RT Journal Article
SR Electronic
T1 APPLICATIONS OF PET/MRI IN PEDIATRIC PATIENTS
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 2001
OP 2001
VO 62
IS supplement 1
A1 Paul-Robert Derenoncourt
A1 Maria Ponisio
YR 2021
UL http://jnm.snmjournals.org/content/62/supplement_1/2001.abstract
AB 2001Introduction: Many pediatric conditions required both functional and anatomic information to provide adequate diagnosis and clinical management. Functional data can be obtained with Positron Emission Tomography (PET) tracers and anatomic information with Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). The addition of CT to PET has positively changed the accuracy of interpretation, as widely noted in the literature. However, the ionizing radiation delivered by CT makes it less desirable for pediatric patients who are known to have a greater risk than adults to developing cancer after exposure. Furthermore, the common use of low dose CT performed with the PET lowers the diagnostic quality, impacting imaging interpretation. In contrast, MRI does not use ionizing radiation and renders better anatomical correlation due to high soft-tissue contrast. We retrospectively reviewed oncologic and non-oncologic pediatric PET/MRI studies performed at our institution from 2014-2020 and identified the most common indications. This exhibit examines in pediatric patients the most common clinical and research PET/MRI indications at our institution, the strengths and challenges of this technology, and the available PET tracers for specific applications in this population. Methods: We retrospectively reviewed 216 pediatric PET/MRI performed at our institution from 2014-2020. The indications were identified, and the final interpretation correlated with the definitive diagnoses, when available. All studies were performed on a simultaneous PET/MRI system, 3.0T Siemens Biograph mMR (Siemens Health Care, Erlangen, Germany). The radiopharmaceutical most commonly used was 18F-FDG. Results: The most common indication for obtaining a PET/MRI in pediatric patients was presurgical planning for seizure, sarcomas, neurofibromatosis, and lymphomas. 18F-FDOPA was used for the evaluation of gliomas and congenital hyperinsulinism. The use of simultaneous PET/MRI allows precise coregistration of the anatomical details of MRI with the brain's metabolic abnormalities, improving localization of the epileptogenic foci. The increased use of PET/MRI in the diagnosis and follow-up of common pediatric tumors such as neurofibroma and lymphoma is due to the advantages of using radiation-free MRI instead of CT for anatomical co-registration of PET data, markedly reducing radiation exposure. In neuro-oncology, MRI combined with amino acid PET tracers allowed better tumor volume delineation for adequate staging and therapy. Soft tissue PET/MRI allowed detection or exclusion of new tumor necrosis in neurofibromas, critical in determining malignant transformation. In children with congenital hyperinsulinism (CHI), FDOPA-PET/MRI was performed to detect the form of hyperinsulinism, given that focal CHI may be cured by surgery. Conclusion: Simultaneous PET/MRI is an emerging hybrid modality that offers an excellent combination of anatomic, functional, and metabolic imaging. It has been increasingly used in the pediatric population and has a significant advantage by reducing ionizing radiation. The simultaneous acquisition of both PET and MRI in one session reduces the number of sedation and misregistration between modalities. The high cost and low availability of this combined examination remain the major obstacles that prevent its more widespread use.