Next Generation Hybrid Technologies Offer New Capabilities in Coronary Artery Disease Evaluation

The Brigham and Women’s Hospital Cardiovascular Imaging Center’s new state-of-the-art imaging equipment includes a 64-detector CT/PET scanner – the first to be installed in the world – and a new state-of-the-art 64- detector CT scanner. The new equipment provides greater speed, finer resolution, and the ability to visualize greater body volume in a single scan. Using 64-detector CT angiography (CTA), clear pictures of coronary arteries, including smaller ones, can be obtained and used to quantify atherosclerotic load. In addition, PET technology allows clinicians to assess the significance of coronary artery stenosis to determine a diagnosis and make management decisions.

Advances in 64-detector CT Angiography and PET/CT Applications
Specialists at Brigham and Women’s Hospital are targeting 64-detector CTA as an evaluation tool for patients with chest pain and a low likelihood of an abnormal scan. As the strength of CTA lies in its negative predictive value, a normal CTA excludes the presence of coronary artery disease, decreases the need for further testing – including catheterization – and serves as a guide for future medical management. CTA is not currently considered a screening tool for asymptomatic patients. A patient with moderate-to-high risk of coronary artery disease (CAD) may benefit more from hybrid imaging.

Although CTA may pinpoint areas of atherosclerosis, it cannot determine whether these areas are causing cardiac ischemia. Physicians at Brigham and Women’s Hospital are utilizing PET/CT to gain both anatomic and functional information, including evaluation for:

• Patients who have undergone previous revascularization and are experiencing new, non-emergency symptoms;
• Patients who exhibit discordance between imaging and symptoms.

Trial Evaluates Major Imaging Modalities
Marcelo F. Di Carli, MD, Co-director of Cardiovascular Imaging and Chief of Nuclear Medicine at Brigham and Women’s Hospital, is the national principal investigator for a large prospective, multi-center observational study designed to clarify the clinical value of four prominent diagnostic imaging modalities – SPECT, PET, PET/CT, and CT angiography – in the evaluation of CAD.

The SPARC trial (Study of Myocardial Perfusion and Coronary Anatomy Imaging Roles in CAD) will investigate these modalities for post-test resource utilization and patient outcomes. The SPARC trial will include approximately 4,000 patients with intermediate to high likelihood of CAD who have been referred by their physicians for noninvasive imaging. Patients will receive the imaging requested by their physician and additional testing or treatment as indicated by their imaging results. Patients will be followed for two years, specifically at 90 days to determine whether catheterization or revascularization was required and at two years to determine incidence of cardiac death or myocardial infarction.

Based on data derived from the SPARC trial, clinicians and researchers will be able to examine the effects of geography on the utilization and effectiveness of different imaging modalities and the effectiveness of various techniques in diverse patient populations and sub-groups. Ultimately, this trial will provide important information about the benefits of each imaging modality to help physicians make informed clinical decisions. (For more information, or to refer a patient for the SPARC trial, please call (617) 732-0566 or visit www.sparctrial.org.)

On the Horizon
The future of cardiovascular imaging lies in the molecular arena with the ability to visualize and target minute structures. PET/CT can potentially detect both anatomic and biologic features of vulnerable plaque and, in the future, new radio-tracers may allow physicians to identify and treat these lesions before they rupture. This development may also allow the use of PET/CT to assess early results of therapy. CT will reveal the landmarks from which biologic signals arise and PET imaging will read the signals to determine whether the therapy is working.

Indications for Referral
The Cardiovascular Imaging Center at Brigham and Women’s Hospital provides comprehensive, advanced evaluation for:

• Coronary artery disease;
• Congenital heart disease;v
• Aortic aneurysms and dissections;
• Arrhythmogenic right ventricular dysplasia;
• Ischemic and dilated cardiomyopathies;
• Hypertrophic and restrictive cardiomyopathies;
• Assessment of global and regional left ventricular function at rest;
• Ventricular morphology;
• Valvular morphology and function and quantification of regurgitant fraction;
• Pericardial disease.

Access and Information
For more information regarding cardiovascular imaging services at Brigham and Women’s Hospital, or to refer a patient, please contact a Referral Coordinator at (617) 732-9894.