Research Of The Relationship Between3-D Morphology Of Maxillary Sinus And Maxillary Sinusitis

Objective:A3-D morphology of the maxillary sinus is reconstructed. In such3-D morphology, the volumes,3-D shape, and gasification coefficients of the maxillary sinus are measured, analyzed, and compared between the maxillary sinusitis group and the control group. Based on this work, we study the sub-type of3-D morphology of the maxillary sinus, and the relationship between sinusitis,3-D morphology, volume, and gasification coefficients. Furthermore, we investigate the mechanism of how the maxillary sinusitis affects the gasification in the different developmental stages of the maxillary sinus. Finally, from a morphological point of view, we examine the pathological mechanism of the maxillary sinusitis.Methods:1Data sample collection:50cases from each adult group, one with normal bilateral maxillary sinus, and the other with unilateral maxillary sinus inflammation or bilateral maxillary sinus inflammation. Use Siemens SOMATOM Definition CT for sequential scanning the nasal-sinus-head with the slice thickness of1mm. After scanning, the DICOM data is recorded in CD-ROM and transferred into other computer for measurement and analysis.2Firstly reconstruct2-D multi-planar images using Simplant14.13-D medical image processing software. The DICOM data is processed by Simplant software for maxillary sinus reconstruction and measurement. Continuously observe the images, and measure the maximum anteroposterior diameter, longitudinal diameter, and transverse diameter of the bilateral maxillary sinus by the conventional method of measurement. Calculate the gasification coefficient of the maxillary sinus based on the2-D measurement of the maxillary sinus. Then reconstruct3-D shape of the maxillary sinus, and measure the volume of left and right maxillary sinus by the volume calculation in3-D measurements. With the successive slicing of the3-D morphology, identify the foremost and rearmost points, highest and lowest points, leftmost and rightmost points of each maxillary sinus in3-D space. Measure the distance between the corresponding two points on coronal plane, transverse plane, and sagittal plane respectively, and record corresponding data as z, y, x. Calculate the gasification coefficient of the maxillary sinus based on the3-D measurement of the maxillary sinus.Results:1The measurement of the diameters of the maxillary sinus in2-D approach:the anteroposterior diameter of the group with normal bilateral maxillary sinus is36.28±3.07mm, the longitudinal diameter is34.10±2.56mm, and the transverse diameter is23.37±2.40mm. For the inflammation group, the anteroposterior diameter is35.74±2.56mm, the longitudinal diameter is33.54±2.61mm, and the transverse diameter is23.29±2.70mm. There is no significant difference between the values of various diameters for the normal maxillary sinus group and maxillary sinus inflammation group.2Measurement of the volume of the maxillary sinus:the volume of the normal maxillary sinus group is15018.64±473.36mm3. The volume of the maxillary sinus inflammation group is14971.86±360.93mm3. There is no significant difference between the values of volumes for the normal maxillary sinus group and maxillary sinus inflammation group.3The measurement of the diameters of the maxillary sinus in3-D approach:the anteroposterior diameter of the group with normal bilateral maxillary sinus is40.77±2.79mm, the longitudinal diameter is38.37±2.63mm, and the transverse diameter is27.51±2.54mm. For the inflammation group, the anteroposterior diameter is43.72±2.64mm, the longitudinal diameter is42.23±2.06mm, and the transverse diameter is31.07±2.77mm.Compared to the normal group and the inflammatory group, the values of the various diameters as measured in2-D approach and3-D approach are significantly different. Meanwhile, there are significant difference in diameter values between the normal group and the inflammatory group in the3-D measurement.4Calculation of the gasification coefficient:Take the product of the measured diameter values in2-D method as the denominator to calculate the gasification coefficient. The result is0.521±0.047for the normal maxillary sinus group,0.503±0.039for the maxillary sinus inflammation group. There is no significant difference between the two groups.Take the product of the measured diameter values in3-D method as the denominator to calculate the gasification coefficient. The result is0.345±0.071for the normal maxillary sinus group,0.252±0.057for the maxillary sinus inflammation group. There is significant difference between the two groups.5The sub-type of3-D morphology of the maxillary sinus is divided into three types (moderate type, full type and depressed type) and nine subtypes.Conclusion:1Maxillary sinus reconstruction much intuitively reflects the3-D structure and3-D shape of the maxillary sinus, and it provides a better approach to full and deep understanding of the developmental status and the gasification degree of the maxillary sinus.2The occurrence of the maxillary sinus inflammation is closely related to the3-D shape of the maxillary sinus and the gasification coefficient measured by the3-D method. The more regular the3-D shape of the maxillary sinus, with the gasification coefficient>0.300, the lower the probability of the maxillary sinus inflammation. Otherwise, the probability increases.3Speculation:adult inflammation of maxillary sinus may be originated from a relatively larger volume of maxillary sinus in children and adolescents; the affection of the chronic inflammation on the development and gasification of the maxillary sinus has different roles in different stages of human development.