PubMed Health⌕ Search

Biomedical subjects

Peter G Danias

Publications and source records attributed to Peter G Danias.

14 recordsLinked to original sources
PubMed2003

Comparison of aortic elasticity determined by cardiovascular magnetic resonance imaging in obese versus lean adults.

The vascular properties of large vessels in the obese have not been adequately studied. We used cardiovascular magnetic resonance imaging to quantify the cross-sectional area and elastic properties of the ascending thoracic and abdominal aorta in 21 clinically healthy obese young adult men and 25 men who were age-matched lean controls. Obese subjects had greater maximal cross-sectional area of the ascending thoracic aorta (984 +/- 252 vs 786 +/- 109 mm(2), p <0.01) and of the abdominal aorta (415 +/- 71 vs 374 +/- 51 mm(2), p <0.05). When indexed for height the differences persisted, but when indexed for body surface area, a significant difference between groups was found only for the maximal abdominal aortic cross-sectional area. The obese subjects also had decreased abdominal aortic elasticity, characterized by 24% lower compliance (0.0017 +/- 0.0004 vs 0.0021 +/- 0.0005 mm(2)/kPa/mm, p <0.01), 22% higher stiffness index beta (6.0 +/- 1.5 vs 4.9 +/- 0.7, p <0.005), and 41% greater pressure-strain elastic modulus (72 +/- 25 vs 51 +/- 9, p <0.005). At the ascending thoracic aorta, only the pressure-strain elastic modulus was different between obese and lean subjects (85 +/- 42 vs 65 +/- 26 kPa, respectively; p <0.05), corresponding to a 31% difference-but arterial compliance and stiffness index were not significantly different between groups. In clinically healthy young adult obese men, obesity is associated with increased cross-sectional aortic area and decreased aortic elasticity.

Adult↗
PubMed2003

Coronary magnetic resonance angiography.

Coronary magnetic resonance angiography (CMRA) is a technique in clinical evolution. Current clinical applications include assessment for coronary anomalies, aneurysms, bypass graft patency, and, in experienced centers, the exclusion of proximal and multivessel coronary artery disease (CAD). As local expertise increases and more extensive multicenter data become available, additional applications will be established. CMRA promises to supplement and in some cases obviate the need for X-ray contrast angiography, and to expand our understanding of the pathophysiology of CAD.

Coronary Aneurysm↗
PubMed2003

Coronary MR angiography clinical applications and potential for imaging coronary artery disease.

Over the past decade, CMRA has emerged as a unique clinical imaging tool with applications in selected populations. Patients with suspected coronary artery anomalies and patients with Kawasaki disease and coronary aneurysms are among those for whom CMRA has demonstrated clinical usefulness. For assessment of patients with atherosclerotic CAD, CMRA is useful for detection of patency of bypass grafts. At centers with appropriate expertise and resources, CMRA also appears to be of value for exclusion of severe proximal multivessel CAD in selected patients. Data from multicenter trials will continue to define the clinical role of CMRA, particularly as it relates to assessment of CAD. Future developments and enhancements of CMRA promise better lumen and coronary artery wall imaging. This may become the new target in noninvasive evaluation of CAD.

Coronary Disease↗
PubMed2003

Cardiac structure and function in the obese: a cardiovascular magnetic resonance imaging study.

