It should be no surprise
that a visit to a doctor can reveal something is wrong. After all, most who
define themselves as unwell expect a medical explanation based on the best
available diagnostic technology. Unfortunately, the increasing use of imaging
technologies is leading clinicians to identify abnormalities that have nothing
to do with the presenting problem, and no one knows quite what to do with them,
particularly when it comes to insurance.
Incidental findings from
brain magnetic resonance imaging (MRI) that need further evaluation occur in
about 3% of middle-aged and elderly populations - that’s one for every 37
scans.1 The majority are without clinical consequences, but
0.7% of scans show tumours, mostly benign menigiomas that can be managed with
routine annual imaging.2 It takes 2,000 scans to find one
clinically silent low-grade glioma.3
But early treatment of
these cancers improves outcomes. A tumour may be present but silent for a
decade or more and do well if removed early. This success has led to calls for
a screening program that would identify all the other incidental findings, each
with its own problems.4
Cerebrovascular
abnormalities are by far the largest category but present greater management
challenges. Identifying one aneurysm requires 286 scans. Aneurysms have a 1.3%
risk of rupture per year but treatment with coiling carries a 4.7% risk of
death or disability.5 Similar risk/benefit questions arise in
arteriovenous malformations and cerebral cavernous malformations.6
Silent strokes, or
excessive white matter changes, should prompt cardiovascular risk review and
alert the underwriter to the impact of these problems. Whether the
identification and management of these otherwise asymptomatic lesions makes any
difference to outcomes is not clear.7
The detection of
unexpected serious problems on MRI screening is fortuitous and usually good
news because providing the appropriate treatment early improves the prognosis.
For many there will be difficult decisions to make. It is imperative that
anyone undergoing MRI investigations is aware of this possibility before the
scan is performed. This is especially the case in research settings and the
growing market for direct to consumer investigations. The ways in which
findings are shared is also important, to ensure that joint decision making
about management can take place, often in the face of significant uncertainty
and anxiety.8
For the insurer, the
situation is usually more straightforward. It is important to wait until all
relevant investigations and the treatment plan is complete. The vast majority
of non-specific findings (e.g. minor white matter changes) are of little
consequence, whilst the insurance risk of those specifically diagnosed can be
assessed case by case each on its own merits.
Endnotes
1. Morris Z, Whiteley
WN, Longstreth WT, et al. Incidental findings on brain magnetic resonance
imaging: systematic review and meta-analysis. BMJ. 2009;339:b3016.
2. Rogers, L et al.
(2015) Meningiomas: knowledge base, treatment outcomes and uncertainties.
Journal of Neurosurgery. 122. 4-23.
3. Morris Z, Whiteley
WN, Longstreth WT, et al. Incidental findings on brain magnetic resonance
imaging: systematic review and meta-analysis. BMJ. 2009;339:b3016.
4. Holton, T et al.
(2015) Advances in the Surgical Management of Low-grade Glioma. Seminars in
Radiation Oncology. 25. 181-188.
5. Al-Shahi alman, R et al.
(2014) Outcome after conservative management or iontervention for unruptured
brain arteriovenous malformations. JAMA. 311. 1661-9.
6. Moultrie, F et al.
(2014) Outcome after surgical or conservative management of cerebral cavernous
malformations. Neurology. 83. 582-9.
7. Langner, S et al.
(2016) Management of Intracranial Incidental Findings on Brain MRI. Fortschr.
Röntgenstr. doi.org/10.1055/s-0042-111075
8. Presidential
Commission for the study of bioethical issues (2013) Anticipate and
communicate. Ethical management of incidental and secondary findings in the
clinical, research and direct to consumer contexts. Washington, D.C.
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