Incidental findings on brain magnetic resonance imaging: systematic review and meta-analysis

Abstract

Objective To quantify the prevalence of incidental findings on magnetic resonance imaging (MRI) of the brain.Design Systematic review and meta-analysis of observational studies.Data sources Ovid Medline (1950 to May 2008), Embase (1980 to May 2008), and bibliographies of relevant articles.Review methods Two reviewers sought and assessed studies of people without neurological symptoms who underwent MRI of the brain with or without intravenous contrast for research purposes or for occupational, clinical, or commercial screening.Main outcome measures Overall disease specific and age specific prevalence of incidental brain findings, calculated by meta-analysis of pooled proportions using DerSimonian-Laird weights in a random effects model.Results In 16 studies, 135 of 19 559 people had neoplastic incidental brain findings (prevalence 0.70%, 95% confidence interval 0.47% to 0.98%), and prevalence increased with age (χ2 for linear trend, P=0.003). In 15 studies, 375 of 15 559 people had non-neoplastic incidental brain findings (prevalence 2.0%, 1.1% to 3.1%, excluding white matter hyperintensities, silent infarcts, and microbleeds). The number of asymptomatic people needed to scan to detect any incidental brain finding was 37. The prevalence of incidental brain findings was higher in studies using high resolution MRI sequences than in those using standard resolution sequences (4.3% v 1.7%, P<0.001). The prevalence of neoplastic incidental brain findings increased with age.Conclusions Incidental findings on brain MRI are common, prevalence increases with age, and detection is more likely using high resolution MRI sequences than standard resolution sequences. These findings deserve to be mentioned when obtaining informed consent for brain MRI in research and clinical practice but are not sufficient to justify screening healthy asymptomatic people.

Discovery and informing research participants of incidental findings detected in brain magnetic resonance imaging studies: Review and multi‐institutional study

“…(2009), the discovery rates of severe IFs with a significant impact on health and requiring treatment were 0.7% for neoplastic findings and 2.0% for nonneoplastic findings. For all other studies, the discovery rates of IFs of an urgency level of 2 or above were below 2.0% (Illes, Rosen, et al., 2004; Kaiser et al., 2015; Katzman et al., 1999; Kim et al., 2002; Orme et al., 2010; Royal & Peterson, 2008; Seki et al., 2010; Shoemaker et al., 2011).…”

“…We reviewed one meta‐analysis and 14 reports (6 countries) (Boutet et al., 2016; Hartwigsen, Siebner, Deuschl, Jansen, & Ulmer, 2010; Hoggard, Darwent, Capener, Wilkinson, & Griffiths, 2009; Illes, Rosen, et al., 2004; Kaiser et al., 2015; Katzman et al., 1999; Kim et al., 2002; Kumra et al., 2006; Morris et al., 2009; Orme et al., 2010; Reneman et al., 2012; Royal & Peterson, 2008; Sandeman et al., 2013; Seki et al., 2010; Shoemaker et al., 2011). Details of the subject type and IF discovery rate (percentage of individuals in whom IFs were discovered to the total number of participants in whom images were taken) for each of the studies are summarized in Table 2.…”

“…(2006), only the results regarding the findings with potentially significant health impacts are included in the meta‐analysis of Morris et al. (2009). …”

“…The discovery rate of IFs as a whole varied widely, ranging between 8.8 and 77.9%, depending on the report, even after excluding one study that exclusively focused on highly urgent findings (Morris et al., 2009). The reason for this might be attributable to the institutional differences in either the definition of IFs, subject population, or reviewer or judgment process of images.…”

“…In a review, while referring to a systematic‐review of IFs in MRI by Morris et al. (2009), we focus on only the research setting and cover the follow‐up study data after IF finding.…”