title: Prevalence of misregistration between SPECT and CT for attenuation-corrected myocardial perfusion SPECT.
abstract: BACKGROUND
  Nonuniform attenuation artifacts may reduce the diagnostic accuracy of cardiac single photon emission computed tomography (SPECT) studies. Compensation strategies using an attenuation map (eg, from x-ray tomography) have been reported to improve accuracy. Because the computed tomography (CT) and SPECT images are obtained sequentially, misregistration of the emission and transmission scans can occur. Our objective was to qualitatively assess these misregistration errors.
  
  
  RESULTS
  This study included 60 patients who consecutively underwent CT attenuation-corrected myocardial perfusion studies acquired on a SPECT/CT system equipped with a nondiagnostic CT scanner. The cardiac SPECT/CT and fused images were reviewed and qualitatively assessed for misregistration of the heart between the CT and emission image data sets. The degree of misregistration was qualitatively rated on a 5-point scale. Misregistration was judged to be none in 4 of 55 patients, minimal in 9, mild in 19, moderate in 21, and severe in 2 patients. Five studies could not be assessed because of severe artifacts on CT.
  
  
  CONCLUSIONS
  Forty-two percent of the CT attenuation-corrected myocardial perfusion studies had moderate to severe cardiac misregistration qualitatively. Our data suggest that careful review of attenuation correction maps and registration is needed to avoid reconstruction artifacts due to misregistration.
authors: Division of Nuclear Medicine, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, Md 21287-0817, USA.
authors: Sibyll
authors: S
authors: Goetze
authors: Richard L
authors: RL
authors: Wahl
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000150:complications / Q000175:diagnosis*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010477:Perfusion / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000209:etiology