MRI scans during an ALS assessment

A clinician may request images of the brain, spine or both, depending on the pattern of weakness, stiffness, speech changes or other findings. The scan is one part of an assessment that can also include a neurological examination, electrical tests of nerves and muscles, and blood tests.

MRI creates detailed images using a strong magnet and radio waves. Doctors review them for problems such as pressure on the spinal cord, changes in the neck or back, a stroke, inflammation or a mass that could offer another explanation for the symptoms.

A report with no explanatory structural abnormality does not prove ALS. Diagnosis depends on the history, the distribution and progression of clinical signs, and tests that assess how motor nerves and muscles are working.

Tell the imaging team about implanted devices, metal fragments, previous surgery, pregnancy, kidney problems, allergies and difficulty lying flat. Bring device details if you have them. The team must confirm whether an implant is suitable for the scanner.

You will usually remove metal objects and lie still while images are taken. The scanner is noisy, and hearing protection is provided. If enclosed spaces worry you or weakness makes positioning difficult, contact the department beforehand so it can plan support. Contrast material is used only when the requested images require it.

Seek urgent medical help for sudden new weakness, facial drooping, difficulty speaking, loss of consciousness or severe breathing difficulty. These features need prompt assessment and should not wait for a routine MRI appointment. Contact the clinical team soon if swallowing is becoming difficult, falls are increasing or weakness is progressing, because supportive care and further assessment may need adjustment.

Clarify which body area will be scanned, whether contrast is planned, what alternative causes the images are intended to check and when results will be discussed. Ask what other assessments are needed if the MRI does not explain your symptoms.