title: Synergistic impact of attenuation correction and gating in routine myocardial SPECT reporting: 2 year follow-up study.
abstract: OBJECTIVE
  To look at the combined impact of non-uniform attenuation correction (AC) and gated SPECT in the visual interpretation of myocardial SPECT imaging. This was compared to the individual benefit obtained by adding AC information and gated SPECT information to non-AC image information.
  
  
  METHODS
  We retrospectively studied a group of 141 patients with a 22-26 month follow-up who underwent myocardial perfusion scintigraphy imaging. All the studies were corrected for attenuation with Gd line source transmission data and were ECG gated. In patients who had abnormal studies, follow-up coronary angiography information was also obtained in addition to medical follow-up information.
  
  
  METHODS
  Two experienced nuclear medicine physicians interpreted the images independently and were blinded to the other person's report. Non-attenuation corrected data was first evaluated followed by attenuation corrected data and gated SPECT data. Four approaches to interpretation of images were undertaken: (1) non-AC images only, (2) non-AC+AC images, (3) non-AC+gated images, and (4) non-AC+AC+gated images. Study results were divided into four categories based on how confident the observers were of the diagnosis: (1) normal, (2) borderline normal, (3) borderline abnormal, and (4) abnormal.
  
  
  RESULTS
  When results for sensitivity and specificity using the four different interpretation techniques were compared there was a statistically significant improvement in the specificity compared to non-AC image (48%) with the addition of AC (77%) and gating (82%) information (P<0.001). The best improvement in the specificity was noted when both AC and gated information (91%) was used along with non-AC information. The normalcy rates almost doubled following the addition of AC and gated data. There was also a decrease in the number of borderline results, showing an improvement in the reporter confidence in interpreting myocardial SPECT studies. Sensitivity, however, did not show a significant change between the four different approaches to interpretation of the study.
  
  
  CONCLUSIONS
  Attenuation correction and gating when combined have a synergistic impact upon improving the specificity of myocardial SPECT reporting when compared to the use of individual techniques alone to improve the specificity.
authors.affiliation: Department of Nuclear Medicine, Guys Hospital, London, UK.
authors.forename: Sheeba
authors.initials: S
authors.lastname: Taneja
authors.forename: Hosahalli K
authors.initials: HK
authors.lastname: Mohan
authors.forename: Glen M
authors.initials: GM
authors.lastname: Blake
authors.forename: Lefteris
authors.initials: L
authors.lastname: Livieratos
authors.forename: Susan E M
authors.initials: SE
authors.lastname: Clarke
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D005260:Female; D005500:Follow-Up Studies; 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; D012189:Retrospective Studies; D016037:Single-Blind Method; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*