Dynamic multi-section CT imaging in acute myocardial infarction: preliminary animal experience

Abstract

To evaluate the feasibility of myocardial first-pass perfusion imaging with multidetector CT (MDCT). In five pigs, myocardial infarction was induced by permanent balloon occlusion of the left anterior descending coronary artery. Dynamic contrast-enhanced MDCT (12x1.5 mm, 120 kV, 30 mAs, 64 acquisitions, 40 ml iopromide 370@4 ml/s) and contrast-enhanced first-pass perfusion magnetic resonance (MR) imaging (TR 7.7 ms/TE 2.6 ms, 64 acquisitions, 0.05 mmol/kg Gd-DTPA) were performed. Finally, the animals were sacrificed, and the heart was excised and stained with triphenyltetrazolin-chloride (TTC). Maximum signal intensity (SImax), contrast material arrival time (CAT), wash-in time (Tmax) and slope were calculated from time-density/signal-intensity curves. The area of myocardial hypoperfusion was measured as the percentage of the left-ventricular area (%LV). Parameters were compared using Bland-Altman plots and Student's t-tests. The hypoperfused area on MDCT was 19.3+/-4.5%LV (MR imaging 17.2+/-4.0%LV). The mean size of infarction was 18.7+/-5.7%LV with TTC. Semiquantitative analysis of MR imaging and MDCT for SImax, Tmax and slope showed significant differences between normal and infarcted myocardium (P<0.05). No significant differences were found for CAT. MDCT and MR imaging both allowed for the differentiation of hypoperfused and normal myocardium. Results given in absolute values differed significantly between both imaging modalities (P<0.05). MDCT has the potential for visual and semiquantitative assessment of first-pass myocardial perfusion.

Heterogeneous Microinfarcts Caused by Coronary Microemboli: Evaluation with Multidetector CT and MR Imaging in a Swine Model

“…dimensional coverage, high spatial resolution, and excellent contrast between the myocardium and blood pool. Retrospectively, electrocardiographically gated multidetector CT has been used to quantify LV volumes, ejection fraction, and contractility ( 48 ). Our fi ndings indicate that global LV functional measurements-namely, ejection fraction, end-diastolic volume, end-systolic volume, and cardiac output-quantifi ed on multidetector CT images are comparable with those quantifi ed on the reference standard MR images.…”

Comprehensive Assessment of Myocardial Perfusion Defects, Regional Wall Motion, and Left Ventricular Function by Using 64-Section Multidetector CT

“…Data on the accuracy of coronary artery assessment is rapidly evolving, with many articles showing high sensitivity and specificity for detection of substantial coronary artery stenosis by using multidetector CT as compared with invasive coronary angiography (3)(4)(5)(6)(7). While promising reports on ventricular function (8)(9)(10)(11)(12) and infarct imaging by using multidetector CT (13)(14)(15)(16) have been published, data on global LV function, regional wall motion (RWM), and PD assessment with multidetector CT in the acute MI setting are somewhat limited. If these assessments can be reliably obtained by using multidetector CT, it may provide an excellent tool for the rapid noninvasive diagnostic and prognostic evaluation of patients with acute MI.…”

Assessment of Cardiac Computed TomographyMyocardial Perfusion Imaging

“…Using several parameters derived from TACs, they compared infarcted and normal myocardium and demonstrated significant differences in the maximum attenuation density, time to maximum attenuation density, and upslopes of the myocardial TACs. 39 Furthermore, they showed that the area at risk as evident on gross pathology (in triphenyltetrazolium chloride-stained specimens) corresponded well to hypoperfused areas noted on CT-MPI. 39 So et al, in a porcine model of acute myocardial infarction, performed quantitative myocardial perfusion and showed that perfusion measurement of MBF with dynamic CT was accurate and correlated well with histology and microsphere measurements.…”

“…39 Furthermore, they showed that the area at risk as evident on gross pathology (in triphenyltetrazolium chloride-stained specimens) corresponded well to hypoperfused areas noted on CT-MPI. 39 So et al, in a porcine model of acute myocardial infarction, performed quantitative myocardial perfusion and showed that perfusion measurement of MBF with dynamic CT was accurate and correlated well with histology and microsphere measurements. 40 George et al, using a 64-detector CT in a canine ischemia model, performed CT-MPI during adenosine infusion.…”