Standard-b-value vs low-b-value DWI for differentiation of benign and malignant vertebral fractures: a meta-analysis

Objective: To determine the comparative diagnostic performance of standard-b-value (>= 500 mm(2)) vs low-b-value (<500s mm(-2)) diffusion-weighted imaging (DWI) for discriminating malignant from benign vertebral compression fractures. Methods: 12 studies with a total of 350 malignant and 312 benign vertebral fractures were included. Results: The apparent diffusion coefficient (ADC) value of benign vertebral compression fractures was lower than that of malignant vertebral compression fractures (SMD=1.81, 95% CI 0.98 to 2.64 Z=4.27, p<0.05). ADC value difference was more pronounced in the group of low-b-value DWI (SMD=2.31, 95% CI 1.02 to 3.60 Z=3.51, p<0.05) than in the group of standard-b-value DWI (SMD=1.38, 95% CI 0.18 to 2.59 Z=2.25, p<0.05). Ethnicity stratified analysis demonstrated higher ADC values in benign vertebral compression fractures in comparison to malignant tissues in both the Asian and Caucasian subgroups (Asians: SMD=2.400, 95% CI 1.45 to approximately 3.35, p<0.05; Caucasians: SMD=0.592, 95 % CI 20.848 to approximately 2.032, p<0.05). And the ADC value difference was more pronounced in the Asian subgroup. Conclusion: ADC value appears to be a reliable method to differentiate benign from malignant fractures. Low-b-value DWI was more a valuable parameter than standard-b-value DWI for discriminating malignant from benign vertebral compression fractures. And the diffusion characteristics of the benign vertebral fractures such as osteoporosis, trauma and infection have rarely been investigated separately. Advances in knowledge: The use of low-b-value DWI for differentiation of benign and malignant vertebral fractures is recommended.