Dynamic Multislice Computed Tomography of Left Ventricular Function
A 56-year-old man (known to have hypercholesterolemia) was hospitalized with signs of an acute inferior myocardial infarction, as evidenced by typical chest pain lasting for 2 hours and typical ECG changes (ST-T-segment elevation in leads II, III, AvF; no Q-wave formation). Plasma levels of cardiac enzymes (including troponins) were not yet elevated. On the basis of these findings, he was treated by thrombolysis (streptokinase), with relief of chest pain and normalization of ST-T segments.
During hospitalization, he experienced an episode of heart failure with dyspnea at rest. Chest x-ray demonstrated pulmonary edema. Treatment with intravenous diuretics and inotropic agents was initiated with adequate response. Resting 2D echocardiography demonstrated an enlarged left ventricle with a resting left ventricular ejection fraction of 35%, regional akinesia of the entire inferior wall, and severe hypokinesia of the inferoseptal segments.
Coronary angiography was performed and showed a 90% stenosis of the (dominant) right coronary artery (directly after a small side branch). The left coronary artery showed a 40% to 50% stenosis of the proximal left anterior descending coronary artery. The left circumflex coronary artery was small and exhibited no significant stenosis (Figure 1).
Multislice computed tomography (MSCT) was performed and showed normal anatomy of the coronary arteries. Severe stenosis of the right coronary artery was confirmed (Figure 2). On the basis of the acquired MSCT dataset, functional analysis of the left ventricle was performed. Retrospective data reconstruction allowed wall motion analysis and accurate calculation of the left ventricular ejection fraction (see Figure 3 and Data Supplement Movie). Wall motion analysis revealed akinesia in the inferior and inferoseptal segments. The left ventricular ejection fraction was calculated as 37% using an automated contour detection algorithm on sequential short-axis slices of 5-mm thickness.
In patients presenting with acute coronary syndromes, the dilemma is frequently whether invasive or noninvasive testing for risk stratification should be performed. In that light, it would be desirable to have a noninvasive imaging technique that allows direct visualization of the coronary arteries (instead of surrogate measurements such as myocardial perfusion scintigraphy) combined with information on left ventricular function/volumes. MSCT may provide this information, as demonstrated in the present case report. In particular, the possibility that MSCT could provide cine loops of short-axis slices on left ventricular function has not been demonstrated until recently and may largely expand the use of MSCT in evaluation of unstable coronary artery disease.
The Movie is available in the online-only Data Supplement at http://www.circulationaha.org.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
Circulation encourages readers to submit cardiovascular images to the Circulation Editorial Office, St Luke’s Episcopal Hospital/Texas Heart Institute, 6720 Bertner Ave, MC1-267, Houston, TX 77030.