Diffusion-Weighted Magnetic Resonance Imaging as a Potential Tool in Differentiation of Vertebral Bone Marrow Lesions

Background: Pathological lesions usually replace normal components of the vertebral bone marrow including benign and malignant lesions, as well as, fractures, inflammatory and degenerative marrow process. DWI is considered to be a potential tool which can help in characterization of different bone marrow lesions by exploiting the structural differences of biologic tissue. Objective: To evaluate the role of diffusion weighted magnetic resonance imaging (DWI) as a potential tool in differentiation of vertebral bone marrow lesions. Material and Methods: Forty patients with bone marrow abnormal MRI signal intensity were included in the study and according to MRI finding they were classified to four groups. DWI was performed with b values of 0 and 500s/mm 2 . As well as apparent diffusion coefficient (ADC) values also estimated. Results: Four cases of malignant collapse displayed high signal intensity on DWIs and low signal intensity on ADC map, however, benign osteoporotic collapse cases (7 cases 17.5%) were hypo intense (3 cases) and iso to hypo intense (4 cases) on DWIs and being hyper intense on ADC. Twelve cases with endplate changes, the eight infectious spondylitis recorded mean ADC value (1.03±0.33x10-3mm/s). The remaining, 4 cases with degenerative changes recorded ADC value (1.76±0.33x10-3mm/s). Another three cases of malignant bone marrow infiltration without collapse were hyperintense on DWIs and hypointense on ADC map. The mean ADC in hemangioma was (1.9±0.33x10-3mm/s) and in ABC (1.93±0.33x10-3mm/s). DW study of 4 cases respond to therapy recorded mean ADC value (1.64±0.33x10-3mm/s), however, the 2 cases with residual viable tumor tissue record (0.79±0.33x10-3mm/s). Conclusion: DWI with quantitative ADC measurements using b-value (b=500s/mm) can be good indicator tool in differentiating benign from malignant bone marrow lesions, as well as differentiating between end plate changes causes, also, may be used in post therapy follow-up.