Incidentally recognised thyroid focal uptake of 99mTc-sestamibi during stress myocardial perfusion scintigraphy.

INTRODUCTION: 99mTc-sestamibi, a radiopharmaceutical widely used in the assessment of myocardial perfusion, can be used as an indicator of thyroid disease due to its oncophilic character. The aim of this study was to establish the usefulness of performing additional examinations of radiotracer uptake in the thyroid gland during standard stress scintigraphy with sestamibi in order to identify thyroid diseases.

MATERIAL AND METHODS: After a retrospective evaluation of 330 consecutive myocardial perfusion scintigraphies performed in our hospital during one year, 41 patients with a focal accumulation of 99mTc-sestamibi in the thyroid were enrolled in the study. The patients underwent clinical examinations, including thyroid ultrasonography and TSH, fT4, fT3, aTPO, TRAB, calcitonin, and CEA levels. Based on the thyroid ultrasounds, 21 patients were referred for fine-needle aspiration biopsy of the thyroid.

RESULTS: An abnormal accumulation of radiotracer in the thyroid was found in 41(12.4%) of 330 patients who underwent stress cardiac scintigraphy. Thirteen (31.7%) of those patients had multinodular euthyroid goitres, 12 (29.2%) had a single thyroid nodule (including two autonomous nodules), 11 (26.8%) had autoimmune thyroid disease, and one (2.4%) had papillary thyroid carcinoma. In 12 (29.2%) with thyroid tracer uptake there was no thyroid pathology.

CONCLUSIONS: Additional evaluation of radiotracer uptake in the thyroid during standard myocardial perfusion scintigraphy is a valuable tool in the detection of thyroid diseases. The additional or parallel evaluation of radiotracer uptake in the thyroid should be considered during every myocardial scintigraphy.