title: Critical stenoses of the left anterior descending artery: predominant role in stress-induced pulmonary uptake of 201thallium.
abstract: OBJECTIVE
  To relate the diagnostic finding of stress-induced pulmonary uptake of 201thallium to the severity and site of stenoses in specific coronary arteries.
  
  
  METHODS
  An ad hoc series of 525 referred cases had planar myocardial perfusion scintigraphy studies within four months of correlating invasive studies; patients who had previous revascularization procedures were excluded.
  
  
  METHODS
  Invasive studies were read by a cardiovascular radiologist with rating of stenoses as percentage luminal diameter, and grading of ventricular function from 1 (normal) to 5 (globally hypokinetic). Lung:myocardial ratios were quantitated independently on immediate poststress 201thallium myocardial perfusion images by a nuclear medicine physician. Multivariate regression equations were used to relate pulmonary uptake to stenoses in specific arteries and to the degree of ventricular dysfunction.
  
  
  RESULTS
  Lung:myocardial ratios showed only a minor relationship to the number of subcritical (less than 90%) stenoses, but were considerably increased when severe (at least 90%) stenoses were present. Severe stenoses in the left anterior descending artery (LAD), particularly its proximal portion, provided the most dramatic increase in this index, modified by the contrast ventriculography score and to a lesser extent by additional stenoses at other sites. Regression analysis suggested a weighting of lesions in the LAD or left mainstem by a factor of at least 3 in comparison with the right coronary and left circumflex arteries.
  
  
  CONCLUSIONS
  Stenoses in the LAD, particularly its proximal position, play a key role in the induction of increased pulmonary uptake of 201thallium on poststress scintigrams.
authors.affiliation: Department of Diagnostic Radiology/Nuclear Medicine, University of Western Ontario, London.
authors.forename: G A
authors.initials: GA
authors.lastname: Hurwitz
authors.forename: A C
authors.initials: AC
authors.lastname: MacDonald
mesh_terms: D000328:Adult; D000368:Aged; D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis* / Q000503:physiopathology; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015425:Myocardial Reperfusion; D011877:Radionuclide Imaging; D012044:Regression Analysis; D013794:Thallium Radioisotopes
chemical_list: D013794:Thallium Radioisotopes