Tumoural perfusion as measured by dynamic computed tomography in head and neck carcinoma

Purpose: To investigate the intra- and interobserver variability, as well a s the intra- and interpatient variability of CT-determined tumour perfusion in head and neck rumours, and to evaluate the preliminary value of this pa rameter as predictive factor of local failure after treatment by definitive radiotherapy. Materials and methods: In 41 patients the perfusion of a primary head and n eck squamous cell carcinoma was estimated using dynamic CT. A 40-ml intrave nous bolus of a low-osmolar non-ionic contrast agent was rapidly injected o ver 5 s (8 ml/s), while a dynamic acquisition of image data was obtained du ring the first pass at the level of the largest axial tumour surface. A tim e-density curve was constructed for the primary tumour and the carotid arte ry. The perfusion in the selected tumour region of interest was calculated by dividing the slope of the tumour-time density curve by the maximal value in arterial density. Tumour volume was calculated on the CT-images and cor related with perfusion rate. Results: The mean perfusion rate was 86.4 ml/min per 100 g (median, 80.6; S D, 43.05; range, 31.7-239.8 ml/min per 100 g). No systematic difference was found between the measurements performed by two independent observers. The intratumoural COV was 0.22, the intertumoural COV 0.37. No correlation was found with tumour volume. Ten out of 20 patients with a perfusion rate < 8 0 ml/min per 100 g were not locally controlled, while nine out of 21 patien ts with a value > 80 ml/min per 100 g did show a local failure (P = 0.19). Conclusions. CT-determined perfusion measurements of head and neck rumours are feasible. No correlation with tumour volume and a sufficiently large CO V were found to consider this parameter as a possible prognostic factor for outcome after radiotherapy. More patients need to be investigated to rest the hypothesis that rumours with a low CT determined perfusion rate have a higher risk of local failure. (C) 1999 Elsevier Science Ireland Ltd. All ri ghts reserved.