Novel Developments in Cardiac Computed Tomography

Indications for Coronary and Cardiac Computed Tomographic Angiography

Cardiovascular disease remains the leading cause of death and disability in the developed world. Over the last several years, many noninvasive imaging techniques have been used to enhance the diagnosis of cardiac disease. One of these advances, multidetector computed tomographic angiography (CTA), has transformed computed tomography from a single-slice transaxial imaging modality to a true 3-dimensional imaging technique with the ability to acquire submillimeter volumetric data. These benefits enable novel applications of CTA for the assessment of cardiac and coronary anatomy that were not previously possible. In this report, we discuss evolving indications for coronary CTA, noncoronary cardiac CTA, and several potential future indications for cardiac CTA.

High-resolution imaging of murine myocardial infarction with delayed-enhancement cine micro-CT

The objective of this study was to determine the feasibility of delayed-enhancement micro-computed tomography (microCT) imaging to quantify myocardial infarct size in experimental mouse models. A total of 20 mice were imaged 5 or 35 days after surgical ligation of the left coronary artery or sham surgery (n=6 or 7 per group). We utilized a prototype microCT that covers a three-dimensional (3D) volume with an isotropic spatial resolution of 100 microm. A series of image acquisitions were started after a 200 microl bolus of a high-molecular-weight blood pool CT agent to outline the ventricles. CT imaging was continuously performed over 60 min, while an intravenous constant infusion with iopamidol 370 was started at a dosage of 1 ml/h. Thirty minutes after the initiation of this infusion, signal intensity in Hounsfield units was significantly higher in the infarct than in the remote, uninjured myocardium. Cardiac morphology and motion were visualized with excellent contrast and in fine detail. In vivo CT determination of infarct size at the midventricular level was in good agreement with ex vivo staining with triphenyltetrazolium chloride [5 days post-myocardial infarction (MI): r(2)=0.86, P<0.01; 35 days post-MI: r(2)=0.92, P<0.01]. In addition, we detected significant left ventricular remodeling consisting of left ventricular dilation and decreased ejection fraction. 3D cine microCT reliably and rapidly quantifies infarct size and assesses murine anatomy and physiology after coronary ligation, despite the small size and fast movement of the mouse heart. This efficient imaging tool is a valuable addition to the current phenotyping armamentarium and will allow rapid testing of novel drugs and cell-based interventions in murine models.