title: Metabolism substrate with negative myocardial uptake of iodine-123-BMIPP.
abstract: Iodine-123-BMIPP is an iodinated methyl-branched-chain fatty acid. Low uptake of BMIPP relative to thallium or other perfusion tracer indicates metabolically damaged but viable myocardium (for example, ischemic but viable myocardium). In some cases, however, negative myocardial uptake of BMIPP is observed. The main purposes of this study were to assess the frequency of such BMIPP findings and to clarify metabolism of such cases by using PET.
  
  
  METHODS
  Among the 1258 patients who underwent BMIPP scintigraphy, 11 patients (0.9%) showed negative myocardial uptake of BMIPP. Under fasting condition, PET using [11C]palmitate, 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) and [11C]acetate was performed in nine of these 11 patients.
  
  
  RESULTS
  Global myocardial uptake of [11C]palmitate, expressed as the standardized uptake value, was significantly lower in the patients than in control (3.62 +/- 0.44 versus 5.49 +/- 1.62; p < 0.01). However, the early phase clearance rate of [11C]palmitate and oxidative metabolism was not significantly different. In the fasting state, PET studies showed increased FDG accumulation in seven of nine patients (high group) and decreased accumulation in two patients (low group). In the high group patients, glucose metabolism in the fasting state was similar to that in the normal volunteers after glucose loading (Kcomplex: 0.050 +/- 0.016 versus 0.038 +/- 0.015; p = ns). However, low glucose metabolism was noted in the low group patients (Kcomplex: 0.007 and 0.005).
  
  
  CONCLUSIONS
  Negative myocardial uptake of BMIPP is occasionally, but not often, observed. Global uptake of [11C]palmitate was decreased in these patient. The majority of these patients showed "metabolic switching" from normal free fatty acid metabolism to abnormally enhanced glucose metabolism in the fasting state. However, some patients showed decreases in both exogenous glucose utilization and free fatty acid uptake in the fasting state.
authors.affiliation: Department of Nuclear Medicine, Kyoto University, School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kudoh
authors.forename: N
authors.initials: N
authors.lastname: Tamaki
authors.forename: Y
authors.initials: Y
authors.lastname: Magata
authors.forename: J
authors.initials: J
authors.lastname: Konishi
authors.forename: R
authors.initials: R
authors.lastname: Nohara
authors.forename: A
authors.initials: A
authors.lastname: Iwasaki
authors.forename: S
authors.initials: S
authors.lastname: Ono
authors.forename: Y
authors.initials: Y
authors.lastname: Ohtake
authors.forename: H
authors.initials: H
authors.lastname: Sugihara
authors.forename: H
authors.initials: H
authors.lastname: Sugihara
authors.forename: K
authors.initials: K
authors.lastname: Kuze
authors.forename: Y
authors.initials: Y
authors.lastname: Tsujimura
authors.forename: T
authors.initials: T
authors.lastname: Miyazaki
mesh_terms: D000085:Acetates; D000328:Adult; D000368:Aged; D002250:Carbon Radioisotopes; D003847:Deoxyglucose / Q000031:analogs & derivatives; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D010168:Palmitates; D014055:Tomography, Emission-Computed
chemical_list: D000085:Acetates; D002250:Carbon Radioisotopes; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D005462:Fluorine Radioisotopes; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D010168:Palmitates; C049338:iodofiltic acid; D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose; D005947:Glucose