The patient would be strapped into an open-backed chair, which allowed the spinal needle to be inserted, and they would need to be secured well, for they would be turned upside down at times during the procedure and then somersaulted into a face-down position in a specific order to follow the air to different areas in the ventricles.

Moreover, all the structures captured in the image are superimposed on top of each other, which makes it difficult to pick out individual items of interest (unlike modern scanners, which are able to produce fine virtual slices of the body, including of soft tissues).

This was partially compensated by increased use of angiography as a complementary diagnostic tool, often in an attempt to infer the condition of non-neurovascular pathology from its secondary vascular characteristics.

Another drawback of pneumoencephalography was that the risk and discomfort it carried meant that repeat studies were generally avoided, thus making it difficult to assess disease progression over time.

These revolutionized the field of neuroimaging by not only being able to non-invasively examine all parts of the brain and its surrounding tissues, but also by doing so in much greater detail than previously available with plain X-rays, therefore making it possible to directly visualize and precisely localize soft-tissue abnormalities inside the skull.