c# 判断是否是DICOM文件

public bool isDicom(string filename)
        {
            FileStream fs = File.OpenRead(filename);

            byte[] data = new byte[];
            fs.Read(data, , data.Length);

            int b0 = data[] & , b1 = data[] & , b2 = data[] & , b3 = data[] & ;

            if (data[] ==  && data[] ==  && data[] ==  && data[] == )
            {
                return true;
            }
            else if ((b0 ==  || b0 == ) && b1 ==  && b3 == )
            {
                return true;
            }
            return false;
        }