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La radiologia medica

, Volume 115, Issue 7, pp 1003–1014 | Cite as

Impact of tube current in the quantitative assessment of acute reperfused myocardial infarction with 64-slice delayed-enhancement CT: a porcine model

  • C. Martini
  • E. Maffei
  • A. Palumbo
  • A. Weustink
  • T. Baks
  • A. Moelker
  • D. Dunker
  • A. Cuttone
  • E. Emiliano
  • N. Mollet
  • G. Krestin
  • P. De Feyter
  • F. CademartiriEmail author
Cardiac Radiology/Cardioradiologia
  • 51 Downloads

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.

Keywords

Acute reperfused myocardial infarction 64-slice CT Radiation dose Delayed enhancement Animal model 

Impatto della corrente del tubo sulla valutazione quantitativa dell’infarto miocardico acuto riperfuso mediante TC 64 strati e tecnica di delayed enhancement: esperienza in modello animale porcino

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.

Parole chiave

Infarto miocardico acuto riperfuso TC-64 strati Corrente del tubo Dose di radiazione Delayed enhancement Modello animale 

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Copyright information

© Springer-Verlag Italia 2010

Authors and Affiliations

  • C. Martini
    • 1
    • 2
  • E. Maffei
    • 1
  • A. Palumbo
    • 1
  • A. Weustink
    • 2
  • T. Baks
    • 2
  • A. Moelker
    • 2
  • D. Dunker
    • 2
  • A. Cuttone
    • 1
  • E. Emiliano
    • 1
  • N. Mollet
    • 2
  • G. Krestin
    • 2
  • P. De Feyter
    • 2
  • F. Cademartiri
    • 1
    • 2
    • 3
    Email author
  1. 1.Department of Radiology and CardiologyAcademic Hospital/Azienda Ospedaliero-UniversitariaParmaItaly
  2. 2.Department of Radiology and CardiologyErasmus Medical CenterRotterdamThe Netherlands
  3. 3.Dipartimento di Radiologia e Diagnostica per Immagine, c/o Piastra Tecnica - piano 0Azienda Ospedaliero-UniversitariaParmaItaly

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