The Comparison Of Cephalometric Measurements Between X-ray Cranial Lateral Radiographs And Pseudo-color MRI Transforming Lateral Slices In The Skull

Objective: The cephalometric measurement is an important approach to obtain information in clinical diagnosis,treatment and scientific research such as orthodontics and maxillofacial surgery.MRI(Magnetic Resonance Imaging)black bone sequence provides a new image for cephalometric measurement,but still belong to grayscale image.Because the human eye does not recognize the grayscale image as much as the color image,so we compare the pseudo-color processed MRI transforming the skull lateral slice with the traditional X-ray skull lateral slice are performed in the cephalometric analysis.The observation of pseudo-color MRI transforming the lateral side slice and the X-ray lateral slice are the same in cephalometric measurement,providing a new strategy for orthodontic clinical imaging and providing accurate diagnosis for orthodontic treatment.Methods: A total of 30 newly diagnosed patients with orthodontic orientation in the Department of Orthodontics in Tongliao Hospital from December 2017 to December 2018 were selected as subjects.Thirty subjects were examined by X-ray lateral radiograph and MRI.MRI used black bone sequence.The original image data were processed by GE AW4.6 workstation for three-dimensional post-processing.After MRI established the median sagittal plane of the cerebral palsy,pseudo-color processing was performed on the lateral image of the skull.Digital cephalometric analysis of X-ray lateral radiographs and pseudo-color MRI skull lateral radiographs was performed by a senior orthodontist.The Steiner analysis method,which is widely used in orthodontic clinical practice in China,was measured 5 times with an interval of 2 weeks.Identify and mark 8 tissue markers and measure 10 widely used angles and distances.Statistical analysis was performed using SPSS 22.0 software package.There was no statistical difference in cephalometric measurements between X-ray cranial lateral slices and MRI pseudo-color virtual cranial lateral slices.The difficulty in identifying the marker points of the two skull lateral slices during the measurement was evaluated by the subjective image clarity five-point scale.Results: The ICC coefficients of all subjects in the X-ray cranial lateral slice and the pseudo-color MRI transformed cranial lateral slice were greater than 0.9(10/10),and there was no ICC <0.75 measurement project,which proved that the experimental operator has high internal stability.It shows good consistency in each measurement.There were no significant differences between the MRI virtual skull lateral radiograph and the X-ray skull lateral radiograph except the Po-NB distance,UI-NA distance and LI-NB distance(P>0.05).In addition to the statistically significant difference in point A(P=0.00<0.05),the other points were not statistically different.That is,the mark point sharpness X-ray head side slice and the pseudo-color MRI transform the skull side slice,and the pseudo-color MRI has a more prominent advantage at the point A which is difficult to be recognized by the X-ray,and is more clear and accurate than the X-ray slice.Conclusion: There is no statistically significant difference between the pseudo-color MRI skull lateral slices and the X-ray cephalometric measurements(P>0.05),which shows the same X-ray consistency.At the same time,the pseudo-color MRI transforms the lateral tissue of the skull to identify the same sharpness as the X-ray skull.Even in some markers that are difficult to identify by traditional methods,the pseudo-color MRI transforms the lateral slice of the skull more clearly.Therefore,the lateral color slice transformed by pseudo-color has high clinical value and potential ability in cephalometric analysis,which can provide accurate and reliable diagnosis basis for orthodontic treatment.