title: Evaluation of myocardial ischemia using a rest metabolism/stress perfusion protocol with fluorine-18 deoxyglucose/technetium-99m MIBI and dual-isotope simultaneous-acquisition single-photon emission computed tomography.
abstract: OBJECTIVE
  This study sought to develop a dual-isotope single-acquisition single-photon emission computed tomographic (SPECT) protocol using a multihead SPECT camera equipped with an ultra-high energy collimator to evaluate rest metabolism/stress perfusion simultaneously with fluorine-18 (F-18) deoxyglucose/technetium-99m (Tc-99m) 2-hexakis-2-methoxy-2-methylpropyl isonitrile (MIBI).
  
  
  BACKGROUND
  The most accurate and logistic method of identifying injured but viable myocardium remains a diagnostic challenge.
  
  
  METHODS
  Sixty-five patients were given 25 to 50 g of glucose and, after approximately 60 min, an injection of 370 MBq (10 mCi) of F-18 fluorodeoxyglucose. After a 35-min distribution phase, patients underwent exercise or pharmacologic stress followed by administration of 925 MBq (25 mCi) of Tc-99m MIBI. Five patients underwent F-18 fluorodeoxyglucose position emission tomography before dual-isotope SPECT:
  
  
  RESULTS
  With a window of 20% for both photopeaks and a technetium-99m/fluorine-18 concentration of 3.2:1, the "spillover" from fluorine-18 into the technetium-99m window is < 6% of the total counts in the window in patients with a normal distribution of both radiopharmaceuticals. Phantom images clearly demonstrated cardiac defects measuring 2 x 1 and 2 x 0.5 cm. There was no significant difference in the images of the five patients who underwent both positron emission tomography and SPECT: Fifty-seven patients (mean [+/- SD] age 55 +/- 15 years, range 25 to 83; 38 men, 19 women) had satisfactory images and were included in the study. Twenty-one patients had normal study results; 15 had mismatched defects; 14 had matched defects; and 7 had both matched and mismatched defects. Twenty-three patients (mean age 54 +/- 6 years, range 30 to 83; 14 men, 9 women) underwent coronary angiography within 3 months of dual-isotope SPECT: There were seven normal studies, eight with mismatched defects, one with a matched defect and seven with matched and mismatched defects. When stenosis > 70% was used as the criterion for a diagnosis of coronary artery disease, dual-isotope SPECT had a sensitivity of 100%, specificity of 88%, positive predictive value of 93%, negative predictive value of 100% and an accuracy of 96%.
  
  
  CONCLUSIONS
  Dual-isotope SPECT may provide an alternative, accurate, cost-effective method to nitrogen-13 ammonia/F-18 fluorodeoxyglucose positron emission tomography or thallium-201 reinjection for identifying injured or dysfunctional but viable myocardium.
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2675, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Sandler
authors.forename: S
authors.initials: S
authors.lastname: Videlefsky
authors.forename: D
authors.initials: D
authors.lastname: Delbeke
authors.forename: J A
authors.initials: JA
authors.lastname: Patton
authors.forename: C
authors.initials: C
authors.lastname: Meyerowitz
authors.forename: W H
authors.initials: WH
authors.lastname: Martin
authors.forename: I
authors.initials: I
authors.lastname: Ohana
mesh_terms: D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000453:epidemiology; D003847:Deoxyglucose / Q000031:analogs & derivatives*; D004176:Dipyridamole; D005080:Exercise Test; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000453:epidemiology; D009206:Myocardium / Q000378:metabolism; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014665:Vasodilator Agents
chemical_list: D005462:Fluorine Radioisotopes; D014665:Vasodilator Agents; D019788:Fluorodeoxyglucose F18; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi; D003847:Deoxyglucose