State of the art review: MR imaging, stent outcomes, ER triage

A study at UCLA looks at milestones in the development of cardiac MR. A large-scale study finds no difference in thrombosis rates between bare metal and drug-eluting stents. A study at Massachusetts General Hospital confirms that multislice CT can eliminate unnecessary hospital admissions by ruling out myocardial infarction for patients with chest pain who have nondiagnostic ECG results and normal cardiac enzymes.

Cardiac MRI

Cardiac MR imaging: state of the technology

Radiology 2006:241:338-354

University of California, Los Angeles clinicians, including lead author Dr. J. Paul Finn, review the status of MRI's applications in cardiology. The report covers milestones in the development of cardiac MR technology and practice. Functional imaging, myocardial viability and perfusion imaging, flow quantification, and coronary artery imaging are featured in the discussion.

Outcomes: drug-eluting stents

Outcomes of 6906 patients undergoing percutaneous coronary intervention in the era of drug-eluting stents. Report of the DEScover Registry

Circulation 2006 Oct 23; [Epub ahead of print]

Reporting for the DEScover Registry, Dr. David O. Williams, director of the cardiovascular laboratory at the Rhode Island Hospital Division of Cardiology in Providence, describes clinical outcomes from bare metal, sirolimus-eluting, and paclitaxel-eluting coronary artery stents installed at 140 medical centers from January to June 2005. The unadjusted incidence of death and myocardial infarction in the year after installation was 9% for patients who received bare metal stents compared with 5.2% for patients who received drug-eluting stents. No significant difference was seen in patients with sirolimus-eluting or paclitaxel-eluting stents. The clinical characteristics and lesion types treated with bare metal stents differed from the clinical indications preceding drug-eluting stent installation, however. After adjusting for these factors, the committee found that the risk of death or MI was not significantly lower for patients who received drug-eluting stents. Stent thrombosis rates were similar among the two drug-eluting and one metal stent configurations.

Early triage

MDCT in early triage of patients with acute chest pain

AJR 2006;187:1240-1247

Dr. Udo Hoffmann and colleagues at Massachusetts General Hospital confirmed that multislice CT can eliminate unnecessary hospital admissions by ruling out myocardial infarction for patients with chest pain who have nondiagnostic ECG results and normal cardiac enzymes. The MGH emergency room physicians referred 40 patients who meet these criteria for contrast-enhanced coronary artery CT angiography before admission. All five patients with acute coronary syndrome had at least one significant coronary stenosis on MSCT, according to Hoffmann, an assistant professor of radiology. ACS was ruled out in 35 patients, and significant coronary stenosis was excluded in 26 of 35 patients, thereby potentially cutting the hospitalization rate for these patients by 70%.

MSCT image quality

Noninvasive coronary angiography with 64-section CT: Effect of average heart rate and heart rate variability on image quality

Radiology 2006;241:378-385

Despite its faster image acquisition rate, a 64-slice CT scanner still shows improvement in the quality of coronary artery imaging when beta blockers are administered to slow patient heart rate. Dr. Sebastian Leschka and colleagues in the radiology and cardiovascular surgery departments at the University Hospital Zurich in Switzerland came to that conclusion from a study of 125 patients who underwent gated 64-slice cardiac CT to investigate suspected coronary artery disease. The average heart rate during these procedures was 63.3 bpm. Beta blockers reduced heart rate variability and improved image quality. Faster heart rates tended to degrade the image quality of left circumflex artery segments but had no apparent effect for imaging the right coronary and left anterior descending arteries, according to Leschka. The best images were captured in diastole with heart rates of less than 80 bpm and in systole with faster heart rates.

Vulnerable plaque imaging

In vivo F18-fluorodeoxyglucose positron emission tomography imaging provides a noninvasive measure of carotid plaque inflammation in patients

J Am Coll Cardio 2006;48:1818-1824

Dr. Ahmed Tawalkol and colleagues from the cardiology and radiology units at Massachusetts General Hospital established that FDG-PET imaging can assess the severity of inflammation in carotid plaques. The application promises to identify which patients with carotid atherosclerosis warrant intensified therapies to prevent stroke.

Application of F18 FDG PET for monitoring the therapeutic effect of anti-inflammatory drugs on stabilization of vulnerable atherosclerotic plaques

JNM 2006;47(11):1845-1850

Dr. Mikako Ogawa and colleagues at Hamamatsu University School of Medicine in Japan demonstrated in an animal study that quantitative FDG-PET imaging can noninvasively monitor the response of atherosclerotic plaques to the cholesterol-lowering drug probucol. Standard uptake values of FDG fell significantly for probucol-treated rabbits after three months of treatment. The decline correlated with lower inflammation and macrophage activity in the aortic plaque.