Quantitative dynamic contrast-enhanced and diffusion-weighted MRI for differentiation between nasopharyngeal carcinoma and lymphoma at the primary site.

OBJECTIVES: To investigate the value of quantitative dynamic contrast-enhanced MRI (QDCE-MRI) and diffusion-weighted MRI (DW-MRI) in differentiating nasopharyngeal carcinoma (NPC) from lymphoma. METHODS: We retrospectively analysed the data from 102 patients (82 with NPC and 20 with lymphoma) who underwent pre-treatment QDCE-MRI and DW-MRI on a 1.5-T MR unit. QDEC-MRI parameters [influx transfer constant (K(trans)), efflux rate constant (Kep), fractional volume of extravascular extracellular space (Ve) and fractional volume of plasma (fPV)] based on pharmacokinetic model and apparent diffusion coefficient (ADC) were compared between the two nasopharyngeal malignancies. RESULTS: The K(trans), Kep, Ve, fPV and ADC values (mean +/- standard deviation) for NPC were 0.366 +/- 0.155 min(-1), 1.353 +/- 0.468 min(-1), 0.292 +/- 0.117, 0.027 +/- 0.024 and 0.981 +/- 0.184 x 10(-3) mm(2) s(-1), respectively. The K(trans), Kep, Ve, fPV and ADC values (mean +/- standard deviation) for lymphoma were 0.212 +/- 0.059 min(-1), 1.073 +/- 0.238 min(-1), 0.213 +/- 0.104, 0.008 +/- 0.007 and 0.760 +/- 0.182 x 10(-3) mm(2) s(-1), respectively. Optimal cut-off values (area under the curve, sensitivity, specificity) for distinguishing the two tumours were as follows: K(trans) = 0.262 min(-1) (0.866, 80.49%, 85.00%), Kep = 1.401 min(-1) (0.681, 43.90%, 100.00%), Ve = 0.211 (0.784, 76.83%, 85.00%), fPV = 0.012 (0.779, 60.98%, 85.00%), ADC = 0.761 x 10(-3) mm(2) s(-1) (0.781, 93.90%, 55.00%). CONCLUSIONS: QDCE-MRI together with DW-MRI is useful for differentiation between NPC and lymphoma.