多层螺旋CT血管成像在不典型主动脉夹层中的诊断价值

目的探讨CT血管成像技术在不典型主动脉夹层(AAD)中的表现。方法对12例不典型主动脉夹层病例行多层螺旋CT血管造影检查,结合二维和三维重建技术进行图像分析。结果采用Stanford分类法分型:8例为A型,4例B型。AAD CT表现为:(1)均未见撕裂内膜片和双腔影像;(2)主动脉壁新月形或环状增厚(假腔)达5.0～30 mm;(3)平扫假腔密度高于、等于或低于主动脉真腔者,分别为6例、4例和2例;(4)增强扫描假腔均无强化;(5)83%(10例)病变主动脉无明显受压改变;(6)随诊假腔有变化。二维图像(多平面重建及曲面重建)能较好地显示病变范围、大小及细节,而三维重建(最大密度投影、表面遮盖成像和容积重建)良好显示管壁钙化情况和病变空间关系,模拟内镜可以显示动脉内膜情况。结论多层螺旋CT血管造影结合图像后处理技术,是一种准确、有效诊断不典型主动脉夹层的检查方法。

Value in the Diagnosis of Multi - slice Spiral CT Angiography in Atypical Aortic Dissection

Objective To investigate the multi-slice spiral CT（MSCT） angiography In the diagnosis of Atypical Aortic Dissection（AAD）.Methods 12 cases suspected of Atypical Aortic Dissection were examined by MSCT.To combine two-dimension and three dimensional image reconstruction technique.Then executing image was analyzed.Results 8 Debakey type A cases,4 type B cases of Atypical Aortic Dissection were found in our experiments,ADD CT showed that（1） AAD had no split intimal flap and double channels;（2） The aortic wall was crescentic or circumferential incrassation（false lumen） to 5.0～30 mm;（3）On unenhanced CT scan,the density of false lumen was higher or isodensity or lower than that of true lumen respectively in 6 cases,4 cases and 2 cases;（4） The false lumen had on-enhancment on postcontrast CT scan;（5）10 cases（83 %） were lack of serious depression in the involved aortic lumen;（6） Some changes were shown in atypical false lumen with follow up CT scan.Two dimensional imaging（MPVR and CPR） could clearly showed the extent,size and details of lesions.The space relationship and calcifation of aorta were displayed in three dimensional imaging（SSD,VR and MIP）.The presence of intimal flap and reentry of dissection could be clarified by CTVE.Conclusion Associated with image post processing,MSCT angiography might be an effective method for diagnosing Atypical aortic dissection.