Dynamic contrast enhanced MRI in nodal lymphoma: correlation of quantitative MR perfusion parameters with lymphoma subtype, Lugano stage and Ki-67 index.

Background: Research into the intratumoral microenvironment in lymphoma has been escalated along with improved survival and new targeted therapies with an intent to refine risk stratification and prognostication. Various studies have reported significance of quantitative DCE-MRI parameters for predicting biological behaviour of various tumors. This study is an endeavour to supplement the existing literature on quantitative DCE-MRI in nodal lymphoma.

Objectives: To study the correlation of quantitative DCE-MRI parameters of Ktrans, Kep and Ve with subtype, Lugano stage at diagnosis and Ki-67 proliferation index (PI) in nodal lymphoma.

Methods: 33 patients of age > 12 years with newly diagnosed nodal lymphoma underwent DCE-MRI. Ktrans, Kep and Ve were generated from extended Tofts model and correlated with lymphoma subtype, Lugano staging and Ki-67 PI.

Results: Mean Ktrans and Kep values were significantly higher in non-Hodgkin's lymphoma (NHL) than in Hodgkin's lymphoma (HL). Considering Ki-67 PI value of > 45% as aggressive lymphoma, the mean Ktrans (659.37 x 10-3min-1 versus 288.00 x 10-3min-1, p < 0.001) and Kep (1256.63 x 10-3min-1 versus 689.82 x 10-3min-1, p = 0.004) values in aggressive lymphomas were significantly higher compared to non-aggressive lymphomas. ROC curve analysis revealed a threshold Ktrans value of ≥ 359 x 10-3min-1 and Kep value of ≥ 853 x10-3 min-1 for diagnosing aggressive lymphomas with a sensitivity of 95%, 90%, specificity of 100%,82% and diagnostic accuracy of 91.7%,86.7% respectively. There was no significant difference in DCE-MRI parameters of various Lugano stage subgroups.

Conclusion: DCE-MRI parameters have the potential to non-invasively predict the subtype, aggression and Ki-67 PI in nodal lymphoma.

Advances In Knowledge: The knowledge that Ktrans is higher in aggressive lymphomas is novel. It adds to previous literature regarding MR perfusion in various neoplasms.