Abstract
Purpose
This study evaluated the impact of tube current (mAs) in delayed-enhancement computed tomography (CT) imaging for assessing acute reperfused myocardial infarction in a porcine model.
Materials and methods
In five domestic pigs (mean weight 24 kg), the circumflex coronary artery was balloon-occluded for 2 h and then reperfused. After 5 days, CT imaging was performed following administration of iodinated contrast material. A 64-slice CT system was used to perform first-pass coronary angiography with a tube current of 15 mAs/kg [Arterial Phase (ART)] followed by two delayed-enhancement (DE) scans 15 min after contrast material administration, with a tube current of 15 mAs/kg and 37.5 mAs/kg, respectively (DE1 and DE2). The mean heart rate decreased to 51±9 beats/min after administration of zatebradine (10 mg/kg IV). The data set was reconstructed during the end-diastolic phase of the cardiac cycle. Areas with DE, no reflow and remote myocardium [remote left ventricular (LV)] were calculated. CT values expressed in Hounsfield units (HU) were measured using five regions of interest (ROI): DE, no reflow, remote LV, LV cavity (LV lumen) and in air, respectively. Differences, correlations, image quality [signal-to-noise ratio (SNR)] and contrast resolution [contrast-to-noise ratio (CNR)] were calculated.
Results
Significant differences were found between attenuation of areas of DE, no reflow and remote LV (p<0.001) within the different scans. There was a fair correlation between DE and no-reflow attenuation (r=0.6; p<0.001). In DE1 vs. DE2, areas of DE and no reflow were not significantly different (p>0.05). The SNR and CNR were not significantly different in DE1 vs. DE2 (p>0.05).
Conclusions
Tube current does not significantly affect infarction area, image quality or contrast resolution of DE imaging with CT.
Riassunto
Obiettivo
Obiettivo del nostro lavoro è stato valutare l’impatto della corrente del tubo (mAs) nella tecnica di tomografia computerizzata in delayed-enhancement (DE-CT), utilizzata per la valutazione quantitativa dell’infarto miocardico acuto riperfuso in un modello animale porcino.
Materiali e metodi
In 5 maiali domestici (peso medio 24 kg), il ramo circonflesso dell’arteria coronarica sinistra è stato occluso mediante pallone e sottoposto a riperfusione a distanza di 2 h. Dopo 5 giorni, le scansioni di tomografia computerizzata (TC) sono state eseguite previa somministrazione di agente di contrasto iodato ev. Le scansioni sono state eseguite mediante TC a 64-strati: la prima, angiografia-coronarica convenzionale di primo passaggio, eseguita ad una corrente del tubo di 15 mAs/kg (ART); le restanti due scansioni DE-CT eseguite 15 min dopo somministrazione di agente di contrasto iodato, ad una corrente del tubo di 15 mAs/kg e 37,5 mAs/kg, rispettivamente (DE1 e DE2). La frequenza cardiaca media è stata ridotta a 51±9 battiti per minuto (bpm) mediante somministrazione di zatebradina (10 mg/kg ev). I dataset sono stati ricostruiti durante la fase tele-diastolica del ciclo cardiaco. Sono state calcolate le aree di delayed-enhancement (miocardio infartuato, DE), No-Reflow (miocardio infartuato con ostruzione microvascolare, No-Reflow), e miocardio normale (LV Remoto). I valori di attenuazione TC (espressi in unità Hounsfield [UH]) sono stati misurati in cinque regioni d’interesse: DE, No-Reflow, LV Remoto, cavità ventricolare sinistra (LV Lume) e in aria, rispettivamente. Sono state valutate le differenze, le correlazioni, la qualità d’immagine (come rapporto segnale rumore, S/N) e la risoluzione di contrasto (come rapporto contrasto rumore, C/N).
Risultati
Significative differenze sono state trovate tra le attenuazioni dell’area DE, No-Reflow e LV Remoto, in ogni protocollo di scansione (p<0,001). Una buona correlazione è stata trovata tra le attenuazioni di DE e No-Reflow (r=0,6; p<0,001). In DE1 vs. DE2, non sono state trovate significative differenze tra l’area DE e No-Reflow (p>0,05), ed i valori di S/N e C/N (p>0,05).
Conclusioni
Nell’imaging DE eseguito mediante TC, la corrente del tubo non influenza significativamente le dimensioni dell’area di infarto, la qualità d’immagine e la risoluzione di contrasto.
