Primary Hyperparathyroidism: Outcomes of Repeated Imaging After Initial Negative Radiological Localization.

Background: Radiological localization imaging aids in the identification of abnormal parathyroid glands resulting in primary hyperparathyroidism (PHPT), thereby facilitating minimally invasive parathyroid surgery. Sometimes initial imaging may fail to identify the abnormal gland and imaging may therefore be repeated. This study explored patient outcomes of repeated parathyroid localization imaging, after initial negative gland localization, at a United Kingdom institution.

Methodology: Data was retrospectively collected and analyzed for patients with PHPT undergoing repeated imaging during a five-year period (2015-2020). The total number of episodes of scanning, types of scans performed, the time interval between scans and the imaging success of gland localization were recorded. We explored the reasons for repeated imaging and attempted to identify any factors that might predict subsequent positive radiological localization.

Results: A total of 45 patients were identified who underwent repeated localizing imaging after first localizing imaging was negative. Of these, 39 did not undergo surgery despite repeat imaging being undertaken; 11 out of these 39 patients (28%) had subsequent positive localization scans. Again, a large proportion of patients were managed conservatively, despite the repeated sets of imaging being done. Patients undergoing three or four sets of repetitive imaging did not have imaging or surgical success.

Conclusion: A streamlined parathyroid pathway should be followed whereby patients should be triaged for suitability for surgery prior to repeated imaging. A second set of scans should be offered when patients are unsuitable for conservative management and are willing and fit to undergo surgery. There is no merit to repeating imaging more than twice.