F-18 FDG uptake of pulmonary lymphangitic carcinomatosis according to the interstitial involvement patterns in the lung cancer patients

Abstract

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Objectives: Our purpose was to analyze the FDG uptake in pulmonary lymphangitic carcinomatosisPLC) in the concern of interstitial involvement pattern.

Methods: We analyzed 33 consecutive PLC cases in the lung cancer patients. We carefully categorized the extent of the thickening of the axial and/or peripheral interstitium seen on the CT. And, we recorded the FDG uptake of the region of PLC on the F-18 FDG PET/CT, the metabolic size of primary tumor and both hilar lymph nodes.

Results: In 19 patients, CT revealed marked thickening of bronchovascular bundles and with or without interlobular septal thickening. In 14 cases, CT revealed irregular interlobular septal thickening and subtle or no axial interstitial thickening. F-18 FDG PET/CT revealed abnormally increased FDG uptake of the PLC regions in the 15 of 19 axial interstitial involved cases(78.9%), and showed abnormally increased FDG uptake in the 7 of 14 in the only peripheral interstitial involved cases(50%). But, there was no statistically significant difference(Chi-square=1.867, p=0.17). In the axial interstitial involved pattern, the maximal SUV of PLC regions was significantly higher than that of only peripheral interstitial involved pattern(2.84+/-1.45 vs 1.22+/-0.58, p=0.0022). Multiple regression analysis revealed that the metabolic size and maximal SUV of hilar lymph nodes, and the metabolic size and maximal SUV of primary tumor were not related with maximal SUV of PLC regions.

Conclusions: We concluded that the axial interstitial thickening pattern in PLC revealed more increased FDG uptake than only peripheral interstitial thickening pattern. The metabolic size and maximal SUV of the tumor or hilar lymph nodes were not related with the maximal SUV of the PLC regions.