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References/Bibliografia
Baks T, van Geuns RJ, Biagini E et al (2005) Recovery of left ventricular function after primary angioplasty for acute myocardial infarction. Eur Heart J 26:1070–1077
Miller TD, Christian TF, Hopfenspirger MR et al (1995) Infarct size after acute myocardial infarction measured by quantitative tomographic 99mTc sestamibi imaging predicts subsequent mortality. Circulation 92:334–341
Judd RM, Lugo-Olivieri CH, Arai M et al (1995) Physiological basis of myocardial contrast enhancement in fast magnetic resonance images of 2-days-old reperfused canine infarcts. Circulation 92:1902–1910
Kim RJ, Fieno DS, Parrish TB et al (1999) Relationship of MRI delayed contrast enhancement to irreversible injury, infarct age, and contractile function. Circulation 100:1992–2002
Gerber BL, Rochitte CE, Melin JA et al (2000) Microvascular obstruction and left ventricular remodeling early after acute myocardial infarction. Circulation 101:2734–2741
Raff Gl, Gallagher MJ, O’Neill WW, Goldstein JA (2005) Diagnostic accuracy of non invasive coronary angiography using 64-slice spiral computed tomography. J Am Coll Cardiol 46:552–557
Mollet NR, Cademartiri F, van Mieghem CA et al (2005) High-resolution spiral computed tomography coronary angiography in patients referred for diagnostic conventional coronary angiography. Circulation 112:2318–2323
Maknken AH, Koos R, Katoh M et al (2005) Assessment of myocardial viability in reperfused acute myocardial infarction using 16-slice computed tomography in comparison to magnetic resonance imiging. J Am Coll Cardiol 45:2042–2047
Gosalia A, Haramati LB, Sheth MP, Spindola-Franco H (2004) CT detection of acute myocardial infarction. AJR Am J Roentgenol 182:1563–1566
Buecker A, Katoh M, Krombach GA et al (2005) A feasibility study of contrast enhancement of acute myocardial infarction in multislice computed tomography: comparison with magnetic resonance imaging and gross morphology in pigs. Invest Radiol 40:700–704
Hoffmann U, Millea R, Enzweiler C et al (2004) Acute myocardial infarction: contrast-enhanced multi-detector row CT in a porcine model. Radiology 231:697–701
Higgins CB, Sovak M, Schmidt W, Siemers PT (1978) Uptake of contrast materials by experimental acute myocardial infarctions: a preliminary report. Invest Radiol 13:337–339
Baks T, Cademartiri F, Moelker AD et al (2006) Multislice computed tomography and magnetic resonance imaging for the assessment of reperfused acute myocardial infarction. J Am Coll Cardiol 48:144–152
Baks T, Cademartiri F, Moelker AD et al (2007) Assessment of acute reperfused myocardial infarction with delayed-enhancement 64-MDCT. AJR Am J Roentgenol 188:W135–W137
Gray WR, Buja LM, Hagler HK et al (1978) Computed tomography for localization and sizing of experimental acute myocardial infarcts. Circulation 58:497–504
Doherty PW, Lipton MJ, Berninger WH et al (1981) Detection and quantitation of myocardial infarction in vivo using transmission computed tomography. Circulation 63:597–606
Higgins CB, Siemers PT, Newell JD, Schmidt W (1980) Role of iodinated contrast material in the evaluation of myocardial infarction by computerized transmission tomography. Invest Radiol 15:S176–S182
Lardo AC, Cordeiro M, Silva C et al (2006) Contrast-enhanced multidetector computer tomography viability imaging after myocardial infarction: characterization of myocyte death, microvascular obstruction, and chronic scar. Circulation 113:394–404
Stenner P, Kachelriess M (2008) Dual energy exposure control (DEEC) for computed tomography: algorithm and simulation study. Med Phys 35:5054–5060
Stolzmann P, Leschka S, Scheffel H et al (2008) Dual-source CT in step-and-shoot mode: noninvasive coronary angiography with low radiation dose. Radiology 249:71–80
Martini C, Maffei E, Palumbo A et al (2009) Impact of contrast material volume on quantitative assessment of acute reperfused myocardial infarction using delayed enhancement 64 slice CT: experience in a porcine model. Radiol Med, 2009 Dec 16. [Epub ahead of print]
Cademartiri F, La Grutta L, Palumbo A et al (2009) Computed tomography coronary angiography vs. stress ECG in patients with stable angina. Radiol Med 114:513–523
Cademartiri F, La Grutta L, Malagò R et al (2009) Assessment of left main coronary artery atherosclerotic burden using 64-slice CT coronary angiography: correlation between dimensions and presence of plaques. Radiol Med 114:358–369
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Martini, C., Maffei, E., Palumbo, A. et al. Impact of tube current in the quantitative assessment of acute reperfused myocardial infarction with 64-slice delayed-enhancement CT: a porcine model. Radiol med 115, 1003–1014 (2010). https://doi.org/10.1007/s11547-010-0541-0
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DOI: https://doi.org/10.1007/s11547-010-0541-0