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

Aim of the study was to show that changing patient position from supine to prone results in improved specificity of myocardial SPECT (MS). Methods: We examined the influence of patient position in MS on the diagnosis of coron ary heart disease (CHD) in 151 patients. By using a Tc-99m-labeled compound (Tetrofosmin, Myoview(TM) Nycomed, Amersham) examinations could be perform ed in supine and prone position within 35 minutes. Examinations were perfor med as a two-day stress rest protocol with one gamma camera head and 180 de grees rotation without absorption correction. Results: Semi-quantitative pa tient and heart phantom data show similar values for anterior and inferior wail in prone position in contrast to a lower count ratio of inferior to an terior 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 wail in men (from 58% to 90%) and in the anterior wall in women (f rom 80% to 93%). Sensitivity is the same for both techniques. Conclusion: C hanging patient position from supine to prone significantly improves diagno stic specificity while sensitivity remains unchanged.