Quantitative measurements of perfusion and permeability of oropharyngeal and oral cavity cancer, recurrent disease, and associated lymph nodes using first-pass contrast-enhanced computed tomography studies

Objectives: We sought to evaluate the routine clinical use of perfusion computed tomography in the detection and differentiation of primary and recurrent oropharynx and oral cavity tumors as well as of nodal disease. Materials and Methods: A total of 77 patients with primary cancer as well as suspected recurrent disease and lymph nodes were evaluated. A dynamic acquisition (4 X 6-mm slices) of the largest axial tumor surface was performed and the tumor blood flow (BF), blood volume (BV), and mean transit time (MTT) were calculated by using a modified deconvolution-based analysis taking into account the extravasation of the contrast agent for permeability surface area product imaging (PS). Tumor volume was calculated and region of interest analysis was performed on the pathologic and normal tissue. Results: The mean BF, BV, and PS values in the primary tumors (77.48 mL/min/100 g tissue; 5.29 mL/min; 13.33 mL/min/100 g tissue, respectively) were highly significantly different (P < 0.01) than those obtained in the normal structures. Mean MTT values (9.01 seconds) also were significantly lowered in the tumors compared with normal tissue (P < 0.05). There was no statistical difference in the perfusion values between the primary and the recurrent tumors. Recurrent disease could be differentiated on the basis of BF (P < 0.05) from tissue changes after chemo-radiation-treatment (mean BF: 69.71 versus 45.31 mL/min/100 g tissue, respectively). Differentiation of the lymph nodes was not possible by means of perfusion values. Tumor volume did not significantly correlate with any perfusion parameter. Conclusions: Perfusion CT of oropharyngeal and oral cavity cancer in clinical routine is feasible and helps outlining the malignant tissue as well as differentiating recurrent disease from nonspecific posttherapeutic changes.