The occurrence of ischaemic incidental findings on routine MRI brain scanning is well known and is reportedly as high as 87%.1-5
It is the responsibility of the requesting physician to review final reports of investigations performed while under their care, as well as act on the results obtained.6
In many cases brain MRI scans performed at the secondary care level will be assessed for the presence of overt pathology and referred back to general practice if clear of this.
However, although these scans may not have significant evidence of pathology, that is not to say they are 'normal'. Many are likely to contain varying levels of ischaemic changes presenting potential anxiety in patients and doctors, especially if these findings have not been discussed with the patient.
Ischaemic changes are becoming more prevalent, in part due to the advent of more sophisticated MRI scanning and an ageing population, so GPs are more likely to see them and be in a position to take action.
In an audit of 103 patients presenting with audiovestibular symptoms undergoing brain MRI scanning, two patients' scans revealed evidence of significant retrocochlear pathology (acoustic neuroma in both cases) and 33 had evidence of ischaemic brain changes (silent brain infarct or white matter changes).
Figure 1 shows the age of patients studied and its association with ischaemic changes, in keeping with evidence in the medical literature.2,7 With increasing age, the likelihood of incidental findings also rises.2,7,8
White matter changes, high signal areas, small vessel disease and old infarcts represent ischaemic changes within the brain.
Current clinical practice and evidence in the literature suggest that patients with old infarcts or moderate to severe white matter changes should undergo tight BP control to prevent progression and future complications, and BP in particular could be related to the degree of small vessel disease present.3
Future stroke risk
When MRI scans are interpreted by radiologists, white matter changes are normally graded as mild, moderate or severe. Severe white matter changes with silent brain infarcts are associated with higher risk of future stroke and these patients are potentially more amenable to treatment of cardiovascular risk factors, especially BP control, to reduce progression and subsequent risk of stroke.
Patients with ischaemic brain changes can be reassured that such findings on MRI scanning are common and hypertension could potentially increase their severity.
Good BP control and management of other cardiovascular risk factors associated with stroke are important as they may reduce this risk, although compelling evidence for this is lacking. Regardless, control of BP and cardiovascular risk benefits many organs, especially the heart, and treatment in the presence of disease is in the best interests of all, regardless of its specific effect on the brain, ischaemic changes and future risk of stroke.
- Mr Biggs is a clinical research fellow in otorhinolaryngology, University Hospital Southampton NHS Foundation Trust, Dr Pickering is a GP trainee and Mr Jog is an associate specialist in otorhinolaryngology, Royal Hampshire County Hospital, Winchester.
1. De Leeuw FE, de Groot JC, Achten E et al. Prevalence of cerebral white matter lesions in elderly people: a population based magnetic resonance imaging study. The Rotterdam Scan Study. J Neurol Neurosurg Psychiatr 2001; 70(1): 9-14.
2. Vermeer SE, Hollander M, van Dijk EJ. Silent brain infarcts and white matter lesions increase stroke risk in the general population - the Rotterdam Scan Study. Stroke 2003; 34(5): 1126-9.
3. Liao DP, Cooper L, Cai JW et al. Stroke 1996; 27(12): 2262-70.
4. Bernick C, Kuller L, Dulberg C et al. Silent MRI infarcts and the risk of future stroke - the cardiovascular health study. Neurology 2001; 57(7): 1222-9.
5. Kuller LH, Longstreth WT, Arnold AM et al. White matter hyperintensity on cranial magnetic resonance imaging - a predictor of stroke. Stroke 2004; 35(8): 1821-5.
6. GMC. Good medical practice. 2006.
7. Vernooij MW, Ikram MA, Tanghe HL et al. Incidental findings on brain MRI in the general population. N Engl J Med 2007; 357(18): 1821-8.
8. Papanikolaou V, Khan MH, Keogh IJ. Incidental findings on MRI scans of patients presenting with audiovestibular symptoms. BMC Ear, Nose and Throat Disorders 2010; 10: 6.