CT measurement of perfusion and permeability within lymphoma masses and its ability to assess grade, activity, and chemotherapeutic response

Purpose: Structural CT criteria such as nodal size and appearance have a poor correlation with the grade and activity of a lymphoma mass. This study investigates the potential for functional CT perfusion and permeability measurements to assess lymphoma grade and activity. Method: Thirty-nine patients with proven lymphoma underwent 47 dynamic contrast-enhanced CT studies. Lymphoma grade was classified as low or intermediate/high. In seven patients who underwent repeated studies, measurements were correlated against change in disease activity in the intervening period. Results: Median perfusion values were higher in active disease (0.55 vs. 0.37 ml/min/ml) and intermediate/high-grade lymphoma (0.56 vs. 0.46 ml/min/ml). Perfusion below 0.2 ml/min/ml implied inactive disease (p < 0.03), whereas >0.5 ml/min/ml suggested intermediate/high-grade lymphoma (p = 0.11). Median values of permeability were little different between patient groups. Only perfusion fell when disease became inactive. Conclusion: Only CT perfusion measurements of nodes have potential for assessing lymphoma grade, activity, and treatment response.