The analysis of intraobserver and interobserver variability in the evaluation of Tc-99m MIBI parathyroid scintigraphy

Aim and hypothesis: Demonstration of the presence of intraobserver and interobserver agreement in the evaluation of Tc-99m MIBI parathyroid scintigraphies.Methods: We find out the patients with Tc-99m MIBI parathyroid scintigraphies from the digital archive who were imaged during the last 18 months. The cases without standart imaging protocols and without optimal images were excluded. Finally, 98 cases were included in the study and were evaluated by four different observers who are experienced at least for eight years as a nuclear medicine specialist. The cases were evaluated twice at least two weeks apart. The evaluations were performed directly on the workstations with digital images. A questionnaire was filled for every evaluation by the observers. The presence of a lesion, the number and the localizations of the lesions, whether the lesion is clear or suspicious, if present the cause of the suspicion, the need for an additional examination for the evaluation and the final interpretation were all evaluated. Cohen kappa statistics and the total agreement percentages were calculated using SPSS 11.0.Results: The four different observers performed eight different evaluations and identified a minimum of 38 and a maximum of 43 cases with lesion(s). The intraobserver agreement was ?very high?. The interobserver agreement was also ?very high? at least in one comparison between the observers. The intraobserver agreement was also ?very high? and the interobserver agreement was ?high? and ?very high? in the evaluation of number of the lesions and the final interpretation.When we evaluated the lesion localization the intraobserver agreement was ?very high? for the second and third observers in lesion localization and again ?very high? for the third observer in evaluation of lesions as clear or suspicious. The intraobserver agreement for other observers and the interobserver agreements were ?high? for in lesion localisation and the presence of suspicion.The intraobserver and interobserver agreements were ?moderate?, ?weak? or ?very weak? in evaluation of the cause of suspicion and the need for an additional examination.Results: Tc-99m MIBI parathyroid scintigraphy is an optimal study in lesion detection, in the determination of the number of lesions and localizations and in the final interpretation with ?high? and ?very high? intraobserver and interobserver agreements.Keywords;Tc-99m MIBI, parathyroid scintigraphy, interobserver agreement, intraobserver agreement