Objectives: We aimed to compare the inter-observer agreement between two experienced readers using supine vs combined supine/prone myocardial perfusion SPECT (MPS) in a large population.
Methods: 1,181 consecutive patients without known coronary artery disease (CAD) undergoing rest (201)Tl/stress (99m)Tc-sestamibi MPS studies were evaluated. Visual reads were performed in two consecutive steps, with readers scoring the stress supine perfusion images during step 1 and rescoring the images using both supine/prone data during step 2. Visual summed stress scores (SSS) of two readers including regional scores in different vascular territories were compared.
Results: The specificity for both readers improved using combined supine/prone imaging (reader 1: 92% vs 86% [P = .0002], reader 2: 88% vs 72% [P < .0001]). The inter-observer correlation for SSS (0.90 vs 0.84, P < .0001) and inter-observer agreement for combined supine/prone reading (bias = 1.0, 95% confidence interval (CI) 0.9-1.2 vs bias = 3.1, 95% CI 2.8-3.4, P < .0001) were significantly better as compared to supine-only reading. The overall correlation between SSS scores for two readers improved with supine/prone imaging for both genders, as well as in the left anterior descending and right coronary territories.
Conclusion: The inter-observer correlation and agreement significantly improve using two-position supine/prone vs supine-only imaging.