Diagnostic Value Of MR Diffusion-weighted Imaging In Necrosis Of The Femoral Head

Objective: acquired the image of hip joint on healthy volunteers and patients with necrosis of the femoral head using diffusion weighted imaging (Diffusion Weighted Imaging, DWI), measured the Apparent Diffusion Coefficient of the region of interest of double femoral head, femoral neck and the muscle tissue around the hip joint capsule, to obtain ADC value range of normal and femoral head necrosis regional, and study the value of DWI sequence in the diagnosis and staging of necrosis of the femoral head.Materials and Methods: 90 healthy volunteers were randomly selected, a total of 180 hips in this study, 42 male cases, 48 female cases, aged 24-78 years, mean age 57.3 years volunteer inclusion criteria:①symmetrical development of bilateral hip, without hip pain, hip joint disease imaging excluded;②without the history of hip trauma and surgery;③without the history of metabolic bone disease and bone tumors.40 hips of 34 patients with necrosis of femoral head in the study included 19 males and 15 females, aged 25-80 years, mean age 47.6 years, of which 6 cases with bilateral necrosis patients with necrosis of femoral head were divided into three groups according to Steinberg stage, (I-II of Group 1,Ⅲ-Ⅳof Group 2, V-VI of Group 3).All subjects were performed on a 1.5T scanner(Signa, 8-channel body coil, GE Medical Systems)with conventional MR sequences and DWI(SE-EPI sequence), diffusion sensitivity factor b were respectively selected 300 s/mm~2, 500s/mm~2, 700s/mm~2, all-directional dispersion, the original DWI images were transmitted to ADW4.3 workstations, and analyzed with Functool software, to obtain ADC map, the ROI (region of interest ROI) size was set 100mm~2.The ADC values of bilateral femoral head, femoral neck and the muscle tissue around hip joint capsule were measured in DWI images, averaged the three measurements independent sample t test, analysis of variance analysis and correlation analysis with SPSS16.0 software was used.Results:一,Application of DWI sequences in normal human hip joint . 1. Normal hip anatomy was shown when the b values of DWI sequences were 300 s/mm~2, 500 s/mm~2,700 s/mm~2and there was obvious geometric distortion in original diffusion images . 1) when the b = 300s/mm~2, the ADC values of femoral head, femoral neck were (3.63±1.34)×10- 4mm~2/s,(5.36±1.50)×10- 4mm~2/s; 2) when the b = 500s/mm~2, the ADC values of femoral head, femoral neck were (1.87±0.76)×10- 4mm~2/s,(3.75±1.03)×10- 4mm~2/s; 3) when the b = 700s/mm~2, the ADC values of femoral head, femoral neck were (1.49±0.53)×10- 4mm~2/s,(3.54±0.93)×10- 4mm~2/s; 2. Obtained by Pearson correlation analysis, the ADC values of normal femoral head correlated with age, the trend of ADC values decreased while the age increased. 3. As the b value increased, the ADC values of corresponding region reduced , the differences of the ADC values to the different b values were significant (P <0.01). 4. The differences of the ADC values of femoral head and femoral neck were significant (P <0.01)二,Application of DWI sequences in necrosis of the femoral head 1. Necrotic area in DWI was map-like and uniform hyper intensity, several round hyper-high signal area could often be found. 1) when b = 300s/mm~2, the ADC value of femoral head necrosis was (13.00±2.54)×10 - 4mm~2 / s; 2) when b = 500s/mm~2, the ADC value of femoral head necrosis was (10.73±3.10)×10- 4mm~2/s; 3) when b = 700s/mm~2, the ADC value of femoral head necrosis was (8.77±1.55)×10- 4mm~2/s; 2. The changes of the ADC value of femoral head necrosis 1) The ADC values of femoral head necrosis region was significantly higher than the normal, and the difference was significant (P <0.01). 2) The ADC values of femoral head necrosis in stageⅠ,Ⅱwere minimum, and that were maximum in stageⅢandⅣ,then reduced in stageⅤ,Ⅵ. The differences of the ADC values of femoral head necrosis region were significant when the b value 300 s/mm~2,500 s/mm~2,700 s/mm~2.Conclusion:1. DWI sequences could be clearly demonstrated the hip anatomic structure when b= 300 s/mm~2,500 s/mm~2,700 s/mm~2.2. DWI sequences distinguish the normal and pathological regions, staging necrosis of the femoral head by measuring the ADC values.3. There was certain value of DWI sequences and ADC values in the diagnosis and staging of necrosis of femoral head.