Problems with MRI

Why PET CT offers more detailed results

Are MRIs Accurate in Diagnosing Cancer?


An MRI can provide more details than both an ultrasound and a CT scan, yet still lack the detail and accuracy of a PET/CT scan. An acronym for Magnetic Resonance Imaging, MRIs use magnetism and radio waves to build a picture of the inside of the body. They look at variations in density of tissues, exploring shapes and shadows. This leaves technologists to make a best guess as to which shapes are cancerous or not, which can lead to false negatives and delay treatment.

Doctor in hospital in scrubs

Problems with MRIs

  • MRI cancer detection failure
    MRIs can not effectively differentiate between cancerous tumours and non cancerous tumours:
    • Therefore, people are frequently misdiagnosed.
    • They also can’t differentiate between cancerous tissue and cysts (or fibroids).
  • MRIs lack detail
    They do not identify the most aggressive tumours:
    • Therefore, doctors are unable to prioritize treatment effectively.
  • MRIs miss tumours
    They do not clearly identify the location of all tumours in your body:
    • Therefore, it is common for tumours to be completely missed.
    • It's also common to have only partial tumour removal during surgery.
  • MRI inaccuracy in treatment monitoring
    After cancer treatment, an MRI is unable to determine whether remaining masses are cancerous:
    • The MRI might show signs of cancer, but that cancer might not be active.
    • For example, it could be scar tissue left over from cancer killed off by your treatment.
    • This means you won’t know whether or not you need to continue treatment.

On the other hand, a PET/CT scan can show whether tissue is cancerous or not; so you can avoid false negatives, as well as continuing treatment unnecessarily.

Best Diagnostic Imaging Test for Cancer

If MRIs are less detailed than PET/CT scans, why are they still being used (usually after both an ultrasound and a CT scan have been conducted)?

  • MRIs are cheaper than PET/CTs.
  • There are far more MRI machines than PET/CT machines.
  • MRIs are more detailed than ultrasounds and CT scans.
  • More doctors are familiar with the older technology of MRIs than with the newer technology of PET/CT scans.
  • MRIs do not expose people to radiation.

A PET/CT scan remains your best option for diagnostic imaging: PET/CTs can identify exactly where the cancer is in your body, its level of aggression, and if your treatment is working optimally. Please read more about why PET/CT scans are so effective and how you can get one immediately.

If you have any questions, please reach out to us today. We’re standing by to help you access the best tests and treatments for your form of cancer.

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