Pre-operative localization of abnormal parathyroid tissue by 99m Tc-sestamibi in primary hyperparathyroidism using four-quadrant site analysis: an evaluation of the predictive value of vitamin D deficiency.

Context: Accurate preoperative localization of abnormal parathyroid tissue aids importantly in minimally invasive parathyroidectomy in patients with primary hyperparathyroidism. Vitamin D deficiency may possibly influence the success and characteristics of pre-operative localization because it is associated with more active disease and possibly larger adenomas. This could increase the sensitivity of the sestamibi to identify abnormal parathyroid tissue, but earlier reports are conflicting. Vitamin D deficiency could also influence the nature of preoperative localization because it could lead to multi-gland stimulation of parathyroid tissue giving an appearance of multi-gland disease, which may lower accuracy of preoperative localization with sestamibi.
Objective: To examine the relationship between vitamin D deficiency and correct parathyroid tissue localization by four-pole thyroid quadrant analysis.
Design: Retrospective study.
Setting: Referral center.
Participants: A total of 138 patients were divided into three groups according to the level of 25OHD; <20 ng/mL (vitamin D deficient), ≥20 to <30 ng/mL (vitamin D insufficient) and ≥30 ng/mL (vitamin D replete).
Main Outcomes: Quadrant localization using ^99m Tc-sestamibi/SPECT.
Results: Among those with single-gland disease, the proportion of patients with correct quadrant localization were 60.0, 68.3 and 63.5% (p = 0.778), and the accuracy of sestamibi was 89.3, 90.6 and 89.9% for the deficient, insufficiency and replete groups, respectively. Among those with multi-gland disease, the proportion of patients with correct quadrant localization were 50.0, 25.0 and 18.2% (p = 0.619) while the accuracy was 50.0, 50.0 and 45.5%, respectively. Multi-gland disease did not occur more frequently in any of the three groups (p = 0.296).
Conclusions: Vitamin D levels do not affect the accuracy of preoperative localization with sestamibi.