title: Comparison of exercise-rest-reinjection Tl-201 imaging and rest sublingual isosorbide dinitrate Tc-99m MIBI imaging for the assessment of myocardial viability.
abstract: OBJECTIVE
  Nitrate administration has been proposed to enhance the detection of myocardial viability when performing myocardial perfusion imaging. In this study, we aimed to compare Tl-201 exercise-rest-reinjection protocol with rest isosorbide dinitrate (ISDN)-Tc99m MIBI study in the same population examined for the myocardial viability.
  
  
  METHODS
  Twenty-six patients with coronary artery disease who had fixed segmental defects on exercise-rest-Tl-201 imaging were studied. All of them underwent Tl-201 reinjection study. Within 1 week of Tl-201 imaging, rest-Tc99m MIBI imaging was performed after sublingual 5 mg ISDN administration (2-day protocol). For each study, tomograms were divided into 20 segments based on three short-axis slices, one vertical long-axis representing the totality of the left ventricle and regional tracer uptake was quantitatively analyzed. Regional tracer uptake was evaluated in 20 myocardial segments for all patients. Viability was defined as presence of tracer uptake >/=50% of peak activity on each study. A total 520 myocardial segments were assessed by semi quantitative analysis.
  
  
  RESULTS
  On the baseline rest Tl-201 studies, 211 segments of the 520 segments that were analyzed had <50% of peak activity. Of these segments, 42 (20%) showed reversibility after reinjection Tl-201 imaging and 55 segments (27%) described as viable on the rest ISDN-Tc99m MIBI imaging. There was 89% concordance between the ISDN-Tc99m MIBI study and Tl-201 reinjection study regarding viable myocardial segments. Of the 23 segments with discordant results, 18 were irreversible on Tl-201 reinjection study, but showed >/=50% uptake on ISDN-Tc99m MIBI.
  
  
  CONCLUSIONS
  Observation of good agreement between Tl-201 reinjection and ISDN-Tc99m MIBI study studies led us to suggest the use of ISDN enhanced imaging in the evaluation of myocardial viability.
authors.affiliation: Department of Nuclear Medicine, Faculty of Medicine, Baskent University, Ankara, Turkey. sevaler@yahoo.com
authors.forename: Seval Erhamamci
authors.initials: SE
authors.lastname: Günel
authors.forename: Ayşegul
authors.initials: A
authors.lastname: Akgun
mesh_terms: D000286:Administration, Sublingual; D002908:Chronic Disease; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D015444:Exercise; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006439:Hemodynamics; D006801:Humans; D007267:Injections; D007548:Isosorbide Dinitrate / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D012146:Rest; D017256:Technetium Tc 99m Sestamibi / Q000008:administration & dosage / Q000378:metabolism; D013794:Thallium Radioisotopes / Q000008:administration & dosage / Q000378:metabolism; D014022:Tissue Survival; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left
chemical_list: D013794:Thallium Radioisotopes; D017256:Technetium Tc 99m Sestamibi; D007548:Isosorbide Dinitrate; C030397:isosorbide-5-mononitrate