Yes, they can resolve themselves, as long as they are not scar tissue. My daughter's stricture was so bad in 2006 that a doc mentioned surgery.
Imagine our surprise to see, in 2009, that it had vanished! Confirmed by SBFT and colonoscopy.
Daughter (22) Dx'd Crohn's 3/06. Misdiagnosed for two years, including by top pediatric Crohn's specialist as stress. No symptoms for the past three years. March '09 colonoscopy showed stricture gone but two spots of inflammation in TI. Used LDN to taper off Entocort last fall. (Was on Entocort since April 06.) Never had D. 4.5 mg LDN, SCD multivit, homemade yogurt, 5000IU vit D3, 1000 mg calcium, 27-54 mg iron, monthly B12 shots, daily oral B12 1000, 10mg zinc. SCD diet modified years ago to include potatoes and rice.