Comparison of 18F-FDG PET SUV and CT in Neck Lymph Node Metastasis Diagnosis of Oral Squamous Cell Carcinoma Patients
[Materials and methods-This was a retrospective review of 55 patients with oral squamous cell carcinoma. They were treated in our department during January 2009 through February 2014. Before the neck dissection, pre-operative CT and PET were performed. 27 cases were pN0 and 28 cases were pN+. CT and PET findings were correlated with histopathological results of surgical specimens in every LN region. The size and volume of LN were measured from CT and standardized uptake value (SUV) was measured from PET. In addition, SUV/volume ratio (SVR) was computed. LN metastasis cut-off threshold was set at 4.0.
[Results-Positive and negative LN metastasis were observed in 66, 814 sites. Positive LN of SUVmax was 3.5-23.3 (mean 8.4), Negative LN was 1.0-4.3 (mean 2.6). The volume of positive LN was 449-2480 mm3 (mean 1124), negative LN was 102-1890 mm3 (mean 881). Positive LN of minor axis was 5.5-14.5 mm (mean 8.8) and negative LN was 2.7-7.5 mm (mean 5.4). Positive LN of SVR was 2.2-23.1 (mean 8.9) and negative LN was 0.2-6.0 (mean 2.2). By univariate analysis with prognosis, histopathological results of LN metastasis, SUV max, minor axis, and SVR were correlated.
In the evaluation by CT, sensitivity, specificity, positive predictive value (PPV), negative predictive (NPV) and accuracy were 35, 100, 100, 94 and 94%, respectively. In the evaluation by SUV, sensitivity, specificity, PPV, NPV and accuracy were 82, 98, 87, 98 and 97%, respectively. In the evaluation by CT and PET, sensitivity, specificity, PPV, NPV and accuracy were 94, 99, 88, 99 and 98%, respectively.
[Conclusion-It was suggested that the existence of LN metastasis can be evaluated by combining CT, SUV, and SVR.