Diffusion-Weighted Imaging Shows a False-Negative Finding for Bone Marrow Involvement on 18F-FDG PET/MRI in a Patient...

Area of Science:

• Oncology
• Radiology
• Hematology

Background:

• Iron overload is a significant complication of frequent blood transfusions, particularly in patients with hematological conditions.
• Accurate staging of malignant lymphoma is crucial for effective treatment planning and prognosis.
• Diffusion-weighted imaging (DWI) on MRI is a key technique for assessing bone marrow involvement in lymphoma.

Observation:

• A case study involving a patient with malignant lymphoma presented discordant findings between F-FDG PET and MRI DWI.
• F-FDG PET imaging indicated positive bone marrow involvement, consistent with lymphoma.
• MRI DWI studies yielded negative results for bone marrow involvement.

Findings:

• The discrepancy was attributed to iron deposition in the reticuloendothelial system, a consequence of posttransfusion iron overload.
• This iron deposition led to decreased signal intensity on DWI, causing a false-negative MRI finding.
• F-FDG PET imaging remained unaffected by the iron deposition and correctly identified lymphoma involvement.

Implications:

• Clinicians should be aware of potential false-negative MRI findings in patients with iron overload, especially those undergoing transfusions.
• F-FDG PET imaging may offer a more reliable method for assessing bone marrow involvement in such cases.
• This highlights the importance of integrating multiple imaging modalities for accurate lymphoma staging in complex patient populations.