Segmental colitis

At the age of 39 I had most of my sigmoid colon removed due to severe diverticulitis (hospitalized twice age 35 and 38).   Now at age 47 I have been having rectal bleeding with almost every bowl movement.  I had a colonoscopy last week and am waiting for the pathology results to come back.  The doctor did tell me I had a lot of diverticulosis and segmental colitis.  I of course have been researching like crazy since then and can only find diverticular colitis when I search segmental colitis.  The doctor that did my colonoscopy didn't mention this as a possible cause he mentioned crohn's disease and also Ischemic colitis.  I am curious what other medical professionals may think.  Since from what I have read diverticular colitis almost always only effects the sigmoid colon and I don't have one.