Tracer kinetics analysis of dynamic contrast‐enhanced CT and MR data in patients with squamous cell carcinoma of the upper aerodigestive tract: comparison of the results

Abstract

(i) To evaluate the feasibility of tracer kinetics analysis of dynamic contrast-enhanced (DCE) CT and T2-weighted MR data of squamous cell carcinoma (SCCA) of the upper aerodigestive tract. (ii) To compare functional parameters derived by both modalities and examine the interchangeability of them as well as the intra- and inter-rater agreement. Dynamic contrast-enhanced-CT and MR images of 23 patients with SCCA were postprocessed using a distributed-parameter (DP) tracer kinetic model. The evaluated parameters included blood flow (F), intravascular blood volume (v(1)), extravascular extracellular blood volume (v(2)), intravascular mean transit time (t(1)), lag time (t(0)), permeability surface area product (PS) and extraction ratio (E). Mean perfusion values, based on region-of-interest analysis, of the tumors and the healthy muscle tissue were compared and correlated. Inter-rater and intra-rater variability were assessed. Interchangeability of the tumor functional parameters was tested using Pearson's correlation coeficients and Bland-Altman plots. The mean values in tumor and healthy muscle tissues were significantly different for each modality (0.0001< or =P< or =0.03). The mean values of all tumor perfusion parameters apart from v(2) and E were significantly different (0.001< or =P< or =0.009) between the two modalities. The intra-rater variability was good to very good for all parameters. The inter-rater variability was moderate to good. Bland-Altman plots of F, t(1), t(0), and v(2) showed moderate interchangeability. There was a proportionality error in v(1) and PS graphs. The estimation of functional parameters in SCCA is feasible using DCE-CT and -MR with a DP model. The parameters are mostly significantly different and the interchangeability of them is limited.