Non-invasive imaging in coronary artery disease including anatomical and functional evaluation of ischaemia and viability assessment

Coronary artery disease has an important impact on the morbidity and mortality statistics and health economics worldwide. Diagnosis of coronary artery disease is important in risk stratification and guides further management. Invasive coronary angiography is the traditional method of imaging the coronary arteries and remains the gold standard. It detects luminal stenosis but provides little information about the vessel wall or plaques. Besides, not all anatomical lesions are functionally significant. This has lent itself to a wide variety of imaging techniques to identify and assess a flow-limiting stenosis. The approach to diagnosis of coronary artery disease is broadly based on anatomical and functional imaging. Coronary CT and MRI of coronary arteries provide an anatomical assessment of coronary stenosis. Coronary calcium score and coronary CT assess subclinical atherosclerosis by assessing the atherosclerotic plaque burden. The haemodynamic significance of a coronary artery stenosis can be assessed by stress radioisotope studies, stress echocardiography and stress MRI. The more recent literature also focuses on plaque assessment and identification of plaques that are likely to give rise to an acute coronary syndrome. There is an explosion of literature on the merits and limitations of the different imaging modalities. This review article will provide an overview of all the imaging modalities in the diagnosis of coronary artery disease.

Review of novel clinical applications of advanced, real-time, 3-dimensional echocardiography

Advances in computer processing speed and memory along with the advent of the microbeam former that can sample an entire crystal of the ultrasound transducer made possible the performance of 3-dimensional echocardiography in real time (RT3DE). The miniaturization of a 3-dimensional transducer permitting its extension to transesophageal mode rapidly expanded its use in a variety of conditions. Recent development of user-friendly automated/semiautomated cropping and display software may make it rather simple, even for the novice to gather useful information from RT3DE. We discuss the background, technique, and cutting-edge research and novel clinical applications of advanced RT3DE, including left ventricular dyssynchrony assessment, 3-D speckle tracking, myocardial contrast echocardiography, complete 4-dimensional (4-D) shape and motion analysis of the left ventricle, 4-D volumetric analysis of the right ventricle, 3-D volume rendering of the mitral valve, and other percutaneous and surgical procedural applications.

Value of real-time three-dimensional adenosine stress contrast echocardiography in patients with known or suspected coronary artery disease

AIM

The aim of this study was to evaluate the feasibility of myocardial wall-motion and perfusion assessment using contrast echocardiography during real-time three-dimensional (RT3D) adenosine stress test, and compare its diagnostic accuracy with the two-dimensional (2D) method using coronary angiography as reference.

METHODS AND RESULTS

Patients with known or suspected coronary artery disease (CAD) have been submitted to adenosine stress contrast echocardiography and coronary angiography, within a 1-month period. Two-dimensional apical four, two, and three chamber, as well as three-dimensional (3D) pyramidal full-volume data sets were acquired at rest and at peak stress. The 17-segment division of the left ventricle was used and each segment was evaluated based on wall motion and perfusion. Sixty patients (age: 60.1 ± 8.5 years, 38 men) were enrolled, i.e. 1020 segments were evaluated at rest and at peak stress. Wall-motion analysis per patient revealed that the sensitivity and specificity of 2D to detect CAD were 80 and 82% and of RT3D echocardiography were 82 and 64%, respectively, whereas in the per patient perfusion analysis the respective percentages were 88, 64% for 2D and 90, 73% for RT3D. Regarding left anterior descending artery and right coronary system, there seems to be no statistical significant difference in terms of wall-motion and perfusion evaluation between the two modalities.

CONCLUSIONS

Real-time 3D adenosine stress echocardiography is a feasible and valuable technique to evaluate myocardial wall motion and perfusion in patients with suspected CAD, despite existing problems concerning lower spatial and temporal resolution when compared with 2D echocardiography.

Assessment of nuchal translucency thickness and the fetal anatomy in the first trimester of pregnancy by two- and three-dimensional ultrasonography: a pilot study

AIM

To evaluate the use of three-dimensional ultrasonography (3D) as an alternative for examining fetal anatomy and nuchal translucency (NT) in the 1(st) trimester of pregnancy.

METHOD

Prospective study of 199 low risk pregnant women undergoing 1(st) trimester ultrasound scan for fetal anomalies. The NT and fetal anatomy were evaluated by three-dimensional (3D) ultrasonography after the standard two-dimensional (2D) examination. The gold standard in this study was the 2D ultrasonography.

RESULTS

In some of the evaluated parameters the 3D method approaches the conventional 2D results. These parameters are the crown-rump length (CRL), the skull - brain anatomy (93.5%), the spine (85.4%), the upper (88.4%) and lower limbs (87.9%) and the examination of the fetal abdomen (98.5%). Some of the anatomic parameters under evaluation revealed a statistically significant difference in favor of the 2D examination. During the 3D examination the nasal bone was identified in 62.1% of the cases, the stomach in 85.9%, and the urinary bladder in 57.3% of the cases. The NT was assessed accurately in half of the cases compared to 2D examination.

CONCLUSION

The 3D ultrasound is insufficient for the detailed fetal anatomy examination during the 1(st) trimester of pregnancy. Nevertheless, the method might be improved in order to be considered as a screening method.

Myocardial ischaemia and viability: the pivotal role of echocardiography

Echocardiography has a central role for the diagnosis and management of patients with known or suspected coronary artery disease. Besides the fact that it provides an essential role in the differential diagnosis of patients presenting with chest pain in the emergency department, echocardiography provides a comprehensive non-invasive haemodynamic and functional assessment of those patients. Stress echocardiography in many institutions is now the preferred stress modality associated with imaging as it is cost-effective and does not use ionizing radiation. It is used for assessing patients with known or suspected coronary artery disease, risk stratification and for assessing myocardial viability. The recent introductions of ultrasound contrast agents as well as deformation imaging techniques have eliminated the last limitations of stress echocardiography such as image quality and quantification, respectively.