Abstract
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Objectives: To explore the value of 18F FDG PET/MR in staging of nasopharyngeal carcinoma.
Methods: A TNM staging was done by retrospective analysis of histologically confirmed nasopharyngeal carcinoma including 78 untreated and 51 after treatment, for each of patients whole body imaging was conducted on the integrated TOF PET/MR (GE SIGNA).The results of TNM staging and re-staging according to the 8th edition of AJCC with PET/MR images were compared with the clinical diagnosis and staging. The correlation between semi-quantitative value (SUVmax, SUVmean, ADCmean, ADCmin) and T stage and clinical staging in nasopharyngeal lesions were evaluated with spearman correlation analysis.
Results: The accuracy of PET/MR in T stage, N stage, M stage and overall stage were 98.72% (77/78), 91.02% (71/78), 100% (78/78), and 96.15% (75/78) respectively. And the overall sensitivity, specificity, and accuracy of PET/MR on nasopharyngeal carcinoma staging were 94.44% (17/18), 81.82% (27/33), and 86.27% (44/78) respectively. SUVmax and SUVmean are well correlated with T stage (r=0.448, 0.427, P<0.01) while there was no significant correlation between ADCmean, ADCmin and T stage (r=-0.017, -0.175, P>0.05). No significant correlation between semi-quantitative value (SUVmax, SUVmean, ADCmean, ADCmin) and overall staging (r=0.199, 0.198, -0.087, -0.081, P>0.05) was found. For N staging of lymph nodes, no significant correlation was found with SUVmax (r=0.328, P>0.05). 18F-FDG accumulation was shown on images of 18 of the treated 51 patients, indicating residual lesion or recurrence.
Conclusions: 18F FDG PET/MR whole-body imaging can accurately stage and re-stage nasopharyngeal carcinoma and 18F-FDG PET has a better detection effect on distant organ metastasis and the second primary tumor, while MR imaging can provide excellent diagnostic for T and N stages..The correlation between SUVmax, SUVmean of primary tumor and T staging demonstrated SUVmax and SUVmean can be used as a prognostic factor for nasopharyngeal carcinoma.Fig. (a,b,c,d) 32y, male, with right nasopharyngeal carcinoma Nasopharyngeal mass was confined to the nasopharyngeal cavity (d, arrow), no lymph nodes and distant metastasis were observed.T1N0M0, staging:I.(e,f,g,h)39y, female, with the left nasopharyngeal carcinoma (h, arrow). The tumor invaded the left Pharynx side clearance, involved the left long head muscle, and lymph node metastasis was found in the VII area of the left neck (g, arrow).No distant metastasis was observed.T2N1M0, staging:II. (I,g,k,l)52y, male, with the left nasopharyngeal carcinoma (l, arrow). Nasopharyngeal mass involved left Pharynx side clearance, sloping bone (k, arrow). bilateral cervical lymph node metastasis, left neck area IV involvement, no distant metastasis.T3N3M0, staging: IVa. (m~t) 37y, male, with nasopharyngeal carcinoma (p, arrow).Nasopharyngeal mass involving left cavernous sinus, invading left internal carotid artery (o, arrow), bilateral neck (q, arrow) and retroperitoneal Paraventricular lymph nodes metastasis is common Multiple lung (r, arrow), liver (s, arrow) and bone (t, arrow) metastases, T4N4M1,staging:IVb