The sensitivity and PPV of a sestamibi/I-123 subtraction technique are least negatively impacted by concomitant thyroid disease when SPECT/CT is included in the protocol [75]. Sestamibi Scan and Pertechnetate Thyroid Scan Subtraction scintigraphy of parathyroid glands using a combination of sestamibi and Tc-99m pertechnetate is a commonly utilized alternative or adjunct to the dual-phase sestamibi technique. Unlike the dual-tracer method with I-123, the pertechnetate method requires 2 separate acquisitions, which prolongs the overall examination time. Although techniques based solely on planar imaging have largely been supplanted by methods with SPECT or SPECT/CT, there are some noteworthy applications of a planar sestamibi and pertechnetate subtraction in recent literature with reported sensitivities ranging from 69% to 79% [59,80]. A meta-analysis including 5 studies utilizing a dual-tracer technique reported sensitivities ranging from 47% to 87%; however, it is unclear which studies relied purely on a subtracted dual-tracer (sestamibi and pertechnetate) planar method and which were performed in combination with a dual-phase sestamibi scan [17]. In a study of 116 patients with PHPT, the addition of pertechnetate subtraction to a dual-phase sestamibi scan increased reader confidence in adenoma localization and changed the final interpretation in 15% of patients from the dual-phase study [81]. MGD decreases the sensitivity of the subtraction sestamibi and pertechnetate scan from 71% to 64% [82]. There is no clear consensus regarding the superiority between dual-tracer subtraction and sestamibi dual-phase planar imaging. One recent study of 63 patients showed greater sensitivity with dual-phase sestamibi (79%) over both dual-tracer (sestamibi and pertechnetate) (69%) and a combined dual-tracer/dual-phase technique (65%) [59].
Parathyroid Adenoma. The sensitivity and PPV of a sestamibi/I-123 subtraction technique are least negatively impacted by concomitant thyroid disease when SPECT/CT is included in the protocol [75]. Sestamibi Scan and Pertechnetate Thyroid Scan Subtraction scintigraphy of parathyroid glands using a combination of sestamibi and Tc-99m pertechnetate is a commonly utilized alternative or adjunct to the dual-phase sestamibi technique. Unlike the dual-tracer method with I-123, the pertechnetate method requires 2 separate acquisitions, which prolongs the overall examination time. Although techniques based solely on planar imaging have largely been supplanted by methods with SPECT or SPECT/CT, there are some noteworthy applications of a planar sestamibi and pertechnetate subtraction in recent literature with reported sensitivities ranging from 69% to 79% [59,80]. A meta-analysis including 5 studies utilizing a dual-tracer technique reported sensitivities ranging from 47% to 87%; however, it is unclear which studies relied purely on a subtracted dual-tracer (sestamibi and pertechnetate) planar method and which were performed in combination with a dual-phase sestamibi scan [17]. In a study of 116 patients with PHPT, the addition of pertechnetate subtraction to a dual-phase sestamibi scan increased reader confidence in adenoma localization and changed the final interpretation in 15% of patients from the dual-phase study [81]. MGD decreases the sensitivity of the subtraction sestamibi and pertechnetate scan from 71% to 64% [82]. There is no clear consensus regarding the superiority between dual-tracer subtraction and sestamibi dual-phase planar imaging. One recent study of 63 patients showed greater sensitivity with dual-phase sestamibi (79%) over both dual-tracer (sestamibi and pertechnetate) (69%) and a combined dual-tracer/dual-phase technique (65%) [59].