BACKGROUND: Obesity is a major health problem in the Western world. Among obese subjects cardiac pathology is common, but conventional noninvasive imaging modalities are often suboptimal for detailed evaluation of cardiac structure and function. We investigated whether cardiovascular magnetic resonance imaging (CMR) can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. METHODS: In this prospective cross-sectional study, CMR was used to quantify left and right ventricular volumes, ejection fraction, mass, cardiac output, and apical left ventricular rotation in 25 clinically healthy obese men and 25 age-matched lean controls. RESULTS: Obese subjects had higher left ventricular mass (203 +/- 38 g vs. 163 +/- 22 g, p < 0.001), end-diastolic volume (176 +/- 29 mL vs. 156 +/- 25 mL, p < 0.05), and cardiac output (8.2 +/- 1.2 L/min vs. 6.4 +/- 1.3 L/min, p < 0.001). The obese also had increased right ventricular mass (105 +/- 25 g vs. 87 +/- 18 g, p < 0.005) and end-diastolic volume (179 +/- 36 mL vs. 155 +/- 28 mL, p < 0.05). When indexed for height, differences in left and right ventricular mass, and left ventricular end-diastolic volume remained significant. Apical left ventricular rotation and rotational velocity patterns were also different between obese and lean subjects. CONCLUSIONS: Obesity is independently associated with remodeling of the heart. Cardiovascular magnetic resonance imaging identifies subtle cardiac abnormalities and may be the preferred imaging technique to evaluate cardiac structure and function in the obese.

Adult↗
PubMed2003

ECG-gated 99mTc single-photon emission CT for assessment of right ventricular structure and function: is the information provided similar to echocardiography?

STUDY OBJECTIVE: (99m)Tc single-photon emission CT (SPECT) and ECG-gated SPECT can visualize well the right ventricle (RV) in most patients, but their utility for assessment of the RV has not been formally evaluated. We examined whether (99m)Tc SPECT/ECG-gated SPECT provide similar information to transthoracic two-dimensional Doppler echocardiography (2D-ECHO) regarding RV cavity size, wall thickness, and systolic function. DESIGN: Retrospective analysis. SETTING: A major university teaching hospital. PATIENTS: A consecutive series of 194 patients with good quality stress SPECT and 2D-ECHO studies performed within 1 day of each other and no significant interim cardiac events. MEASUREMENTS AND RESULTS: RV size and function were visually assessed by SPECT/ECG-gated SPECT and 2D-ECHO. RV wall thickness was visually assessed by SPECT and measured in mm in end-diastole by 2D-ECHO. Of 142 patients with normal RV cavity size by SPECT, 134 patients (94%) had normal RV cavity size by 2D-ECHO. However, of 52 patients with RV dilation by SPECT, only 9 patients (17%) had RV dilation by 2D-ECHO. A perfusion abnormality in the right coronary artery territory was significantly associated with RV dilation by SPECT (p < 0.005) and 2D-ECHO (p < 0.05). Among 150 patients with ECG-gated SPECT, only 2 patients had abnormal RV systolic function, as compared with 18 patients by 2D-ECHO. RV wall thickness measurements by SPECT and 2D-ECHO did not correlate. CONCLUSIONS: For normal interpretations regarding RV cavity size, wall thickness, and systolic function, there is good agreement between (99m)Tc stress SPECT/ECG-gated SPECT and 2D-ECHO. However, there is poor overall agreement between gated SPECT/ECG-gated SPECT and 2D-ECHO regarding the presence of RV dilation, hypertrophy, and systolic dysfunction.

Echocardiography, Doppler↗
PubMed2002

Electrocardiogram-gated single-photon emission computed tomography versus cardiac magnetic resonance imaging for the assessment of left ventricular volumes and ejection fraction: a meta-analysis.

OBJECTIVES: The purpose of this study was to evaluate the accuracy of electrocardiogram (ECG)-gated single-photon emission computed tomography (SPECT) for assessment of left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) compared with the gold standard of cardiac magnetic resonance imaging (MRI). BACKGROUND: Several comparisons of ECG-gated SPECT with cardiac MRI have been performed for evaluation of LV volumes and EF, but each has considered few subjects, thus leaving uncertainty about the frequency of discrepancies between the two methods. METHODS: We performed a meta-analysis of data on 164 subjects from nine studies comparing ECG-gated SPECT versus cardiac MRI. Data were pooled in correlation and regression analyses relating ECG-gated SPECT and cardiac MRI measurements. The frequency of discrepancies of at least 30 ml in EDV, 20 ml in ESV and 5% or 10% in EF and concordance for EF < or =40% versus >40% were determined. RESULTS: There was an overall excellent correlation between ECG-gated SPECT and cardiac MRI for EDV (r = 0.89), ESV (r = 0.92) and EF (r = 0.87). However, rates of discrepancies for individual subjects were considerable (37% [95% confidence interval [CI], 26% to 50%] for at least 30 ml in EDV; 35% [95% CI, 23% to 49%] for at least 20 ml in ESV; 52% [95% CI, 37% to 63%] for at least 5% in EF; and 23% [95% CI, 11% to 42%] for at least 10% in EF). The misclassification rate for the 40% EF cutoff was 11%. CONCLUSIONS: Electrocardiogram-gated SPECT measurements of EDV, ESV and EF show high correlation with cardiac MRI measurements, but substantial errors may occur in individual patients. Electrocardiogram-gated SPECT offers useful functional information, but cardiac MRI should be used when accurate measurement is required.

