Evaluation of Surgeon-Performed Ultrasonography With or Without Contrast Enhancement vs Scintigraphy in Patients With Primary Hyperparathyroidism

IMPORTANCE Scintigraphy and ultrasonography are common imaging modalities for the preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism. When comparing the 2 modalities, the benefits of ultrasonography in terms of convenience, patient comfort, duration, cost, and lack of radiation should be taken into account. OBJECTIVE To investigate whether surgeon-performed ultrasonography, with or without contrast-enhanced ultrasonography (CEUS), is noninferior to scintigraphy for localizing pathological parathyroid glands in patients with primary hyperparathyroidism. DESIGN, SETTING, AND PARTICIPANTS Prospective, paired, noninferiority cohort study performed at a high-volume tertiary referral center for parathyroidectomy with blinded examiners and a 6-month follow-up. Participants were adults (age >= 18 years) referred for parathyroidectomy due to primary hyperparathyroidism. Of 207 eligible patients, 35 were excluded, leaving 172 enrolled in the study. Inclusion lasted from September 2019 until February 2021. Follow-up ended in December 2021. EXPOSURES (99m)Technetium-pertechnetate/(99m)technetium-sestamibi subtraction scintigraphy with (99m)technetium-sestamibi single-photon emission computed tomography/computed tomography, followed by surgeon-performed ultrasonography and CEUS. MAIN OUTCOMES AND MEASURES The sensitivity of each imaging modality in localizing pathological parathyroid glands, calculated on a per-quadrant and a per-patient basis, respectively. The a priori noninferiority margin was a lower 95% confidence limit for the difference in sensitivity not falling below -10%. RESULTS Out of 172 participants, 139 (80.8%) were women, the median (range) age was 65 (24-87) years, and the median (IQR) follow-up was 200.5 (181-280.25) days. Quadrant sensitivity (95% CI) was 70.9% (63.2%-78.5%) for ultrasonography, 68.4% (60.4%-76.5%) for ultrasonography plus CEUS, and 67.0% (60.0%-74.0%) for scintigraphy. The sensitivity difference (95% CI) compared with scintigraphy was 3.9% (-4.1% to 11.8%) for ultrasonography and 1.5% (-6.4% to 9.3%) for ultrasonography plus CEUS, establishing noninferiority for both modalities. Per-patient sensitivity was 81.4% (74.8%-86.9%) for ultrasonography and 79.1% (72.2%-84.9%) for both scintigraphy and ultrasonography plus CEUS. The sensitivity difference compared with scintigraphy was 2.3% (-6.8% to 11.4%) for ultrasonography and 0.0% (-9.1% to 9.1%) for ultrasonography plus CEUS, establishing noninferiority for both modalities. CONCLUSIONS AND RELEVANCE In this cohort study, conventional ultrasonography by an experienced parathyroid surgeon-sonographer was noninferior to scintigraphy and may constitute a valid first-line imaging modality in patients with primary hyperparathyroidism, even without the addition of CEUS. Further imaging should be reserved for cases that are equivocal or nonlocalizing on ultrasonography.

Automated summary

This study investigated whether surgeon-performed ultrasonography is as effective as scintigraphy in localizing pathological parathyroid glands in patients with primary hyperparathyroidism. The results showed that conventional ultrasonography by an experienced parathyroid surgeon-sonographer was noninferior to scintigraphy and may be considered as a valid first-line imaging modality.