title: New reconstruction algorithm allows shortened acquisition time for myocardial perfusion SPECT.
abstract: OBJECTIVE
  Shortening scan time and/or reducing radiation dose at maintained image quality are the main issues of the current research in radionuclide myocardial perfusion imaging (MPI). We aimed to validate a new iterative reconstruction (IR) algorithm for SPECT MPI allowing shortened acquisition time (HALF time) while maintaining image quality vs. standard full time acquisition (FULL time).
  
  
  METHODS
  In this study, 50 patients, referred for evaluation of known or suspected coronary artery disease by SPECT MPI using 99mTc-Tetrofosmin, underwent 1-day adenosine stress 300 MBq/rest 900 MBq protocol with standard (stress 15 min/rest 15 min FULL time) immediately followed by short emission scan (stress 9 min/rest 7 min HALF time) on a Ventri SPECT camera (GE Healthcare). FULL time scans were processed with IR, short scans were additionally processed with a recently developed software algorithm for HALF time emission scans. All reconstructions were subsequently analyzed using commercially available software (QPS/QGS, Cedars Medical Sinai) with/without X-ray based attenuation correction (AC). Uptake values (percent of maximum) were compared by regression and Bland-Altman (BA) analysis in a 20-segment model.
  
  
  RESULTS
  HALF scans yielded a 96% readout and 100% clinical diagnosis concordance compared to FULL. Correlation for uptake in each segment (n = 1,000) was r = 0.87at stress (p < 0.001) and r = 0.89 at rest (p < 0.001) with respective BA limits of agreement of -11% to 10% and -12% to 11%. After AC similar correlation (r = 0.82, rest; r = 0.80, stress, both p < 0.001) and BA limits were found (-12% to 10%; -13% to 12%).
  
  
  CONCLUSIONS
  With the new IR algorithm, SPECT MPI can be acquired at half of the scan time without compromising image quality, resulting in an excellent agreement with FULL time scans regarding to uptake and clinical conclusion.
authors.affiliation: Cardiac Imaging, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland.
authors.forename: Ines
authors.initials: I
authors.lastname: Valenta
authors.forename: Valerie
authors.initials: V
authors.lastname: Treyer
authors.forename: Lars
authors.initials: L
authors.lastname: Husmann
authors.forename: Oliver
authors.initials: O
authors.lastname: Gaemperli
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Schindler
authors.forename: Bernhard A
authors.initials: BA
authors.lastname: Herzog
authors.forename: Patrick
authors.initials: P
authors.lastname: Veit-Heibach
authors.forename: Ronny R
authors.initials: RR
authors.lastname: Buechel
authors.forename: René
authors.initials: R
authors.lastname: Nkoulou
authors.forename: Aju P
authors.initials: AP
authors.lastname: Pazhenkottil
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
mesh_terms: D000241:Adenosine; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D016277:Ventricular Function, Left
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin; D000241:Adenosine