Gating provides improved accuracy of differentiating artifacts from true lesions in equivocal fixed defects on technetium 99m tetrofosmin perfusion SPECT

• Published in: Journal of nuclear cardiology 1998-07, Vol.5 (4), p.395-401
• Main Authors: Joon Young Choi, Lee, Kyung Han, Kim, Sun Jung, Kim, Sang Eun, Kim, Byung-Tae, Lee, Sang Hoon, Lee, Won Ro
• Format: Article
• Language: English
• Subjects: Accuracy; attenuation artifacts; Cardiovascular disease; coronary artery disease; Coronary Disease - diagnostic imaging; Coronary Disease - epidemiology; Exercise Test; Female; fixed defect; Humans; Image Processing, Computer-Assisted; Male; Medical diagnosis; Middle Aged; Observer Variation; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; receiver operating characteristic curve analysis; ROC Curve; Sensitivity and Specificity; SPECT; technetium 99m tetrofosmin; Tomography, Emission-Computed, Single-Photon - methods; Tomography, Emission-Computed, Single-Photon - statistics & numerical data
• ISSN: 1071-3581; 1532-6551
• DOI: 10.1016/S1071-3581(98)90145-3

Background. Because equivocal fixed perfusion defects on single photon emission computed tomography (SPECT) often cause a diagnostic dilemma in patients with suspected coronary artery disease (CAD), we used receiver-operating characteristic (ROC) curve analysis to evaluate the degree of increased accuracy provided by adding gated images for interpretation of such cases. Methods and results. One hundred five (29%) of 365 consecutive patients undergoing technetium 99m tetrofosmin gated SPECT for evalation of CAD demonstrated an equivocal fixed defect. Two independent observers graded the probability for true lesion with a 5-point system over 3 steps of interpretation: reviewing tomographic images alone (step 1), adding projection images (step 2), and adding gated cine images (step 3). Based on clinical criteria, 66 patients were categorized as disease negative and 25 as disease positive, while the final diagnosis was undetermined in 14 cases. Diagnostic performance was significantly higher at step 3 than at step 1 for both observers ( p < 0.05 and < 0.0001) and at step 2 for observer B ( p < 0.005). The maximum accuracy increased from 78.0% to 80.2% at step 2 to 84.6% to 86.8% at step 3. Moreover, the agreement of interpretation between the 2 observers was higher at step 3 (κ = 0.53) than at step 1 (κ = 0.29) or step 2 (κ = 0.25). Conclusion. In patients showing an equivocal fixed defect on 99mTc tetrofosmin SPECT, gated cine images provide improved differential accuracy and enhanced objectivity of interpretation by reducing interobserver variance.