Diagnostic accuracy of radionuclide imaging for parathyroid lesions in patients with primary hyperparathyroidism and nodular and autoimmune thyroid disorders: a cross-sectional study

BACKGROUND: Concomitant thyroid disorders can decrease the diagnostic accuracy of topical imaging modalities used to localize primary hyperparathyroidism. Therefore, in such cases, the effectiveness of radionuclide imaging for parathyroid lesions should be confirmed. AIM: This study aimed to evaluate the effects of nodular and autoimmune thyroid disorders on the diagnostic accuracy of radionuclide imaging for parathyroid lesions in patients with primary hyperparathyroidism and compare the accuracy of radionuclide imaging with that of other imaging modalities. METHODS: The study included three patient groups: patients with primary hyperparathyroidism without a concomitant thyroid disease (group 1; n = 50), patients with autoimmune thyroid disorder (group 2; n = 50), and patients with thyroid nodule/multinodular goiter (group 3; n = 50). All the patients underwent ultrasound, planar scintigraphy, and single-photon emission computed tomography with X-ray computed tomography prior to parathyroidectomy. If negative or equivocal results were obtained (e.g., suspected parathyroid lesion), a contrast-enhanced computed tomography scan was performed. The intervals between scans and between the first scan and parathyroidectomy did not exceed 6 months and 12 months, respectively. Sensitivity and the positive predictive value were estimated. RESULTS: In group 2, the diagnostic accuracy of radionuclide imaging for parathyroid lesions was lower than that of other imaging modalities. Moreover, in group 2, contrast-enhanced computed tomography demonstrated a diagnostic sensitivity of 79%, and its combination with ultrasound achieved a higher sensitivity of 85%. In group 3, the highest diagnostic value was obtained for single-photon emission computed tomography combined with X-ray computed tomography (85%) or ultrasound (88%). The results of radionuclide imaging of parathyroid lesions in patients with primary hyperparathyroidism and autoimmune thyroid disease depended on the volume, density, and vascularization of the thyroid gland. CONCLUSION: Single-photon emission computed tomography combined with X-ray computed tomography is an accurate diagnostic modality for identifying parathyroid lesions in patients with primary hyperparathyroidism and concomitant nodular thyroid disorder. Contrast-enhanced computed tomography showed the highest sensitivity in patients with primary hyperparathyroidism and autoimmune thyroid disease.