Nucl Med Mol Imaging.  2026 Apr;60(2):131-139. 10.1007/s13139-025-00962-w.

Comparison of Semi-Quantitative Parameters of 18 F-FDG Digital PET/ CT and Simultaneous PET/MRI in Lymphoma Patients

• Panperee P
• Thongdonpua S
• Jantarato A
• Promteangtrong C
• Kunawudhi A
• Kiatkittikul P
• Siripongsatian D
• Keeratipiriyakul J
• Onanong Konggasame O
• Chotipanich C

• KMID: 2580296
• DOI: http://doi.org/10.1007/s13139-025-00962-w

Abstract

Purpose
This study evaluated the comparative performance of standardized uptake value (SUV) measurements derived from positron emission tomography/magnetic resonance imaging (PET/MRI) and digital positron emission tomography/ computed tomography (PET/CT) in lymphoma patients. A retrospective analysis was conducted to compare semi-quantitative measures and assess the correlation and concordance between the two imaging modalities.
Methods
A total of 106 lymphoma patients underwent both PET/CT and PET/MRI, either in the order of PET/CT followed by PET/MRI (PET/CT_first group, n = 51) or PET/MRI followed by PET/CT (PET/MRI_first group, n = 55). SUV measurements in lesions, liver, and mediastinal blood pool were compared between modalities.
Results
SUV max and SUV mean were significantly lower in PET/MRI than PET/CT (P < 0.001), except SUV mean for mediastinal blood pool in the PET/MRI_first group (P = 0.090). Correlation between modalities was very high for the lesions (ρ = 0.90–0.96). The Deauville five-point scale (D5PS) scores had good agreement between modalities (κ = 0.6566 for PET/ CT_first and κ = 0.4846 for PET/MRI_first ; P < 0.001), but the response categorization would have been different in 22/262 PET/ CT_first group and 21/155 PET/MR_first group.
Conclusion
SUV measurements from PET/MRI demonstrated strong correlation and good agreement in D5PS classification compared to digital PET/CT. Nonetheless, variations in PET subsystem technologies across modalities may influence quantitative values, and such differences should be carefully considered when interpreting results.

Keyword

Positron emission Tomography/Computed tomography; Positron emission tomography/Magnetic resonance imaging; Lymphoma; Standardized uptake value