Standard PET/CT of the chest during shallow breathing is inadequate for comprehensive staging of lung cancer.
The incidence of malignancy associated with subcentimeter pulmonary nodules (micronodules) in patients with malignant disease has been reported to be as high as 58%. Thus, detection of small lung nodules is important for appropriate staging of lung cancer. Because of respiratory motion, small parenchymal lung lesions can be missed on CT acquired during shallow breathing. Micronodules are usually too small to be characterized reliably with 18F-FDG PET. We aimed to determine the incidence of missed pulmonary micronodules on PET/CT studies acquired during shallow breathing.


METHODS
The study included 142 consecutive cancer patients (62 male and 80 female; mean age, 54 y) who underwent whole-body PET/CT during shallow breathing and breath-hold CT of the chest during maximal inspiration. CT findings were reviewed independently, and noncalcified nodules missed on the shallow-breathing scan were evaluated for size, location, and metabolic activity.


RESULTS
Breath-hold chest CT detected an additional 125 parenchymal lung nodules (mean size, 3.4 +/- 1.6 mm; range, 1-9 mm) in 48 (34%) of the 142 patients. In these patients, 3 nodules, on average, were missed during shallow breathing. In 18 patients (13%), micronodules were identified exclusively on breath-hold images. None of the missed nodules demonstrated 18F-FDG uptake.


CONCLUSIONS
Acquisition of standard PET/CT chest images during shallow breathing is inadequate for comprehensive cancer staging.
Allen-Auerbach
Martin
M
Department of Molecular and Medical Pharmacology, Ahmanson Biological Imaging Center, UCLA David Geffen School of Medicine, Los Angeles, California, USA. mauerbach@mednet.ucla.edu
Yeom
Kristen
K
Park
John
J
Phelps
Michael
M
Czernin
Johannes
J
D016477:Artifacts; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000175:diagnosis*; D013382:Subtraction Technique; D013909:Thorax / Q000000981:diagnostic imaging
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18