title: Metabolic imaging with beta-methyl-p-[(123)I]-iodophenyl-pentadecanoic acid identifies ischemic memory after demand ischemia.
abstract: BACKGROUND
  After myocardial ischemia, prolonged suppression of fatty acid metabolism may persist despite restoration of blood flow, which is called metabolic stunning. We hypothesized that a branched-chain fatty acid, beta-methyl-p-[(123)I]-iodophenyl-pentadecanoic acid (BMIPP), might identify the presence of myocardial ischemia late after demand ischemia at rest up to 30 hours later.
  
  
  RESULTS
  In 32 patients with exercise-induced ischemia on thallium SPECT, BMIPP was injected at rest within 30 hours of ischemia. SPECT images were acquired beginning 10 minutes after injection (early) and again 30 minutes after injection (delayed). Thallium and BMIPP SPECT data were read separately by 3 observers blinded to other imaging and clinical data. Agreement between BMIPP and thallium data for the presence of an abnormality on the patient level was 91% (95% CI, 75 to 98) for the early BMIPP data and 94% (95% CI, 79 to 99) for the delayed BMIPP data. Agreement between delayed BMIPP and thallium was 95% among 21 patients studied on the same day, a mean of 6.2+/-1.4 hours after exercise-induced ischemia, and 91% among the 11 patients studied on the next calendar day, a mean of 24.9+/-2.6 hours after ischemia (P=NS). The magnitude of resting BMIPP metabolic defect by semiquantitative visual analysis was correlated to the magnitude of exercise-induced thallium perfusion defect (r=0.6, P<0.001 for early BMIPP; r=0.5, P=0.005 for delayed BMIPP).
  
  
  CONCLUSIONS
  Metabolic imaging with BMIPP identifies patients with recent exercise-induced myocardial ischemia. These findings support the concept that BMIPP imaging can successfully demonstrate the metabolic imprint of a stress-induced ischemic episode, also known as ischemic memory.
authors.affiliation: Division of Nuclear Medicine, University of Maryland Hospital and School of Medicine, Baltimore, MD 21201-1595, USA. vdilsizian@umm.edu
authors.forename: Vasken
authors.initials: V
authors.lastname: Dilsizian
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Bateman
authors.forename: Steven R
authors.initials: SR
authors.lastname: Bergmann
authors.forename: Roger
authors.initials: R
authors.lastname: Des Prez
authors.forename: Martin Y
authors.initials: MY
authors.lastname: Magram
authors.forename: Anne E
authors.initials: AE
authors.lastname: Goodbody
authors.forename: John W
authors.initials: JW
authors.lastname: Babich
authors.forename: James E
authors.initials: JE
authors.lastname: Udelson
mesh_terms: D005080:Exercise Test; D005227:Fatty Acids; D006801:Humans; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D005227:Fatty Acids; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D013794:Thallium Radioisotopes; C049338:iodofiltic acid