Coronary Artery Disease: Gerber TC

Bluemke DA, Achenbach S, Budoff M, Gerber TC, Gersh B, Hillis LD, Hundley WG, Manning WJ, Printz BF, Stuber M, Woodard PK. · No affiliation provided · Circulation. · Pubmed #18586979 links to  free full text

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Gerber TC, Taylor AJ. · No affiliation provided · Mayo Clin Proc. · Pubmed #19252107 No free full text.

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Gerber TC, Kantor B, Chareonthaitawee P. · No affiliation provided · Eur Heart J. · Pubmed #17604292 links to  free full text

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Gerber TC, Breen JF, Kuzo RS, Kantor B, Williamson EE, Safford RE, Morin RL, Anonymous00093. · Division of Cardiovascular Diseases, Mayo Clinic, Jacksonville, FL 32224, USA. · Semin Ultrasound CT MR. · Pubmed #16562571 No free full text.

Abstract: Computed tomographic coronary angiography (CT-CA) is a direct but minimally invasive method of visualizing coronary arteries. Multidetector-row computed tomography (MDCT) is currently the CT modality most commonly used for coronary artery imaging. MDCT has been successfully used to detect stenoses in coronary arteries and coronary artery bypass grafts and to assess congenital coronary anomalies. Patients should not undergo CT-CA with MDCT if they have an irregular heart rhythm, a heart rate greater than 70 beats/min, and contraindications to pharmacologic agents for heart rate control, or if they have severe coronary artery disease or are likely to require revascularization.

Möhlenkamp S, Schmermund A, Gerber TC, Kerkhoff G, Pump H, Budde T, Erbel R. · Klinik für Kardiologie, Universitätsklinikum Essen, Germany. · Herz. · Pubmed #12669224 No free full text.

Abstract: BACKGROUND: Invasive, selective coronary angiography remains the "gold standard" of direct visualization of epicardial coronary arteries. Technical advances in recent years and improvements in image quality in both electron beam computed tomography (EBT) and multislice spiral/helical computed tomography (MSCT) brought along an increasing interest in the potential clinical role of noninvasive computed tomographic coronary angiography (CTCA). POTENTIAL AND LIMITATIONS: Measurement of coronary calcification permits quantitative estimation of overall coronary plaque burden and thereby allows assessment of cardiovascular risk and likelihood of the presence of a significant stenosis. However, the precise site and degree of stenoses cannot be measured. Contrast-enhanced CTCA lumenography permits visualization of epicardial coronary artery stenoses with a sensitivity and specificity of about 90%. Noncalcified plaques may also be detected in individual cases, but very few data are available on this aspect of CTCA. Image artifacts due to rapid motion, especially in the distal segments of the right and circumflex coronary arteries, may preclude reliable assessment of 20-30% of these segments. Also, in-stent restenoses and distal bypass anastomoses will, in the foreseeable future, remain difficult to confidently diagnose by CTCA. Combined assessment of calcified plaque burden and CTCA may enhance diagnostic accuracy especially in patients with low or moderate calcium scores. In the presence of heavy calcifications, stenoses may be masked. INDICATIONS: Noninvasive CT-based evaluation of coronary arteries seems useful in patients with a low to intermediate pretest likelihood for significant coronary artery disease (CAD). This holds for several ACC/AHA class II indications described for invasive, selective coronary angiography and for few class I indications. Further prospective studies are required to establish the clinical value of combined assessment of coronary calcium quantification and CTCA.

Gerber TC, Kuzo RS, Karstaedt N, Lane GE, Morin RL, Sheedy PF, Safford RE, Blackshear JL, Pietan JH. · Division of Cardiovascular Diseases, Mayo Clinic, Jacksonville, FL 32224, USA. · Mayo Clin Proc. · Pubmed #11794459 links to  free full text

Abstract: Electron beam computed tomography (EBCT) is the reference standard for x-ray-based tomographic imaging of the heart because of its high temporal resolution, but it is available in only a few centers. Quantification of coronary calcium is the most widely recognized use of EBCT for cardiac imaging. This technique requires no contrast media and provides an accurate assessment of overall plaque burden in the coronary tree; however, it does not directly identify or localize coronary stenoses. Multislice spiral (helical) CT (MSCT) is a new technology that provides images of the beating heart in diagnostic quality under many circumstances and may facilitate the broader application of cardiac and coronary CT. Currently, for imaging of the heart, much more experience exists with EBCT than with MSCT. Contrast-enhanced CT coronary angiography (CTCA) can be done with EBCT or MSCT to obtain images of the major branches of the coronary tree and to define luminal narrowing. Studies at experienced centers performed with small numbers of patients show that sensitivity, specificity, and negative predictive value are good with CTCA in the assessment of obstructive coronary artery disease, but CTCA remains an investigational technique for these applications. Computed tomographic coronary angiography can be clinically useful for assessing coronary artery bypass graft patency and congenital coronary abnormalities.

Kantor B, Nagel E, Schoenhagen P, Barkhausen J, Gerber TC. · No affiliation provided · Curr Probl Cardiol. · Pubmed #19269527 links to  free full text

Abstract: Cardiac computed tomography and magnetic resonance are relatively new imaging modalities that can exceed the ability of established imaging modalities to detect present pathology or predict patient outcomes. Coronary calcium scoring may be useful in asymptomatic patients at intermediate risk. Computed tomographic coronary angiography is a first-line indication to evaluate congenitally abnormal coronary arteries and, along with stress magnetic resonance myocardial perfusion imaging, is useful in symptomatic patients with nondiagnostic conventional stress tests. Cardiac magnetic resonance is indicated for visualizing cardiac structure and function, and delayed enhancement magnetic resonance is a first-line indication for assessing myocardial viability. Imaging plaque and molecular mechanisms related to plaque rupture holds great promise for the presymptomatic detection of patients at risk for coronary events but is not yet suitable for routine clinical use.

