European multicenter study on recurrent imaging practice in computed tomography

This study compares recurrent CT imaging practices across European centers using incidence and prevalence metrics and evaluates the feasibility of a novel benchmarking tool for recurrent imaging practice.

CT exposure data were collected from 31 facilities across 18 European countries. The single-year incidence proportion (I100;1), 3-year cumulative incidence (I100;3), and 3-year prevalence proportion (P100;3) of patients with cumulative effective dose (CED) ≥ 100 mSv were calculated and statistically analyzed against relevant indicators. The reference year was 2023, and the 3-year period covered 2022-2024.

The database comprised 711 749 patients in 2023 who underwent 1 658 246 CT exams, with an average of 1.5 ± 0.6 CT exams per patient in this year and 2.4 ± 0.6 exams over 3 years. Across facilities, I100;1 ranged from 0% to 2.9%, I100;3 from 0% to 8.6%, and P100;3 ranged from 0% to 4.4%. A strong linear correlation was found between the third quartile values of yearly CED and I100;1. Multiple linear relationship was identified between I100;3, third quartile of yearly CED and percentage of recurrent patients. Third quartiles of yearly CED varied between 7.5 and 29.5 mSv, with the 75th percentile of their distribution 17.6 mSv, lower than in previous studies.

Incidence proportion is preferred for assessing recurrent imaging rates as prevalence substantially underestimates these rates. The 75th percentile of distribution of third quartiles of yearly CED is a reasonable benchmark level to trigger optimization. Investigating the underlying factors and addressing high recurrent rates can contribute to enhanced patient care.

This first European multicenter study showed that the epidemiological index incidence proportion is a better metric to quantify recurrent imaging compared to prevalence. The distribution of early CED values can be used to benchmark recurrent imaging practices and inform patient management strategies.