Dual Manganese-Enhanced and Delayed Gadolinium-Enhanced MRI Detects Myocardial Border Zone Injury in a Pig Ischemia-Reperfusion Model

• Published in: Circulation. Cardiovascular imaging Vol. 4; no. 5; pp. 574 - 582
• Main Authors: DASH, Rajesh, CHUNG, Jaehoon, YEUNG, Alan C, BRINTON, Todd J, HARNISH, Phillip P, YANG, Phillip C, IKENO, Fumiaki, HAHN-WINDGASSEN, Annett, MATSUURA, Yuka, BENNETT, Mihoko V, LYONS, Jennifer K, TERAMOTO, Tomohiko, ROBBINS, Robert C, MCCONNELL, Michael V
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.09.2011
• Subjects: Animals; Biological and medical sciences; Cardiology. Vascular system; Cardiovascular system; Contrast Media; Coronary heart disease; Diagnosis, Differential; Disease Models, Animal; Gadolinium DTPA; Heart; Injections, Intravenous; Investigative techniques of hemodynamics; Investigative techniques, diagnostic techniques (general aspects); Magnetic Resonance Imaging, Cine - methods; Manganese - administration & dosage; Medical sciences; Myocardial Reperfusion Injury - diagnosis; Myocarditis. Cardiomyopathies; Myocardium - pathology; Radioisotopes - administration & dosage; Reproducibility of Results; Severity of Illness Index; Swine; Heart; Myocardial infarction; Animal model; magnetic resonance imaging; Acquired; Cardiomyopathy; Injury; Cardiovascular disease; Gadolinium; Myocardial ischemia; Myocardial disease; Hypothesis; Delay; Myocyte; Result; Vascular disease; Swine; Adult; Tumor; Anterior intraventricular artery; Ungulata; Contrast media; Human; Ischemia reperfusion; Zone; Injection; Method; Coronary heart disease; Contrast; Nuclear magnetic resonance imaging; Uptake; Left ventricle; Pig; ischemia-reperfusion injury; In vivo; Anatomic pathology; Vertebrata; Mammalia; cell viability; Animal; Myocardium; Medical imagery; Artiodactyla; Hemodynamics; Technique; Day; Manganese
• ISSN: 1941-9651; 1942-0080
• DOI: 10.1161/circimaging.110.960591

Gadolinium (Gd)-based delayed-enhancement MRI (DEMRI) identifies nonviable myocardium but is nonspecific and may overestimate nonviable territory. Manganese (Mn(2+))-enhanced MRI (MEMRI) denotes specific Mn(2+) uptake into viable cardiomyocytes. We performed a dual-contrast myocardial assessment in a porcine ischemia-reperfusion (IR) model to test the hypothesis that combined DEMRI and MEMRI identifies viable infarct border zone (BZ) myocardium in vivo. Sixty-minute left anterior descending coronary artery IR injury was induced in 13 adult swine. Twenty-one days post-IR, 3-T cardiac MRI was performed. MEMRI was obtained after injection of 0.7 mL/kg Mn(2+) contrast agent. DEMRI was then acquired after injection of 0.2 mmol/kg Gd. Left ventricular (LV) mass, infarct, and function were analyzed. Subtraction of MEMRI defect from DEMRI signal identified injured BZ myocardium. Explanted hearts were analyzed by 2,3,5-triphenyltetrazolium chloride stain and tissue electron microscopy to compare infarct, BZ, and remote myocardium. Average LV ejection fraction was reduced (30±7%). MEMRI and DEMRI infarct volumes correlated with 2,3,5-triphenyltetrazolium chloride stain analysis (MEMRI, r=0.78; DEMRI, r=0.75; P<0.004). MEMRI infarct volume percentage was significantly lower than that of DEMRI (14±4% versus 23±4%; P<0.05). BZ MEMRI signal-to-noise ratio (SNR) was intermediate to remote and core infarct SNR (7.5±2.8 versus 13.2±3.4 and 2.9±1.6; P<0.0001), and DEMRI BZ SNR tended to be intermediate to remote and core infarct SNR (8.4±5.4 versus 3.3±0.6 and 14.3±6.6; P>0.05). Tissue electron microscopy analysis exhibited preserved cell structure in BZ cardiomyocytes despite transmural DEMRI enhancement. The dual-contrast MEMRI-DEMRI detects BZ viability within DEMRI infarct zones. This approach may identify injured, at-risk myocardium in ischemic cardiomyopathy.