All patients undergoing imaging in the setting of PHPT should have biochemically proven disease, as imaging has no role in confirming or excluding the diagnosis [2]. As such, assessing the imaging test specificity and negative predictive value is not clinically relevant. Rather, the role of initial imaging in PHPT is to aid in selecting appropriate patients for MIP by accurately identifying and localizing a single parathyroid adenoma; accordingly, these criteria focus on imaging test sensitivity and PPV. Patients with negative or inconclusive imaging results typically remain surgical candidates but will likely require BNE; inconclusive findings on imaging should not preclude surgical referral [2]. Parathyroid Adenoma Multiple imaging modalities may be utilized in combination during the initial imaging evaluation of PHPT in an attempt to maximize the accuracy and confidence of parathyroid localization via concordant imaging results [2,8,15]. This is supported by multiple studies in the literature showing improved sensitivity and PPV in parathyroid lesion localization with a combination of examinations over each examination in isolation [16-23,25]. CT Neck Neck CT for preoperative localization of PHPT is most commonly performed without and with IV contrast (4-D parathyroid CT) [34]. As such, most published data relate to the performance of CT neck without and with IV contrast; however, there are also some data on the performance of CT neck with IV contrast. There is no relevant literature regarding the use of CT neck without IV contrast in the evaluation of PHPT. As the initial imaging study, retrospective studies report the overall sensitivity of CT neck without and with IV contrast to range between 62% and 88% [35,36] and the overall PPV to range between 84% and 90% [32,37]. The largest retrospective study (400 patients) reports an overall sensitivity of 79% and PPV of 90% [32].
Parathyroid Adenoma. All patients undergoing imaging in the setting of PHPT should have biochemically proven disease, as imaging has no role in confirming or excluding the diagnosis [2]. As such, assessing the imaging test specificity and negative predictive value is not clinically relevant. Rather, the role of initial imaging in PHPT is to aid in selecting appropriate patients for MIP by accurately identifying and localizing a single parathyroid adenoma; accordingly, these criteria focus on imaging test sensitivity and PPV. Patients with negative or inconclusive imaging results typically remain surgical candidates but will likely require BNE; inconclusive findings on imaging should not preclude surgical referral [2]. Parathyroid Adenoma Multiple imaging modalities may be utilized in combination during the initial imaging evaluation of PHPT in an attempt to maximize the accuracy and confidence of parathyroid localization via concordant imaging results [2,8,15]. This is supported by multiple studies in the literature showing improved sensitivity and PPV in parathyroid lesion localization with a combination of examinations over each examination in isolation [16-23,25]. CT Neck Neck CT for preoperative localization of PHPT is most commonly performed without and with IV contrast (4-D parathyroid CT) [34]. As such, most published data relate to the performance of CT neck without and with IV contrast; however, there are also some data on the performance of CT neck with IV contrast. There is no relevant literature regarding the use of CT neck without IV contrast in the evaluation of PHPT. As the initial imaging study, retrospective studies report the overall sensitivity of CT neck without and with IV contrast to range between 62% and 88% [35,36] and the overall PPV to range between 84% and 90% [32,37]. The largest retrospective study (400 patients) reports an overall sensitivity of 79% and PPV of 90% [32].