الفهرس 
pathological reviewOnly 14 pages are availabe for public view
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Abstract
Head and neck cancers encompass a diverse group of uncommon tumors of which squamous cell carcinoma are the fifth most common cancer worldwide which accounts for greater than 90% of HN cancers.
The assessment of tumor volume changes after treatment by CT may be used as an objective technique for therapy monitoring, with good correlation with histology. Furthermore CT-determined tumor volume is a strong predictor of local and loco-regional outcome of laryngeal carcinoma.
Moreover the knowledge about the cellularity or the perfusion of a tumor may help in the differentiation of the biological behavior during and after treatment of lesions having the same histologic type.
Therefore, CT Perfusion is a technique that can be readily incorporated into the existing CT protocols to provide an in vivo marker of tumor angiogenesis. By capturing physiological information reflecting the tumor vasculature, perfusion CT can be useful for diagnosis and therapeutic monitoring.
In the current study, there were significant differences in perfusion parameters between studied benign and malignant lesions as regards BF and between responder and non-responder groups as regards BF at baseline and BV at 40 Gy.
The parametric differentiation of responder and non- responder groups regarding baseline BF and BV at 40 Gy were demonstrated in our study with greater diagnostic sensitivity and specificity than other studied CT perfusion parameters. And according to these results, CT perfusion may be of great clinical use in differentiation between responder and non-responder groups.
Therefore, in our study BF and BV parameters were found to be the most sensitive CT perfusion parameter rather than PS.