ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the usefulness of two- dimensional (2D) and three-dimensional (3D) computed tomography (CT) in the identification and classification of Le Fort type fractures.</p><p><b>METHODS</b>Sixty-two patients with different types of Le Fort fractures underwent CT scanning and 3D-CT reconstruction. The data were analyzed by multiplanar reconstruction (MPR), surface shaded display (SSD) and volume rendering (VR) respectively.</p><p><b>RESULTS</b>The patients with Le Fort I, Le Fort II fracture and Le Fort III fracture accounted for 16.1%, 14.5% and 12.9% respectively. The compound fractures were the most common type and accounted for 56.5% (n=35, 18 cases with Le Fort I+II fracture, 10 cases with Le Fort II+III fracture and 7 cases with Le Fort I+ II+III fracture). Fifty-five cases coexisted with other fractures in maxillofacial region. 2D-CT could be used to define the tiny fractures and the deep-structure fractures more accurately compared with 3D-CT, but the real impression of Le Fort type fractures could not be correctly evaluated on 2D-CT. 3D-CT could clearly demonstrate the whole shape of Le Fort type fractures and identify the classification of Le Fort fractures.</p><p><b>CONCLUSIONS</b>3D-CT is the best imaging method for the diagnosis of Le Fort type fractures and can provide valuable information of space relationship, especially for the design of treatment plan before operation.</p>
Subject(s)
Adolescent , Adult , Female , Humans , Male , Middle Aged , Facial Bones , Diagnostic Imaging , Wounds and Injuries , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Retrospective Studies , Skull Fractures , Classification , Diagnostic Imaging , Tomography, X-Ray Computed , MethodsABSTRACT
Objective To evaluate the quality of the portal images acquired by computed radiography(CR)system and conventional screen-film system,respectively.Methods imaging plates (IP)and X-ray films of a home-devised lead phantom with a leakage of 6.45% were acquired,and modulation transfer function(MTF)curves of the both images were measured using edge method.Portal images of 40 nasopharyngeal cancer patients were acquired by IP and screen-film system respectively.Two doctors with similar experience evaluated the damage degree of petrosa] bone,the receiver operating characteristic(ROC)curve of CR images and general images were drawn according to two doctors evaluation results.Results The identification frequency of CR system and screen-film system were 1.159 and 0.806 Lp/mm respectively.For doctor one,the area under ROC curve of CR images and general images were 0.802 and 0.742 respectively.For doctor two,the area under ROC curve of CR images and general images were 0.751 and 0.600 respectively.The MTF curve and ROC curve of CR are both better than those of screen-film system.Conclusion The image quality of CR portal imaging is much better than that of screen-film system.The utility of CR in linear accelerator for portal imaging is promising in clinic.
ABSTRACT
Objective To evaluate the CT findings and classification of the Le Fort fracture. Methods Sixty-two cases with Le Fort fractures were studied with thin-slice high-resolution CT scanning and analyzed with three-dimensional(3D)imaging reconstruction.Results Of the 62 patients,10 had Le Fort type Ⅰ fracture,9 had Le Fort type Ⅱ fracture,8 had Le Fort type Ⅲ fracture,and 35 had various combinations of the three types of Le Fort fractures,including 18 Le Fort Ⅰ+Ⅱ fracture,7 Le Fort Ⅰ+ Ⅱ+Ⅲ fracture and 10 Le Fort Ⅱ+Ⅲ fracture.Fifty-five cases had associated multiple fractures in the maxillofacial region.On 2D CT images,Le Fort fracture manifested as multiple and complex fractures. Though 2D image was better than 3D image in accurately defining tiny fractures and fractures of deep structures,the diagnosis of Le Fort fracture could not be correctly made solely on 2D image.3D CT clearly and stereoscopically demonstrated the entire shape and orientation of Le Fort fracture,thus facilitating the correct classification of Le Fort fracture.Conclusion 3D CT image is important in providing information about the space relationship of Le Fort fracture,thus very valuable for the preoperative planning.