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Incidental findings on brain magnetic resonance imaging: systematic review and meta-analysis
Zoe Morris1, William N Whiteley, W T Longstreth
1Division of Clinical Neurosciences, Western General Hospital, Edinburgh.
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 (chi(2) 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.
Insights
Incidental findings on brain MRI are common, especially in older individuals. High-resolution MRI increases detection rates, but findings do not justify screening asymptomatic people.
Area of Science:
- Neuroradiology
- Medical Imaging
- Public Health
Background:
- Incidental findings on brain MRI are frequently encountered in clinical and research settings.
- Understanding the prevalence and characteristics of these findings is crucial for patient management and informed consent.
- Previous studies have varied in their methodologies and populations, necessitating a comprehensive synthesis of data.
Purpose of the Study:
- To systematically review and meta-analyze the prevalence of incidental findings on brain MRI.
- To investigate the influence of age and MRI resolution on the detection of incidental brain abnormalities.
- To determine the clinical implications of these findings for asymptomatic individuals.
Main Methods:
- A systematic review and meta-analysis of observational studies were conducted.
- Data were sourced from Ovid Medline, Embase, and bibliographies of relevant articles, including studies of asymptomatic individuals undergoing brain MRI.
- Pooled proportions using a random effects model were calculated to determine age-specific and disease-specific prevalence.
Main Results:
- Neoplastic incidental brain findings were present in 0.70% of 19,559 individuals, with prevalence increasing with age.
- Non-neoplastic incidental findings (excluding specific conditions) were found in 2.0% of 15,559 individuals.
- High-resolution MRI sequences detected incidental findings more frequently (4.3%) than standard sequences (1.7%).
Conclusions:
- Incidental findings on brain MRI are prevalent and increase with age.
- High-resolution MRI enhances the detection of these findings.
- While important for informed consent, these findings do not support routine screening of asymptomatic individuals.
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