TC-99M PERTECHNETATE THYROID IMAGES IN HYPERTHYROIDISM - SIZE, DISTRIBUTION, AND PRESENCE OF A PYRAMIDAL LOBE

One hundred consecutive thyroid images obtained by use of Tc-99m perte chnetate, in authenticated cases of hyperthyroidism, were reviewed. Ca librated images showed that only 42 of the 200 thyroid lobes (21%) wer e greater than 5 cm in length, The enlarged lobes occurred in 29 patie nts. Of these, only 4 had a multinodular appearance (and 7 patients wi th smaller lobes also had multinodular glands). Neither thyromegaly (b y length) nor multinodular appearance are common features of hyperthyr oidism in this area. There were 12 instances of pyramidal robes in the hyperthyroid men (12 of 26 = 46%) and 24 cases in women (24 of 74 = 3 2%). The site of origin of the pyramidal lobe was from the left in 17, from right in 16, and from the midline in 3 cases, During the period of review of all thyroid images, only one other case of a pyramidal lo be was found (a case of multinodular goiter).