Clinical Significance of Pulmonary Nodules Missed on Non-Breath-Hold PET/CTSeng Thipphavong1*, Remy C. Lim2, Emily C Zabor3 and Heiko Schöder2
- *Corresponding Author:
- Seng Thipphavong
Women’s College Hospital, Department of Medical Imaging
76 Grenville St, 2nd Floor, W2 67,Toronto, Ontario, M5B 1S2, Canada
E-mail: [email protected]
Received date: July 06, 2013; Accepted date: July 20, 2013; Published date: July 24, 2013
Citation: Thipphavong S, Lim C, Zabor EC, Schöder H (2013) Clinical Significance of Pulmonary Nodules Missed on Non-Breath-Hold PET/CT. J Nucl Med Radiat Ther 4:159. doi:10.4172/2155-9619.1000159
Copyright: © 2013 Thipphavong S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Objective: In clinical practice, PET images are acquired during shallow breathing and CT images of the PET/ CT during shallow breathing or at near end-expiration. We determined the clinical significance of pulmonary nodules that were missed on PET/CT acquired during non-breath-hold (NBH) imaging in patients with proven non-thoracic solid malignancies. Methods: 200 consecutive cancer patients who underwent both PET/CT and diagnostic breath-hold (BH) chest CT within 30 days, and who had a follow-up with BH CT at least 2 years after these baseline studies, were evaluated. NBH CT of the PET/CT was analyzed first, followed by the baseline BH CT. Missed nodules were defined as nodules not detected on NBH PET/CT, but detected on BH CT. Missed nodules were then evaluated on BH CT performed at least 2 years later. A second radiologist was used to evaluate inter observer variability for a subset of 50 patients. Results: 343 nodules were identified in 121 patients. 166 nodules from 86 patients were classified as missed nodules. Seven of these 166 nodules were excluded due to interval surgery or development of consolidation. When a change in size was counted only if it was ≥2 mm, only 11 of the 159 nodules (6.9%) grew, 113 nodules (71.1%) did not change, and the remaining 35 nodules (22.0%) were not present at follow-up. Malignancy was deemed the most likely diagnosis in only 6 of the original 159 missed nodules. Conclusion: Although the incidence of pulmonary nodules missed on NBH PET/CT was high, most of these nodules did not show any growth on follow-up and few were proven to be metastatic. Current clinical practice of PET/CT, with acquisition during shallow breathing or at near end expiration is sufficient; performing additional deep inspiration BH CT does not appear warranted.