title: Reverse redistribution in resting thallium-201 myocardial scintigraphy in chronic coronary artery disease: an index of myocardial viability.
abstract: The aim of this study was to evaluate whether segments with reverse redistribution on rest-redistribution 201Tl scintigraphy represent viable tissue or scar.
  
  
  METHODS
  Nineteen patients (17 men, 2 women; mean age 53 +/- 8 yr) with coronary artery disease underwent rest-redistribution 201Tl study before coronary revascularization. Regional 201Tl uptake was analyzed quantitatively. Regional left ventricular wall motion was assessed before and after coronary revascularization using two-dimensional echocardiography and a three-point scale (1 = normal, 2 = hypokinetic, 3 = akinetic/dyskinetic). Two patterns of reverse redistribution were identified: pattern with normal 201Tl uptake in rest and abnormal in redistribution images and pattern with abnormal 201Tl uptake in rest and a significant decrease in redistribution images.
  
  
  RESULTS
  Of the 247 segments analyzed, 85 were classified as normal, 37 as reversible defects, 83 as fixed defects and 42 as reverse redistribution (19 RR-A, 23 RR-B). Segments with RR-A differed from those with RR-B in wall motion score (1.4 +/- 0.7 versus 2.0 +/- 1.0). Electrocardiographic Q-waves were present in 26% of segments with RR-A and in 57% of segments with pattern B. After revascularization, all dyssynergic segments with pattern A showed improved wall motion, while only 40% of segments with pattern B and abnormal wall motion had such improvement.
  
  
  CONCLUSIONS
  Our results suggest that dyssynergic segments with pattern A should be considered viable, while more caution should be used in classifying those with pattern B.
mesh_terms: D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000628:therapy; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization; D011877:Radionuclide Imaging; D013794:Thallium Radioisotopes
chemical_list: D013794:Thallium Radioisotopes