If there is no other major cause (obstruction for example), there is nothing to worry. You have already seen a doctor; CT scan
was normal - and benefited from enema
The stool could be hard - that is the reason in many cases. Drink plenty of fluids
The bowel may be 'lazy' - may need to be 'trained'. Due to social pressures, one may not be able to anser the call of nature, at times...When this happens frequently, the bowel habits change. Allot a particular time, allow time, associate with an event - the bowel will move regularly by reflex.
A repeat enema will be of immediate help. For long term, lactulose
, fibres (diet/bulk laxatives) will help