SONOGRAPHY IN HYPOFUNCTIONING NODULES

The diagnosis of hypofunctioning nodules belongs exclusively to the do main of nuclear medicine (functional-topographic) examination methods such as scintigraphy and determination of global and regional uptake. Nevertheless, sonography of the thyroid and the neck region is a valua ble additional method, which derives its justification not from the pr imary establishment of the diagnosis of hypofunctioning nodules but th e crucial question of their benignity or malignancy. Unlike fine needl e biopsy, which provides unequivocal information on malign processes, scintigraphy and sonography can at best indicate the probability as to whether a nodule is malign or not. Apart from topographic information and secondary tumor signs such as lymph node metastases, it is above all the close relationship between echopattern and follicel size which contributes information not accessible to nuclear medicine methods. A hypoechoic basic pattern (solid, calciferous or cystic) increases the probability of malignancy of a hypofunctioning nodule significantly. Hypoechoic nodules have a much higher risk of malignancy than nodules with normal echogenicity, whereas the probability of malignancy is ext remely low in hyperechoic nodules. Although not all carcinomas show hy poechoic internal structures and thus sonography is not a fail-safe me thod to exclude malignancy, it is a valuable diagnostic tool in cases where conventional methods have not provided clear guidelines for the therapeutic approach. However, notwithstanding the numerous technical acids, anamnesis (rapid growth, pain, etc.) and palpation findings (ha rd nodule, largely immobile during swallowing, etc.) should not be aba ndoned completely but in combination with scintigraphy, sonography and fine needle biopsy determine the therapeutic regimen.