Evaluation of cervical lymph nodes with CT perfusion in patients with hypopharyngeal and laryngeal squamous cell cancer

BACKGROUND: In patients with head and neck squamous cell cancer, metastases in cervical lymph nodes still remain the single most important negative predicting factor. Their presence reduces overall 5-year survival by 50%. The aim of the study was to evaluate the role of computed tomography perfusion (CTP) for differentiation between metastatic and non-metastatic cervical lymph nodes in patients with squamous cell cancer of hypopharynx and larynx. MATERIAL/METHODS: This was a prospective single center study of 18 consecutive patients. Eleven patients with squamous cell cancer of the hypopharynx and seven patients with laryngeal cancer underwent CT examination of the neck followed by CTP. Group II, III, and V of lymph nodes were evaluated. Perfusion maps of basic parameters (blood flow [BF], blood volume [BV], mean transit time [MTT] and permeability surface [PS]) were reconstructed for all patients. In all patients resection of primary tumour along with neck dissection was performed. Lymph nodes underwent histopathological examinations for presence of metastases. CTP parameters were related with histological analysis of resected nodes. RESULTS: CTP and histological findings of 65 nodes were correlated. 24 of them were metastatic and 41 were non-metastatic. Metastatic nodes showed significant hyperperfusion, comparing to non-metastatic ones. An average value of BF in metastatic nodes was 136.4 ml/100 g/min, BV was 7.7 ml/100 g, MTT was 4.4 s and PS was 19.4 ml/100 g/min. The average values for non-metastatic nodes were: BF was 80.7 ml/100 g/min, BV was 4.7 ml/100 g, MTT was 5.6 s and PS was 12.8 ml/100 g/min. The differences were significantly higher for BF, BV and PS values (p<0.05). CONCLUSIONS: CTP may be useful in differentiation between metastatic and non-metastatic lymph nodes, based on evaluation of the value of BF, BV and PS.