PET-MRI is a hybrid imaging technique utilizing the functional uptake information of positron emission tomography (PET) with the anatomical and soft tissue detail of magnetic resonance imaging (MRI).
Early systems were tested in the late 2000s with commercial availability from 2010 1,2. The availability of PET-MRI remains limited, largely due to the costs and expertise required. PET-MRI acquisition times are longer than those experienced with PET-CT.
PET-MRI offers a lower ionizing radiation dose alternative with higher detection rates in a variety of studies when compared with the widely established PET-CT hybrid imaging technique 3. PET-MRI is of particular benefit to pediatric patients with chronic inflammatory conditions or malignancy, where serial follow up examinations following therapy are required 4. Additional benefits of PET-MRI include improved image alignment/coregistration due to simultaneous acquisition of PET and MRI images, superior soft tissue contrast to PET-CT and ability to use MRI contrast agents 5.
Applications
Current applications of PET-MRI include 3,4:
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oncology
head and neck cancers (particularly post-surgery)
lung cancer particularly for evaluation of brain metastases and local invasion in the thorax
hepatobiliary cancers (primary and secondary) +/- using novel PET tracers such as Ga68-DOTATATE
pelvic malignancies including prostate, rectal, ovarian, cervical and endometrial cancers
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hematology
lymphoproliferative disorders, particularly for detection and staging of disease
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infectious and inflammatory disorders
neurological conditions including temporal lobe epilepsy