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Updated: Mar 25, 2026
Whole-body PET/MRI of Pediatric Patients: The Details That Matter
Published on: December 19, 2017
Assessment of Sequential PET/MRI in Comparison With PET/CT of Pediatric Lymphoma: A Prospective Study
Andrew C Sher1, Victor Seghers1, Michael J Paldino1
11 Department of Pediatric Radiology, Texas Children's Hospital, 6701 Fannin St, Ste 470, Houston, TX 77030.
Objective:
The objective of our study was to compare the diagnostic performance of sequential (18)F-FDG PET/MRI (PET/MRI) and (18)F-FDG PET/CT (PET/CT) in a pediatric cohort with lymphoma for lesion detection, lesion classification, and disease staging; quantification of FDG uptake; and radiation dose.
Subjects And Methods:
For this prospective study of 25 pediatric patients with lymphoma, 40 PET/CT and PET/MRI examinations were performed after a single-injection dual-time-point imaging protocol. Lesions detected, lesion classification, Ann Arbor stage, and radiation dose were tabulated for each examination, and statistical evaluations were performed to compare the modalities. Quantification of standardized uptake values (SUVs) was performed for all lesions. All available examinations and clinical history were used as the reference standard.
Results:
No statistically significant differences between PET/MRI and PET/CT were observed in lesion detection rates, lesion classification, or Ann Arbor staging. Fifty-four regions of focal uptake were observed on PET/MRI compared with 55 on PET/CT. Both modalities accurately classified 82% of the lesions relative to the reference standard. Disease staging based on PET/MRI was correct for 35 of the 40 studies, and disease staging based on PET/CT was correct for 35 of the 40 studies; there was substantial agreement between the modalities for disease staging (κ = 0.684; p < 0.001). PET SUVs were strongly correlated between PET/CT and PET/MRI (ρ > 0.72), although PET/MRI showed systematically lower SUV measurements. PET/MRI offered an average 45% reduction in radiation dose relative to PET/CT.
Conclusion:
In a pediatric cohort with lymphoma, sequential PET/MRI showed lesion detection, lesion classification, and Ann Arbor staging comparable to PET/CT. PET/MRI quantification of FDG uptake strongly correlated with PET/CT, but the SUVs were not interchangeable. PET/MRI significantly reduced radiation exposure and is a promising new alternative in the care of pediatric lymphoma patients.
Insights
Sequential fluorine-18-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (FDG PET/MRI) demonstrated diagnostic performance comparable to FDG PET/CT in pediatric lymphoma patients. PET/MRI significantly reduced radiation dose, offering a promising alternative for lymphoma care.
Area of Science:
- Nuclear Medicine
- Radiology
- Pediatric Oncology
Background:
- Positron emission tomography/computed tomography (PET/CT) is a standard imaging modality for pediatric lymphoma.
- Magnetic resonance imaging (MRI) offers superior soft tissue contrast and avoids ionizing radiation.
- Evaluating the diagnostic performance of integrated PET/MRI in pediatric lymphoma is crucial.
Purpose of the Study:
- To compare the diagnostic performance of sequential fluorine-18-fluorodeoxyglucose PET/MRI (PET/MRI) versus PET/CT in pediatric lymphoma.
- To assess lesion detection, classification, disease staging, FDG uptake quantification, and radiation dose between the two modalities.
Main Methods:
- Prospective study of 25 pediatric lymphoma patients undergoing 40 dual-time-point imaging examinations.
- Comparison of lesion detection, classification, Ann Arbor staging, and standardized uptake values (SUVs) between PET/MRI and PET/CT.
- Radiation dose comparison between the imaging modalities.
Main Results:
- No statistically significant differences in lesion detection, classification, or Ann Arbor staging between PET/MRI and PET/CT.
- Strong correlation of PET SUVs between modalities (ρ > 0.72), with systematically lower values on PET/MRI.
- PET/MRI provided an average 45% reduction in radiation dose compared to PET/CT.
Conclusions:
- Sequential PET/MRI demonstrates comparable diagnostic performance to PET/CT for lesion detection, classification, and staging in pediatric lymphoma.
- FDG uptake quantification by PET/MRI correlates strongly with PET/CT but is not interchangeable.
- PET/MRI offers a significant reduction in radiation exposure, representing a promising alternative for pediatric lymphoma management.
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