Purpose or Case Report: PET/MRI plays a significant role in Pediatric Oncology, but its implementation in Pediatric Neuro-Oncology has not been well established. PET/MRI addresses a major challenge in pediatrics by providing capability for serial imaging to track disease response to therapy, while minimizing radiation exposure and sedation events. PET/MRI has become a critical imaging modality in the management of pediatric brain neoplasms and metastases, aiding in diagnosis, staging, treatment planning, and follow-up, all while reducing radiation burden, minimizing time spent in the hospital, and reducing the number of sedation events.
At our tertiary center for pediatric care, we have gained extensive experience in utilizing hybrid PET/MRI to manage complex cases referred from multiple institutions. We present a series of cases where hybrid PET/MRI provided critical information for patient management including nasopharyngeal rhabdomyosarcoma, refractory metastatic germ cell tumor, and neuroblastoma. We offer a forward-looking perspective on the current role of FDG PET/MRI and future applications of amino acid PET in improving patient outcomes and its role in distinguishing tumor progression from post-treatment changes. Amino acid PET/MRI use cases were compiled from literature review and demonstrate definitive roles of amino acid PET/MRI in decision making in brain tumor diagnosis, immediate post-surgical assessment, and delayed treatment response assessment.
18F-FDG PET/MRI representative cases from clinical practice:
Case 1.
18 year old male with refractory metastatic germ cell tumor with anterior mediastinal mass and intracranial metastasis
Clinical Problem: Whole body evaluation in addition to detailed analysis of brain metastases in time efficient manner.
Imaging Solution: PET/MRI allowed detailed evaluation of hypermetabolic metastatic disease to the mediastinum and lungs and further detailed delineation of hemorrhagic brain metastases.
Case2.
4 year old boy with history of nasopharyngeal rhabdomyosarcoma with cerebellar metastasis who underwent resection and chemoradiation.
Clincial Problem: How to monitor nasopharyngeal mass after treatment in the setting of extensive postsurgical changes on MRI
Imaging Solution: PET/MRI provides an excellent imaging method for monitoring disease recurrence in the setting of post-treatment changes in nasopharyngeal location. Recurrent tumor was identified as hypermetabolic lesion, while MRI was not definitive.
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