title: [Superiority of the reinjection method compared with the redistribution of thallium-201 in the evaluation of reversibility after myocardial infarction].
abstract: OBJECTIVE
  To assess the relative capacity of thallium-201 reinjection (RI) and redistribution (RD) for detection of reversibility in patients after myocardial infarction.
  
  
  METHODS
  We prospectively studied patients referred to myocardial scintigraphy for viability evaluation with stress, redistribution and reinjection images.
  
  
  METHODS
  Patients were studied with thallium-201 SPECT using three imaging acquisitions--stress, redistribution three to four hours later and reinjection 30-60 minutes after a second injection of thallium under nitroglycerin effect. Thallium uptake was classified in a 0 to 4 intensity scale in each of 13 myocardial segments and a score obtained. Reversibility was classified as "definite" if the increase in thallium uptake was > or = 2 in a myocardial segment and as "possible" if the increase was one.
  
  
  METHODS
  We studied 44 patients with previous myocardial infarction.
  
  
  RESULTS
  The perfusion score after stress was 37.3 +/- 6.0, improving to 39.8 +/- 6.7 after redistribution and to 43.6 +/- 7.6 after reinjection (p < 0.02 between RD and RI). RD identified reversibility in 38% and RI in 63% (p < 0.001) of the 232 segments with perfusion defects. RI showed reversibility in 39% (definite in 25% and possible in 14%) of the 137 fixed perfusion defects in RD. For the detection of reversibility RI was superior to RD in all sub-groups analyzed. We found a relationship the degree of collateral circulation in the infarct related artery and the amount of reversibility in the infarcted area.
  
  
  CONCLUSIONS
  These data suggest a clear superiority of reinjection over redistribution in thallium-201 scintigraphy for the detection of reversibility of perfusion defects after myocardial infarction, and must probably be considered as a routine procedure for myocardial viability assessment.
authors.affiliation: Serviço de Cardiologia Hospital de Santa Cruz, Carnaxide.
authors.forename: V M
authors.initials: VM
authors.lastname: Gil
authors.forename: J
authors.initials: J
authors.lastname: Ferreira
authors.forename: A
authors.initials: A
authors.lastname: Ventosa
authors.forename: J
authors.initials: J
authors.lastname: Calqueiro
authors.forename: P
authors.initials: P
authors.lastname: Abreu
authors.forename: R
authors.initials: R
authors.lastname: Seabra-Gomes
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D010477:Perfusion; D011446:Prospective Studies; D015635:Radionuclide Ventriculography; D013794:Thallium Radioisotopes / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D013794:Thallium Radioisotopes
vernacular_title: Superioridade do método de reinjecção sobre a redistribuição de tálio-201 na avaliação da reversibilidade após enfarte do miocárdio.