Staging primary head and neck cancers with (18)F-FDG PET/CT: is intravenous contrast administration really necessary?
OBJECTIVE
The aim of our study was to prospectively evaluate whether intravenous contrast media in integrated positron emission tomography and computed tomography (PET/CT) with (18)F-fluorodeoxyglucose ((18)F-FDG) significantly contributes to evaluation of primary head and neck cancers compared with unenhanced PET/CT, regional contrast-enhanced CT of head and neck (neck CE-CT) and regional magnetic resonance imaging of head and neck (neck MRI).


METHODS
Subjects were 42 consecutive patients (35 men, 7 women; age range: 36-91 years) with biopsy-proven primary head and neck cancers. Lesion detection of primary and nodal sites and TNM classification were assessed on a per-patient basis. McNemar test and kappa statistics were employed for statistical analyses.


RESULTS
Forty patients (95%) were successfully followed up: 24 patients had nodal disease and 3 had distant metastasis. Contrast-enhanced and unenhanced PET/CT detected 98 and 95% of the primary tumours, respectively, and both detected 92% of patients with nodal disease, which revealed no statistically significant difference. Accuracy for T status was 75 and 73%, respectively, which proved significantly more accurate than neck CE-CT, which had an accuracy of 53% (p = 0.0133 and 0.0233, respectively). Neck MRI correctly classified the T status in 58% of patients; however, no statistically significant difference was found between PET/CT and neck MRI. Contrast-enhanced PET/CT, unenhanced PET/CT, neck CT and neck MRI correctly staged the N status in 90, 90, 79 and 90% of patients, respectively, with no statistically significant difference. Overall TNM classification was correctly classified in 68 and 65% of patients, respectively. Weighted kappa values between enhanced and unenhanced PET/CT for primary tumour detection, nodal detection, T status and N status were 0.655, 1.000, 0.935 and 1.000, respectively.


CONCLUSIONS
We found almost perfect correlation between enhanced and unenhanced PET/CT for lesion detection and initial staging of primary head and neck cancers. Routine contrast administration for PET/CT imaging may not be justified.
Department of Radiology, Yokohama City University, 3-9 Fukuura, Yokohama, Japan. kei-yoshida@nyc.odn.ne.jp
Keisuke
K
Yoshida
Akiko
A
Suzuki
Toshiyuki
T
Nagashima
Jin
J
Lee
Choichi
C
Horiuchi
Mamoru
M
Tsukuda
Tomio
T
Inoue
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18