ARRS 2022 Abstracts

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1803. 4D-SPECT-CT: A Hybrid Approach to Hyperparathyroidism
Authors * Denotes Presenting Author
  1. Ashima Agarwal *; University of Pittsburgh Medical Center
  2. Katie Traylor; University of Pittsburgh Medical Center
  3. Barton Branstetter; University of Pittsburgh Medical Center
  4. Allison Weyer; University of Pittsburgh Medical Center
  5. Kelly McCoy; VA Pittsburgh Healthcare System
  6. Ashok Muthukrishnan; University of Pittsburgh Medical Center
Objective:
Pre-operative localization of functioning parathyroid adenomas has classically relied upon ultrasound, technetium-99m sestamibi single photon emission computed tomography (SPECT), or multiphase high-resolution (4D) CT. The choice of modality usually reflects individual practitioner preferences and local availability, with no clear consensus on the optimal localization procedure for parathyroid disease. We describe a technique for optimizing and individualizing the imaging of these patients using SPECT-CT and 4D CT in tandem as a 4D-SPECT-CT, as well as an optimized approach to patient selection and imaging workflow.

Materials and Methods:
Ultrasound remains the initial modality of choice for patients with primary hyperparathyroidism, but it can overlook multiglandular and ectopic disease, so additional modalities are usually needed. Uncomplicated patients can be further imaged with either SPECT-CT or 4D CT, depending on the preferences of the institution or the referring surgeon. There are several criteria that prompt the use of a combined single-session two-phase 4D-SPECT-CT, including obesity, recurrent disease, suspected multiglandular disease, multinodular thyroid (as seen on ultrasound), and an unrevealing or confusing imaging examination performed at another institution.

Results:
The use of 4D SPECT-CT capitalizes on the strengths of each modality and addresses the limitations that exist when these modalities are used in isolation. By using appropriate patient selection, pre-operative imaging in these patients can be both cost-effective and accurate, and limit extraneous radiation exposure. These examinations require that the SPECT-CT gamma camera be capable of proper 4D-CT imaging simultaneous with the SPECT study. Optimal interpretation requires collaboration between nuclear medicine physicians and head and neck imagers on each case. Quality improvement sessions with surgical correlation are essential to improving the experience level of the radiologists.

Conclusion:
Patients with primary hyperparathyroidism require a personalized approach to pre-operative imaging to ensure optimal surgical strategies. The judicious use of 4D-SPECT-CT should be part of a cost-effective, efficacious imaging paradigm for these patients.