This is exactly what I described in my previous post.
Note that if you want the spine to appear on top then you don’t need to use reverse perspective. However, most commonly in vascular applications the X-ray source is under the table and the patient lies on the table in supine position, therefore clinicians usually prefer to see the ribs appear on top. To show the ribs on top with correct projection you need the reverse perspective.
For spinal applications (pedicle screw placement, facet joint injections, etc.) you want the spine appear on top but then the patient is in prone position, so again, you need reverse perspective.
For electrophysiology applications, the clinician may want to see the anterior or posterior wall of the left atrium, so you need quick switch between normal and reverse perspective.