Dual-energy CT in the differentiation of stage T1 nasopharyngeal carcinoma and lymphoid hyperplasia.

PURPOSE: To explore the value of dual-energy CT for the differentiation between stage T1 nasopharyngeal carcinoma (NPCT1) and lymphoid hyperplasia (LH).

METHOD: Patients with histopathological proven nasopharyngeal lesions (stage T1 NPCs, n = 30; LHs, n = 47) who underwent dual-energy CT were enrolled in this retrospective study. Quantitative parameters derived from dual-energy CT were measured. Statistical analyses were performed using the independent sample t-test, Wilcoxon rank sum test, and receiver operating characteristic curve (ROC) analysis.

RESULTS: There was significantly higher iodine concentration (IC), normalized iodine concentration (NIC, to internal jugular vein) in NPCT1 compared with LH (p < 0.001). The effective atomic number (Zeff) was significantly higher in NPCT1 than that in LH (p <  0.001). The virtual monochromatic images (VMIs) at 50 keV-110 keV (20 keV-interval) of NPCT1 were all significantly higher than those of LH (all p <0.001). The slope (k) value of spectral attenuation curve was also significantly higher in NPCT1 than LH (p <  0.001). There was no significant difference in virtual noncontrast (VNC) and 130 keV-190 keV (20 keV-interval) between the NPCT1 and LH. For discriminating NPCT1 from LH, the area under curve (AUC) using 70 keV was the highest in all single parameter (AUC, 0.92; sensitivity, 80.00 %; specificity, 91.49 %). Combined multiple parameters (IC, NIC, Zeff, 50 keV, 70 keV, 90 keV, slope (k)) by performing multivariate logistic regression model significantly improve the diagnostic capability in differentiating these two entities, with AUC, sensitivity, and specificity values of 0.99, 93.33 %, 97.87 %, respectively.

CONCLUSIONS: Dual-energy CT can be helpful for the differentiation between NPCT1 and LH lesions.