The Novel Approach of Minimally Invasive Parathyroid Surgery Requires Precise Identification and Localization of the Lesion Prior to Exploration

A Novel Approach to Ultrafast Parathyroid SPECT Imaging Using a Solid State CZT SPECT Camera

Purpose of this study is to compare the image quality and diagnostic accuracy obtained with ultrafast solid state short SPECT in comparison with the routine SPECT protocol.

Single-tracer, dual-phase Tc-MIBI parathyroid scintigraphy is based on the differential washout rate of the tracer (MIBI) from the thyroid and the parathyroid tissue. A distinct focus of increased MIBI uptake relative to the thyroid gland, either on the early or late image or on both, or a focal uptake in the mediastinum, is considered positive for abnormal parathyroid tissue. Tc99m-MIBI planar scintigraphy was found to play a major role in the preoperative localization of a parathyroid adenoma (PTA), with a sensitivity ranging from 85% to 95% and specificity of up to 99%. Subsequently, the use of MIBI- Single photon emission computed tomography (SPECT) significantly improved the sensitivity of the test and improved the accuracy of lesion localization.

A limitation of adding the SPECT component is related to its relatively long duration. The duration of a MIBI-SPECT acquisition of neck and the mediastinal area may take up to 15-20 minutes using a standard nuclear medicine camera. Long acquisition time may lead to patient discomfort and movement resulting in image degradation, artifacts and may lead to overall decreased diagnostic accuracy.

A reduced SPECT acquisition time without image quality degradation may decrease patient discomfort and increase clinical throughput. An ultrafast solid state CZT camera (GE Healthcare Discovery 570C) is currently used for routine cardiac SPECT imaging achieving high quality cardiac studies for a significantly shorter acquisition time. Present study evaluates the potential use of the ultrafast camera in patients with a clinically suspected PTA who perform Tc-MIBI imaging.

Inclusion Criteria:

1) The subject is 18 years old or older. (2) The subject is clinically suspected or known to have parathyroid adenoma and is scheduled to have a MIBI study as part of his/her standard clinical evaluation.

(3) The subject is able and willing to comply with the additional procedure (ultrafast MIBI SPECT) and a signed and dated informed consent is obtained before any procedure for study purposes is performed.

Exclusion Criteria:

1. Pregnancy.
2. Psychosis or any other condition, which, in the investigators opinion would prevent adherence to the study protocol.