PT - JOURNAL ARTICLE AU - Wong, Ching-yee Oliver AU - Thie, Joseph AU - Parling-Lynch, Kelly J. AU - Zakalik, Dana AU - Margolis, Jeffrey H. AU - Gaskill, Marianne AU - Hill, Jack AU - Qing, Feng AU - Fink-Bennett, Darlene AU - Nagle, Conrad TI - Glucose-Normalized Standardized Uptake Value from <sup>18</sup>F-FDG PET in Classifying Lymphomas DP - 2005 Oct 01 TA - Journal of Nuclear Medicine PG - 1659--1663 VI - 46 IP - 10 4099 - http://jnm.snmjournals.org/content/46/10/1659.short 4100 - http://jnm.snmjournals.org/content/46/10/1659.full SO - J Nucl Med2005 Oct 01; 46 AB - Our objective was to derive the best glucose sensitivity factor (g-value) and the most discriminating standardized uptake value (SUV) normalized to glucose for classifying indolent and aggressive lymphomas. Methods: The maximum SUV obtained from 18F-FDG PET over the area of biopsy in 102 patients was normalized by serum glucose ([Glc]) to a standard of 100 mg/dL. Discriminant analysis was performed by using each SUV100 (SUV × {100/[Glc]}g, calculated using various g-values ranging from −3.0 to 0, one at a time) as a variable against the lymphoma grades, and plotting the percentage of correct classifications against g (g-plot) to search for the best g-value in normalizing SUV100 for classifying grades. To address the influence of the extreme glucose conditions, we repeated the same analyses in 12 patients with [Glc] ≤ 70 mg/dL or [Glc] ≥ 110 mg/dL. Results: SUV100 correctly classified lymphoma grades ranging from 62% to 73% (P &lt; 0.0005), depending on the g-value, with a maximum at a g-value of −0.5. For the subgroup with extreme glucose values, the g-plot also revealed higher and more optimal discrimination at a g-value of −0.5 (92%) than at a g-value of 0 (83%) (P = 0.03). The discrimination deteriorated at g &lt; −1 in both analyses. The box plot for all cases using a g-value of −0.5 showed little overlap in classifying lymphoma grades. For a visually selected threshold SUV100 of 7.25, the sensitivity, specificity, and accuracy of identifying aggressive grades were 82%, 79%, and 81%, respectively. Conclusion: The results suggest that metabolic discrimination between lymphoma grades using a glucose-normalized SUV from 18F-FDG PET is improved by introducing g-value as an extra degree of freedom.