J Dorgelo

Detection, visualization and evaluation of anomalous coronary anatomy on 16-slice multidetector-row CT

Early identification and evaluation of relatively frequent anomalous coronary anatomy is quite relevant because of the occurrence of sudden cardiac death or related symptoms of myocardial ischemia. Selective coronary angiography (CAG) is invasive, expensive and cannot always provide the required information adequately. Recently, non-invasive imaging techniques such as magnetic resonance imaging and multidetector-row computed tomography (MDCT) have been shown to provide a good anatomical view of the coronary artery tree. This study aims to demonstrate the value of 16-MDCT for evaluation of anomalous coronary anatomy. In 13 patients scanned using 16-MDCT, six different coronary anomalies were diagnosed [two absent left main, one single vessel left coronary artery (LCA), three LCA originating from the right (two with interarterial course), six right coronary artery originating from the left, one double left anterior descending (LAD)]. Mean diagnostic quality, recorded by two observers using a 5-point scale (1= non-diagnostic to 5= excellent diagnostic quality), resulted in a mean score of 3.73 (SD 1.19) without any non-diagnostic result. MDCT offers an accurate diagnostic modality to visualize the origin and course of anomalous coronary arteries by a three-dimensional display of anatomy. Shortcomings in CAG can be overcome by the use of contrast-enhanced MDCT.

Multidetector computed tomography-guided treatment strategy in patients with non-ST elevation acute coronary syndromes: a pilot study

Patients with non-ST elevation acute coronary syndrome (ACS) and evidence of myocardial ischaemia are scheduled for coronary angiography (CAG). In most patients CAG remains a single diagnostic procedure only. A prospective study was performed to evaluate whether 16-slice multidetector CT (MDCT) could predict treatment of the patients and to determine how many CAGs could have been prevented by MDCT scanning prior to CAG. Twenty-two patients with ACS were scanned prior to CAG. Based on MDCT data, a fictive treatment was proposed and compared to CAG-based treatment. Excellent accuracy was observed to detect significant stenoses using MDCT (sensitivity 94%, specificity 96%). In 45%, no PCI was performed during CAG, because of the absence of significant coronary artery disease (27%) or severe coronary artery disease, demanding CABG (18%). MDCT predicted correct treatment in 86%. By using MDCT data, 32% of the CAGs could have been prevented.

Assessment of coronary artery bypass graft patency by multidetector computed tomography and electron-beam tomography.

This case report describes the use of retrospectively ECG-gated 16-slice multidetector computed tomography (MDCT) and electron-beam tomography (EBT) for assessing bypass graft patency in two patients with recurrent angina after coronary artery bypass graft surgery. The results of each tomographic modality were compared to the findings of traditional coronary angiography. In the first patient MDCT showed occlusion of the left internal mammary artery (LIMA) and saphenous vein graft after the second anastomosis. Coronary angiography confirmed these findings. In the second patient EBT showed patency of the LIMA and saphenous vein graft. After the first anastomosis of the saphenous vein graft, the connected vessel filled poorly. Coronary angiography confirmed both grafts to be patent, and detected an occlusion distal to the first anastomosis. These findings support the evidence that both MDCT and EBT are suitable techniques for establishing bypass graft patency by non-invasive means.

Multi-Slice Cumputed Tomography Technical Principles, Clinical Application and Future Perspective

Coronary artery imaging is a demanding application for any non-invasive imaging modality. On the one hand, high temporal resolution is needed to virtually freeze the cardiac motion and to avoid motion artifacts in the images. On the other hand, sufficient spatial resolution - at best sub-millimeter - is required to adequately visualize small and complex anatomical structures like the coronary arteries. The complete coronary artery tree has to be examined within one short breath-hold time to avoid breathing artifacts and to limit the amount of contrast agent if necessary. In 1984, electron beam CT (EBCT) was introduced as a non-invasive imaging modality for the diagnosis of coronary artery disease (Boyd and Liption 1982; Agatstonet al. 1990; Achenbach et al. 1998; Becker et al. 2000a). The temporal resolution of 100 ms allows for motion-free imaging of the cardiac anatomy in the diastolic heart phase even at higher heart rates. Due to the restriction to non-spiral scanning in ECG-synchronized cardiac investigations, a single breath-hold scan of the heart requires slice widths not smaller than 1.5-3 mm.