Whole-body magnetic resonance imaging (WB-MRI) with diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) in prostate cancer: Prevalence and clinical significance of incidental findings

Abstract Background Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) is now recommended as a first-line staging modality in prostate cancer patients, and the widespread use of DWIBS may lead to an increased frequency of incidental findings. The aim of this study is to evaluate the prevalence and clinical significance of incidental findings detected on whole-body magnetic resonance imaging (WB-MRI) with DWIBS in patients with prostate cancer. Methods Data from 124 patients (age, 76.5 ± 5.6 years; range, 60–90) with pathologically confirmed prostate cancer, who underwent WB-MRI between December 2016 and April 2020, were retrospectively analyzed. Findings unrelated to prostate cancer were considered as incidental findings and categorized into two groups based on their clinical implications, as follow: imaging follow-up or additional examinations was required (significant incidental findings) and no need to additional work-up (non-significant incidental findings). A Chi-square test was performed to compare the differences in the prevalence of significant incidental findings based on age (≤ 75 and > 75 years old). Results A total of 334 incidental findings were found, with 8.1% (n = 27) as significant incidental findings and 91.9% (n = 307) as non-significant incidental findings. Significant incidental findings were more frequent in patients over 75 years old than those of 75 years old or younger (28.6% vs 11.1%, p = 0.018). Nineteen of the 27 significant incidental findings (70.4%) were observed on non-DWIBS sequences. Conclusion Clinically significant incidental findings, which required imaging follow-up or additional examinations, were commonly observed in patients with prostate cancer on WB-MRI/DWIBS.