An Improved MR Imaging Technique for the Visualization of Myocardial Infarction

TLDR

The study aimed to develop a segmented inversion‑recovery turboFLASH MR imaging pulse sequence to visualize myocardial infarction, compare it with other MR approaches in a canine model, and assess its clinical utility in patients with coronary artery disease. The authors examined six dogs and 18 patients, acquiring images with 10 different pulse sequences in dogs and using the segmented turboFLASH technique to obtain contrast‑enhanced images approximately 19 days after infarction in patients. The segmented turboFLASH sequence produced the greatest signal‑intensity contrast, with infarcted myocardium showing ~1,080 % higher intensity than normal in dogs and ~485 % higher in patients, enabling clear differentiation of injured from normal tissue.

Abstract

PURPOSE: To design a segmented inversion-recovery turbo fast low-angle shot (turboFLASH) magnetic resonance (MR) imaging pulse sequence for the visualization of myocardial infarction, compare this technique with other MR imaging approaches in a canine model of ischemic injury, and evaluate its utility in patients with coronary artery disease. MATERIALS AND METHODS: Six dogs and 18 patients were examined. In dogs, infarction was produced and images were acquired by using 10 different pulse sequences. In patients, the segmented turboFLASH technique was used to acquire contrast material–enhanced images 19 days ± 7 (SD) after myocardial infarction. RESULTS: Myocardial regions of increased signal intensity were observed in all animals and patients at imaging. With the postcontrast segmented turboFLASH sequence, the signal intensity of the infarcted myocardium was 1,080% ± 214 higher than that of the normal myocardium in dogs—nearly twice that of the next best sequence tested and approximately 10-fold greater than that in previous reports. All 18 patients with myocardial infarction demonstrated high signal intensity at imaging. On average, the signal intensity of the high-signal-intensity regions in patients was 485% ± 43 higher than that of the normal myocardium. CONCLUSION: The segmented inversion-recovery turboFLASH sequence produced the greatest differences in regional myocardial signal intensity in animals. Application of this technique in patients with infarction substantially improved differentiation between injured and normal regions.