It is important to present a rationale for this component of therapy as you introduce it to the patient. The patient should understand why imaginal exposure is a critical component of PE and how it will help treat PTSD.
You can use the same techniques you used previously in the treatment rationale. In addition, the key points to convey in the imaginal rationale are:
it will help the patient process and organize the memory.
it will emphasize the difference between the trauma memory and the actual trauma, so the patient won't feel "re-traumatized" when recalling the memory.
it will promote habituation to the memory.
it will counteract the generalization of fear from the specific trauma to other, safe situations.
it will provide a sense of mastery and self-control.