CAT SCANS help.
In the modern era, ct's of the abdomen have been very helpful for diagnosing appendicitis
for the non-classic presentations.
In the past, it was not uncommon to operate for appendicitis only to find a normal appendix 10-15% of the time. Thanks to ct scans, this 'negative appendectomy' rate has decreased. Of course, there are radiation risks associated with ct scans' so we have to be selective.