Predilection of brain metastasis in gray and white matter junction and vascular border zones

BACKGROUND The purpose of this study was to assess the importance of the vascular border zone and the gray and white matter junction in the distribution of brain metastases. METHODS We reviewed the medical records, computed tomography (CT) or magnetic resonance imaging (MRI) of 105 patients with secondary brain tumors. The metastatic lesions noted on CT scans or MRI were matched with a predetermined standard sheet containing axial images with shading on the border zones. To be included in the border zones, the center or more than 50% of the lesion had to be situated within these zones. RESULTS Among 100 evaluable patients, there were 302 metastatic brain lesions. Of the 302 lesions, 210 lesions were 2 cm or smaller in greatest dimension and located in cerebral and cerebellar hemispheres. The major vascular border zones were the site of predilection for 103 lesions (62%) although the border zones constitute only 29% of the area. Gray and white matter junction was the preferred site for 135 lesions (64%). CONCLUSIONS The results demonstrated that brain metastasis occurs in the vascular border zone regions and the gray and white matter junction more frequently than previously recognized, and also supported the notion that metastatic emboli tend to lodge in an area of sudden reduction of vascular caliber (gray/white matter junction) and in the area most distal vascular field (border zone). Cancer 1996; 77:1551-5.