title: [Improved tumor site and contrast resolution in ultrasound diagnosis by using harmonic frequencies].
abstract: BACKGROUND
  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.
  
  
  METHODS
  We studied whether these techniques improve sonographic detection of head and neck lymph nodes and primary tumours of the upper aerodigestive tract.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Hals-Nasen-Ohrenklinik der Johannes Gutenberg Universität Mainz. jecker@hno.klinik.uni-mainz.de
authors.forename: P
authors.initials: P
authors.lastname: Jecker
authors.forename: J
authors.initials: J
authors.lastname: Maurer
authors.forename: W J
authors.initials: WJ
authors.lastname: Mann
mesh_terms: D003287:Contrast Media; D006801:Humans; D007089:Image Enhancement; D008198:Lymph Nodes / Q000098:blood supply / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D009361:Neoplasm Invasiveness; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging; D010039:Otorhinolaryngologic Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D011134:Polysaccharides; D012016:Reference Values; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508