Intra-reader reliability of FDG PET volumetric tumor parameters: effects of primary tumor size and segmentation methods

• Published in: Annals of nuclear medicine Vol. 26; no. 9; pp. 707 - 714
• Main Authors: Shah, B., Srivastava, N., Hirsch, A. E., Mercier, G., Subramaniam, R. M.
• Format: Journal Article
• Language: English
• Published: Japan Springer Japan 01.11.2012; Springer Nature B.V
• Subjects: Computed tomography; Female; Fluorodeoxyglucose F18; Glycolysis; Humans; Image processing; Image Processing, Computer-Assisted; Imaging; Language; Male; Medicine; Medicine & Public Health; Middle Aged; Neoplasms - diagnostic imaging; Neoplasms - pathology; Nuclear Medicine; Observer Variation; Original Article; Positron-Emission Tomography - methods; Radiology; Reproducibility of Results; Retrospective Studies; Segmentation; Solid tumors; Statistical analysis; Tumor Burden; Tumors; Metabolic tumor volume; Reader reliability; Total glycolytic activity
• ISSN: 0914-7187; 1864-6433
• DOI: 10.1007/s12149-012-0630-3

Objective To establish the effects of size and segmentation methods on intra-reader reliability of primary tumor metabolic tumor volume (MTV) and total glycolytic activity (TGA) in human solid tumors. Methods This is a retrospective study of 121 patients who had a baseline FDG PET/CT scan for oncologic staging. Volumetric parameter readings were performed in random order on two separate occasions, 12 weeks apart, by the same reader. The MTV and TGA were segmented using gradient and fixed maximum standardized uptake value (SUV max ) threshold methods. Intra-reader reliability was established by the intraclass correlation coefficient (ICC) and Bland–Altman analysis. Results The biases for MTV were 2.95, 14.76 and 11.13 % for gradient segmentation, 38 and 50 % SUV max fixed threshold segmentations, respectively ( p  < 0.0001). For TGA, the corresponding biases were 0.76, 10.36 and 7.46 % ( p  < 0.0001). There were no statistically significant differences in the biases between the first and second reads for MTV segmented for small and large volume tumors by the gradient method ( p  < 0.34) or 50 % SUV max threshold segmentation ( p  < 0.08). However, there were statistically significant differences in the corresponding biases for the 38 % SUV max threshold segmentation ( p  < 0.04). There were no statistically significant differences in the biases between the first and second reads for TGA segmented for small and large volume tumors ( p  < 0.98). Conclusion Intra-reader reliability for primary tumor FDG MTV and TGA is affected by the tumor size and segmentation methods. The segmentation bias was smaller for gradient method than percentage fixed threshold method for MTV. The segmentation biases were smaller for TGA than MTV.