[Radiological diagnosis of the lateral ventricle tumor (author's transl)].

The radiological characteristics of intraventricular tumors were studied with special reference to differential diagnosis from paraventricular tumors by careful analysis of seven cases intraventricular tumors and five cases paraventricular tumors. As, in the radiological term, intraventricular tumors have been dividied into two groups according to their location by Bernasconi et al., seven cases intraventricular tumors reported in this paper were also divided into two groups; 1) 2 cases ependymom occupying the frontal horn and the body of lateral ventricle, 2) 4 cases meningioma and one plexus papilloma occupying the trigone and the adjucent regions. In case of tumors belonged to group 1, the filling defect showing the circumference of tumors and the associated unilateral hydrocephalus were characteristic findings on the ventriculogram, while the depression of ventricular wall was observed in paraventricular tumors. Angiographic characteristics in group 1 tumors were the splay of subependymal veins of the medial group from those of lateral group and the increased density of deep veins due to raised circulation, and these findings demonstrated in all cases of ependymoma reported here. On the other hand, in all meningiomas belonged to group 2, the hypertrophia of choridal arteries was noticed in the angiogram. Moreover, the anterior choroidal artery was shown to be divided into two branches at its plexal segments, and the tumor stain at the trigone always lied between these two branches. We named this dissociation of these two plexal branches due to tumor as "flare sing". This is considered to be specific finding for a trigone meningioma, and this "flare sing" was observed in all of our 4 cases meningioma. In two cases out of four, the inferior ventricular vein was displaced anteriorly delineating the anterior margin of the tumor. This again is considered as a sign indicating the tumor occupying the trigone and adjacent regions.