Comparison of Parathyroid Scintigraphy with Different Radionucleotides – 99mТс MIBI and 99mТс Tetrofosmin in one and the same Patient with Primary Hyperparathyroidism
Issue: 2/2017
Author: Botushanova, Albena D1., Botushanov, Nikolay P.2
1 Department of Clinical Oncology, Section Nuclear Medicine; Medical University, Plovdiv
2 Second Department of Internal Diseases, Section/Clinic of Endocrinology; Medical University, Plovdiv
Abstract:
We present the case of a 56-year old woman with laboratory and clinical data for primary hyperparathyroidism following unsuccessful surgical treatment. Due to the persistently high levels of calcium – 2,71 mmol/l, PTH − 273,6 pg/ml and low phosphorus – 0,78 mmol/l and the lack of CT and MRI data for pathologically changed parathyroid glands, we performed a single-isotope dual-phase parathyroid scintigraphy with 99mТс-Tetrofosmin combined with SPECT, which showed no definite areas of abnormal parathyroid tissue in the areas of the neck or mediastinum. Five months later, the patient was referred again for parathyroid scintigraphy because of the continuously rising levels of calcium − 2,92 mmol/l and PTH − 334,6 pg/ml, and worsening of her complaints. This time we performed a single-isotope dual-phase parathyroid scintigraphy with 99mТс-MIBI combined with SPECT, which revealed a focus of radionucleotide accumulation in the right lower neck on the early SPECT images and also visible on the late planar images being highly suspicious for parathyroid adenoma. She underwent successful removal of a right lower parathyroid adenoma. This case gives us an opportunity to compare two scans with different radionucleotides obtained during the course of development of primary hyperparathyroidism in one and the same patient. Several reasons can explain the conversion of the initially negative scan into a positive one. Different factors of biological and technical origin can influence the accumulation of 99mТс-MIBI and 99m Тс-Tetrofosmin into the parathyroid adenomas and affect sensitivity and specificity of the imaging method and finally the outcome of the scan.
Key words: primary hyperparathyroidism, scintigraphy, 99mTc-sestamibi, 99mTc-tetrofosmin
