Regional cerebral blood flow correlated with flashback intensity in patients with posttraumatic stress disorder

Background: Nuclear imaging studies have examined cerebral blood flow (rCBF) in subjects with posttraumatic stress disorder (PTSD) using symptom evocation paradigms. To date, no such studies have investigated rCBF as related to subjects' reports of flashback intensity. Methods: Subjects with varying traumatic histories and longstanding PTSD were studied using [¹⁵O]-H₂O positron emission tomography with an auditory script of their traumatic event. Eight subjects had three resting scans followed by their script and additional scans. Heart rate responses as well as the presence of flashbacks and their intensity were recorded. rCBF was correlated with flashback intensity in each subject's scan. Combined analysis of all subjects' data yielded common regions related to the flashback experience. Results: rCBF correlated directly with flashback intensity in the brainstem, lingula, bilateral insula, right putamen and left hippocampal and perihippocampal, somatosensory and cerebellar regions. Inverse correlations with rCBF were found in bilateral dorsolateral prefrontal, right fusiform and right medial temporal cortices. Conclusions: This study correlated flashback intensity and rCBF in a group of patients with chronic PTSD suggesting involvement of brainstem, and areas associated with motor control, complex visual/spatial cues and memory.