Utility of Single-Phase Computed Tomography in Identifying Parathyroid Adenomas: A Feasibility Study.

OBJECTIVE

We tested the hypothesis that a single-phase neck computed tomography (CT) is not inferior to multiphase neck CT (MPNCT), ultrasound, or nuclear medicine sestamibi scan in identifying parathyroid adenomas (PAs).

METHODS

A total of 29 patients who had an MPNCT for the evaluation of a PA were identified; 11 patients met the inclusion criteria. During the 30-second arterial phase CT (APNCT), a normalized Hounsfield unit of suspected PA was compared to Hounsfield unit of a normal-appearing level I and a level II lymph node. A PA was defined as a lesion with a ratio of greater than 1.4 when compared to the level I and level II lymph node. This cutoff was determined based on the normalized ratios between level II and level I lymph nodes. Results of intraoperative parathyroid hormone assays and surgical pathology were used to validate the accuracy of this technique.

RESULTS

The sensitivity of this method in APNCT is 90.9% whereas positive predictive value is 100%. The sensitivity or positive predictive value of ultrasound and nuclear medicine are 60% or 100% and 90% or 100%, respectively.

CONCLUSION

The sensitivity of APNCT is equivalent to that of MPNCT in identifying PA.