title: Gated SPECT assessment of left ventricular function is sensitive to small patient motions and to low rates of triggering errors: a comparison with equilibrium radionuclide angiography.
abstract: BACKGROUND
  Patient displacements and errors in R-wave detection are the main causes of inaccurate acquisition for gated single photon emission computed tomography (SPECT) and equilibrium radionuclide angiography (RNA). This study aimed to compare the influences of both factors between gated SPECT and RNA determinations of left ventricular ejection fraction.
  
  
  RESULTS
  On gated SPECT and RNA acquisitions, recorded in 20 patients with coronary artery disease, we simulated the consequences of (1) 3-dimensional patient displacements of low (6.7 mm), moderate (13.4 mm), and high amplitude (20.1 mm) and (2) an erroneous triggering on T waves in 10% to 40% of recorded beats. Absolute values of left ventricular ejection fraction changes from baseline were higher with gated SPECT compared with RNA for patient displacements of low amplitude (5.0% +/- 3.8% vs 1.2% +/- 0.9%, P < .001) or moderate amplitude (10.0% +/- 6.2% vs 3.0% +/- 2.3%, P = .001) but not for patient displacements of high amplitude (12% +/- 9% vs 9% +/- 7%, P = not significant) and inaccurate triggering (for 20% T-wave triggering, 8.9% +/- 3.6% vs 7.9% +/- 3.0%; P = not significant).
  
  
  CONCLUSIONS
  Contrary to RNA, gated SPECT is vulnerable to small patient displacements, and thus, specific efforts might be useful for limiting this potential cause of erroneous results. Both techniques may be affected by low rates of triggering errors, suggesting that small acceptance windows on cycle length should be recommended not only for RNA but also for gated SPECT.
authors.affiliation: Department of Nuclear Medicine, UPRES EA 3447, CHU-Nancy, France. wassila.djaballah@wanadoo.fr
authors.forename: Wassila
authors.initials: W
authors.lastname: Djaballah
authors.forename: Marc A
authors.initials: MA
authors.lastname: Muller
authors.forename: Anne C
authors.initials: AC
authors.lastname: Bertrand
authors.forename: Pierre Y
authors.initials: PY
authors.lastname: Marie
authors.forename: Bernard
authors.initials: B
authors.lastname: Chalon
authors.forename: Karim
authors.initials: K
authors.lastname: Djaballah
authors.forename: Pierre
authors.initials: P
authors.lastname: Olivier
authors.forename: Andreï
authors.initials: A
authors.lastname: Codreanu
authors.forename: Gilles
authors.initials: G
authors.lastname: Karcher
authors.forename: Alain
authors.initials: A
authors.lastname: Bertrand
mesh_terms: D016477:Artifacts; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D004562:Electrocardiography / Q000379:methods; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D009068:Movement; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology