Detection and evaluation of parathyroid adenomas using 4DCT

Primary hyperparathyroidism is a common endocrine disease. Affected patients present with one or more enlarged parathyroid glands and associated signs of hypercalcemia as well as increased or inappropriately normal plasma parathyroid hormone. Patients may develop osteodynia and pathologic fractures,
necessitating treatment. The only cure is the resection of the affected parathyroid gland(s). Minimal invasive surgery is only possible thanks to effective means of preoperative imaging. 4DCT for the detection of parathyroid adenomas was introduced in 2005 and considers the enhancement pattern of suspected lesions during different contrast phases. We examined the literature to examine the different technical parameters as defined by other researchers and institutions. We then set out to define parameters to allow further extension of the time dimension within acceptable dose limits, obtaining 16 different phases at a similar exposure dose as given for classic helical 4DCT, despite typically only
obtaining three or four phases. Our proposed 4DCT protocol can also be used to calculate perfusion values. We find a strong and significant increase in blood flow and blood volume in parathyroid adenomasas compared to normal thyroid tissue. These two perfusion parameters may be used as possible discriminating tool to discern between parathyroid adenomas and thyroid tissue.