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Impact of Point Spread Function Reconstruction on Thoracic Lymph Node Staging With 18F-FDG PET/CT in Non–Small Cell Lung Cancer

Lasnon, Charline, MS*; Hicks, Rodney J., MD; Beauregard, Jean-Mathieu, MD, MS; Milner, Alvin, PhD§; Paciencia, Maria, MD, MS; Guizard, Anne-Valérie, MD; Bardet, Stéphane, MD, MS*; Gervais, Radj, MD, MS#; Lemoel, Gabriel, MD**; Zalcman, Gérard, MD, PhD††; Aide, Nicolas, MD, PhD*

doi: 10.1097/RLU.0b013e318251e3d1
Original Articles
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Aim The aim of the present study was to evaluate the impact of point spread function (PSF) reconstruction on quantitative values and diagnostic accuracy of FDG PET/CT for nodal staging in non–small cell lung cancer.

Patients and Methods Fifty-eight consecutive PET/CT examinations were reconstructed with both ordered subset expectation maximization (OSEM) and PSF algorithms. Two readers independently performed a randomized blinded review of PET/CT examinations and gave a nodal status (N0, N1, N2, or N3) to each PET data set. When discordant, a consensus was reached with a third reader. Sensitivity, specificity, positive and negative predictive values (NPV), and positive and negative likelihood ratios (LRs) were assessed and compared using a McNemar test. All PET data sets were then independently analyzed to extract quantitative PET values in 208 nodes and compare them using Bland-Altman analysis.

Results Bland-Altman analysis showed that, on average, PSF reconstruction increased SUVmax, SUVmean, and node/background ratios by 48%, 28%, and 27%, respectively. This increase was more marked for nodes less than 1 cm than for nodes 1 cm or greater (P < 0.0001 for SUVmax, SUVmean, and node/background ratios). Point spread function PET had higher sensitivity (97%) and NPV (92%) than OSEM PET (78% and 57%, respectively; P = 0.01 and P = 0.04, respectively). Negative LR was 0.04 for PSF PET and 0.31 for OSEM PET.

Conclusions By improving activity recovery, especially for nonenlarged nodes, PSF significantly improves the sensitivity, NPV, and negative LR of FDG-PET for nodal staging in non–small cell lung cancer. These data suggest that preoperative invasive nodal staging may be omitted in the case of a negative PSF FDG-PET/CT.

From the *François Baclesse Cancer Centre and University Hospital PET unit, University Hospital, Caen, France; †Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, Australia; ‡Department of Medical Imaging, Centre Hospitalier Universitaire de Québec and Laval University, Quebec City, Canada; §Centre for Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne, Australia; ∥Pathology Department, University Hospital, Caen; ¶Cancer Registry and #Thoracic Oncology, François Baclesse Cancer Centre, Caen; **Pulmonology Department, Cherbourg Hospital, Cherbourg; and ††Pulmonology Department, University Hospital, Caen, France.

Received for publication December 17, 2011; revision accepted February 22, 2012

Conflicts of interest and sources of funding: none declared.

Reprints: Nicolas Aide, MD, PhD, Service de Médecine Nucléaire, Centre François Baclesse, Avenue Général Harris, 14076 Caen cedex 5, France. E-mail: n.aide@baclesse.fr.

© 2012 Lippincott Williams & Wilkins, Inc.