Applying dual energy computed tomography to postmortem coronary computed tomographic angiography

Medical examiners' offices are increasingly utilizing postmortem computed tomography (CT). While dual energy CT (DECT) has been applied in both clinical and postmortem settings, research on the application to postmortem coronary computed tomographic angiography (PMcCTA) is extremely limited. This study aims to evaluate whether DECT performed following PMcCTA using two contrast agents with differing chemical and physical properties allows for agent discrimination and simultaneous characterization of coronary artery patency and myocardial perfusion.

Phantoms were created using iodine (lipophilic Angiofil, aqueous Omnipaque) and gadolinium (aqueous Dotarem) contrast agents with water dilutions of the aqueous agents, and imaged using single-source DECT. Ex vivo PMcCTA of six porcine hearts was conducted, with imaging before and serially after injection of aqueous gadolinium followed by viscous iodinated Angiofil. The hearts were then imaged using single-source DECT and SyngoVia software was used to post-process the image data.

SyngoVia post-processing of DECT image data allowed for calculation of a material separation ratio of 1.7, and application of this ratio allowed discrimination between the iodinated and gadolinium agents. In the hearts, injection of Angiofil allowed for isolation of the epicardial vessels from tissue perfusion as assessed by the gadolinium which perfused the microcirculation and diffused into the extracellular space of the myocardial tissue.

This study demonstrates the capacity of DECT to isolate lipophilic iodinated contrast from aqueous gadolinium contrast in the setting of ex vivo PMcCTA, allowing for simultaneous characterization of vascular patency and changes in myocardial perfusion associated with vessel obstruction or infarction.