Of standard of reference and accuracy: the problem of truth in imaging

Excerpt

In this issue of EJNMMI we report a comprehensive review [1] of the most important clinical application of ¹¹C-choline PET, restaging of patients with biochemical recurrence of prostate cancer, in the form of a systematic review and meta-analysis of the literature. A major problem in conducting this review was the identification of a reference standard. It could be considered paradoxical that there is no agreement on the definition of a reference standard, but the difficulty was very clear from the beginning, and is one of the best known problems in the pooling of data, even if not frequently discussed. Out of 43 original articles that were judged potentially relevant and for which the full text was acquired for more detailed evaluation, no reference standard was reported in 5 studies, making it impossible to consider these studies further. Even considering the 29 articles finally selected, we had to use a composite reference standard (different for locoregional recurrence and distant metastases) because there was no consistency among the different studies. …