The Clinical Utility of FDG PET-CT in Evaluation of Bone Marrow Involvement by Lymphoma

Purpose Bone marrow biopsy is a standard method for the evaluation of bone marrow infiltration by lymphoma; however, it is an invasive and painful procedure. Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) is a noninvasive imaging technique with the potential to detect bone marrow involvement by lymphoma. Materials and Methods We retrospectively reviewed medical records of lymphoma patients. All patients were examined by FDG PET-CT and iliac crest bone marrow biopsy for initial staging work-up. Results The study population comprised 94 patients (median age, 60 years; 56 males) with Hodgkin's lymphoma (n=8) or non-Hodgkin's lymphoma (n=86). Maximum standardized uptake values on the iliac crest of patients with lymphoma infiltrated bone marrow were significantly higher than those of patients with intact bone marrow (2.2 +/- 1.2 g/mL vs. 1.3 +/- 0.4 g/mL; p=0.001). The calculated values for FDG PET-CT during evaluation of bone marrow involvement were as follows: sensitivity 50%, specificity 96%, positive predictive value 80%, negative predictive value 85%, and positive likelihood ratio (LR+) 11.7. The value of LR+ was 16.0 in patients with aggressive subtypes of non-Hodgkin's lymphoma (NHL). Conclusion FDG PET-CT could not replace bone marrow biopsy due to the low sensitivity of FDG PET-CT for detection of bone marrow infiltration in lymphoma patients. Conversely, FDG PET-CT had high specificity and LR+; therefore, it could be a useful tool for image-guided biopsy for lymphoma staging, especially for aggressive subtypes of NHL. In addition, unilateral bone marrow biopsy could be substituted for bilateral bone marrow biopsy in lymphoma patients with increased FDG uptake on any iliac crest.