.5, 99.5%. At multivariate analysis, age <40 (0.000, OR 2.79), the presence of syncope associated with tachycardia (0.000, OR 5.075) or chest pain (0.000, OR 17.923) was an independent factor of negative EPS. CONCLUSIONS: Among patients complaining of nondocumented tachycardia, suspected of SVT, the association of tachycardia with chest pain and/or syncope and age <40 years generally was correlated with a negative EPS and did not indicate initially invasive studies. In the remaining patients transesophageal EPS is indicated.