PET-MRI Hybrid Scans

PET-MRI scans combine positron emission tomography (PET) and magnetic resonance imaging (MRI) into one imaging tool. The joint scans combine the features of magnetic resonance imaging, giving high quality soft-tissue images, with the metabolic data of PET scans.  

 

This relatively new scanning technique demonstrates particular usefulness for mapping recurrent cancers (such as recurrent prostate cancer). Tracking the spread and stability of recurrent cancers is vital to planning the best possible treatment. PET-MRI compound imaging demonstrates a superior ability to map recurrent cancers than PET alone or PET-CT scanning (both of which are already widely used) as PET-MRI scans offer better soft tissue contrast (owing to the MRI component) compared to PET-CT (which instead provides more information on structure and density). This enables better imaging of metastatic tumours. [1]

 

PET-MRI scans have a longer scanning time than PET-CT but reduce patient radiation exposure as they have no CT scanning element. In recurrent cancers, where multiple scans are given over the course of the disease, the use of PET-MRI could significantly reduce overall patient radiation exposure. [1]

 

PET-MRI scanning is a technique that is commercially available and clinically useful. At present, limitations in PET-MRI technology mean that only around 70 scanners have been installed worldwide. [3] These limitations include attenuation correction (AC) issues (as MRI depends on bone for AC calculations, it is difficult to calculate attenuation coefficients that characterise a reduction in signal amplitude for combined PET-MRI scans of none-bone areas). It has also been difficult to establish cooperation between radiologists and nuclear doctors, which is essential for interpreting hybrid PET-MRI images. [3].  

 

PET-MRI development is a rapidly moving field, and it is expected that PET-MRI compound scans will become more widespread in the near future.  

 

For more information about PET scanning in the future, click here. 

For more information about MRI scanning in the future, click here. 

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References:

[1] ITN (2013). PET/MR Effective for Imaging Recurrent Prostate Cancer. Available at: https://www.itnonline.com/article/petmr-effective-imaging-recurrent-prostate-cancer [Accessed 20/02/19]

[2] Metastatic Cancer (National Caner Institute). Available at: https://www.cancer.gov/types/metastatic-cancer [Accessed 26/02/19]

[3] INT (2017) The Past, Present and Future of PET/MRI Scanners. Available at: https://www.itnonline.com/article/past-present-and-future-petmri-scanners [Accessed 20/02/19]

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