Objective To analyze the pattern of normal bone marrow on whole body diffusionweighted imaging (WB-DWI) and its influence factors.MethodsA total of 98 healthy volunteers (male 47 and female 51). All volunteers underwent WB-DWI at 1.5 T MR scan. The ADC value,the signal intensity on DWI obtained with a b value of 800 s/mm2 ( SIDWI ),and the signal intensity on short time inversion recovery images ( SISTIR ) of thoracic vertebrae,lumber vertebrae,bilateral head of femur,bilateral neck of femur,bilateral superior segment of femur,bilateral inferior segment of femur,bilateral ilium,bilateral head of humerus,bilateral scapula were measured and compared with ANOVA test and StudentNewmar-Keuls test.The normal appearance of bone marrow on WB-DW[ was assessed. The relationship between the SIDwI and the ADC,and the SIDWI and the SISTIR of bone marrow were analyzed.The ADC of bone marrow between male and femaIe were compared. Spearman correlation analysis was performed for different age groups.Results( 1 ) Bone marrow signal intensity was different among 98 healthy volunteers.Bone marrow in 69 healthy volunteers (female 24,male 45 ) showed low to intermediate signal intensity,whereas in the remaining 29 healthy volunteers (female 27,male 2) showed high signal intensity.(2) The SIDWI of thoracic vertebrae ( median 44.54),lumber vertebrae ( median 35.01 ),head of femur ( median 13.61 ),neck of femur ( median 16.00),superior segment of femur ( median 21.45 ),ilium ( median 25.77),head of humerus (median 18.35),scapula (median 36.12) was positively correlated with the ADC [ (0.55 ±0.08) × l0-3,(0.53 ±0.08) × 10-3,(0.30 ± 0.10) × 10-3,(0.42 ± 0.16) × 10-3,(0.74±0.14) ×l0- 3,(0.49±0.10) ×10-3,(0.36±0.13) ×10-3,(0.49±0.11) × 10-3mm2/s]and the SISTIR ( median 61.81,64.99,53.27,69.08,73.10,66.35,73.16,79.81 ),r =0.513 and 0.695,0.741 and 0.764,0.443 and 0.489,0.641 and 0.656,0.510 and 0.648,0.475 and 0.715,0.366 and 0.446,0.437 and 0.739 ;P ＜ 0.01. (3) There was significant difference of the ADC of bone marrow in different bone,F =138.69,P ＜ 0.01. Student-Newman-Keuls test revealed that no significant difference was found in the ADC between thoracic vertebrae and lumbar vertebrae,ilium and scapula,head of humerus and inferior segment of femur ( P ＞ 0.05 ),and significant difference was found in the ADC values between the remaining two groups ( P ＜ 0.05 ). The bones associated with decreasing ADC values were superior segment of femur,thoracic vertebrae and lumber vertebrae,ilium and scapula,neck of femur,head of humerus,head of femur and inferior segment of femur. ( 4 ) The ADC values of bone marrow of female subjects in thoracic vertebrae [ (0.59 ±0.07) × 10-3 mm2/s],lumber vertebrae [ (0.58 ±0.06) × 10 -3 mm2/s],head of femur ( median 0.33 × 10 -3 mm2/s),neck of femur ( median 0.53 × 10 -3 mm2/s),superior segment of femur ( median 0.81 × 10-3 mm2/s),inferior segment of femur ( median 0.32 ×10-3 mm2/s),ilium [ (0.52 ± 0.09 ) × 10-3 mm2/s ],head of humerus (median 0.42 × 10-3 mm2/s),scapula [ (0.53 ± 0.09) × 10-3 mm2/s] were significantly higher than those of male subjects [ (0.51 ±0.07) × 10-3,(0.48 ±0.07) × 10-3,median 0.23 × 10-3,median 0.31 × 10-3,median 0.66 × 10-3,median 0.23 × 10-3,(0.46 ±0.10) × 10-3,median 0.27 × 10-3,(0.45 ±0.11 ) × 10 3mm2/s].(5)There was significant negative correlation between the ADC values of bone marrow and age in thoracic vertebrae,lumber vertebrae,head of femur,neck of femur,superior segment of femur,ilium,head of humerus for female subjects,r =-0.549, -0.629, -0.329, -0.524, -0.338, -0.548 and -0.416,respectively,P ＜ 0.05.There was no significant correlation between ADC values and age in inferior segment of femur and scapula for female subjects and all the regions for male subjects ( P ＞ 0.05 ).Conclusions The ADC and the SIsTIR of bone marrow correlates with the SIDW1.The ADC values of bone marrow is affected by age and sex,and is different for different bones.