c# 判断是否是DICOM文件

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

            byte[] data = new byte[132];
            fs.Read(data, 0, data.Length);

            int b0 = data[0] & 255, b1 = data[1] & 255, b2 = data[2] & 255, b3 = data[3] & 255;

            if (data[128] == 68 && data[129] == 73 && data[130] == 67 && data[131] == 77)
            {
                return true;
            }
            else if ((b0 == 8 || b0 == 2) && b1 == 0 && b3 == 0)
            {
                return true;
            }
            return false;
        }