Electrocardiography↗
PubMed2002

Respiratory maneuvers decrease irradiated cardiac volume in patients with left-sided breast cancer.

Late cardiac morbidity and mortality among left breast cancer survivors treated with radiation therapy is related to cardiac volume included in the radiation portals. To determine if respiratory maneuvers can help decrease cardiac volume included in the radiation portals for left-sided breast cancer, 17 women with breast cancer, who had undergone left breast radiation therapy, underwent cardiac magnetic resonance imaging (MRI). Cardiac volume within the radiation portals was assessed from a transverse stack of eight, 10-mm thick, contiguous slices, covering the entire heart and obtained during breathholding at (1) endtidal volume (ETid) and (2) deep inspiration. Fourteen subjects (93% of those who completed the study) had inclusion of at least a portion of their heart within the radiation portals at ETid (median: 25.9 cm3, range 4.2-119.1 cm3). In all subjects, inspiratory breathholding decreased irradiated cardiac volume [median change: -18.1 cm3 (-49%), p < or = 0.001 vs. ETid]. In 21% of patients, the entire heart could be displaced outside the radiation field with deep inspiration. Age was not correlated with change or percentage change in cardiac volume with respiratory maneuvers. We conclude that in breast cancer patients, deep inspiratory maneuvers significantly decrease irradiated cardiac volume included in the left breast radiation field. Such an approach during delivery of radiation therapy allows preservation of radiation dosage to the breast, while reducing cardiac involvement and possible associated cardiovascular toxicity.

Adult↗
PubMed2002

Apical hypertrophic cardiomyopathy: clinical, electrocardiographic, scintigraphic, echocardiographic, and magnetic resonance imaging findings of a case.

The apical variant of nonobstructive hypertrophic cardiomyopathy (HCM) constitutes a minority of all cases of HCM and generally carries a favorable clinical outcome. We describe a 68 year-old Caucasian woman who presented with exertional dyspnea. The patient underwent stress testing with electrocardiogram-gated single-photon emission computed tomography imaging and resting transthoracic echocardiography. The patient also underwent cardiac magnetic resonance imaging at rest, including conventional structural and functional imaging and cine complementary spatial modulation of magnetization-tagged imaging (CSPAMM). The noninvasive evaluation of the heart demonstrated apical hypertrophy with regional systolic dysfunction, establishing the diagnosis of apical HCM. This case suggests a potential value of CSPAMM in characterizing apical HCM.

Aged↗
PubMedDate not supplied

Visual assessment of left ventricular perfusion and function with electrocardiography-gated SPECT has high intraobserver and interobserver reproducibility among experienced nuclear cardiologists and cardiology trainees.

