Information from March 2023
As direct access to brain imaging opens to General Practice and with the development of Community Diagnostic Centres, you as the referrer, will be receiving a number of incidental findings. This document covers different incidental findings on brain imaging including both malignant and non-malignant with clear actions for General Practice. If you need any further clarification please consider using Advice and Guidance (A&G) query to Neurology via the usual routes. Do remember that incidental findings are common on brain imaging and may result in substantial resources expenditure and patient anxiety but are often of little clinical significance.
What are the different types of brain cancers that can be found on brain MRI/CT?
Plain CT (acquired without giving the patient injected contrast) will show up the majority of high grade (rapidly growing) brain tumours, either primary or metastases (secondary deposits). Plain CT will also show the majority of meningiomas; these are tumours of the lining of the brain. The vast majority of these are small and very slow growing and don’t cause any symptoms so really require little further input; some are larger and grow slightly faster or may be positioned where they can put pressure on important structures like the nerve to the eye, so may need treatment, either removal or radiotherapy.
Plain CT doesn’t show the posterior fossa (the co-ordinating part of the brain, the cerebellum, and brainstem) well so if that is where the suspected problem lies, it may not show up. Plain CT is also not always sensitive enough to show small metastases, so if the patient has active cancer we would recommend CT with injected contrast as a minimum.
Plain MRI (acquired without giving the patient injected contrast) will show the majority of brain tumours, including those seen on CT and is better for visualising the posterior fossa. It will also show some low grade (slow growing) brain tumours, tumours in the pituitary (central hormone) gland or the optic neuromas or vestibular schwannomas (benign tumours on the nerves going to the eye or ears). However these sorts of tumours can be very small and difficult to see, so the ‘screening’ MRI that is done as part of the direct access pathway may not show these, which is why we have separate referral pathways for suspected pituitary lesions, vestibular schwannomas which involve specialised scans.
What do I do if a suspected small meningioma is found on brain imaging?
A small, asymptomatic meningioma should be re-scanned at 12 months and then, if there is no change, re-scanned at five years. There are no hard and fast rules for what constitutes a small, asymptomatic meningioma but, in general they are 1 to 2 cm in diameter, calcified (which can be seen on CT), smooth and not associated with any brain oedema. If in doubt, it would be best to refer the patient to the neurosurgeons for a routine appointment including detail of where and when the scan was done so the scans can be imported to the UHB system.
The patient would not necessarily need to be seen in neurosurgery clinic, and the surgeons may simply advise a repeat scan at 12 months and five years as above.
GP action: use generic neuro-oncology email for new diagnosis of brain cancer for onward referral.
What do I do if a suspected brain abnormality/lesion either malignant or non-malignant is found on brain imaging?
About 10% of all brain MRI scans will show some ‘abnormality’; these are more frequently variants than true abnormalities in that they are unlikely to be causing any symptoms. We have tried to give guidance on some of the commonplace variants in the subsequent questions.
What do I do if a suspected vestibular abnormality both malignant or non-malignant is found on brain imaging?
If a suspected vestibular schwannoma or other posterior fossa lesion is found, the patient should be referred to local ENT services.
GP action: ENT Advice and Refer (A+R).
What do I do if a suspected pituitary abnormality both suspected malignant or non- malignant is found on brain imaging?
If a suspected pituitary lesion is found, you need to ask the patient about vision. If they report any visual disturbance then they need to be discussed with ophthalmology. Rarely there is compression of the optic chiasm which needs urgent referral to neurosurgery/neuro-ophthalmology at QEHB; the patient would need to have visual field testing before being referred.
If there is no visual impairment then the patient can be referred to local ENT services; they may advise pituitary blood tests (prolactin, IGF1, etc.) pending assessment.
GP action: if vision affected discuss with on call ophthalmology.
If Vision not affected, refer to ENT A+R.
What do I do if a brain aneurysm is found?
If an aneurysm is found, the patient should be referred to the neurovascular team at UHB. At this time the service is led by Mr Ed White, neurosurgeon.
GP action: refer to neurovascular team (Via Advice and Guidance to Neurosurgery).
What to do if brain infarct/s is/are found?
Strokes often don’t cause any pain, so patients can sometime have small strokes without anyone (including themselves) knowing. If you find one of these ‘incidental’ strokes, we would advise discussing the patient with the stroke team via the Advice and Guidance system. In the absence of any advice to the contrary we would advise that the patient has usual secondary prevention: antiplatelet, hypertension, cholesterol and diabetes management.
GP action: stroke team A&R. Review risk factors.
What do I do if a sinus abnormality is found?
Sinus congestion is very common on brain imaging. Unless the patients have symptoms of sinus disease, this can be ignored.
GP action: review if any sinus symptoms present. If none: no action. If present, provide first line treatment.
What do I do if a chiari malformation is found?
Chiari malformations are usually asymptomatic. Occasionally they can be associated with a tethered cord and/or syringomyelia. In the case of the former, we usually expect patients to develop continence issues as the cord is stretched during the adolescent growth spurt; with the latter you would usually be able to see it on the brain scan. However we would usually get a whole spine MRI anyway to make sure nothing is being missed.
Chiari malformations can be associated with ‘pressure dissociation headache’; this is headache that occurs immediately after Valsalva (coughing, laughing, sneezing, bending over, straining to go to the toilet etc.). Headache that is simultaneous with Valsalva is more like to be ‘mechanosensitivity’ which is neck pain associated with migraine.
Unless there is a large or expanding syrinx or the majority of the headache burden is pressure dissociation, surgery is likely to be counterproductive. You can refer the patient to a neurosurgeon, but the patient should be made aware that surgery is usually not recommended.
GP action: please use this email address until Neurosurgery A&R is up and running.
What do I do if a Pineal abnormality is found?
Pineal cysts are usually benign and asymptomatic. There are rare tumours of the pineal gland, pyneocytomas. I would routinely get a contrast enhanced scan and ask the neurosurgeons to assess the scan, counselling the patient that it is unlikely they will need surgery or extensive follow up. The surgeon may not need to see the patient, just advise on suitable follow up imaging. Where there is a solid component to the lesion or abnormal enhancement it is likely the patient will need to see the neurosurgeons, although surgery may still not be required.
GP action: please use this email address until Neurosurgery A&R is up and running.
What do I do about arachnoid cysts?
The majority of arachnoid cysts are congenital and need no further intervention. Rarely arachnoid cysts can expand and become symptomatic and so we would recommend a scan after an interval. Very rarely they can be the cause of epilepsy; however the vast majority of people with arachnoid cysts do not have epilepsy and so we would not recommend referral to neurology or long term follow up of these patients in case the develop epilepsy later.
GP action: please use this email address until Neurosurgery A&R is up and running.
What do I do about non-specific white matter lesions/microvascular disease?
In the majority of cases these are a feature of aging, like grey hairs or wrinkles in the skin. There is an association between high volumes of white matter lesions and cerebrovascular disease in the form of ischaemic strokes and intracerebral haemorrhages; however the association is weak and not known to be causative. In other words the white matter disease itself may not cause strokes but there may be common risk factors for both, hypertension, smoking, poorly controlled diabetes.
Very rarely inherited disorders of the blood vessels such as CADASIL or COL4A mutations can be associated with very high levels of white matter disease in young people. If in doubt you can seek advice through the A+G service, but it is very important that detail is included of where the scan was done and when. The scan will need to be imported to the QE system, which in turn may require the patient to be registered with UHB, so the turnaround time for these sort of enquiries may be slower than expected.
It is very rare that someone with white matter disease of this kind to require neurology assessment.
GP action: to review risk factors / neurology A+R.
Last reviewed: 03 October 2024
