Interobserver and intraobserver agreement in parathyroid scintigraphy: How can parathyroid scintigraphy be made more...

To determine the intraobserver and interobserver agreement levels in the evaluation of technetium Tc 99m sestamibi parathyroid scintigraphic images.

Ninety-eight patients with hyperparathyroidism were included in the study, and their parathyroid images were evaluated by 4 experienced nuclear medicine observers. The 98 cases were evaluated twice by each observer within an interval of 2 weeks. The evaluations were performed directly on workstations with use of digital images. A questionnaire was completed by each observer. The presence of a lesion, the number and the localizations of the lesions, and whether the lesion was clear or doubtful were all evaluated. Cohen kappa statistics and total agreement percentages were calculated by using SPSS version 11.0 software.

The 4 observers performed 8 different evaluations and identified a minimum of 38 and a maximum of 43 cases with a parathyroid lesion (or lesions). Both the intraobserver and the interobserver agreements were "very good" for the presence of a parathyroid lesion. The intra-observer agreement was also "very good" and the interobserver agreement was "good" (for only 1 pair of observers) or "very good" for the evaluation of the number of parathyroid lesions. The intraobserver agreement was "very good" or "good" and the interobserver agreement was "good" for the lesion localization and for the presence of a doubtful lesion.

Parathyroid scintigraphy seems to be an observer independent method in the detection of a parathyroid lesion, in the determination of the number of lesions, and in the localizations of the lesions. The measured high agreement between observers increases the reliability of parathyroid scintigraphy.