BACKGROUND: Stress electrocardiography (ECG)-gated single photon emission computed tomography (SPECT) for assessment of left ventricular perfusion and function improves the confidence of interpretation and enhances specificity for detection of coronary artery disease. The reproducibility of visual interpretation of ECG-gated SPECT images and the significance of training and experience have not been reported previously in a large series of consecutive patients. We evaluated both intraobserver and interobserver agreement of interpretation of ECG-gated SPECT images among 3 cardiology trainees and 3 experienced nuclear cardiologists from 3 institutions. METHODS AND RESULTS: Three nuclear cardiologists and 3 cardiology trainees who had fulfilled American College of Cardiology/American Society of Nuclear Cardiology Core Cardiology Training Symposium (ACC/ASNC COCATS) guidelines for level II training in nuclear cardiology independently evaluated 106 consecutive technetium 99m sestamibi SPECT images with ECG gating of either the stress or rest images. All cases were interpreted blindly, twice in random sequence, without clinical data. We assessed intraobserver and interobserver agreement for myocardial perfusion, left ventricular regional and global systolic function, and overall clinical impression, by means of percent agreement and Cohen's kappa statistic. Intraobserver agreement was good (82%-92%, kappa = 0.54-0.84) for assessment of myocardial perfusion, systolic function, and overall impression. Interobserver agreement was also good, ranging from 65% to 90% (kappa = 0.32-0.76), with better agreement found for assessment of function (77%-85%, kappa = 0.52-0.7) than for perfusion (65%-80%, kappa = 0.32-0.6). For all measures, there were no significant differences in reproducibility between nuclear cardiologists and cardiology trainees. CONCLUSIONS: Interpretation of ECG-gated SPECT images has high reproducibility and agreement among both nuclear cardiologists and cardiology trainees.

Electrocardiography↗
PubMedDate not supplied

Increased resting Tl-201 lung-to-heart ratio is associated with invasively determined measures of left ventricular dysfunction, extent of coronary artery disease, and resting myocardial perfusion abnormalities.

BACKGROUND: Stress lung thallium 201 uptake correlates with left ventricular (LV) dysfunction and extent of coronary artery disease (CAD). Although Tl-201 is used less commonly for stress imaging, dual-isotope stress and viability protocols continue to use Tl-201 for rest imaging. We sought to investigate the association between increased resting Tl-201 lung-to-heart ratio (LHR) and hemodynamic indices of LV dysfunction, indices of myocardial perfusion, and extent of CAD. METHODS AND RESULTS: Over a 1-year period, we identified 192 consecutive patients who underwent dual-isotope stress perfusion imaging and cardiac catheterization within 30 days, without interim events or revascularization. Resting LHR was measured, and its association with invasively measured hemodynamic parameters, extent of CAD, and indices of myocardial perfusion at rest and stress was examined. Increased resting Tl-201 LHR was weakly but significantly associated with lower LV ejection fraction (EF) (r = 0.209, P <.05), higher pulmonary capillary wedge pressure (r = 0.25, P <.005), and LV end-diastolic pressure (r = 0.215, P <.01) but not with pulmonary artery systolic pressure. Increased LHR was also weakly associated with rest perfusion abnormalities including the sum rest score (r = 0.271, P <.001) and number of abnormally perfused segments (r = 0.25, P <.001) bud did not correlate with stress perfusion indices or ischemic burden. The 76 patients (40%) with LHR greater than 0.5 were more likely to have LVEF lower than 40% and 3-vessel/left main CAD. CONCLUSIONS: Increased rest Tl-201 LHR is weakly associated with higher LV end-diastolic pressure and pulmonary capillary wedge pressure and lower LVEF. LHR is also associated with the extent of previously infarcted myocardium and may indicate the presence of 3-vessel/left main CAD.

Age Factors↗
PubMedDate not supplied

Novel Internet-based tool for correcting apparent sensitivity and specificity of diagnostic tests to adjust for referral (verification) bias.

Referral (verification) bias-the selective sampling of a population under evaluation for definitive confirmation of disease status-has been recognized as affecting the measured sensitivity and specificity of diagnostic tests. The authors developed an Internet-based Java applet to correct the apparent (measured) values of sensitivity and specificity of diagnostic tests to adjust for referral (verification) bias. The applet was applied to the diagnosis of coronary artery disease by means of exercise stress testing. Referral rates for coronary arteriography can be adjusted separately for patients with positive and negative test results. The more complicated situation, in which the results are stratified in terms of exercise heart rate, was also investigated.

Coronary Angiography↗