title: Early and delayed Tc-99m-tetrofosmin myocardial SPECT in patients with left bundle branch block.
abstract: To determine the utility of the myocardial tracer Tc-99m-tetrofosmin in the examination of patients with left bundle branch block (LBBB) and to investigate Tc-99m-tetrofosmin uptake and retention in the myocardium, early and delayed Tc-99m-tetrofosmin SPECT was performed in 10 patients having LBBB without coronary stenosis.
  
  
  METHODS
  After 740 MBq of Tc-99m-tetrofosmin injection in the resting state, the early and delayed SPECT imaging was done at 30 min and 180 min, respectively.
  
  
  RESULTS
  Decreased Tc-99m-tetrofosmin uptake in the septal segments was observed in 4 patients (40%) at 30 min and in 9 (90%) at 180 min. Reverse redistribution was seen in 9 of 10 patients. In patients with LBBB, the septal-to-lateral uptake ratio was lower in the delayed images than in the early images (0.80 +/- 0.09 vs. 0.89 +/- 0.09, p < 0.001). In patients with LBBB, the washout rate of Tc-99m-tetrofosmin was higher in the septal segments than in the lateral segments (28.3 +/- 4.3% vs. 22.8 +/- 3.3%, p < 0.001).
  
  
  CONCLUSIONS
  The SPECT data indicate that in LBBB without coronary stenosis, the uptake of Tc-99m-tetrofosmin is decreased in the septal wall, and that reverse redistribution occurs frequently. Our results contribute to the elucidation of both the cellular biokinetics of Tc-99m-tetrofosmin in the myocardium and the hemodynamics of the septum in LBBB, and indicate the possible clinical utility of Tc-99m-tetrofosmin.
authors.affiliation: Department of Radiology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sugihara
authors.forename: N
authors.initials: N
authors.lastname: Kinoshita
authors.forename: Y
authors.initials: Y
authors.lastname: Adachi
authors.forename: Y
authors.initials: Y
authors.lastname: Taniguchi
authors.forename: K
authors.initials: K
authors.lastname: Ohtsuki
authors.forename: A
authors.initials: A
authors.lastname: Azuma
authors.forename: H
authors.initials: H
authors.lastname: Adachi
authors.forename: Y
authors.initials: Y
authors.lastname: Ushijima
authors.forename: M
authors.initials: M
authors.lastname: Nakagawa
authors.forename: T
authors.initials: T
authors.lastname: Maeda
mesh_terms: D000328:Adult; D000368:Aged; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012016:Reference Values; D015899:Tomography, Emission-Computed, Single-Photon; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin