Multimodal Imaging Analysis Of Ameloblastomas

Purpose:(1)To analyze and compare the X-ray panoramic radiography and computed tomography(CT)features of amelobastomas,CT classification method was put forward to make radiological classification and pathological classification more unified.(2)To analyze the MR features of amelobastomas and explore the feasibility of MR classification method by using the CT classification method of primary amelobastomas as the reference.(3)To analyze and compare the CT and MR features of amelobastomas,and to compare the effectiveness of X-ray,CT and MR classification methods.Materials and methods:(1)181 subjects who suffered from amelobastoma were performed with X-ray panoramic radiography and CT priored to surgery and pathologic verification.CT classification method was put forward.The features between all sorts of X-ray and CT types of amelobastomas were contrasted,and the two different radiological classification methods were compared.(2)34 pathologically proven amelobastomas performed with conventional MR and functional magnetic resonance imaging(fMRI)were reviewed and analyzed to explore the feasibility of MR classification method developed from CT classification method of primary amelobastomas.(3)34 pathologically proven amelobastomas performed with CT and MR were reviewed.The radiological features were compared between CT and MR.Their respective advantages and disadvantages were discussed.32 pathologically proven amelobastomas were classified by X-ray,CT and MR classification method separately.Then the effectiveness of the three classification methods was compared.Results:(1)Amelobastomas are usually multilocular and cystic-solid.There were contrast enhancements in cystic wall,septa and solid regions,and the contrast enhancement of cystic wall could be mural nodular.The degree of enhancement could be mostly more than 50%.The edges were clear and often company with linear scleroses.The expansile changes and the adjacent bone cortex thin or breakup could be found in the lesions frequently.Generally,they can lead to the changes of the adjacent tooth.CT displayed better than X-ray with regard to the component in tumor,septa and the changes of adjacent bone cortex and surrounding soft tissues.The difference between all sorts of radiological types could be distinguished more correctly by CT classification method than by X-ray classification method.And CT classification method was more accurate than X-ray classification method in distinguishing unicystic type or solid/multicystic type amelobastomas.(2)The MR features of amelobastomas are multilocular and cystic-solid.There are contrast enhancements in cystic wall,septa and solid regions.The surrounding soft tissues are often invaded.The mean ADC values of solid regions and cystic regions were 1.23±0.32×10-3mm~2/s and 2.18±0.48×10-3mm~2/s,obtained with b values of 0 and 1000 s/mm~2.The difference of the mean ADC values in solid regions and cystic regions in tumors between primary and recurrent amelobastomas was non-existent stastically(P>0.05).TIC types of contrast-enhanced regions in amelobastomas were I or II types after DCE-MRI.TTPs of I types were more than 150s,and the mean TTP values of II types were 50.62±10.31s.The difference of the mean TTP values between primary and recurrent amelobastomas was non-existent stastically(P>0.05).(3)Except for 2 extraosseous type,there were 10 cystic,4 solid and 18 cystic-solid lesions distinguished by CT in 32 amelobastomas performed with CT and MRI.And there were 12 cystic,4 solid and 16 cystic-solid lesions distinguished by MRI.The difference of the mean ADC values in cystic regions between cystic and cystic-solid tumor was non-existent stastically(P>0.05).The mean TTP values of the tumors,in which TIC types were II after DCE-MRI,were different between primary and recurrent amelobastomas(56.86±5.27s vs.44.38±10.68s)significantly and stastically(P?0.05).The sensitivity,specificity and accuracy of MR was 100%,100%and 100%for distinguishing unicystic type amelobastomas,and was88.46%,100%,90.63%for distinguishing solid/multicystic type amelobastomas.MR classification method is the best in three radiological classification methods.Conclusion:(1)CT classification is closer to pathological classification,it can provide more information for guiding clinical treatment.(2)The indifference of mean ADC values and TIC types between primary and recurrent ameloblastomas proves MR classification method,developed from CT classification method of primary amelobastomas,is feasible.It can be used for classifying not only primary but also recurrent amelobastomas.(3)In three methods,X-ray,CT and MR classification method,MR classification method is the closest to pathological classification.It can provide more valuable information for estimating pathological classification of amelobastomas preoperatively.