The Study Of MRI Combined With Pseudo-color Processing Technology In Facial Soft Tissue Symmetry

Objective The MRI(Magnetic Resonance Imaging)combined with pseudo-color processing technology was to applied to evaluate the symmetry of facial soft tissue.The 3D data was collected to evaluate facial muscle symmetry facial muscles quantitatively and objectively.Finally,we compare the MRI grayscale images and pseudo-color image to evaluate the muscle symmetry.Provide a basis for the diagnosis and treatment of facial symmetry.Methods Twenty patients with facial asymmetry and 20 patients with facial symmetry were selected from the Tongliao Hospital of Inner Mongolia from 2016 to 2018 as the experimental group and the control group.The head MRI raw data of the two groups of patients were collected and imported into the GE AW4.6 workstation for three-dimensional reconstruction.Two different image display methods are applied.Method A is the original grayscale image of MRI,and method B is the color image processed by the pseudo-color technique of the MRI image.The three-dimensional image obtained by the two methods is segmented using the Segmentation technique in AW4.6 workstation.The bilateral masseter and temporalis muscles were segmented and the volumetric measurements of the muscles after segmentation were performed using the Measure Volume technique.The difference in muscle volume measured under two different image display methods,Method A and method B,was compared.The image clarity under the two display methods was compared using the way the image was scored.For the data measured by Method B,Contrast the volume difference between left and right muscles,the symmetry index of the muscles in the experimental group and the control group are calculated respectively,and the difference of the symmetry index between the experimental group and the control group is analyzed.The asymmetry index of the defined muscle is the absolute value of the left and right volume difference.One month later,grayscale images and color images of 10 patients were randomly selected from 20 patients in the control group and the experimental group.The same experimenter divided the muscles and measured the volume under the same experimental conditions 2 times.The reliability of the segmentation and measurement was evaluated using ICC(Intra-Class Correlation Coeffi).Results There was no significant difference in muscle volume measured between the method A and the method B(P>0.05).There was no significant difference in sharpness of image between method A and method B under subjective evaluation(P > 0.05).On average,the scoring results of method B were more concentrated in very clear and clear scoring areas,and method B was better than method A.In the method B image,the volume difference between the left masseter muscle and the right masseter muscle was statistically significant in the experimental group(P<0.05),and the volume difference between the left temporalis and the right temporalis was statistically significant in the experimental group(P<0.05).There was no significant difference in the volume between the left masseter muscle and the right masseter muscle in the control group(P>0.05).There was no significant difference in the volume of the left temporalis and the right temporalis muscle in the control group(P>0.05).There was a statistically significant difference between the symmetry index of the masseter muscle in the experimental group and the symmetry index of the masseter muscle in the control group(P<0.05).The difference between the symmetry index of the temporalis of the experimental group and the symmetry index of the temporalis of the control group was statistically significant(P<0.05).The patients were randomly measured and the reliability of the measurement was calculated.The calculation results of Method A and Method B were both >0.75,and both had good reliability.In contrast,the repeated experimental ICC values performed under Method B were higher.Conclusion There is no significant difference in muscle volume measured between MRI gray image and pseudo color image.The scoring results show that the pseudo color image is clearer than the gray image,and the contour and fine structure of the muscle can be accurately identified.The data obtained by the experimenter when the experiment was repeated was more stable.In patients with facial asymmetry,the proportion of muscle asymmetry is higher than that of patients with facial symmetry,and the degree of asymmetry is also higher than that of patients with facial symmetry.The application of MRI combined with pseudo-color processing technology can easily and accurately segment the measurement of facial muscles,and can accurately and quantitatively analyze facial soft tissue,and more intuitively obtain the location and asymmetry of facial soft tissue asymmetry,which is facial soft tissue.Symmetry research opens up new ideas and provides more accurate information for the diagnosis and treatment of orthodontic orthognathic and facial aesthetics in patients with facial asymmetry.