What does “No restricted diffusion” mean on a radiology report?
The MRI shows no sign of an acute stroke, or of the other conditions that show up as bright spots on the diffusion images.
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General explanations of common wording, not advice about your own scan. Ask the doctor who ordered it what your results mean for you.
Why the radiologist wrote it that way
Diffusion-weighted imaging (DWI) is an MRI sequence that measures how freely water molecules move in tissue. In brain cells starved of blood, water movement becomes restricted within minutes to hours of a stroke, and those areas light up on DWI. It is the most sensitive standard test for an acute ischaemic stroke, so a brain MRI report usually states whether restricted diffusion is present.
Is this good or bad news?
When the question is "has there been a recent stroke?", this is the reassuring answer. Restricted diffusion is also seen in some other conditions, such as abscesses, some tumours and certain types of brain inflammation, so its absence is helpful in more than one way. Very small or very early strokes can occasionally be missed even on DWI, and some causes of symptoms such as dizziness or numbness do not show on MRI at all, so the result is interpreted with your symptoms.
What it does not mean
- That the whole MRI is normal. Other findings are reported separately.
- That there has never been a stroke. Older strokes no longer restrict diffusion and are described differently.
- That your symptoms have no cause.
Where you will see it
Words in this phrase
- Diffusion-weighted imaging (DWI)An MRI sequence that shows how freely water moves in tissue. Areas where movement is restricted look bright; it is the most sensitive standard MRI test for a recent stroke.
- InfarctionDeath of tissue due to lack of blood supply (like a heart attack or stroke).
- IschemiaReduced blood flow to tissue or organs.
- MRI (Magnetic Resonance Imaging)Imaging using magnetic fields and radio waves to create detailed images of soft tissues.
One phrase is not the whole report
What this sentence means for you depends on everything else your report says. Radily reads the whole thing and explains it in plain English — and can talk you through it on video, so you are not reading medical language alone.
Other phrases on your report
- No acute intracranial abnormalityThe scan found nothing new or urgent inside the skull — no bleeding, no swelling, no sign of injury needing treatment today.
- UnremarkableNormal. There was nothing worth remarking on.
- Mild degenerative changesOrdinary age-related wear in the joints or spine — the kind almost everyone develops, to some degree, as they get older.
- No acute cardiopulmonary processThe chest X-ray shows no new problem with the heart or lungs — no pneumonia, no fluid around the lungs, no collapsed lung, and a heart that looks a normal size.
This explains how a phrase is commonly used in radiology reports. It is not a diagnosis, not a reading of your scan, and not medical advice. Only your doctor can tell you what your own report means.