What imaging modalities are recommended for primary parathyroidism?

From the Guidelines

For primary hyperparathyroidism, the recommended initial imaging modality is a thyroid scan with SPECT or SPECT/CT, specifically a sestamibi dual-phase scan with SPECT or SPECT/CT, as it provides precise anatomic localization of parathyroid adenomas 1. This approach is supported by the American College of Radiology, which suggests that sestamibi scan with SPECT or SPECT/CT is a usually appropriate initial imaging procedure for primary hyperparathyroidism 1. Some key points to consider when choosing an imaging modality include:

• The addition of a pertechnetate thyroid scan may further improve localization 1
• The use of SPECT or SPECT/CT provides more precise anatomic localization of parathyroid adenomas compared to planar imaging 1
• In patients with concomitant thyroid disease, the addition of CT to a dual-tracer sestamibi and pertechnetate SPECT scan increases sensitivity 1
• Ultrasound and sestamibi scintigraphy are often used in combination to improve diagnostic accuracy, although the provided evidence does not specifically support this combination as the first-line option 1
• The goal of preoperative imaging is to accurately localize abnormal parathyroid tissue, which helps surgeons plan for minimally invasive parathyroidectomy rather than bilateral neck exploration, resulting in shorter operative times and fewer complications 1

From the Research

Imaging Modalities for Primary Parathyroidism

The following imaging modalities are recommended for primary parathyroidism:

• Ultrasonography: can be used as the primary screening modality for the localization of parathyroid disease prior to surgery for primary hyperparathyroidism 2
• Sestamibi scintigraphy: has been proposed as a screening modality for the detection of abnormal parathyroid glands in patients with primary hyperparathyroidism 2, 3
• Four-dimensional computed tomography (4D CT): has emerged as a promising method for preoperative localization of parathyroid adenomas 4, 5
• Magnetic resonance imaging (MRI) and positron emission tomography (PET): may be useful alternatives in cases with negative or discordant findings at first-line imaging methods, but there is insufficient evidence to recommend their routine use 6

Diagnostic Performance of Imaging Modalities

The diagnostic performance of different imaging modalities is as follows:

• Ultrasonography: sensitivity of 72% (95% CI 67-76) for correct localization of a single parathyroid adenoma 2
• Sestamibi scintigraphy: sensitivity of 83% (95% CI 78-86) for correct localization of a single parathyroid adenoma 2
• 4D CT: superior preoperative localization compared with sestamibi SPECT/CT in patients with single and multigland disease, with a sensitivity of 79.3% (414 of 522) 4
• Combination of ultrasonography and sestamibi SPECT/CT: may be an optimal first-line strategy in the preoperative planning of patients with primary hyperparathyroidism, taking into account several data beyond the diagnostic performance 6

Recommendations

Based on the available evidence, the following recommendations can be made:

• Ultrasonography and sestamibi scintigraphy are the most commonly employed first-line investigations in patients with primary hyperparathyroidism 6
• 4D CT may be considered as an alternative or additional imaging modality, particularly in cases with negative or discordant findings at first-line imaging methods 4, 5
• Patients with primary hyperparathyroidism who are candidates for parathyroidectomy should be referred to an expert clinician to decide which imaging studies to perform based on regional imaging capabilities 6