The value of oblique images in pre-operative localisation with 99Tcm-MIBI for primary hyperparathyroidism

Full text: Primary hyperparathyroidism has traditionally been treated with bilateral neck dissection and surgical inspection of all parathyroid glands. However, there had been growing interest in less invasive parathyroid surgery, ranging from unilateral neck dissection to minimally invasive endoscopically assisted procedures. For this approach, precise localisation is essential, including the depth of the adenoma in relation to the thyroid gland. While 99Tcm-MIBI has been extensively utilised for pre-operative localisation of parathyroid adenomas, imaging techniques have varied, with some centres not performing oblique and delayed images or correlative thyroid scanning. In our institution, early and delayed anterior oblique pinhole images are routinely obtained in addition to standard anterior pinhole images and a thyroid study. Studies from 38 patients (found to have 38 adenomas at surgery) were reviewed blindly comparing anterior and oblique images and anterior images only. When compared to anterior images only, oblique views improved overall sensitivity from 74% - 89% (p < 0.05) and improved the confidence of interpretation. Furthermore, the oblique view provides the surgeon with important information regarding the depth of the gland and can influence the surgical approach. We conclude that for these reasons, oblique views should be performed in pre-operative parathyroid localisation with 99Tcm -MIBI. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc