Lee, Grace S.

AbstractIntroductionFocused parathyroidectomy in primary hyperparathyroidism (1°HPT) is possible with accurate preoperative localization and intraoperative PTH monitoring (IOPTH). The added benefit of multimodal imaging techniques for operative success is unknown.MethodPatients with 1°HPT, who underwent parathyroidectomy in 2012–2014 at a single institution, were retrospectively reviewed. Only the patients who underwent the standardized multimodal imaging workup consisting of 123I/99Tc‐sestamibi subtraction scintigraphy, SPECT, and SPECT/CT were assessed.ResultsOf 360 patients who were identified, a curative operation was performed in 96 %, using pre‐operative imaging and IOPTH. Imaging analysis showed that 123I/99Tc‐sestamibi had a sensitivity of 86 % (95 % CI 82–90 %), positive predictive value (PPV) 93 %, and accuracy 81 %, based on correct lateralization. SPECT had a sensitivity of 77 % (95 % CI 72–82 %), PPV 92 % and accuracy 72 %. SPECT/CT had a sensitivity of 75 % (95 % CI 70–80 %), PPV of 94 %, and accuracy 71 %. There were 3 of 45 (7 %) patients with negative sestamibi imaging that had an accurate SPECT and SPECT/CT. Of 312 patients (87 %) with positive uptake on sestamibi (93 % true positive, 7 % false positive), concordant findings were present in 86 % SPECT and 84 % SPECT/CT. In cases where imaging modalities were discordant, but at least one method was true‐positive, 123I/99Tc‐sestamibi was significantly better than both SPECT and SPECT/CT (p < 0.001). The inclusion of SPECT and SPECT/CT in 1°HPT imaging protocol increases patient cost up to 2.4‐fold.Conclusion123I/99Tc‐sestamibi subtraction imaging is highly sensitive for preoperative localization in 1°HPT. SPECT and SPECT/CT are commonly concordant with 123I/99Tc‐sestamibi and rarely increase the sensitivity. Routine inclusion of multimodality imaging technique adds minimal clinical benefit but increases cost to patient in high‐volume setting.