J. Tramalloni

Conduite à tenir devant un nodule thyroïdien : échographie, cytoponction

All ultrasound examinations for thyroid nodule should include a malignancy risk assessment based on the markedly hypoechoic nature of the nodule, presence of microcalcifications, ill-defined margins, nodule with shape taller than wide and intra-nodular hypervascularity at color Doppler. In patients with multinodular thyroid gland, precise nodule mapping is necessary to allow accurate follow-up of each nodule, correctly identify which nodule(s) is hyper functioning on iodine scan (if done) and guide fine needle aspiration (FNA) of suspicious nodules. As such, all reports of US examinations for thyroid nodule(s) should include a diagram or map of the nodule(s). An evaluation of cervical lymph nodes also helps to determine the malignancy risk. The main US features for malignant adenopathy include: rounded lymph node, loss of normal echogenic fatty hilum, and loss of normal hilar vascularization. Several patterns are highly suggestive of thyroid cancer metastasis: microcalcifications, cystic components, hyperechoic nodes, mimicking thyroid tissue. FNA is a routine procedure in experienced hands. It is the best test to determine which nodule(s) needs to be surgically removed. Thyroglobulin assay on needle-washing fluids after FNA is mandatory when lymph node metastasis is suspected. Preoperative lymph nodes mapping with neck ultrasound is commonly repeated prior to surgery to assess the need for node dissection in patients with proven thyroid malignancy.

Echographie de contraste des organes superficiels : avantages et limites

Resume L’echographie de contraste des organes superficiels represente un challenge technologique puisque la frequence de resonance des microbulles qui composent les agents de contraste varie generalement de 1 a 2 MHz, alors que l’imagerie est typiquement realisee entre 10 et 15 MHz. D’autre part son interet clinique doit se justifier face a une imagerie ultrasonore qui offre deja une excellente resolution spatiale et des performances elevees en mode Doppler. L’introduction de traitements specifiques du signal ultrasonore et de transducteurs dont la gamme frequentielle est tres large ouvre la voie vers cette nouvelle imagerie. Actuellement peu evaluee, elle concerne des champs tres divers comme la thyroide, le sein, le testicule, la prostate, la caracterisation des adenopathies cervicales et les tumeurs cutanees.