The purpose of study is to evaluate serial MR imaging of myocardial infarction using non-surgical model of myocardial infarction after percutaneous transcatheter coronary arterial embolization in dogs.

We evaluated serial pre- and post-contrast MR images with Gd-DTPA (gadolinium-diethylenetriamine-pentaacetic acid) of heart of the eleven mongrel dogs (immediate group (n=3), one week group (n=3), three weeks group (n=5)) after making non-surgically induced myocardial infarction. We confirmed the infarct with TTC staining and microscopically. The location and extents of the myocardial infarction were correlated.

A total of 24 MR images were archived; 11 images of the immediate post-embolic period, 8 images of one-week follow-up, and five of 3-week follow-up images. Comparing with the signal intensity of normal myocardium, immediate post-embolic MR images showed low or iso signal intensities (SI) of the infarct area on T1-weighted images (T1WI) and high SI on T2-weighted images (T2WI). No contrast enhancement with Gd-DTPA was made in all cases of the immediate post-embolic MRI. One-week and 3-week follow-up MR images showed low or iso SI on T1WI and slight high or iso SI on T2WI. Contrast enhancement images in both one-week and 3-week follow-up MRI showed denser enhancement of infarct area in one-week follow-up. The myocardial wall thinning was seen in 5 of eight dogs after one week and in 3 of five after 3 weeks.

In non-surgical animal models of myocardial infarction, MR images showed low or iso SI on T1WI, and high SI on T2WI in various stages, and contrast enhancement was maximum after one week and gradual decrease to 3 weeks. The myocardial wall thinning was seen in one-to 3-week follow-up MR images.