Late iodine enhancement computed tomography with image subtraction for assessment of myocardial infarction

Abstract

Objective

To evaluate the feasibility of image subtraction in late iodine enhancement CT (LIE-CT) for assessment of myocardial infarction (MI).

Methods

A comprehensive cardiac CT protocol and late gadolinium enhancement MRI (LGE-MRI) was used to assess coronary artery disease in 27 patients. LIE-CT was performed after stress CT perfusion (CTP) and CT angiography. Subtraction LIE-CT was created by subtracting the mask volume of the left ventricle (LV) cavity from the original LIE-CT using CTP dataset. The %MI volume was quantified as the ratio of LIE to entire LV volume, and transmural extent (TME) of LIE was classified as 0%, 1–24%, 25–49%, 50–74% or 75–100%. These results were compared with LGE-MRI using the Spearman rank test, Bland-Altman method and chi-square test.

Results

One hundred twenty-five (29%) of 432 segments were positive on LGE-MRI. Correlation coefficients for original and subtraction LIE-CT to LGE-MRI were 0.79 and 0.85 for %MI volume. Concordances of the 5-point grading scale between original and subtraction LIE-CT with LGE-MRI were 75% and 84% for TME; concordance was significantly improved using the subtraction technique (p <0.05).

Conclusion

Subtraction LIE-CT allowed more accurate assessment of MI extent than the original LIE-CT.

Key Points

• Subtraction LIE-CT allows for accurate assessment of the extent of myocardial infarction.

• Subtraction LIE-CT shows a close correlation with LGE-MRI in %MI volume.

• Subtraction LIE-CT has significantly higher concordance with TME assessment than original LIE-CT.