Dynamic contrast-enhanced magnetic resonance imaging for characterising nasopharyngeal carcinoma: comparison of semiquantitative and quantitative parameters and correlation with tumour stage

Objectives

To evaluate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for characterising nasopharyngeal carcinoma (NPC).

Methods

Forty-five newly diagnosed NPC patients were recruited. The initial enhancement rate (E _R ), contrast transfer rate (k _ep ), elimination rate (k _el ), maximal enhancement (MaxEn) and initial area under the curve (iAUC) were calculated from semiquantitative analysis. The K ^trans (volume transfer constant), v _e (volume fraction) and k _ep were calculated from quantitative analysis. Student’s t-test was used to evaluate the differences among tumour stages. Pearson’s correlation between the two sets of k _ep was performed.

Results

Comparing tumours of T1/2 stage (n?=?18) and T3/4 stage (n?=?27), MaxEn (P?=?0.030) and iAUC (P?=?0.039) were both significantly different; however, the iAUC was the only independent variable with 69.6 % sensitivity and 76.5 % specificity respectively; v _e was also significantly different (P?=?0.010) with 69.6 % sensitivity and 70.6 % specificity respectively. No significant difference was found among N stages. The two sets of k _ep s were highly correlated (r?=?0.809, P?k _el, E _R, MaxEn and iAUC tended to be higher.

Conclusions

Neovasculature in higher T stage NPC exhibits some parameters of increased permeability and perfusion. Thus, DCE-MRI may be helpful as an adjunctive technique in evaluating NPC.

Key Points

? The correct assessment of nasopharyngeal carcinoma (NPC) is important for planning treatment. ? Neovasculature in higher T stage NPC exhibits increased permeability and perfusion. ? Correlation between quantitative and semi-quantitative analysis validates the robustness of DCE-MRI. ? DCE-MRI may be helpful as an adjunctive parameter in evaluating NPC.