Gäbler K, Brühschwein A, Kiefer I, Loderstedt S, Oechtering G, Ludewig E
Klinik für Kleintiere, der Universität Leipzig, An den Tierkliniken 23, 04103 Leipzig.
Tierarztl Prax Ausg K Kleintiere Heimtiere. 2011;39(3):145-53.
Temporomandibular joints (TMJs) of dogs and cats were examined with multislice computed tomography (MSCT) using different technical scan parameters in order to investigate their impact on image quality. Another aspect was to analyze whether size differences of the TMJ affect the display of small joint structures.
The TMJs of two dogs and two cats were examined using MSCT. Scan parameters were varied including tube current, scan matrix, resolution mode, slice thickness, and reconstruction increment. Three observers being blinded with respect to the used scan parameters independently assessed the image quality in terms of "contrast resolution", "bone structure", "spatial resolution", "evaluation of the joint space", and "artefacts" according to a 4-point scale.
The criteria "spatial resolution" and "evaluation of the joint space" emphasize the influence of the size of the TMJ. The image quality of the TMJ of the dogs was evaluated superior (by 0.5 to 1.5 points higher graded) compared to the smaller ones of the cats. In terms of "spatial resolution" and "bone structure" the images of an ultra high resolution technique achieved a higher evaluation level (scoring one point superior) compared to the images created by a high resolution protocol. The tube current did not significantly influence the image quality in any of the pictures.
The display quality of small structures of the TMJ is dependent on the spatial resolution of the CT images. Therefore, a thin slice collimation, a small field of view, and a high resolution reconstruction matrix should be used. Under those aspects subtle alterations of bone structure of the TMJ can be reliably detected. The soft tissue structures of the TMJ can not be visualized with MSCT in small animals. In principle, the results can be applied to any other MSCT-scanner. However, adjustments of the technical parameters may be still necessary.
使用多层螺旋计算机断层扫描(MSCT)并采用不同的技术扫描参数对犬猫的颞下颌关节(TMJ)进行检查,以研究这些参数对图像质量的影响。另一个方面是分析TMJ的大小差异是否会影响小关节结构的显示。
使用MSCT对两只犬和两只猫的TMJ进行检查。扫描参数包括管电流、扫描矩阵、分辨率模式、层厚和重建增量等均有所变化。三名对所使用的扫描参数不知情的观察者根据4分制独立评估图像质量,评估指标包括“对比分辨率”“骨结构”“空间分辨率”“关节间隙评估”和“伪影”。
“空间分辨率”和“关节间隙评估”标准强调了TMJ大小的影响。与较小的猫的TMJ相比,犬的TMJ图像质量评估更高(评分高0.5至1.5分)。在“空间分辨率”和“骨结构”方面,与高分辨率协议生成的图像相比,超高分辨率技术的图像获得了更高的评估水平(评分高1分)。管电流在任何一幅图像中均未对图像质量产生显著影响。
TMJ小结构的显示质量取决于CT图像的空间分辨率。因此,应使用薄层准直、小视野和高分辨率重建矩阵。在这些方面,可以可靠地检测到TMJ骨结构的细微变化。小动物的TMJ软组织结构无法通过MSCT显示。原则上,这些结果可应用于任何其他MSCT扫描仪。然而,可能仍需要调整技术参数。