title: Clinical validation of SPECT attenuation correction using x-ray computed tomography-derived attenuation maps: multicenter clinical trial with angiographic correlation.
abstract: BACKGROUND
  Nonuniform attenuation artifacts cause suboptimal specificity of stress single photon emission computed tomography (SPECT) myocardial perfusion images. In phantoms, normal subjects, and patients suspected of having coronary artery disease (CAD), we evaluated a new hybrid attenuation correction (AC) system that combines x-ray computed tomography (CT) with conventional stress SPECT imaging.
  
  
  RESULTS
  The effect of CT-based AC was evaluated in phantoms by assessing homogeneity of normal cardiac inserts. AC improved homogeneity of normal cardiac phantoms from 11% +/- 2% to 5% +/- 1% (P < .001). Attenuation-corrected normal patient files were created from 37 normal subjects with a low likelihood (<3%) of CAD. The diagnostic performance of AC for detection of CAD was evaluated in 118 patients who had stress technetium 99m sestamibi or tetrofosmin stress SPECT imaging and coronary angiography. SPECT images with and without AC were interpreted by 4 blinded readers with different interpretative attitudes. Overall, AC improved the diagnostic performance of all readers, particularly the normalcy rate. The degree of improvement depended on interpretative attitude. Readers prone to high sensitivity or with less experience had the greatest gain in the normalcy rate, whereas a reader prone to higher specificity had improvements in sensitivity and specificity but not the normalcy rate. Importantly, improvement of one diagnostic variable was not associated with worsening of other variables.
  
  
  CONCLUSIONS
  CT-based AC of SPECT images consistently improved overall diagnostic performance of readers with different interpretive attitudes and experience. CT-based AC is well suited for routine use in clinical practice.
authors.affiliation: Cardiovascular Nuclear Imaging Laboratory, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Masood
authors.forename: Yi-Hwa
authors.initials: YH
authors.lastname: Liu
authors.forename: Gordon
authors.initials: G
authors.lastname: Depuey
authors.forename: Raymond
authors.initials: R
authors.lastname: Taillefer
authors.forename: Luis I
authors.initials: LI
authors.lastname: Araujo
authors.forename: Steven
authors.initials: S
authors.lastname: Allen
authors.forename: Dominique
authors.initials: D
authors.lastname: Delbeke
authors.forename: Frank
authors.initials: F
authors.lastname: Anstett
authors.forename: Aharon
authors.initials: A
authors.lastname: Peretz
authors.forename: Mary-Jo
authors.initials: MJ
authors.lastname: Zito
authors.forename: Vera
authors.initials: V
authors.lastname: Tsatkin
authors.forename: Frans J Th
authors.initials: FJ
authors.lastname: Wackers
mesh_terms: D000792:Angiography / Q000706:statistics & numerical data*; D016477:Artifacts; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D015899:Tomography, Emission-Computed, Single-Photon / Q000706:statistics & numerical data*; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology