Pretty much, it takes a colonoscopy to determine that. UC starts at the rectum and moves upwards, and the most distal part of the colon is also the last to heal. Oral meds have a tough time treating the far reaches of the colon. If your UC is at all active up the left side, the enema will do a better job than the suppository, because it reaches much further up.
Co-Moderator, UC Forum
Status: Remission since May 2009!
Symptoms began in November 2008, ~4 weeks after giving birth to my son
Diagnosed with pancolitis on 1/30/09
Meds: Apriso (4 0.375g pills ONCE!! daily), mesalamine enema twice weekly, Natural Factors Ultimate probiotic 12/12 Formula, multivitamin. Used prednisone (starting dose 40 mg) to get into remission.