Greyscale texture reading with Xenko

//context - GraphicsContext
//texture - Height map texture with disabled mipmaps, streaming and imported as greyscale!!!
var image = texture.GetDataAsImage(context.CommandList);
var heightData = GetHeightDataFromTexture(image);
 //Method makes greyscale reading from Xenko image
 private byte[,] GetHeightDataFromTexture(Image image)
 {
            var box = image.ToDataBox().First();
            var dataArray = new int[box.SlicePitch / 4];
            Marshal.Copy(box.DataPointer, dataArray, 0, dataArray.Length);
            var imageWidth = box.RowPitch / 4;
            var imageHeight = box.SlicePitch / box.RowPitch;
            var heightData = new byte[imageWidth, imageHeight];
            for (int y = 0; y < imageHeight; y++)
            {
                for (int x = 0; x < imageWidth; x++)
                {
                    heightData[x, y] = (byte) (dataArray[y * imageWidth + x] & 0xFF);
                }
            }
            return heightData;
}