title: Single-photon emission computed tomography myocardial perfusion imaging in the diagnosis of left main disease.
abstract: BACKGROUND
  Left main disease (LMD), defined as > or = 50% lesion stenosis, occurs in 3% to 5% of patients undergoing catheterization. Limited data on the value of single-photon emission computed tomography (SPECT) imaging for diagnosis of LMD exists.
  
  
  OBJECTIVE
  This study sought to evaluate the diagnostic accuracy of SPECT imaging in the diagnosis of LMD.
  
  
  METHODS
  A total of 74 consecutive patients with LMD, identified from our catheterization lab database (January 2003-December 2007) with gated exercise (15 patients) or adenosine (59 patients), thallium 201, or Tc-99m SPECT imaging within 6 months of index angiography were included. Group 1 (Gp 1) included 33 patients with isolated LMD. Group 2 (Gp 2) consisted of 41 patients with LMD and 1-vessel disease (6); LMD and 2-vessel disease (24); and LMD and 3-vessel disease (11).
  
  
  RESULTS
  Reversible perfusion defects (PD) were absent in 6 (18%) of Gp 1 and 8 (20%) of Gp 2 patients. Among Gp 1 patients, PD in 1-vessel, 2-vessel, 3-vessel distribution were seen in 20 (61%), 5 (15%), and 2 (6%) patients respectively. In comparison, PD in 1-vessel, 2-vessel, 3-vessel distribution were observed in 20 (49%), 12 (29%), and 1 (2%) of Gp 2 patients respectively. Left main (LM) pattern was noted in 6 patients (Gp 1: 2, Gp 2: 4). Transient ischemic dilatation (TID) was encountered in 34 patients (Gp 1: 17, Gp 2: 17) and in 4 patients with normal perfusion scans.
  
  
  CONCLUSIONS
  These data represent the largest analysis of patients with "isolated" LMD. Approximately 19% of patients with LMD have no reversible PD on SPECT. While LM pattern is rare, 1-vessel distribution PD and TID represent the most frequent SPECT abnormalities.
authors.affiliation: Division of Cardiology and Department of Internal Medicine, DetroitMedical Center, Wayne State University School of Medicine, Detroit, Michigan 48201, USA. lafonso@med.wayne.edu
authors.forename: Luis
authors.initials: L
authors.lastname: Afonso
authors.forename: Nitin
authors.initials: N
authors.lastname: Mahajan
mesh_terms: D000241:Adenosine; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000175:diagnosis*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents
chemical_list: D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D014665:Vasodilator Agents; D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine