Your brain in pictures

 Q & A with a Neuroradiologist

Dr. Thahn Nguyen, neuroradiologist at Ottawa Hospital


Everyone with a brain tumour knows about MRI (Magnetic Resonance Imaging). This technology in the field of radiology has transformed the way we see our brains. It is essential in diagnosing someone with a brain tumour. And radiologists, like Dr. Thahn Nguyen, a two-time Brain Tumour Foundation of Canada grant recipient, are discovering new ways to better diagnose diseases using only pictures of our brain.





What interested you about radiology?

I could help patients by providing a diagnosis based on detailed images of their body. I also like that radiology is a multi-disciplinary field where one needs to know computer science, physics and medicine.


Does brain imaging differ from other areas of the body?

Yes. The function and anatomy of the brain are more complex than for any other organs. Of course, I am biased because I am a neuroradiologist. I think there are are so many things we do not know about the brain, but we will probably discover in the next few years using brain imaging. 


What sorts of things can you see from an MR image of the brain (with or without contrast)?

First, we can have a detailed anatomy of brain. It is like having a Google map of the city. We can see the buildings. When we give contrast, we see areas where there is the brain-blood barrier is absent or disrupted such as in tumours of infection. This is key to help the neurosurgeon to decide if the tumour can be resected and what deficit(s) a patient might have following the surgery.

Recently, MRI can also provide a little bit more information about the function of the brain such as the white matter tract integrity or blood supply to each region of the brain. For example, we can determine before an operation if a tumour is more likely to be benign or malignant based on the amount of blood supply. In gliomas, the presence of high blood supply to the tumour implies a more malignant tumour.


What can’t you see or determine through an image of the brain?

In general, images of the brain allow us to know the anatomy of the brain in a patient but it is more difficult to learn about the functions. We can tell where the tumour is in the brain but it is more difficult to determine how the tumour alters the function of the adjacent neurons. If a tumour is located near the expected area for speech on an image, we can perform MRI to determine if that area of speech is still functional, but this is not 100% reliable.


Are brain tumours easily detectable with imaging?

Size matters. Large brain tumours are easily detectable but small tumours might be difficult to differentiate from other pathological processes such as stroke and infection.


What are the challenges when diagnosing a tumour this way?

We are trying to predict the tumour subtype using imaging but it is not easy. For example, we know gliomas with the isocitrate dehydrogenase mutation (IDH+) have a better prognosis than the ones which do not have this mutation. We can measure a metabolite (2-hydroxyglutarate) that is produced by the IDH+ gliomas using a special type of MR technique called MR spectroscopy. However, this technique has not been very accurate so far in our hands. In general, it is difficult to accurately measure tumour metabolites in the brain using MRS when those metabolites are in small concentration.


Do scar tissue and tumour look the same in an image?

They can look the same on anatomical(conventional) MRI images but we can differentiate between the two using more advanced MR imaging technique which look at the blood supply or the density of cells.


What is the largest brain tumour you have seen?

I think that I have seen tumours that are at least 5-7 cm in diameter.


What, if any, strange/ unusual or interesting things when looking at images of a brain?

Certain structures of the brain or pathologies look like familiar pictures that we see in our daily life. For example, the midbrain looks the face of Mickey Mouse with his two big ears. Radiation necrosis can have a ‘’swiss-cheese’’ appearance because they are many holes in the image that we see. We give use those terms to help us remember the picture.


Does everyone’s brain look different in an MR image?

Yes and no. All of us will have common elements: cortex, thalamus, white matter, etc…However, each brain might ‘’age’’ differently depending on the presence of or not of underlying systemic diseases such as hypertension, diabetes, etc…


Where do you see imaging going in the future?

There will be more and more images of our body. Artificial intelligence will help the physicians to provide better diagnosis. Computer-aided diagnosis will absolutely be necessary.


What’s next for you in your research?

I am working on developing some standard diagnostic criteria to differentiate between radiation-induced brain damage and tumour recurrence. This will help avoid unnecessary delay in the diagnosis of tumour recurrence or avoid unnecessary surgeries for radiation necrosis. Learn More


What information would you most want patients to know?

Decision and treatment of patients with brain tumours can sometimes be very difficult. Cancer Care Ontario strongly encourages the use of multi-disciplinary tumour board rounds to discuss those cases. Make sure that there is a CNS tumour board round at your institution.


Brain Tumour Foundation of Canada is currently accepting 2018 research grant applications. The deadline for submissions is April 27, 2018. 



  1. What concerns me about brain tumours.. Is the inconsistent information for each individuals case..given to families about the symptoms to look for..example pain management..balance problems..dizzyness..especially nausea..
    These problems items are just as important.
    Also the serious side effects fro. The medication..
    Sitting in the E.R.. With my husband who had a grade 3 brain tumour .. Trying yo manage his pain.

    • If you haven’t already, we encourage you to seek support through our closed Facebook Group or contact our support services team by calling 1-800-265-5106.

  2. My husband was recently with glioblastoma stage 4 and had a crantomy in February. Unfortunately this tumor is approximately 5 cm and he has had only 4 radiation treatments. The doctor is deciding whether or not to continue the radiation therapy and I want them to continue. I have the pills for chemo, but they don’t want him to take them yet. He just turned 65 in February. He has trouble communicating with us and his words are really hard to make out.
    Is there any treatment to help him with his speech so we can understand what it is he is trying to say? Should the oncologist begin treating him with the chemo medication temozolomide.

    • We are saddened to read about your husband and encourage you, if you haven’t already, seek support through our closed Facebook Group or contact our support services team by calling 1-800-265-5106. We are here to listen, although we can’t offer medical advice. You can talk to your oncologist and perhaps a speech language pathologist who can provide alternative ways to communicate better with your husband.

  3. Yes, I”ve had a cancer scare. 4 years ago went for an eye test with Supersavers. Seemingly failed the field of vision test miserably. A few days later a letter arrived from the West Suffolk Hospital telling me to present myself to an ophthalmic surgeon. I was with him about an hour, during which time he performed a number of tests. Then he sat me down and said he was of the opinion I had a brain tumour. He went through the procedures for removal in graphic detail and said, depending on the results of the scan, I could be gone by Christmas without treatment. Talk about straight forward, but it was just what I needed. I had the scan and went home. I”ll admit this was one of the few times in my life fear has gripped me so deeply. Before going to bed my wife was out at work that evening I drank a bottle of wine. Next morning the ophthalmic surgeon called me at home. He is, by nature abrupt, but that morning he was apologetic. The testing machines in his department had proved to be wrongly calibrated and as a result thrown out incorrect results. He had spent the night examining test results and scans and was, rather happily, pleased to tell me I did not have a brain tumour. I wept. But for that valiant man”s diligence I may have gone through an unnecessary and costly procedure. We remained in contact for quite a while after but he”s now retired as I am. Still driving, still living a normal life, well normal for me and very, very grateful for that man”s diligence.

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