Acknowledgment

• Published in: Revista Española de medicina nuclear e imagen molecular (English ed.) 2018, Vol.38 (2), p.72-79
• Main Authors: López Buitrago, Diego F, Muñoz Acosta, Juan M, Cárdenas-Perilla, Rodrigo A
• Format: Article
• Language: English
• Subjects: Radiology
• ISSN: 2253-8089; 2253-8089
• DOI: 10.1016/j.remnie.2018.10.003

Abstract Objective To compare variability, reproducibility and repeatability of four quantitative evaluation methods to interpret the99m Tc-MDP SPECT reports in patients with clinically suspected unilateral condylar hyperplasia (UCH). Method This was a descriptive observational study carried out with SPECT images of 38 patients with clinical and radiographic signs of UCH, and interpreted using four quantitative methods: (1) one image, variable-size region of interest (ROI); (2) one image, fixed-size ROI (1.76 cm2 ), (3) five image variable-size ROI; (4) five image, fixed-size ROI (1.76 cm2 ). Each of the images were report simultaneously but in an independent way by the two nuclear medicine experts in both total radioactive counts as well as normalized counts to quantify the reproducibility (inter-operator variability) and the repeatability (intra-operator variability). Results Higher reproducibility and repeatability were obtained in 5-image fixed-size ROI method (intra-class correlation coefficient: 0.979 [0.959; 0.989]). A high grade of diagnostic agreement (97.4%) was also attained in fixed methods (Kappa 0.940, p value: 0.000) from either total or normalized counts. There was no difference between fixed-size 1 vs 5 image methods. The methods based on variable-size ROI had a low grade of agreement (Kappa < 0.20). More positive cases were identified using one image, ROI variable total counts (27 cases), but when the counts were normalized, they presented a lower number (5 cases). Conclusion Five-image fixed-size ROI provides the best intra-operator and inter-operator reliability for the diagnosis of unilateral condylar hyperplasia. In the four methods using normalized counts fewer positive cases were detected (≥10%), unlike with total counts when more positive cases were found.