Schnelle und akkurate Bestimmung der relativen Infarktgröße am Menschen durch kontrastmittelverstärkte Magnet-Resonanz-Tomographie im Vergleich mit der F-Fluorodesoxyglukose-Positronen-Emissions-Tomographie
OBJECTIVES: The aims of this study were to compare in humans in-vivo relative infarct size measurements with contrast enhanced magnetic resonance imaging (ceMRI) using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) as a reference standard (first part) and to quantify relative infarct sizing using semi-automatic quantitation techniques (second part).BACKGROUND: Assessment of residual myocardial viability in patients with chronic ischemic heart disease and left ventricular dysfunction is of great clinical importance for treatment and decision-making. CeMRI is an imaging modality capable of high spatial resolution and has been shown to identify scar tissue in ischemically damaged myocardium.METHODS: Sixty-two patients (mean age 66±9 years) with ischemic cardiomyopathy (EF 24±8%) underwent ceMRI for viability testing. For the first part of this study, 47patients also underwent FDG-PET imaging for clinical reasons. In these patients short-axis slices of the left ventricular at ceMRI were divided into 100 segments. Infarct size were calculated from the number of segments displaying >50% transmural delayed enhancement relative to the total number of segments. FDG-PET images were displayed in polar plots with infarction area defined as area of 18F-FDG uptake ≤50%. Infarct size were calculated from the relation of infarction area to total myocardial area. In the second part of the study in each of the 62 patients relative infarctsize was assessed by manual tracing and different semi-automatic thresholding methods thus as first a visual definition of a signal-intensity cutoff value, second the full-width-at-half-maximum technique (FWHM) and third a method of mean value plus 2-6 standard deviations (2-6 SD). RESULTS: Infarct size by ceMRI and FDG-PET agreed well (r=0.91; p<0.001; limits of agreement ±9%). Comparing the semi-automatic techniques, visual tresholding showed better agreement with manual contour tracing (r=0.98; limits of agreement ±3%) compared to the FWHM technique (r=0.77, limits of agreement ±12% vs. manual tracing and r=0.65, limits of agreement ±17% vs. FDG-PET). The method of mean value plus 2-6 standard deviation showed best agreement with the manual tracing while using +6SD, but still overestimated infarct size about 11%. CONCLUSIONS: Relative infarct size assessed by ce-CMR agrees well with results obtained by FDG-PET. Visual estimation of signal intensity cutoff values allows rapid and accurate determination of relative infarct size and is superior to the FWHM technique.
info:eu-repo/classification/ddc/610, Positronen-Emissions-Tomographie, NMR-Tomographie, Herzinfarkt, Medizin, Vitalitätsdiagnostik, kardiale Ischämie, Magnetresonanztomographie, kontrastmittelverstärkte MRT, Infarktgrößenquantifizierung, myocardial ischemia, delayed enhancement, infarctsize quantification, MRI, positron emission tomography
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