title: OSEM reconstruction, associated with temporal fourier and depth-dependant resolution recovery filtering, enhances results from sestamibi and 201Tl 16-interval gated SPECT.
abstract: Gated SPECT recorded with 16 intervals determines left ventricular (LV) ejection fraction more accurately than does gated SPECT recorded with 8 intervals but produces higher image noise. This study aimed to assess the results from sestamibi and (201)Tl 16-interval gated SPECT when both signal-to-noise ratio and spatial resolution were enhanced with an original method of reconstruction.
  
  
  METHODS
  Forty patients with coronary artery disease underwent (201)Tl and sestamibi 16-interval gated SPECT and, to be used as a reference, cardiac MRI. Assessments of global and regional LV function provided by ordered-subsets expectation maximization (OSEM) with depth-dependant resolution recovery and temporal Fourier filtering were compared with those from conventional filtered backprojection (FBP) previously optimized by screening various filter frequencies and various temporal smoothing levels.
  
  
  RESULTS
  For both tracers, LV ejection fraction was determined best when the association of OSEM with depth-dependant resolution recovery was used alone, with temporal Fourier filtering, or with a slight 2-frame temporal smoothing: Mean absolute values of relative errors ranged from 3.2% to 3.6% (4.0%-7.9% for FBP), and coefficient correlation ranged from 0.91 to 0.93 (0.70-0.91 for FBP). Among these 3 reconstruction methods, the association of OSEM with depth-dependant resolution recovery with temporal Fourier filtering provided the highest signal-to-noise ratio, with mean increases of 54% for sestamibi and 80% for (201)Tl when compared with FBP, and the best analysis of segmental contractility, with exact agreement rates with MRI being 73% for (201)Tl and 79% for sestamibi.
  
  
  CONCLUSIONS
  OSEM associated with temporal Fourier filtering and depth-dependant resolution recovery filtering enhances the LV function assessment provided by sestamibi and (201)Tl 16-interval gated SPECT and dramatically reduces image noise, a property that enhances and facilitates image interpretation.
authors.affiliation: Department of Nuclear Medicine, University Hospital, Nancy, France. py.marie@chu-nancy.fr
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Marie
authors.forename: Wassila
authors.initials: W
authors.lastname: Djaballah
authors.forename: Philippe R
authors.initials: PR
authors.lastname: Franken
authors.forename: Chris
authors.initials: C
authors.lastname: Vanhove
authors.forename: Marc A
authors.initials: MA
authors.lastname: Muller
authors.forename: Henri
authors.initials: H
authors.lastname: Boutley
authors.forename: Sylvain
authors.initials: S
authors.lastname: Poussier
authors.forename: Pierre
authors.initials: P
authors.lastname: Olivier
authors.forename: Gilles
authors.initials: G
authors.lastname: Karcher
authors.forename: Alain
authors.initials: A
authors.lastname: Bertrand
mesh_terms: D000465:Algorithms; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D005583:Fourier Analysis; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013318:Stroke Volume; D017256:Technetium Tc 99m Sestamibi; D013793:Thallium; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology
chemical_list: D019275:Radiopharmaceuticals; C027549:thallium chloride; D017256:Technetium Tc 99m Sestamibi; D013793:Thallium