Parathyroid sonography: diagnostic accuracy related to shape, location and texture of the gland

The sonographic features of 51 pathological parathyroid glands detected pre-operatively were analysed. Atypical texture was found in 23.5% and variation in shape in 15.6% of the cases. Cystic parathyroid glands are difficult to differentiate from thyroid cysts, and may be the cause of false positive diagnosis, as in three cases in this series. Topographic assessment showed a relatively low sensitivity in detecting disease in the right upper gland (50%) and in the upper mediastinum (70%). The decreased accuracy in these regions is probably because of the particular anatomical location of the right upper gland and sonographic limitations in screening the mediastinal region. Awareness by the radiologist and surgeon of the variations in texture and location may influence both diagnosis and intraoperative detection of the abnormal parathyroid gland. Although high-resolution ultrasound has been established as a sensitive and accurate method of parathyroid imaging, there is still difficulty in identifying disease in 8-20% of cases, according to the major reported series (Sample et al, 1978; Duffy et al, 1980; Scheible et al, 1981; Simeone et al, 1981; Reading et al, 1982). Awareness of different sonographic variations in shape, texture and site of the enlarged parathyroid is essential in the interpretation of results. PATIENTS AND METHODS Sonographic examination of the parathyroid glands was performed in 145 patients with hypercalcaemia and clinical suspicion of hyperparathyroidism. Surgical exploration of the neck was performed in 53 patients who form the basis of this study. Most of the sonograms were performed using a highresolution dynamic scanner with a 10 MHz transducer (Picker Microview). Four cases were examined with a static grey-scale unit using 5 MHz or 7.5 MHz transducers. The patient was placed in the supine position with the head hyperextended. Longitudinal and transverse sections of the entire thyroid area were performed and the upper mediastinum was routinely