Improved tumor site and contrast resolution in ultrasound diagnosis by using harmonic frequencies

Abstract

The aim of new techniques in head and neck sonography is to increase the sensitivity and the specificity of the examination. With tissue harmonic imaging (THI) and contrast harmonic imaging (CHI) new techniques are available which allow increased contrast and resolution in head and neck sonography as well as a better detection of small blood vessels. We studied whether these techniques improve sonographic detection of head and neck lymph nodes and primary tumours of the upper aerodigestive tract. The results indicate that THI allows a better detection of cervical lymph nodes. Furthermore, intranodal structures and the borders of the lymph node can be better detected. Using CHI, typical patterns of vascularization can be seen, allowing a better interpretation of the node's tumour status. Primary tumours can be detected sufficiently well using conventional B-scan techniques although they are easier to detect with THI. Using CHI, many tumour vessels can be detected, but this does not increase the sensitivity of the sonographic examination. THI and CHI may increase the specificity of sonographic diagnostics of cervical lymph nodes but show no clinical benefit regarding the diagnostics of primary tumours of the upper aerodigestive tract.