title: Clinical correlation between increased lung to heart ratio of technetium-99m sestamibi and multivessel coronary artery disease.
abstract: BACKGROUND
  An increased lung to heart ratio (LHR) on thallium-201 (Tl-201) stress myocardial perfusion imaging (MPI) is a predictor of adverse cardiac events and identifies people with extensive coronary artery disease (CAD). The implications of increased LHR in patients undergoing stress technetium-99m (tc-99m) sestamibi are developing. Our aim is to evaluate the relationship between increased LHR and extent of CAD in patients undergoing tc-99m sestamibi MPI.
  
  
  METHODS
  We reviewed the records and images of 530 consecutive subjects who underwent exercise or adenosine tc-99 m sestamibi MPI. One hundred thirty-two had transient or partially reversible myocardial perfusion defects and 79 (exercise=34, adenosine=45, male=43, female=36, mean age=61 years) of these underwent coronary angiography (study population). The average LHR of these 79 subjects was compared to 79 patients (control population) with normal scans (exercise=50, adenosine=29, male=34, female=45, mean age=60 years).
  
  
  RESULTS
  The mean LHR (+/-SE) in subjects with normal scans was 0.30+/-0.01. The mean LHR for those with abnormal scans and single vessel CAD who underwent exercise was 0.32+/-0.01 and pharmacological stress was 0.31+/-0.01. There was no statistically significant difference between the LHR of those with a normal scan and those with single vessel disease and an abnormal scan. However, there was a statistically significant association between the elevated LHR and multi-vessel CAD. The mean LHR for subjects with multi-vessel CAD with exercise was 0.39+/-0.01 (p=0.000) and for adenosine was 0.39+/-0.02 (p=0.000).
  
  
  CONCLUSIONS
  An elevated LHR in patients undergoing exercise or pharmacological tc-99m MPI correlates with multi-vessel CAD.
authors.affiliation: Section of Cardiology, Department of Internal Medicine, PCMH Teaching annex #378, East Carolina University Brody School of Medicine, Greenville, NC 27858-4354, USA.
authors.forename: Shekar P
authors.initials: SP
authors.lastname: Kumar
authors.forename: Stacy D
authors.initials: SD
authors.lastname: Brewington
authors.forename: Kevin F
authors.initials: KF
authors.lastname: O'Brien
authors.forename: Assad
authors.initials: A
authors.lastname: Movahed
mesh_terms: D000241:Adenosine; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D003326:Coronary Circulation / Q000502:physiology; D005080:Exercise Test; D005260:Female; D006801:Humans; D008168:Lung / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics*; D014665:Vasodilator Agents
chemical_list: D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine