load C-Style Images without using vtkImageImport

Hello. I have a question.
Is there a way to load * C-Style Images * without using vtkImageImport? Passing an image buffer using vtkImageImport will refresh the image buffer each time. Is there a way to add image slices one by one, rather than passing large arrays (whole slices) at once?

In my development environment (ex, 32bit application), there are limitations when creating large buffers for multiple large images.

ps. I think that if you load all the images and then render them, the user will think that they are slow, so I want to load and draw the image slices in parallel, is it possible with VTK?
(ex. 1. Pass an empty large array to vtkImageImport and render the VTK.
2. Copy the image slice buffer to the large array using threads in the background, then constantly update the renderer.)