Whole-body MRI Versus [ 18 F]FDG PET/CT in Diagnosing and Monitoring Plasmacytomas : A Comparative Study

Area of Science:

• Oncology
• Radiology
• Diagnostic Imaging

Background:

• Current guidelines recommend [18F]FDG PET/CT for extramedullary plasmacytomas and WB-MRI for solitary bone plasmacytomas.
• Limited evidence exists comparing the diagnostic efficacy of WB-MRI and [18F]FDG PET/CT.
• The study aimed to compare these two imaging modalities in the initial evaluation of plasmacytomas.

Purpose of the Study:

• To compare the diagnostic efficacy of whole-body magnetic resonance imaging (WB-MRI) and [18F]FDG positron emission tomography/computed tomography ([18F]FDG PET/CT) in the initial evaluation of plasmacytomas.
• To assess the detection rates and concordance of WB-MRI and [18F]FDG PET/CT for various types of plasmacytomas.

Main Methods:

• A multicenter, observational, retrospective analysis of 73 patients diagnosed with plasmacytoma.
• Patients underwent either WB-MRI or [18F]FDG PET/CT, with 56 patients undergoing both.
• Statistical analysis, including McNemar and Pearson χ2 tests, was used to compare detection rates.

Main Results:

• WB-MRI detected 98.2% of plasmacytomas, significantly higher than [18F]FDG PET/CT's 83.9% detection rate (OR 9, P=0.021).
• High concordance was observed for osseous plasmacytomas, while moderate concordance was found for extramedullary plasmacytomas.
• The study included patients with solitary plasmacytoma, concurrent multiple myeloma (MM) and plasmacytoma, and plasmacytoma with a prior MM history.

Conclusions:

• WB-MRI is a highly effective alternative to [18F]FDG PET/CT for detecting plasmacytomas.
• A thorough clinical and radiological assessment remains crucial for optimal patient management.
• WB-MRI shows promise in improving the diagnostic accuracy for plasmacytoma detection.