title: A Multimodal Imaging Protocol, (123)I/(99)Tc-Sestamibi, SPECT, and SPECT/CT, in Primary Hyperparathyroidism Adds Limited Benefit for Preoperative Localization.
abstract: BACKGROUND
  Focused 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.
  
  
  METHODS
  Patients 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 (123)I/(99)Tc-sestamibi subtraction scintigraphy, SPECT, and SPECT/CT were assessed.
  
  
  RESULTS
  Of 360 patients who were identified, a curative operation was performed in 96%, using pre-operative imaging and IOPTH. Imaging analysis showed that (123)I/(99)Tc-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, (123)I/(99)Tc-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.
  
  
  CONCLUSIONS
  (123)I/(99)Tc-sestamibi subtraction imaging is highly sensitive for preoperative localization in 1°HPT. SPECT and SPECT/CT are commonly concordant with (123)I/(99)Tc-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.
authors.affiliation: Department of Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA. glee727@gmail.com.
authors.forename: Grace S
authors.initials: GS
authors.lastname: Lee
authors.affiliation: Department of Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
authors.forename: Travis J
authors.initials: TJ
authors.lastname: McKenzie
authors.affiliation: Department of Nuclear Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Mullan
authors.affiliation: Department of Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Farley
authors.affiliation: Department of Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
authors.forename: Geoffrey B
authors.initials: GB
authors.lastname: Thompson
authors.affiliation: Department of Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA. richards.melanie@mayo.edu.
authors.forename: Melanie L
authors.initials: ML
authors.lastname: Richards
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000175:diagnosis* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D016105:Parathyroidectomy; D011300:Preoperative Care / Q000379:methods*; D019275:Radiopharmaceuticals / Q000494:pharmacology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D017256:Technetium Tc 99m Sestamibi / Q000494:pharmacology*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi