title: Comparative analysis of full-time, half-time, and quarter-time myocardial ECG-gated SPECT quantification in normal-weight and overweight patients.
abstract: The introduction of a camera-based dose-reduction strategy in myocardial perfusion imaging (MPI) clinical setting entails the definition of objective and reproducible criteria for establishing the amount of activity to be injected.
  
  
  
  The aim is to evaluate the impact of count statistics on the estimation of summed-scores (SS), end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF).
  
  
  
  Data rest/stress ECG-gated SPECT (2-day protocol and 8 MBq·kg-1) were acquired with Bright View gamma camera and Astonish algorithm for 40 normal-weight and 40 overweight patients. Assuming that count statistics of shorter acquisition time may simulate that of lower injected activity, three simultaneous scans (full-time, half-time, and quarter-time scans) were started at the same time but with different acquisition time/projection (30, 15 and 8 seconds).
  
  
  
  A significant difference between SS values of half-time and quarter-time stress scans was found for overweight group (P = .006). Post hoc test showed significant differences for ESV (P < .05), EDV (P < .01) and EF (P < .05) between half-time and quarter-time scans for both patient groups.
  
  
  
  The reduction of the count-statistics to a quarter of the MPI reference influenced negatively the quantification in overweight patients. The decrease of radiopharmaceutical activity to 25% of the reference seems practicable for normal-weight patients, while it is more appropriate an activity reduction limited to 50% for overweight and obese patients.
authors.affiliation: Nuclear Medicine Unit, Department of Health Sciences, University of Milan, San Paolo Hospital, Via Antonio di Rudini, 8, 20142, Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Lecchi
authors.affiliation: Nuclear Medicine Unit, Department of Health Sciences, University of Milan, San Paolo Hospital, Via Antonio di Rudini, 8, 20142, Milan, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Martinelli
authors.affiliation: Unit of Nuclear Medicine, S. Maugeri Foundation, IRCCS, Scientific Institute of Veruno, Veruno, NO, Italy.
authors.forename: O
authors.initials: O
authors.lastname: Zoccarato
authors.affiliation: Nuclear Medicine Unit, Department of Health Sciences, University of Milan, San Paolo Hospital, Via Antonio di Rudini, 8, 20142, Milan, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Maioli
authors.affiliation: Nuclear Medicine Unit, Department of Health Sciences, University of Milan, San Paolo Hospital, Via Antonio di Rudini, 8, 20142, Milan, Italy. giovanni.lucignani@unimi.it.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Lucignani
authors.affiliation: Nuclear Medicine Unit, Department of Health Sciences, University of Milan, San Paolo Hospital, Via Antonio di Rudini, 8, 20142, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Del Sole
mesh_terms: D000368:Aged; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D055414:Myocardial Perfusion Imaging; D009765:Obesity / Q000000981:diagnostic imaging*; D009943:Organophosphorus Compounds / Q000008:administration & dosage*; D015609:Organotechnetium Compounds / Q000008:administration & dosage*; D000069079:Radiation Exposure / Q000032:analysis* / Q000517:prevention & control*; D011835:Radiation Protection / Q000379:methods; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin
keywords: Myocardial perfusion imaging; gated SPECT; iterative reconstruction; patient dose; quarter-time scan