Ying Liu MD, Presenter: Nothing to Disclose

Lale Kostakoglu MD, MPH, Abstract Co-Author: Nothing to Disclose

Lewen Stempler, Abstract Co-Author: Nothing to Disclose

Yu Htwe MD, Abstract Co-Author: Nothing to Disclose

Mary Margaret Salvatore MD, Abstract Co-Author: Nothing to Disclose

David F. Yankelevitz MD, Abstract Co-Author: Research Grant, AstraZeneca PLC Royalties, General Electric Company

Claudia I. Henschke MD, PhD, Abstract Co-Author: Nothing to Disclose

To correct the SUV value based on CT attenuation of the nonsolid nodule

We retrospectively evaluated 36 patients (24 female, 12 male, median age 71 year-old) with 40 nonsolid nodules who underwent both FDG-PET scanning and thin-section helical CT scanning before undergoing surgical resection. All the nonsolid nodules were adenocarcinoma,  they were classified by histologic grade according to the IASLC/ATS/ERS classification (low, moderate, high). The SUVmax value was corrected based on an estimate of the proportion of soft tissue within the nodule by dividing the SUVmax by the proportion of soft tissue. The proportion of soft tissue was determined by placing an ROI within the nodule on the CT image to determine its attenuation. Based on partial voxel effects and using a 2 component model for air and soft tissue, the proportion could be calculated.

The average nodule diameter was 15.2 mm, 33(82.5%) were larger than 10 mm. Of the 40 nonsolid nodules, 18 had a low histologic grade and 22 had moderate or high histologic grade. The average SUVmax of the 18 nodules with low histologic grade was 1.1 and for the 22 with moderate or high histologic grade it was 1.6. The corrected SUVmax was 2.6 and 2.8, respectively. The increase from the SUVmax to the corrected SUVmax was statistically significant for both groups (P < 0.0001). Using the traditional SUV cutoff for malignancy of 2.5 for these cases, the corrected SUVmax was higher for 8 (44%) of the 18 cases with low grade histology and 13 (59%) of the 22 cases with moderate or high grade histology.

These results demonstrate that the actual cancer within the nonsolid nodule has an SUV similar to traditional cancer manifesting as a solid nodule and the corrected SUV also correlates with the degree of histologic aggressiveness.

Corrected SUV values provide a means to evaluate nonsolid nodules according to standard PET/CT criteria.

Liu, Y, Kostakoglu, L, Stempler, L, Htwe, Y, Salvatore, M, Yankelevitz, D, Henschke, C, Predicting the Metabolic Activity of Nonsolid Nodules with Low Histologic Grade Lung Cancer Based on Corrected SUV.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14014488.html