枕骨蛛网膜粒压迹的影像表现

The imaging manifestations of occipital impression by arachnoid granulation

目的 :了解枕骨蛛网膜粒压迹的影像表现 ,避免误诊。方法 :10例因其它原因检查的患者 ,全部摄有头颅正侧位、汤氏位X线片和CT平扫、MR检查。结果 :X线表现为板障内、位于枕骨中线两旁的类圆形囊状透亮区 ,其边缘清楚 ,直径数毫米至 2 .0～ 3.0cm不等 ,相互间可融合 ,以枕骨中线为中心对称呈蝴蝶翼样或散在分布呈蜂窝样排列。其CT表现为板障内囊状透光区多数相互融合呈串珠样 ,并可见内板穿凿样骨质缺损 ,一般为水样密度 ,有少数密度较高。MRI表现板障内可延伸到枕部蛛网膜下腔的类圆形囊状影 ,可相互融合排列成串珠样。T1和T2 加权像与同一层面脑脊液信号相同。结论 :蛛网膜粒压迹无临床意义 ,影像有特征性 ,诊断不难 ,MRI可确诊。

Objective:To understand the image findings of occipital impression by arachnoid granulation (OlAG),and to avoid misdiagnosis.Methods:10 patients who were examined for other reasons were taken X-ray plain film,CT plain scan and MR.Results:In X-ray,OlAC showed lucent similar round areas beside occipital middle line and in diploё.The lucent areas with border well defined were several mm to 1～2cm in diameter.They might mix together and showed like butterfly or honeycomb beside middle line.In CT,lucent areas within diploe were fused like clusters of pearls.Osteolytic bone defects were found.Its density was like that of water,but some might be slight high.In MR,the similar round sacks which were from diploё to subaracnoid space lined up like pearl cluster.No matter it was in T 1 or T 2,the signal of sacks was identical with cerebrospinal fluid in same layer.Conclusion:The OlAG is not clinical significance and is characteristic in image.Its diagnosis can be made easily.Final diagnosis can be made according MR findings.