title: Disappearance of myocardial perfusion defects on prone SPECT imaging: comparison with cardiac magnetic resonance imaging in patients without established coronary artery disease.
abstract: BACKGROUND
  It is of great clinical importance to exclude myocardial infarction in patients with suspected coronary artery disease who do not have stress-induced ischemia. The diagnostic use of myocardial perfusion single-photon emission computed tomography (SPECT) in this situation is sometimes complicated by attenuation artifacts that mimic myocardial infarction. Imaging in the prone position has been suggested as a method to overcome this problem.
  
  
  METHODS
  In this study, 52 patients without known prior infarction and no stress-induced ischemia on SPECT imaging were examined in both supine and prone position. The results were compared with cardiac magnetic resonance imaging (CMR) with delayed-enhancement technique to confirm or exclude myocardial infarction.
  
  
  RESULTS
  There were 63 defects in supine-position images, 37 of which disappeared in the prone position. None of the 37 defects were associated with myocardial infarction by CMR, indicating that all of them represented attenuation artifacts. Of the remaining 26 defects that did not disappear on prone imaging, myocardial infarction was confirmed by CMR in 2; the remaining 24 had no sign of ischemic infarction but 2 had other kinds of myocardial injuries. In 3 patients, SPECT failed to detect small scars identified by CMR.
  
  
  CONCLUSIONS
  Perfusion defects in the supine position that disappeared in the prone position were caused by attenuation, not myocardial infarction. Hence, imaging in the prone position can help to rule out ischemic heart disease for some patients admitted for SPECT with suspected but not documented ischemic heart disease. This would indicate a better prognosis and prevent unnecessary further investigations and treatment.
authors: Department of Clinical Physiology, Lund University Hospital, Lund, Sweden. bo.heden@med.lu.se
authors: Bo
authors: B
authors: Hedén
authors: Eva
authors: E
authors: Persson
authors: Marcus
authors: M
authors: Carlsson
authors: Olle
authors: O
authors: Pahlm
authors: Håkan
authors: H
authors: Arheden
mesh_terms: D003324:Coronary Artery Disease / Q000150:complications / Q000175:diagnosis*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D055420:Perfusion Imaging / Q000379:methods*; D011187:Posture; D016684:Prone Position; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016683:Supine Position; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000175:diagnosis*