The value of FDG-PET/CT in assessing single pulmonary nodules in patients at high risk of lung cancer.
OBJECTIVE
To evaluate whether PET/low-dose CT (ldCT) using (18)F-fluorodeoxyglucose (FDG) improves characterization of indeterminate single pulmonary nodules (SPNs) in patients at high risk of lung cancer.


METHODS
Retrospective analysis of 307 patients who underwent FDG-PET/CT for indeterminate SPNs identified 93 (70 men, age range 46-90 years) at high risk of lung cancer (age >40 years, minimum 10 pack-year smokers). SPNs were evaluated for the presence and intensity of FDG avidity and ldCT patterns. The performance of visual and semiquantitative FDG-PET/ldCT algorithms for characterization of SPNs was compared to that of ldCT. Incongruent FDG-PET and ldCT patterns were analyzed for significance in further patient management.


RESULTS
Malignancy was diagnosed in 38% patients. FDG avidity defined 33 SPNs as true-positive (TP) and 2 as false-negative (FN) (malignant), and 41 as true-negative (TN) and 17 as false-positive (FP) (benign). For SUVmax of 2.2 (by ROC analysis) there were 27 TP, 8 FN, 48 TN and 10 FP SPNs. LdCT defined 34 TP, 1 FN, 28 TN and 30 FP lesions. Of the FP lesions on ldCT, 60% were FDG-negative. Visual PET/ldCT analysis had a sensitivity of 94%, a specificity of 70%, an accuracy of 80%, a positive predictive value (PPV) of 66%, and a negative predictive value (NPV) of 95% as compared to 77%, 83%, 81%, 73%, 86% for semiquantitative PET/ldCT and 97%, 48%, 66%, 53%, 96% for ldCT, respectively. Both PET/ldCT algorithms had statistically significantly higher specificity and accuracy than ldCT. Semiquantitative analysis showed significantly higher PPV and lower sensitivity and NPV than found with ldCT.


CONCLUSIONS
A single screening procedure encompassing FDG-PET and ldCT may improve screening for lung cancer in high-risk patients. The significantly improved specificity may potentially reduce FP ldCT results and further unnecessary invasive procedures.
Kagna
Olga
O
Department of Nuclear Medicine, Ramban Health Care Campus, Technion, Israel Institute of Technology, Haifa, Israel. o_kagna@rambam.health.gov.il
Solomonov
Anna
A
Keidar
Zohar
Z
Bar-Shalom
Rachel
R
Fruchter
Oren
O
Yigla
Mordechai
M
Israel
Ora
O
Guralnik
Luda
L
D000368:Aged; D000369:Aged, 80 and over; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011829:Radiation Dosage; D012189:Retrospective Studies; D012306:Risk; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging* / Q000378:metabolism; D014057:Tomography, X-Ray Computed
D019788:Fluorodeoxyglucose F18