Quantitative evaluation of Beta-Amyloid brain PET imaging in dementia: A comparison between two commercial software packages and the clinical report.

Objective: To compare commercially available image analysis tools Hermes BRASS and Siemens Syngo.VIA with clinical assessment in F-18-Florbetapir PET scans Methods: 225 scans were reported by clinicians and quantified using two software packages. Scans were classified into Type A (typical features) or non-Type A (atypical features) for both positive and negative scans. For BRASS, scans with z-score >= 2 in 2 >= region of interest were classed positive. For Syngo.VIA a positive scan was indicated when mean cortical standardized uptake value ratio (mcSUVR) >= 1.17. Results: 81% scans were Type A, and 19% scans were non-Type A. The sensitivity of BRASS and Syngo.VIA for Type A scans was 98.8 and 96.3%, specificity was 73 and 92%, respectively. Sensitivity for non-Type A scans was 95.8 and 79.2%, specificity was 36.8 and 57.9%, respectively. A third threshold of identifiable levels of plaque (1.08 <= mcSUVR <= 1.17) was recommended for Syngo.VIA to increase detection of false negative scans. The false positive rate of BRASS significantly decreased when an alternative positive threshold value of mcSUVR >= 1.18. Introduction of alternative criteria did not improve prediction outcome for non-Type A scans. More complex solutions are recommended. Conclusion: Hermes criteria for a positive scan leads to a high sensitivity but a low specificity, Siemens Syngo.VIA criteria gives a high sensitivity and specificity and agrees better with the clinical report. Alternative thresholds and classifications may help to improve agreement with the clinical report. Advances in knowledge: Software packages may assist with clinical reporting of more difficult to interpret cases that require a more experienced read.