Influence of patient position in myocardial SPECT on the diagnosis of CHD

Of the study was to show that changing patient position from supine to prone results in improved specificity of myocardial SPECT (MS).

We examined the influence of patient position in MS on the diagnosis of coronary heart disease (CHD) in 151 patients. By using a Tc-99m-labeled compound (Tetrofosmin, Myoview, Nycomed, Amersham) examinations could be performed in supine and prone position within 35 minutes. Examinations were performed as a two-day stress-rest protocol with one gamma camera head and 180 degrees rotation without absorption correction.

Semi-quantitative patient and heart phantom data show similar values for anterior and inferior wall in prone position in contrast to a lower count ratio of inferior to anterior wall in supine position. This demonstrates the importance of patient position with respect to artifacts specificity. Changing patient position from supine to prone mainly improves diagnostic specificity for CHD in the inferior wall in men (from 58% to 90%) and in the anterior wall in women (from 80% to 93%). Sensitivity is the same for both techniques.

Changing patient position from supine to prone significantly improves diagnostic specificity while sensitivity remains unchanged.