The Role of DWI in Differentiating Metastatic from Non-Metastatic Bone Lesions

Abstract

Background:The bony skeleton is known to be a common site for metastasis which is the third most common site after the lung and liver. Prognosis for patients with metastatic osseous disease is generally poor and management options must be carefully weighted. It is, hence, critical to be able to pick up bone marrow lesions which require further investigations and intervention from benign lesions which can be conservatively managed. Aim of Study:The purpose of this study is to investigate the potential application of DWI and quantitative ADC in differentiation of various bone marrow lesions raising the level of confidence in diagnosing metastatic from nonmetastatic benign bone lesions.Patients and Methods: Our study sample included 32 cases with different bone lesions, which were further classified into metastatic and non-metastatic lesions based on the standard of reference (6 months follow-up and histopathology if feasible). All lesions were subjected to evaluation using DWI-ADC assessment.Results : The ADC value was able to correctly predict 90% (n=9/10) of metastatic lesions and 63.6% (n=14/22) of non-metastatic lesions with sensitivity 90.00% and specificity 63.6%, in predicting the malignant nature of metastatic lesions, a cut-off value of 1.26 x 10 -3 mm 2 /s was generated between the two groups according to the receiver operating characteristic curve (ROC) with p-value 0.012. Conclusion:As a tool, diffusion weighted magnetic resonance imaging is a time efficient procedure that requires no extra patient preparations or contrast injection.Quantitative assessment of DWI using the ADC maps could help in differentiation between benign and malignant nature of bone lesions especially when used in conjunction with conventional MRI sequences and qualitative DWI interpretation raising MRI ability to solve the diagnostic dilemma met while assessing bone lesions encountered in oncology patients.