Infarct density distribution by MRI in the porcine model of acute and chronic myocardial infarction as a potential method transferable to the clinic

Abstract

Purpose To study the feasibility of a myocardial infarct (MI) quantification method (Signal Intensity-based Percent Infarct Mapping, SI-PIM) that is able to evaluate not only the size, but also the density distribution of the MI. Methods In 14 male swine, MI was generated by 90 minutes of closed-chest balloon occlusion followed by reperfusion. Seven (n=7) or 56 (n=7) days after reperfusion, Gd-DTPA-bolus and continuous-infusion enhanced Late Gadolinium Enhancement (LGE) MRI, and R1-mapping were carried out and post mortem triphenyl-tetrazolium-chloride (TTC) staining was performed. MI was quantified using binary (2 or 5 standard deviations, SD), SI-PIM and R1-PIM methods. Infarct Fraction (IF), and Infarct-Involved Voxel Fraction (IIVF) were determined by each MRI method. Bias of each method was compared to the TTC technique. Results The accuracy of MI quantification did not depend on the method of contrast administration or the age of the MI. IFs obtained by either of the two PIM methods were statistically not different from the IFs derived from the TTC measurements at either MI age. IFs obtained from the binary 2SD method overestimated IF obtained from TTC. IIVF among the three different PIM methods did not vary, but with the binary methods the IIVF gradually decreased with increasing the threshold limit. Conclusions The advantage of SI-PIM over the conventional binary method is the ability to represent not only IF but also the density distribution of the MI. Since the SI-PIM methods are based on a single LGE acquisition, the bolus-data-based SI-PIM method can effortlessly be incorporated into the clinical image post-processing procedure.

Cardiovascular imaging 2014 in the International Journal of Cardiovascular Imaging

“…Woie et al [23] presented a new automatic 3D method for estimating infarct size. Another paper developed a method for determining the infarct fraction and density distribution in an attempt to improve viability assessment [24]. Tao et al [25] combined T1 mapping with a Look-Locker sequence to late gadolinium enhancement (LGE) to provide more reliable myocardial scar assessment.…”

Myocardial Late Gadolinium Enhancement: Accuracy of T1 Mapping–based Synthetic Inversion-Recovery Imaging

“…This threshold is higher than the conventionally used cut-off (13,14) because the 2 standard deviation threshold has been found to overestimate infarct size (10,15). The reason for overestimation is mainly because of the partial volume effects affecting the border zone of the infarct (16,17). The 5 standard deviation threshold used herein has been found to be the most accurate among the binary quantification techniques (11).…”

Nonbinary quantification technique accounting for myocardial infarct heterogeneity: Feasibility of applying percent infarct mapping in patients

“…2 However, no established LGE quantification methods have been universally accepted and applied in clinical practice. 4,5 Previous studies have demonstrated that such binary techniques overestimate MI volume, primarily due to misquantification of MI in voxels with mixed tissue typically located at the peri-infarct or gray zone. 4,5 Previous studies have demonstrated that such binary techniques overestimate MI volume, primarily due to misquantification of MI in voxels with mixed tissue typically located at the peri-infarct or gray zone.…”

“…4,5 Previous studies have demonstrated that such binary techniques overestimate MI volume, primarily due to misquantification of MI in voxels with mixed tissue typically located at the peri-infarct or gray zone. 4 Percent infarct mapping (PIM) is a recently introduced quantification technique that can account for MI heterogeneity, effectively providing a more reliable measurement of the MI area. 4 Percent infarct mapping (PIM) is a recently introduced quantification technique that can account for MI heterogeneity, effectively providing a more reliable measurement of the MI area.…”

“…4 Percent infarct mapping (PIM) is a recently introduced quantification technique that can account for MI heterogeneity, effectively providing a more reliable measurement of the MI area. 4 PIM was initially developed for myocardial T 1 -mapping-based MI quantification, and was later applied to conventional SI-based LGE images (SI-PIM). 4 PIM was initially developed for myocardial T 1 -mapping-based MI quantification, and was later applied to conventional SI-based LGE images (SI-PIM).…”