Comparison of FDG-PET, MRI and bone scans in bone marrow metastatic lesions from different primaries

Abstract

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Objectives: The aim of our study was to compare the performance of FDG-PET, bone scan and MRI imaging in detecting bone marrow metastatic lesions from different primaries.

Methods: Sixty-one patients (27 male, 34 female, age 57 ±8 years) with suspected metastatic bone marrow lesions were included in this retrospective analysis. All patients underwent FDG-PET, bone scan and MRI imaging within 60 days interval. All the results were correlated with histopathological examination and/or clinical follow up. The primary cancers were lung, breast, lymphoma, head and neck, and gastrointestinal malignancies. Sensitivity, specificity, accuracy, negative and positive predictive values were calculated for all the three modalities.

Results: Based on biopsy and clinical and/or imaging follow-up for at least 1 year, 37 of the patients did not show any metastasis. In the remaining 24 patients, bone marrow metastases were confirmed at 70 lesions. With analysis on a lesion-by-lesion basis, FDG-PET imaging showed a sensitivity of 91.4% for detection of bone marrow metastasis, which was significantly higher than the sensitivity of 50% for bone scintigraphy, (p<0.05), and was slightly higher than the sensitivity of MRI (90.5%). Specificity of FDG-PET was higher than MRI 81.1% vs 71.4% respectively and the specificity of bone scan was the lowest (59.4%). Accuracy, negative and positive predictive values were 87.9%, 83.3%, 90.1% for FDG-PET, 85.7%, 71.4%, 90.5% for MRI, and 53.8%, 45.2%, 63.9% for bone scan respectively. FDG PET also showed additional information regarding the disease status in outside of the bone in 59% of the patients (36 patient).

Conclusions: The findings of this study indicate that sensitivity, specificity and accuracy of FDG-PET imaging in detecting bone marrow metastases are higher than those of MRI and bone scans. Bone scan has the lowest statistical results in detecting bone marrow metastases from the primary malignancies mentioned above included in this study. Furthermore, FDG-PET imaging can provide more information for the extent of the disease outside the bone marrow. FDG-PET scan should be included in the work up of the patients with suspected bone marrow metastatic disorder.