[Possibilities and limits of Doppler ultrasound in the area of the head-neck].

Sonography has provided an important addition to the tools available for the diagnosis of the soft tissues in the head and neck region. The ENT surgeon himself is able to examine pathological formations by this quick, non-invasive and, last but not least, less expensive method. Due to the high resolution of the procedure the chance of detecting even small changes is increased and the exactness of diagnosis of pathological lymph nodes of the neck has been significantly improved compared to palpation alone. Ultrasound has replaced the sialographic procedures in the field of diagnostic evaluation of salivary gland disease in the daily practice except for special indications. After inauguration of color Doppler sonography non-invasive evaluation of vascular stenosis of the large cervical vessels concerning their hemodynamic effects has become possible. This issue is important for the differential diagnosis of otoneurological diseases such as sudden hearing loss, vertigo and tinnitus. Additionally, the extent of perfusion of space-occupying lesions can be easily examined, and therefore the risk of mass bleeding can be preoperatively assessed by this method without harm to the patient. Especially carotid body tumors may be diagnosed with high accuracy by the evidence of significant diffuse perfusion of the lesion. In several studies the specificity of the assessment of cervical lymph node disease could be increased by examination of resistance indices. However, other authors have shown inconsistent results in differentiation of benign and malignant lumps; therefore, final judgment does not seem to be possible yet. Use of echo-contrast agents to enhance the ultrasound signal seems to be a promising approach for future developments in color Doppler imaging.