Artery Calcifications

In the past numerous imaging modalities have been used to demonstrate coronary calcification, for example fluoroscopy, intravascular ultrasound, EBCT, single-slice CT and MSCT [9].

For a long time fluoroscopy has been used to assess coronary calcifications. However, the capability of fluo-

roscopy to detect small calcium deposits is poor. Usually only highly calcified, larger atherosclerotic lesions are detectable with fluoroscopy. In addition, fluoroscopy may suffer from an impaired accuracy and considerable inter-study variability depending on the patient's individual imaging conditions as well as the training and experience of the examiner [9].

Intravascular ultrasound is a clinically important tool for the assessment of the coronary atherosclerotic lesion including characterization of atherosclerotic plaque composition and visualization of calcifications [9]. However, intravascular ultrasound is invasive, quite expensive and visualizes only an incomplete portion of the entire coronary artery tree. Intravascular ultrasound is therefore not a suitable imaging technique for screening purposes or for repeated follow-up examinations.

Cardiac CT is extremely sensitive in the detection and quite accurate in the quantification of coronary artery calcifications [9]. In addition, cardiac CT is a noninvasive and quick method that is easy to perform. Thus, cardiac CT is currently regarded as the standard-of-care for the detection and quantification of coronary artery calcifications although the radiation exposure of this technique must be taken into account. However, there was recently a controversial debate about the most suitable cardiac CT imaging technique for coronary artery calcium scoring. The arguments advanced in discussing the pros and cons of the potential techniques pertain to temporal resolution, spatial resolution, image noise, radiation exposure, availability and reference values (see below) [10].

On rare occasions, also other imaging techniques, such as chest radiography, echocardiography and magnetic resonance imaging have been used to detect coronary artery calcifications, but all these methods have no clinical value due to the various imaging restrictions and very low diagnostic accuracy [9].

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