Hausleiter J, Meyer T, Hermann F, Hadamitzky M, Krebs M, Gerber TC, McCollough C, Martinoff S, Kastrati A, Schömig A, Achenbach S. · Department of Cardiology, Deutsches Herzzentrum München, Klinik an der Technischen Universität München, Lazarettstrasse 36, 80636 München, Germany. · JAMA. · Pubmed #19190314 links to  free full text

Abstract: CONTEXT: Cardiac computed tomography (CT) angiography (CCTA) has emerged as a useful diagnostic imaging modality in the assessment of coronary artery disease. However, the potential risks due to exposure to ionizing radiation associated with CCTA have raised concerns. OBJECTIVES: To estimate the radiation dose of CCTA in routine clinical practice as well as the association of currently available strategies with dose reduction and to identify the independent factors contributing to radiation dose. DESIGN, SETTING, AND PATIENTS: A cross-sectional, international, multicenter, observational study (50 study sites: 21 university hospitals and 29 community hospitals) of estimated radiation dose in 1965 patients undergoing CCTA between February and December 2007. Linear regression analysis was used to identify independent predictors associated with dose. MAIN OUTCOME MEASURE: Dose-length product (DLP) of CCTA. RESULTS: The median DLP of 1965 CCTA examinations performed at 50 study sites was 885 mGy x cm (interquartile range, 568-1259 mGy x cm), which corresponds to an estimated radiation dose of 12 mSv (or 1.2 x the dose of an abdominal CT study or 600 chest x-rays). A high variability in DLP was observed between study sites (range of median DLPs per site, 331-2146 mGy x cm). Independent factors associated with radiation dose were patient weight (relative effect on DLP, 5%; 95% confidence interval [CI], 4%-6%), absence of stable sinus rhythm (10%; 95% CI, 2%-19%), scan length (5%; 95% CI, 4%-6%), electrocardiographically controlled tube current modulation (-25%; 95% CI, -23% to -28%; applied in 73% of patients), 100-kV tube voltage (-46%; 95% CI, -42% to -51%; applied in 5% of patients), sequential scanning (-78%; 95% CI, -77% to -79%; applied in 6% of patients), experience in cardiac CT (-1%; 95% CI, -1% to 0%), number of CCTAs per month (0%; 95% CI, 0%-1%), and type of 64-slice CT system (for highest vs lowest dose system, 97%; 95% CI, 88%-106%). Algorithms for dose reduction were not associated with deteriorated diagnostic image quality in this observational study. CONCLUSIONS: Median doses of CCTA differ significantly between study sites and CT systems. Effective strategies to reduce radiation dose are available but some strategies are not frequently used. The comparable diagnostic image quality may support an increased use of dose-saving strategies in adequately selected patients.

Gerber TC, O'Brien PC, Pastor K, Kuzo RS, Blackshear JL, Morin RL. · Department of Radiology, Mayo Clinic, Jacksonville, Florida 32224, USA. · Invest Radiol. · Pubmed #12544074 No free full text.

Abstract: RATIONALE AND OBJECTIVES: To search for an optimum reconstruction window in retrospectively gated multislice computed tomography (MSCT) for quantification of coronary calcium. MATERIALS AND METHODS: Coronary calcium quantified was examined as Agatston and volume scores by two experienced observers at 10 time points across the R-R interval of the electrocardiogram in 42 patients. A combination of statistical approaches was used to evaluate the distributions of minimum and maximum scores and of interobserver variability for both scoring methods across the cardiac cycle. RESULTS: Based on the combination of evaluation approaches, 60% to 70% of the R-R interval appeared to be the optimum time point for obtaining maximum calcium scores with minimum interobserver variability. The optimum time point was more clearly defined for the Agatston score than for the volume score. CONCLUSION: A reconstruction window beginning at 60% to 70% of the R-R interval seems to be most advantageous for retrospective gating of MSCT studies performed to quantify coronary calcium.

Behrenbeck TR, Gerber TC, Möhlenkamp S, Laudon DA, Kantor B, Sheedy PF, Rumberger JA. · Division of Cardiology, Mayo Clinic, Rochester, MN 55902, USA. · Z Kardiol. · Pubmed #10907299 No free full text.

Abstract: Electron beam computed tomography (EBCT) allows visualization and quantification of calcium in the coronary arteries. This has been demonstrated to correlate well with the overall plaque burden in the coronary arteries. EBCT is, therefore, well suited for the detection of early stages of coronary atherosclerosis. Especially in asymptomatic patients with several risk factors, staging coronary artery disease by coronary calcium, scanning may allow prognostic assessment and guide preventive and therapeutic interventions. To date, only scant data are available regarding the cost effectiveness and the economic impact of this imaging technique. In this manuscript we compare various methods for the diagnosis of coronary artery disease using a theoretical model and review the results of a prospective trial in our emergency room of coronary calcium scanning in patients with acute chest pain. Using Framingham data and prognostic data from long-term follow-up, we discuss the impact of coronary calcification scanning on primary preventive measures and its economical consequences. EBCT is a promising technique which has created a lot of attention due to its ease of application. It is currently undergoing critical appraisal in the medical literature. Further randomized prospective trials are needed (and underway, i.e., MESA, EDIC, CARDIA II) to better define its value and limitations in the clinical arena.