Objective-To demonstrate the feasibility of using Multi-Detector Computed Tomography with gadolinium (Gd) contrast (Gd-MDCT) for the quantification of myocardial infarct (MI).Materials and Methods-MI was induced in six male swine (n=6). One week later, the animals received 0.2mmol/kg gadopentetate dimeglumine (Gd-DTPA) and were sacrificed. On the excised hearts, Gd-MDCT with several tube voltages (80, 120 and 140kV), Late Gadolinium Enhancement MRI (LGE-MRI), and triphenyl-tetrazolium-chloride (TTC) staining were then conducted. We used a 2SD threshold for the CT images, and several threshold limits (2, 3, 4, 5, 6SD and FWHM) for the LGE-MRI images, to delineate the infarct area. Total infarct volume and infarct fraction (IF) of each heart were calculated.Results-MI size measured by MDCT at 140kV showed good correlation with the reference TTC value. Applying an 80kV tube voltage, however, significantly underestimated MI size. In our study, the LGE-MRI method, using the 6SD threshold provided the most accurate determination of MI size. LGE-MRI, using the 2 and 3SD threshold limits, significantly overestimated infarct size.
Conclusions-TheGd-MDCT technique has been found suitable for the evaluation of MI in an ex-vivo experimental setting. Gd-MDCT has the ability to detect MI even at low kV settings, but accuracy is limited by a high image noise due to reduced photon flux.