Measurement of coronary calcium scores by electron beam computed tomography or exercise testing as initial diagnostic tool in low-risk patients with suspected coronary artery disease

We determined the efficiency of a screening protocol based on coronary calcium scores (CCS) compared with exercise testing in patients with suspected coronary artery disease (CAD), a normal ECG and troponin levels. Three-hundred-and-four patients were enrolled in a screening protocol including CCS by electron beam computed tomography (Agatston score), and exercise testing. Decision-making was based on CCS. When CCS≥400, coronary angiography (CAG) was recommended. When CCS<10, patients were discharged. Exercise tests were graded as positive, negative or nondiagnostic. The combined endpoint was defined as coronary event or obstructive CAD at CAG. During 12±4 months, CCS≥400, 10–399 and <10 were found in 42, 103 and 159 patients and the combined endpoint occurred in 24 (57%), 14 (14%) and 0 patients (0%), respectively. In 22 patients (7%), myocardial perfusion scintigraphy was performed instead of exercise testing due to the inability to perform an exercise test. A positive, nondiagnostic and negative exercise test result was found in 37, 76 and 191 patients, and the combined endpoint occurred in 11 (30%), 15 (20%) and 12 patients (6%), respectively. Receiver-operator characteristics analysis showed that the area under the curve of 0.89 (95% CI: 0.85–0.93) for CCS was superior to 0.69 (95% CI: 0.61–0.78) for exercise testing (P<0.0001). In conclusion, measurement of CCS is an appropriate initial screening test in a well-defined low-risk population with suspected CAD

The 20 year evolution of dobutamine stress cardiovascular magnetic resonance

Over the past 20 years, investigators world-wide have developed and utilized dobutamine magnetic resonance stress testing procedures for the purpose of identifying ischemia, viability, and cardiac prognosis. This article traces these developments and reviews the data utilized to substantiate this relatively new noninvasive imaging procedure

MRI and CT in the diagnosis of coronary artery disease: indications and applications

In recent years, technical advances and improvements in cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI) have provoked increasing interest in the potential clinical role of these techniques in the non-invasive work-up of patients with suspected coronary artery disease (CAD) and correct patient selection for these emerging imaging techniques. In the primary detection or exclusion of significant CAD, e.g. in the patient with unspecific thoracic complaints, and also in patients with known CAD or advanced stages of CAD, both CT and MRI yield specific advantages. In this review, the major aspects of non-invasive MR and CT imaging in the diagnosis of CAD will be discussed. The first part describes the clinical value of contrast-enhanced non-invasive CT coronary angiography (CTCA), including the diagnostic accuracy of CTCA for the exclusion or detection of significant CAD with coronary artery stenoses that may require angioplastic intervention, as well as potentially valuable information on the coronary artery vessel wall. In the second section, the potential of CT for the imaging of myocardial viability and perfusion will be highlighted. In the third and final part, the range of applications of cardiac MRI in CAD patients will be outlined

Myocardial tagging by Cardiovascular Magnetic Resonance: evolution of techniques--pulse sequences, analysis algorithms, and applications

Cardiovascular magnetic resonance (CMR) tagging has been established as an essential technique for measuring regional myocardial function. It allows quantification of local intramyocardial motion measures, e.g. strain and strain rate. The invention of CMR tagging came in the late eighties, where the technique allowed for the first time for visualizing transmural myocardial movement without having to implant physical markers. This new idea opened the door for a series of developments and improvements that continue up to the present time. Different tagging techniques are currently available that are more extensive, improved, and sophisticated than they were twenty years ago. Each of these techniques has different versions for improved resolution, signal-to-noise ratio (SNR), scan time, anatomical coverage, three-dimensional capability, and image quality. The tagging techniques covered in this article can be broadly divided into two main categories: 1) Basic techniques, which include magnetization saturation, spatial modulation of magnetization (SPAMM), delay alternating with nutations for tailored excitation (DANTE), and complementary SPAMM (CSPAMM); and 2) Advanced techniques, which include harmonic phase (HARP), displacement encoding with stimulated echoes (DENSE), and strain encoding (SENC). Although most of these techniques were developed by separate groups and evolved from different backgrounds, they are in fact closely related to each other, and they can be interpreted from more than one perspective. Some of these techniques even followed parallel paths of developments, as illustrated in the article. As each technique has its own advantages, some efforts have been made to combine different techniques together for improved image quality or composite information acquisition. In this review, different developments in pulse sequences and related image processing techniques are described along with the necessities that led to their invention, which makes this article easy to read and the covered techniques easy to follow. Major studies that applied CMR tagging for studying myocardial mechanics are also summarized. Finally, the current article includes a plethora of ideas and techniques with over 300 references that motivate the reader to think about the future of CMR tagging

Optimization of ECG-triggered 3D 23Na MRI of the human heart

Identification of linear systems, a priori known to be stable, from input output measurements corrupted by bounded noise is considered in the paper. A formal definition of the feasible parameter set is provided, taking explicitly into account prior information on system stability. On the basis of a detailed analysis of the geometrical structure of the feasible set, convex relaxation techniques are presented to solve nonconvex optimization problems arising in the computation of parameters uncertainty intervals. Properties of the computed relaxed bounds are discussed. A simulated example is presented to show the effectiveness of the proposed technique

Three-dimensional MR coronary angiography using the navigator technique compared with conventional coronary angiography.

OBJECTIVE: We evaluated the diagnostic accuracy of three-dimensional (3D) MR coronary angiography with the navigator technique for the detection of coronary artery stenoses in comparison with that of conventional radiographic angiography. SUBJECTS AND METHODS: Thirty patients with coronary artery disease were examined with an ECG-triggered 3D fast low-angle shot sequence using retrospective respiratory gating and the navigator technique on a 1.5-T MR scanner. The data set was evaluated as a 3D view with a surface rendering technique. RESULTS: Imaging of the proximal coronary arteries was possible in all patients. The average visualized lengths of the left main, left anterior descending, left circumflex, and right coronary arteries were 1.9+/-0.5 cm (mean +/- SD), 5.2+/-2.3 cm, 4.2+/-1.9 cm, and 5.2+/-2.5 cm, respectively. Irregular breathing reduced image quality in seven of the 30 patients, making diagnosis of stenoses impossible. In the 77% of patients whose examinations resulted in high-quality images, the sensitivity and specificity for detection of significant stenoses and occlusions in all four main coronary arteries were 81% and 89%, respectively. CONCLUSION: The navigator technique allows reproducible imaging of the proximal course of coronary arteries. This technique obviates breath-hold studies, thus allowing more patients to be examined. In patients whose examinations resulted in high-quality images, significant coronary artery lesions could be seen. However, for widespread clinical use, further technical improvement is necessary to increase sensitivity and specificity