Preoperative Localization of Parathyroid Adenomas with Methoxyisobutylisonitrile and Ultrasonography

Aim: To identify whether the combination of Methoxyisobutylisonitrile (MIBI) and ultrasound scan (USS) in localizing the parathyroid gland preoperatively is more effective than either MIBI or USS alone. Materials and methods: Retrospective manual analysis of patients’ operative and medical notes was undertaken. Patients presenting with raised serum calcium and parathyroid hormone (PTH) between February 2009 and April 2012 (n = 76) were included in the study. The sensitivity of localizing parathyroid adenomas via MIBI and USS with confirmation by histological evaluation of tissue following parathyroidectomy was assessed. Results: The combination of MIBI and USS provided a stati s tically significant improvement in preoperative localization of parathyroid adenoma over MIBI or USS alone (p = 0.033 and p = 0.043 respectively). Conclusion: Ultrasound scan alone had a statistically much higher sensitivity to localize a parathyroid adenoma than MIBI and we therefore advise USS to be a first-line investigation with MIBI in reserve for when USS fails to identify an abnormality. However, the combination of both USS and MIBI provides a statistically improved preoperative visualization of parathyroid adenoma and thus reduces the risk of requiring further surgery.