| Objective: To explore the changes of apparent diffusion coefficient(ADC) values in the magnetic resonance diffusion-weighted imaging(DWI) of the benign and malignant lesions of musculo-skeletal system under different b values as well as the preliminary application of susceptibility weighted imaging(SWI) in the differential diagnosis of musculo-skeletal system, and evaluating the diagnosis and differential values of DWI and SWI on the benign and malignant pathology of the musculo-skeletal system. Methods: 39 cases of confirmed musculo-skeletal system patients who have received treatment in our hospital from June,2014 to January, 2015 were collected, among which there are 17 cases of benign group(4 cases of hemangioma, respectively 2 cases of fibrous dysplasia of bone, pigmented villonodular synovitis, bone fibrous dysplasia, chondroblastoma and respectively one case of soft tissue abscess, myxoma of the juxta articular, Langenhanscellhistiocytosis, benign giant cell tumor of bone and neurogenic tumor) and 22 cases of malignant group(6 cases of metastatic tumor, 3 cases of non-Hodgkin lymphoma and osteosarcoma, 2 cases of malignant giant cell tumor of bone, lipoblastoma, chondrosarcoma and multiple myeloma, and one case of chordoma and mesenchymal tumor). The above-mentioned 39 cases of patients have all undergone routine MRI examination and DWI scanning. The b 5values of the ADC graph produced by DWI imaging through Philips Extended Workspace workstation are 200s/mm2, 400s/mm2, 600s/mm2, 800s/mm2 and 1000s/mm2 respectively. Compared the various series of conventional MRI image, we find out the levels with the biggest focus area and uniform material components for the measurement. Meanwhile, the cystic or necrosis area of 13 cases(3 cases of metastatic tumor, 2 cases of fibrous dysplasia of bone, 1 case of osteodysplasia fibrosa, myxoma of the juxta articular, benign giant cell tumor of bone, soft tissue abscess, neurogenic tumor, malignant giant cell tumor of bone, liposarcoma, mesenchymal tumor) in 39 cases are measured, too. 3 regions of interest(ROI) were selected in each focus, and the ROI for three times were selected when the focus is fairly small. The ROI area selected should range from 35 mm2 to 65mm2. Select the average of the three groups of data detected by focus as the final ADC value. 39 cases of SWI image are automatically generated by the SWI software carried by magnetic resonance scanner, and two experienced senior imaging diagnosis physicians evaluate the display conditions of hemorrhage, necrosis, calcification, cystic change, small veins and separated fiber in SWI images to achieve consensus as the final result respectively. Finally, the ADC value detected by the benign group and the malignant group are statistically analyzed using SPSS19.0 software. Results: Firstly, there are 17 cases of benign group, with 7 cases of male patients, 10 cases of female patients.The age ranges between 14 and 69, and the average age is(35.88 ± 13.60); there are 22 cases of malignant group, with 14 cases of male patients, 8 cases of female patients. The age ranges between 13 and 71, and the average age is(43.36 ± 13.45). The gender(Fisher exact test, P>0.05) and age(two independent samples t test, P>0.05)formation of the benign group and the malignant group are of no statistical difference. Secondly, the ADC values(unit×10-3mm2/s) corresponding to the b value of 200s/mm2,400s/mm2, 6 0 0 s / m m2, 8 0 0 s / m m2 a n d 1 0 0 0 s / m m2 i n t h e b e n i g n g r o u p a r e 2.28±0.28,1.79±0.27,1.70±0.25,1.59±0.27,1.53±0.26 respectively. And the ADC values(unit×10-3mm2/s) of the malignant group are 2.11±0.30, 1.60±0.36,1.35±0.32,1.14±0.29,1.11±0.29 respectively. Thirdly, the ADC value of the benign group and the malignant group are of no statistical difference when the b values are 200s/mm2(t =1.733, P>0.05) and 400s/mm2(t=1.865, P>0.05); while they have the statistical difference when the b values are 600s/mm2(t =3.783, P<0.05), 800s/mm2(t =4.901, P<0.05) and 1000s/mm2(t=4.576, P<0.05).Fourthly, the areas under the receiver operating characteristic(ROC) of ADC values are 0.834,0.874 and 0.872 respectively, when the b values are 600s/mm2,800s/mm2 and 1000s/mm2 respectively, and all have diagnostic value(AUC>0.5), which gets the best performance when the b value is 800s/mm2, with the ADC threshold value of 1.39×10-3mm2/s, and the corresponding sensitivity degree and specificity degree of 94.1% and 90.9%. Fifthly, the ADC values(unit×10-3mm2/s) of the cystic or necrosis area in the benign group are 3.31±0.31,3.02±0.25,2.99±0.31,2.94±0.41,2.93±0.42,and the values(unit×10-3mm2/s) in the malignant group are 3.01±0.21,2.87±0.27,2.83±0.29,2.72±0.25,2.60±0.23 respectively. Sixthly, SWI can clearly display the morphological characteristics of 26 cases of pathology of musculo-skeletal system, and can clearly observe the destruction conditions of small vein, cystic change, hemorrhage, necrosis and bone of the pathology. Conclusion: Firstly, the relationship between the shape and size of focus and the surrounding tissues can be demonstrated by DWI and SWI clearly; secondly, when the b value is 600s/mm2, 800s/mm2 or 1000s/mm2, DWI have a certain differential value for judging the benign and malignant lesions of musculo-skeletal system; thirdly, DWI has the best performance in differentiating the pathology nature of the musculo-skeletal system when the b value is 800s/mm2, and the sensitivity degree, specificity degree and accuracy rate are respectively 94.1%, 90.9% and 87.4%, whose corresponding ADC threshold value is 1.39×10-3mm2/s; fourthly, the ADC value of the cystic or necrosis area in the benign group is higher than that in the malignant group; the ADC value in the malignant group decreases with the increasing of the b value, while the change of the ADC value in the benign group is not obviously with the increasing of the b value. fifthly, SWI has certain application value in the observation of some features of pathology of the musculo-skeletal system and the destruction of cystic degeneration, hemorrhage, small vein and bone within the focus. |
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