title: [Individual approach to choosing the exposure time during myocardial perfusion single-photon emission computed tomography].
abstract: OBJECTIVE
  To assess whether the quality of the results of myocardial perfusion single-photon emission computed tomography (SPECT) may be improved by applying an individual approach to choosing the exposure time of a study.
  
  
  METHODS
  The results of myocardial perfusion SPECT with the radiotracer (RT) Technetril upon 25-sec (short) and 60-sec (long) exposures in 22 patients with valvular heart disease (VHD) and coronary heart disease (CHD) were retrospectively analyzed. The basis for the comparative assessment of the study results was the number of myocardial impulses (NMI). The reference informative value was taken as a NMI equal to 21,000-77,000. All the patients were divided into two groups: 1) those with a NMI of below 21,000 and 2) those with a NMI of above 21,000. The raw counts of RT and lesion extent were compared in each group during two exposure modes.
  
  
  RESULTS
  No statistically significant differences were found between the raw counts of RT in the left ventricular segments upon short and long exposure regardless of NMI. Evaluation of lesion extent revealed differences in sizes and/or location in 14 (63,6%) patient upon various exposures, most (10 patients) of them were from Group I and only 4 patients were from Group 2, these patients having marked myocardial hypertrophy.
  
  
  CONCLUSIONS
  To enhance the informative value of myocardial perfusion SPECT, it is expedient to individually choose exposure time for each patient, being oriented to the time taken to achieve a NMI of at least 21,000, which can be determined by making one planar scintigram in the left anterior oblique projection (LAO 45 degrees).
authors.forename: N V
authors.initials: NV
authors.lastname: Maĭorov
authors.forename: V V
authors.initials: VV
authors.lastname: Davydenko
authors.forename: V I
authors.initials: VI
authors.lastname: Amosov
authors.forename: S V
authors.initials: SV
authors.lastname: Lapekin
authors.forename: A P
authors.initials: AP
authors.lastname: Litvinov
mesh_terms: D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*