CLINICAL-STUDY OF ENLARGED INFUNDIBULAR DILATION OF THE ORIGIN OF THEPOSTERIOR COMMUNICATING ARTERY

Although some aneurysmal dilations of the origin of the posterior comm unicating artery (PCoA) that are revealed on carotid angiogram are tru e aneurysms or preaneurysmal lesions, the authors warn that diagnosis should not be based only on the size and shape of the dilation, especi ally when the PCoA does not fill. In the present retrospective study, the authors analyzed intraoperative and angiographic findings in 32 pa tients with 34 lesions of the PCoA that were preoperatively diagnosed as aneurysms. Only 10 of the lesions were true aneurysms (six cases) o r enlarged infundibular dilations with reddish bulges (that is, preane urysmal bulge; four cases) at the origin of the PCoA. All of the other 24 lesions, including one lesion with PCoA occlusion, were merely enl arged infundibular dilations without any wall abnormality. A well-deve loped PCoA was observed only in cases of true aneurysm and dilation wi th reddish bulge. No other clinical or angiographic characteristics pr oved useful in identifying the type of lesions. These findings may be helpful to the physician in evaluating the clinical features of such l esions and in determining the diagnosis of enlarged infundibular dilat ion of the PCoA.