Scans cannot stage a cancer. Biopsy is the only reliable method to stage a cancer. Now, a scan could indicate a metastasis and need further testing to see what is actually going on. On one of my scans something irregular appeared on my liver and scared everyone to death (me included) but it ended up being a fat deposit....so, scans can tell you more testing is required but not necessarily exactly what is going on.
Good luck to you.