Abstract: Objective To explore the diagnostic value of whole-body diffusion weighted imaging(WB-DWI) in multiple myeloma.
Methods In total, 31 patients with multiple myeloma diagnosed initially were collected as the experimental group, and 98 healthy subjects were selected as the control group. Before treatment, WB-DWI was performed, the ADC value of the lesion was measured, and the correlation between ADC value and clinical laboratory indexes was analyzed. 
Results The lesions showed high signal intensity with focal or diffused distribution on DWI(b=800 s/mm2) images and low signal intensity on the ADC maps. Extramedullary lesions were found in 3 cases. The mean ADC value of the lesions in the whole body was(0.77±0.21)×10-3 mm2/s and was significantly different from that of the normal bone marrow(P＜0.05). The mean ADC value of the lesions in iliac bone was positively correlated with the percentage of myeloma cells(rs=0.560，P=0.008). The mean ADC value of the lesions in the whole body was negatively correlated with the blood HBG(rs=-0.490， P=0.011), and positively correlated with the serum and urine β2-MG and serum CRP(rs=0.557,  0.517，P=0.05, 0.004, 0.014). 
Conclusion WB-DWI has an important value in the diagnosis and monitoring of initially diagnosed multiple myeloma, which, therefore, should be used as a routine imaging method for patients initially diagnosed with multiple myeloma.

Key words: multiple myeloma, whole-body diffusion weighted imaging, apparent diffusion coefficient value