锥形束CT三维可视化技术在腮腺造影成像中的应用

The application of three-dimensional visualization technique of cone-beam computed tomography in parotid sialography

目的研究腮腺造影成像中锥形束计算机体层摄影术(CBCT)三维可视化影像特点。方法对25例患者的腮腺造影CBCT影像进行回顾性分析,应用CBCT三维可视化技术如多平面重建(MPR)、最大密度投影(MIP)、三维容积重建(VR)对影像进行三维重建,比较这些技术的腮腺造影成像特点。结果慢性阻塞性腮腺炎12例、复发性腮腺炎7例、腮腺肿瘤6例。MPR、MIP、VR均可以从任意方向显示腺体和导管,MPR可以逐层显示,MIP、VR不能逐层显示,VR只能显示导管与腺体的表面影像。MPR可以清楚地显示腺体内部结构、腺体与周围组织结构的位置关系,正常腺泡成云雾状,腺小叶被纤维间隔分隔,形成一朵朵白云状,分支导管清晰可见。MIP可以清楚地显示腺体、导管的整体影像,正常腺泡呈淡薄的云雾状;主导管及分支导管影像较MPR的清晰。MIP、VR难以确定腺体内部病变的位置。结论腮腺造影CBCT影像清晰,MPR、MIP相结合可以对腮腺疾病进行准确判断及精确定位。

Objective To study the character of three-dimensional visualization image of cone-beam computed tomography （CBCT） in parotid sialography. Methods 25 cases of CBCT image in parotid sialography were retrospective analyzed. The three-dimensional visualization techniques, such as MultiPlanar Reconstruction （MPR）, Maximum Intensity Projection （MIP） and Volume Rendering （VR）, were performed to reconstruct the images. The character of image shown by each technique was discussed. Results 12 cases with chronic obstructive parotitis, 7 cases with recurrent parotitis and 6 cases with benign tumor were identified. The acinus system and ducts system of parotid were clearly displayed from any orientation by MPR, MIP and VR. The gland could be displayed slice to slice by MPR. However, it couldn＇t be done by MIP and VR. VR could only show the surface image of the gland and the main duct. The internal and surrounding structures of parotid were clearly shown by MPR. The regular acinuses look like cloud and mist in MPR. The gland lobulars were separated by fibrous tissue and look like accumulated cloud in MPR. The branch conducts were also clearly shown by MPR. On the other hand, MIP could clearly display acinuses and ducts as whole. Normal acinuses were shown as dilute cloud in MIP. But the main duct and branch ducts were clearer than that was shown by MPR. Finally, it was difficult to identify the location of lesions which occurred in interior of the gland by MIP and VR. Conclusions CBCT image in parotid sialography could clearly show the acinus and ducts system. In order to do precise judgement and accurate localization of the lesion in parotid, MPR and MIP analysis technique might be used together.