Multi-centre data harmonisation applied to heart-to-mediastinum quantification in parkinsonism (ITA-MIBG): a cross-calibration phantom study with tube and bottle

Purpose: Planar cardiac scintigraphy with [123I]I-mIBG is widely used to image myocardial sympathetic activity. In multicentre studies, different γ-cameras can cause variability in quantitative parameters. This study aimed to harmonise multicentre [123I]I-mIBG data using a custom-designed phantom and to assess its feasibility and acceptability. Methods: A ‘tube and bottle’ phantom was designed to standardise the heart-to-mediastinum (H/M) ratio across 15 centres. Each centre prepared three versions of the phantom (A, B, and C) with varying pertechnetate ([99mTc]Tc-O4-) activities, acquired static images using their own γ-camera, and uploaded DICOM data to a shared platform. In the phantom, the tube and bottle represent the heart and mediastinum, respectively, with the tube-to-bottle (T/B) ratio simulating the H/M ratio. The reference centre analysed the images and calculated the T/B ratios, applying linear regression for data harmonisation. A survey was conducted to assess the phantom’s usability. Results: The harmonised T/B ratios for versions A and B were 20.46 ± 0.78 and 6.19 ± 0.39, respectively. The average slope and intercept of the regression line across the participating centres resulted in 1.07 ± 0.38 and − 0.82 ± 4.95. Survey feedback indicated high feasibility and acceptability, with all centres recommending the phantom for multicentre harmonisation. Conclusions: The custom-made phantom effectively harmonised experimental data across different centres, supporting its use in multicentre studies to improve data consistency.