Reproducibility of differential renal function measurement using technetium-99m-ethylenedicysteine dynamic renal scintigraphy: a French prospective multicentre study.

OBJECTIVE: Dynamic renal scintigraphy remains the gold standard for assessing differential renal function (DRF). Recently, technetium-99m-ethylenedicysteine (Tc-EC) was shown to be valuable and had similar quality images as technetium-99m-mercaptoacetyltriglycine (Tc-MAG3). However, its reproducibility has never been confirmed. The aim of this study was to perform the first evaluation of Tc-EC reproducibility for assessing DRF in children who were referred for hydronephrosis or urinary tract dilatation.

PATIENTS AND METHODS: A total of 109 patients from three French nuclear medicine departments prospectively underwent dynamic renal scintigraphy with Tc-EC. DRF reproducibility was assessed by different pairs of raters using a multilevel design that integrated local and centralized predefined procedures.

RESULTS: Both local and centralized procedures yielded near-excellent inter-rater agreements, with all of the intraclass correlation coefficient values over 0.998. Bland-Altman plots showed a systematic bias of less than 1%, with the corresponding limits of agreements not exceeding the 5% threshold cut-off value that corresponds to the clinical definition of acceptable limits for this purpose. Intrarater agreements were also good to excellent.

CONCLUSION: This prospective multicentre study showed that Tc-EC is highly reproducible for assessing DRF in a standard paediatric population, thus validating its use as an alternative to Tc-MAG3 in this setting.