MRI Study On Structural Impairement Of Hippocampus And Corpus Callosum In Patients With Coal Mine Gas-explosion-related Posttraumatic Stress Disorder

Part 1:Structural impairments of hippocampus in coal mine gas-explosion-related posttraumatic stress disorder[Purpose] Investigations on hippocampal volume have revealed inconsistent results in patients with posttraumatic stress disorder (PTSD). Little is known about the structural covariance alterations of the hippocampus in PTSD. In this study, we evaluated the alteration in the hippocampal volume and its structural covariance in the coal mine gas-explosion-related PTSD.[Methods] High resolution T1-weighted magnetic resonance imaging (MRI) was performed on coal mine gas-explosion-related PTSD patients (all males; n= 14) and non-traumatized coalminers without PTSD (all males; n=25). The current and lifetime Clinician Administered PTSD Scale (CAPS) was administered to assess the symptom severity for each patient. For each subject, anxiety and depression symptoms were assessed using the Hamilton Rating Scale for Anxiety (HAMA) and Depression (HAMD), respectively. The voxel-based morphometry (VBM) method was used to test the inter-group differences in hippocampal volume as well as the inter-group differences in structural covariance between the ipsilateral hippocampus and amygdala.[Results] PTSD patients exhibited decreased gray matter volume (GMV) in the bilateral hippocampi compared to controls (p<0.05, FDR corrected). GMV covariances between the ipsilateral hippocampus and amygdala were significantly reduced in PTSD patients compared with controls (p< 0.05, FDR corrected).[Summary] The coalminers with gas-explosion-related PTSD had decreased hippocampal volume and structural covariance with the ipsilateral amygdala, suggesting that the structural impairment of the hippocampus may implicate in the pathophysiology of PTSD.Part 2:DTI study on corpus callosum in coal mine gas-explosion-related posttraumatic stress disorder[Purpose] Impaired corpus callosum (CC) has been reported in childhood trauma-related posttraumatic stress disorder (PTSD); however, the alteration of CC in adult-onset PTSD remains unknown.In this study, we used diffusion tensor imaging (DTI) to divide CC into seven sub-regions (rostrum, genu, rostral body, anterior mid-body, posterior mid-body, isthmus, and splenium). The differences in fractional anisotropy (FA) within seven sub-regions of the CC were compared between the two groups.[Methods] In this study,14 victims of a coal mine gas-explosion with PTSD and 23 matched healthy coalminers were enrolled. The current and lifetime Clinician Administered PTSD Scale (CAPS) was administered to assess the symptom severity for each patient. For each subject, anxiety and depression symptoms were assessed using the Hamilton Rating Scale for Anxiety (HAMA) and Depression (HAMD), respectively. The diffusion tensor imaging was performed using a Siemens 3.0T Magnetom Verio scanner.[Results] (1) Compared to the controls, PTSD coalminers exhibited significantly reduced FA values in the anterior sub-regions (rostrum, genu, rostral body, anterior mid-body) of the CC (Bonferroni correction,p<0.0071), which mainly connected the bilateral frontal lobes. (2) There were no significant correlations between FA values of the whole CC and its sub-regions with symptoms severity of PTSD (total or subtype scores of CAPS).[Summary] The findings suggest that adult-onset PTSD patients also have the CC impairment, especially the anterior part of the CC, which may underlie abnormal information communication between the bilateral frontal cortical regions and may implicate in the pathophysiology of PTSD.ConclusionsTo our knowledge, this is the first study to investigate the structural covariance of the hippocampus in PTSD.We found that bilateral hippocampal GMVs decreased in coal mine gas-explosion-related PTSD patients, especially the left hippocampus; and the hippocampal regions exhibiting reduced GMV had decreased structural covariance with the ipsilateral amygdala, which may implicate in the pathophysiology of PTSD. This is the first study that specially designed to investigate white matter integrity of the CC in adult-onset PTSD patients. Our findings indicate that the CC impairment exists in adult PTSD patients, especially the anterior part of CC, which may underlie abnormal information communication between bilateral frontal cortical regions and may implicate the pathophysiology of PTSD.