Follow-up care of incidental brain findings draws criticism

The number of brain MR scans obtained in the clinical and research setting increases each year, as scanner equipment and scanning protocols become ever more sensitive to subtle abnormalities. Many of these incidental findings are low risk and do not need rigorous imaging follow-up. Researchers therefore suggest revising management guidelines with an eye toward less radiological intervention.

That conclusion was reached by investigators at Erasmus MC University Medical Center in Rotterdam, the Netherlands, after reviewing the brain scans of 2000 asymptomatic research subjects. They found that 1.6% of subjects had benign primary tumors, mainly meningiomas, classified by typical radiological characteristics such as location, shape, and signal intensity (NEJM 2007; 357[18]:1821-1828). Despite a documented slow growth rate for such asymptomatic tumors, current practice dictates close clinical and radiological follow-up.

"Such follow-up for all persons incidentally found to have meningiomas would be performed in otherwise healthy asymptomatic persons, at a considerable financial and psychological cost," senior author Dr. Aad van der Lugt told Diagnostic Imaging.

The group also found a 1.8% incidence of cerebral aneurysms, all but two located in the anterior circulation, and most smaller than 7 mm. The reported risk for such findings is zero over four years. Van de Lugt and colleagues suggested that preventive surgery or treatment is not indicated and noted that the benefit of longer follow-up is not yet proven.

The prevalence of meningiomas and small aneurysms in this study was much higher than previously reported. Van der Lugt credits the scanning protocol, especially the high-resolution proton density-weighted sequence, which permitted excellent visualization of the circle of Willis compared with conventional T1- and T2-weighted sequences.