title: Rest-redistribution thallium-201 myocardial scintigraphic study in cardiac amyloidosis.
abstract: BACKGROUND
  Histopathological study in amyloid heart demonstrates that myocyte destructed by the extracellular deposition of amyloid protein together with viable myocyte is present. We hypothesized that rapid thallium washout may be found in amyloid heart as in regions which have a mixture of viable myocyte and scar tissue in patients with myocardial infarction. Thus, the purpose of this study was to evaluate the extent and severity of myocardial damage due to amyloid deposits using the washout rate of the tracer on rest-redistribution thallium-201 (201Tl) myocardial scans in cardiac amyloidosis patients.
  
  
  METHODS
  Rest-redistribution 201Tl myocardial scintigraphy was performed in 5 patients with biopsy-proved systemic amyloidosis with cardiac involvement (amyloidosis group). The initial and delayed images were obtained 15 min and 4 h, respectively, after intravenous injection of the tracer of 111 MBq. Washout rate of the tracer was calculated. Twelve patients with no apparent heart disease served as controls (control group).
  
  
  RESULTS
  Mean washout rate of the whole heart was higher in the amyloidosis group than in the control group (56 +/- 9% vs 36 +/- 6%, p < 0.001). Particularly, 4 of the 5 patients in the amyloidosis group presented a very high rate of thallium clearance which ranged from 57 to 61%, and died in less than a year. In the remaining 1 patient who had a normal washout rate of the tracer in the first study, it changed from 40 to 53% during the 5-year follow-up period.
  
  
  CONCLUSIONS
  Washout rate in the setting of rest and delayed 201Tl images may represent the severity of amyloid depositions in the myocardium and may provide prognostic information.
authors.affiliation: The Department of Internal Medicine, Yawatahama General Hospital, Ehime, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kodama
authors.forename: M
authors.initials: M
authors.lastname: Hamada
authors.forename: T
authors.initials: T
authors.lastname: Kuwahara
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Shigematsu
authors.forename: K
authors.initials: K
authors.lastname: Hiwada
authors.forename: T
authors.initials: T
authors.lastname: Iwata
authors.forename: Y
authors.initials: Y
authors.lastname: Hoshii
authors.forename: T
authors.initials: T
authors.lastname: Ishihara
mesh_terms: D000368:Aged; D000686:Amyloidosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon; D014463:Ultrasonography; D016277:Ventricular Function, Left
chemical_list: D013794:Thallium Radioisotopes