Abstract
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Objectives: The current study examined the value of F-18 FDG PET/CT for preoperative nodal staging of suamous cell head and neck cancer.
Methods: Seventeen patients (M/F=15/2, 59±11yr) with histologically proven squamous cell head and neck cancer were studied by F-18 FDG PET/CT imaging before surgery. Preoperative CT/MRI were performed in all patients within 3 weeks preceding F-18 FDG PET/CT. The spatial resolution of this PET/CT system in the axial plane is 7mm. The degree of FDG uptake was scored as grade 1 (no enhanced uptake), grade 2(equal to liver uptake), grade 3(lower than cerebellar uptake, but higher than liver uptake), grade 4 (equal to cerebellar uptake). Grade 3, 4 were considered malignant. Maximum standardized uptake values (max SUV) were also calculated. SUV > 2.0 was considered malignant. The sensitivity and specificity of F-18 FDG PET/CT by visual and semiquantitative methods for the detection of cervical lymph node metastasis were compared with CT/MRI.
Results: In the 17 patients, a total of 123 lymph node levels were dissected, 29 of which showed metastatic involvement. The difference of SUV among four groups (G 1-4) was significant (p<0.01). On visual analysis, the sensitivity and specificity of F-18 FDG PET/CT were 69% (20/29) and 99% (93/94), those for semiquantitative analysis were 69% (20/29) and 90% (85/94), respectively. The specificity of F-18 FDG PET/CT by visual analysis was higher than that of semiquantitative analysis (p<0.01). The low sensitivity of F-18 FDG PET/CT was attribued to nine false negative levels in six patients. Among the nine false negative cervical lymph node levels,the size of seven cervical lymph node levels was smaller than 7mm of spatial resolution. The sensitivity and specificity of CT/MRI were 59% (17/29) and 96% (90/94). There was no significant difference in diagnostic accuracy for detecting cervical lymph node metastasis between F-18 FDG PET/CT and CT/MRI (p=ns). F-18 FDG PET/CT detected double primary tumor (hepatocellular carcinoma) in one patient.
Conclusions: F-18 FDG PET/CT displayed relatively low sensitivity and high specificity in detecting cervical LN metastasis in patients with squamous cell head and neck cancer. The limitation of F-18 FDG PET/CT is relatively low sensitivity. And it was due to small size lymph nodes less than resolution of F-18 FDG PET/CT.
- Society of Nuclear Medicine, Inc.