Abstract
1785
Objectives In whole-body (WB) FDG PET/CT, detection, volume definition and SUV quantitation for small pulmonary lesions (PL) are potentially distorted because of the breathing motion and related artifacts. Respiratory gating (RG) software is an upcoming technology that may improve characterization of PL. We evaluated the impact of RG on SUVmax of PL detected on shallow breathing WB FDG PET/CT.
Methods In our PET/CT center, RG software is occasionally used as part of clinical evaluation for PL on a case by case basis. Cases are selected upon reviewing shallow breathing CT images, while the emission data is being collected. If needed, RG images for selected bed positions are acquired immediately after finishing the WB exam. We retrospectively evaluated 50 consecutive studies. Of the 50 studies, 24 had PL ≥ 1 cm (n=31) in WB exams and were selected for further evaluation of changes in size and SUVmax as a result of RG.
Results In the 24 patients (16 M, 8 F; mean age: 61.13 years), 31 PL were located in RUL (n=8), RML (n=1), RLL (n=11), LUL (n=8), and LLL (n=3). Mean SUVmax of the PL in the WB was 2.85 (range 0.8 to 12.5) in comparison to mean SUVmax of 3.49 (range 0.6 to 12.7) after RG. Therefore, RG resulted in a 22.46% increase in the mean SUVmax. Mean size of the PL in WB images was 1.33 cm (range 1 to 2.5) and was 1.31 cm (range 1 to 2.5) after RG.
Conclusions We conclude that, in PL ≥1 cm, RG changed the SUVmax by 22.46% but had no impact on lesion size. Further work is planned to assess the impact of RG on the diagnostic accuracy of FDG PET/CT in patients with PL.
- © 2009 by Society of Nuclear Medicine