A method for thyroid volume calculation based upon ultrasonic scanning is described. The accuracy of the method was estimated by comparing ultrasonically determined volumes with the volumes of surgically removed thyroid glands. The precision (i.e., reproducibility) was estimated by comparing the ultrasonic volumes determined by two separate investigators in a double blind fashion. The normal range of thyroid volume was evaluated in a group of volunteers. The accuracy was acceptable, but the precision was borderline and appears to be the limiting factor in the procedure. We concluded that at present this method offers no significant improvement over other methods currently in use. However, thyroid volume calculation based upon palpation of the gland cannot be standardized, and isotope scanning is a more comprehensive and expensive procedure. Several possibilities exist for improvement of the ultrasonic technique, and the procedure holds promise for the future.
Indexing Words Ultrasonic ScanningDetermination of the volume of the thyroid gland is considered of value in the assessment of patients with thyrotoxicosis, especially in calculating the correct dosage of radioactive iodine (1)(2)(3)(4)(5)(6)(7)(8)(9). Moreover, if the normal range of thyroid volume is known, enlargement of the gland can be diagnosed, and repeated determinations of the volume of the gland might be of help in evaluating the adequacy of treatment A number of methods have been developed for the in uiuo determination of thyroid volume or weight. Judgment by palpation (SO) is subjective and inaccurate. Isotope scanning in one or two planes has been used, but these methods were also found to be inaccurate (1 1 , 12).