Advances in cardiac imaging with 16-section CT systems

Interscan variability of coronary artery calcium quantification using an electrocardiographically pulsed spiral computed tomographic protocol

The use of an electrocardiographically pulsed spiral computed tomographic protocol significantly reduced the radiation dose to patients who underwent coronary calcium screening. For Agatston scores <10, the interscan variability of such a protocol was significantly lower than that for a sequential acquisition protocol. At higher Agatston scores, the 2 protocols had similar variability characteristics.

Left ventricular thin-point detection using multidetector spiral computed tomography

We systematically studied the thickness of the myocardium in the left ventricular apical region in patients without a history of myocardial infarction and with no hemodynamically significant coronary artery disease, using contrast-enhanced multidetector spiral computed tomography with submillimeter collimation. We confirmed previous pathology data and reliably detected a small confined region of the normal apical myocardium with a thickness of <or=3 mm, i.e., the left ventricular thin point.

Sixteen-Row multislice computed tomography: basic concepts, protocols, and enhanced clinical applications

Since its introduction, spiral computed tomography (CT) technology underwent a continuous and fast technical and clinical development. In particular, spatial and temporal resolutions were constantly increased during the last decade. The main breakthrough for clinical application was the introduction of multislice technology, first with 2-row and 4-row equipment and more recently with 16-row scanners. A high-resolution sub-millimeter CT dataset can be acquired easily, although with an increased x-ray exposure for the patient. The high speed of the scan requires up-to-date and careful protocol optimization. Scanner technology and geometry affect image formation procedure and imaging protocols should be adapted accordingly. The technical foundations of spiral CT imaging and the main scan and reconstruction parameters are described in this article. Updated protocols and clinical examples of the latest applications are also discussed.

Radiation dose in multidetector row computed tomography cardiac imaging

Multidetector row computed tomography (MDCT) with its markedly improved temporal and spatial resolution has opened up a new opportunity in cardiac CT imaging. MDCT scanners are increasingly available and have become the preferred CT scanners for the entire spectrum of clinical CT examinations. As a consequence, the number of cardiac CT studies is continuously growing. Because cardiac CT studies involve considerable radiation doses, it is compelling for us to understand the radiation dose estimates associated with cardiac CT imaging. In this article, we review the concepts of radiation dose measurement in CT, discuss MDCT scan parameters affecting radiation exposure, and provide a reference summary of radiation dose estimates associated with MDCT cardiac imaging.

Magnetic resonance and computed tomography imaging of arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is a familial cardiomyopathy that causes fibro-fatty replacement of the right ventricle (RV), leading to sudden death due to ventricular arrhythmias. The disease is an important cause of sudden death in individuals younger than 35 years of age. Structural and functional abnormalities of the RV constitute an important diagnostic criterion for the disease. Diagnosis of ARVD is often a challenge as conventional imaging modalities have significant limitations to visualize the RV. Recently, magnetic resonance imaging (MRI) and computed tomographic (CT) imaging have emerged as robust clinical tools for evaluation of myocardial pathology. In addition to providing morphologic and functional information, both imaging modalities have the ability to demonstrate intramyocardial fat, which is the pathological hallmark in ARVD. This article discusses the current status and role of MRI and CT imaging in the diagnosis of ARVD.

Computed tomography for assessment of cardiac chambers, valves, myocardium and pericardium

The focus to date of MDCT has been primarily on CT applications for evaluating the coronary arteries, notably the measurement of coronary artery calcification, plaque characterization, and atherosclerotic lumen stenosis. This is because of the limited temporal resolution of CT, and the recent rapid improvements in MRI for cardiac applications. However, if the temporal resolution of MDCT can be improved, there will be a compelling argument for undertaking further CT validation studies. Feasibility of CT has already been established by EBT for general cardiac diagnosis. Modifications for MDCT include improved software methods for post processing ECG-gated scan data or higher speed CT hardware for faster image acquisition, both of which are being developed at this time. EBT is also evolving and continuously being refined so that the new generation of scanners have exposure times of 50 msec or less. There are many considerations in comparing the pros and cons of competing cardiac imaging modalities. Published diagnostic validations studies, convenience, procedure time, the comfort level (of patients and physicians), availability, and cost are all critical. The level of acceptance and the accuracy with which specific patient management questions can be appropriately answered are crucial issues in determining which diagnostic procedure to perform. However, the jury is still out regarding the ultimate role of CT in the diagnosis of heart disease; certainly the great potential of cardiac CT has not yet been fully realized.

Cardiac computed tomography imaging: a history and some future possibilities

Cardiac computed tomography (CT) is a special subset of CT, a subject about which much has been written in terms of the underlying concepts and mathematics and the sociologic impact. Cardiac CT has passed through three, chronologically overlapping, developmental stages and is now in its fourth stage of development. The first stage was fluoroscopy-based CT (1972-1995) stimulated by physiologic research needs, and the next was clinical CT-based exploration (1975-1980) of the potential of clinical CT in cardiology. This was followed by the electron beam CT-based stage (1980-present), which was the first CT approach applicable to clinical cardiology. Finally, volume-scanning CT imaging methods achieved with multislice scanning approaches of helical CT and by flat panel-based CT (1990-present), show great promise for clinically applicable CT of the cardiovascular system.