Identification and viability assessment of infarcted myocardium with late enhancement multidetector computed tomography: comparison with thallium single photon emission computed tomography and echocardiography.

BACKGROUND: Recent studies revealed that multidetector computed tomography late enhancement (MDCT-LE) is a reliable technique for detecting necrotic and scarred myocardial tissue. The aims of the study were to identify infarcted myocardium using MDCT-LE protocol in patients after myocardial infarction (MI) and assess viability in resting wall motion abnormalities. METHODS: One hundred one patients with previous MI (62 +/- 13 years, 1-6 months after MI) underwent MDCT-LE (15 minutes after contrast medium administration), rest-redistribution thallium single photon emission computed tomography (Tl-SPECT), and dobutamine echocardiography (DbE). In a 17-segment model, infarcted myocardium detected by MDCT-LE was categorized as none, 1%-25%, 26%-50%, 51%-75%, or >75% segmental extent and was compared with decreased uptake of Tl-SPECT and contractile function by DbE on per patient and segmental basis in a blinded fashion. RESULTS: By per patient analysis, MDCT-LE identified the presence of infarcted myocardium in 97 patients (96%), and Tl-SPECT decreased uptake in 88 patients (87%), (P = .02). By per segment analysis, the concordance for detecting infarcted myocardium was good (kappa value = 0.792). In segments with resting wall motion abnormalities (N = 486), there was moderate concordance in assessing viability (kappa value between MDCT and Tl-SPECT = 0.555, MDCT and DbE = 0.498, Tl-SPECT and DbE = 0.478) with predefined MDCT-LE threshold of 50% segmental extent. Among segments with MDCT-LE >75% segmental extent, the proportion designated nonviable by Tl-SPECT and DbE reached 87.8% and 92.2%, respectively. CONCLUSIONS: Multidetector computed tomography late enhancement is accurate in identifying the presence and extent of infarcted myocardium. Its segmental extent has good correlation with the magnitude of thallium decreased uptake and can predict contractile reserve. Multidetector computed tomography late enhancement can be an alternative to assess viability.

Safety and accuracy of multidetector row computed tomography for early assessment of residual stenosis of the infarct-related artery and the number of diseased vessels after acute myocardial infarction.

BACKGROUND: Recent studies reveal that contrast-enhanced multidetector row computed tomography (MDCT) is a promising technique for noninvasive visualization of coronary artery stenoses. We investigated the safety and accuracy of MDCT for early assessment of the severity of residual stenosis of the infarct-related artery (IRA) and the number of diseased vessels in patients after acute myocardial infarction (AMI). METHODS AND RESULTS: Of 146 AMI cases admitted, 72 fit with criteria and underwent 16-slice MDCT (4 +/- 2 days after AMI) with beta-blockers. There were no complications except 1 patient who had from complete atrioventricular block. Results were compared with conventional coronary angiography (CCA) within 3 days. In 55 (73.3%) of 72 patients, all arteries were assessable. In total, the number of assessable arteries was 253 (87.8%), and 35 (12.2%) vessels were nonassessable, mostly because of motion artifacts and extensive calcification. Overall, 84 of the 115 lesions (> or = 50% lumen reduction) were correctly detected by MDCT (sensitivity 73.0%). The accuracy in classifying patients with nonsignificant, single-, or multiple-vessel diseases was 79.1%. The accuracy for residual lesions with >50% stenosis of IRA was 87.5%. There was a good correlation regarding the severity of residual stenosis of the IRA (0%, 1%-49%, 50%-89%, 90%-99%, or occlusion) between MDCT and CCA (Spearman correlation 0.94, P < .001). Lesions with 90% to 99% or occlusion of the IRA were accurately detected or ruled out in 31 of 36 cases (86.1%). CONCLUSIONS: With appropriate protocol, MDCT is safe and accurate in assessing the severity of IRA and the number of diseased vessels during the first week after AMI. It has the potential to provide triage for early management of patients after AMI.

Assessment of left ventricular end-systolic elastance from aortic pressure-left ventricular volume relations.

The left ventricular (LV) end-systolic pressure-volume relation (ESPVR) is a load-insensitive method for evaluating LV contractility, which needs invasive measurement. Some noninvasive methods substitute peak aortic pressure (Ps) for end-systolic LV pressure by assuming there is no difference between these pressures. However, this assumption has not been directly validated. With conductance catheter and dual micromanometers, ESPVRs and the slope (EesLv) were constructed from simultaneous LV pressures (LVP) and volumes, aortic pressures (AOP) and LV volumes (Ees(AO)), and Ps and LV end-ejection volumes (VEE) (Ees(PP-EEV)) during preload reduction in 50 subjects. The ratio of steady-state P(s) over V(EE) (P(S)/V(EE)) was also checked. AOP and LVP displayed differences of 11 +/- 6 and -30 +/- 12 mm Hg at the onset and end-ejection, respectively, and -2 +/- 4 mm Hg at end-systole. Ees(AO) and Ees(LV) were nearly identical: Ees(AO) = 0.97 x Ees(LV) + 0.05, r2 = 0.99. Ees(PP-EEV) correlated with EesLV (EesPP-EEV = 0.57 x EesLV + 0.61, r2 = 0.46) but with much more scatter. Ps/V(EE) correlated worst with Ees(LV). Central AOP can be substituted for LVP to derive EesLV. Other estimation methods yield weaker and poor correlations to directly measured Ees.