Blood tests
Blood test is used to check thyroid andparathyroidfunction.
Imaging studies (Chest Xray / CT Scan)
This will tell your physician whether the goitre has caused any narrowing of the windpipe or if there is an extension into the chest (retrosternal goitre).
Ultrasound
This test does not use X-Rays and can demonstrate the structure of the thyroid. It can distinguish cysts from solid nodules but cannot distinguish cancers from innocent nodules (benign nodules). However certain features such as “comet tails” are suggestive of a benign nodule.
Nuclear Medicine Scan
This test must not be used in pregnancy. It is useful in a thyrotoxic patient where it shows the extent of the over activity in the thyroid.
Biopsy
Unless there are special circumstances, all single nodules in the thyroid should be subjected to a fine needle aspiration (FNA). This test has two roles: it can be therapeutic, in the case of a simple cyst which may be aspirated to dryness and avoid the need for surgery, or diagnostic in differentiating cancers from innocent nodules.
Trachea evaluation
CAT scan or bronchoscopy (small tube with a camera on the end) may be done if a large thyroid is pushing on the trachea (windpipe). A large mass may cause a deviation or a narrowing of the trachea. In cases of advanced cancer, the tumor may invade (i.e. grow) into the trachea.
Esophageal evaluation
Barium swallow study esophagram or endoscopy may be performed if there is concern about involvement of the esophagus (food pipe).
Voice Box Assessment (Laryngoscopy)
It is valuable for the surgeon to get an independent assessment of the throat pre-operatively. This test is mandatory when there is a suggestion of voice change, a positive fine needle biopsy for cancer, or there has been previous thyroid surgery.
References
http://www.endocrinesurgeon.co.uk/index.php/what-tests-may-be-performed-prior-to-thyroid-surgery
http://endocrinediseases.org/thyroid/surgery.shtml
