Delayed enhancement cardiac computed tomography for the assessment of myocardial infarction: from bench to bedside

Abstract

A large number of studies support the increasingly relevant prognostic value of the presence and extent of delayed enhancement (DE), a surrogate marker of fibrosis, in diverse etiologies. Gadolinium and iodinated based contrast agents share similar kinetics, thus leading to comparable myocardial characterization with cardiac magnetic resonance (CMR) and cardiac computed tomography (CT) at both first-pass perfusion and DE imaging. We review the available evidence of DE imaging for the assessment of myocardial infarction (MI) using cardiac CT (CTDE), from animal to clinical studies, and from 16-slice CT to dual-energy CT systems (DECT). Although both CMR and gadolinium agents have been originally deemed innocuous, a number of concerns (though inconclusive and very rare) have been recently issued regarding safety issues, including DNA double-strand breaks related to CMR, and gadolinium-associated nephrogenic systemic fibrosis and deposition in the skin and certain brain structures. These concerns have to be considered in the context of non-negligible rates of claustrophobia, increasing rates of patients with implantable cardiac devices, and a number of logistic drawbacks compared with CTDE, such as higher costs, longer scanning times, and difficulties to scan patients with impaired breath-holding capabilities. Overall, these issues might encourage the role of CTDE as an alternative for DE-CMR in selected populations.

Myocardial Delayed Enhancement CT for the Evaluation of Heart Failure: Comparison to MRI

“…Immediately after coronary CT angiography, additional infusion of 0.5 mL/kg contrast material was performed for 60 seconds. In total, 1.4 mL/kg body weight of iodine (not exceeding 100 mL) was used as contrast material (19,20). The optimal late scanning timing after injection of contrast material has not been universally determined.…”

“…In investigating myocardial tissue characteristics, delayed gadolinium enhancement MRI has been widely used because of the high diagnostic performance in the detection and localization of LGE. On the other hand, previous studies have revealed that MDE CT helped accurately determine and quantify the spatial extent of acute and healed myocardial infarction and demonstrated diagnostic performances for detecting MDE by using single-energy CT (4,20). To date, some studies have demonstrated the detection of MDE in nonischemic cardiomyopathy (5-7), but the number of studies is limited.…”

Advancement in cardiac imaging for treatment of ventricular arrhythmias in structural heart disease

“…Furthermore, the doses of highly concentrated iodine-based contrast agents used in animals to achieve acceptable results are much higher than those used in clinical practice. 46 Nuclear imaging, including positron emission tomography (PET) and single-photon emission tomography (SPECT) can distinguish non-viable scar, viable hibernating scar, and healthy myocardium by changes in metabolism and/or perfusion, but are hampered by a poor resolution. 47 Intracardiac echocardiography has been used to delineate scar based on wall-thinning, wall motion abnormalities, 48 and occasionally the heterogeneity in SI.…”

“…These techniques include delayed-enhancement CT and virtual monochromatic imaging. 46 Future CT scanners with dual energy sources will also likely reduce contrast load. 46 To improve imaging of the arrhythmogenic substrate there is a need for scanners with better spatial resolution.…”

“…46 Future CT scanners with dual energy sources will also likely reduce contrast load. 46 To improve imaging of the arrhythmogenic substrate there is a need for scanners with better spatial resolution. Current state-ofthe-art navigator gated 3D LGE-CMR at 3T can generate continuous in vivo images with voxel resolution of 1.4 Â 1.4 Â 1.4 mm.…”