Very high frequency (13 MHz) ultrasonographic examination of the normal neck: detection of normal lymph nodes and thyroid nodules.

Very high frequency (13 MHz) ultrasonographic examination of the neck successfully visualized one or more normal lymph nodes (weakly echoic oval structures with an echoic central hilum) in 67.6% of 1000 healthy volunteers. Efficacy was not related to recent ear, nose, and throat infection, sex, or age. The longitudinal-transverse diameter ratio was greater than or equal to 2 in 86.2% of cases. No signal was detected with color Doppler imaging. One or more thyroid nodules were also identified in 34.7% of the subjects: the frequency was 44% in women and 42% in subjects over 50 years of age.