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Neuroimaging Shows Impact of PTSD in Earthquake Survivors

MRI shows surprising differences in brain structure among adult earthquake survivors with and without post-traumatic stress disorder (PTSD), according to a new study appearing online in the journal Radiology.

PTSD is an anxiety disorder triggered by a traumatic event resulting in serious physical injury or with the potential to cause serious physical injury. According to the National Institute of Mental Health, up to 6.8 percent of U.S. adults will experience PTSD in their lifetime. Symptoms can include strong and unwanted memories of the event, bad dreams, emotional numbness, intense guilt or worry, angry outbursts, feeling “on edge,” and avoiding thoughts and situations that are reminders of the trauma.

For the study, the researchers aimed to explore cerebral alterations related to the emergence of PTSD, and to explore the relationship between abnormalities or structural changes in the brain and the clinical severity and duration of time since the trauma.

Patients were recruited from a large-scale survey of 4,200 earthquake survivors. The inclusion criterion for all screened survivors was direct exposure to the massive destruction, medical injury and deaths from the earthquake.

“It is particularly important to compare PTSD patients to similarly stressed individuals in order to learn about the specific brain alterations directly related to PTSD that occur above and beyond general stress responses,” said the study’s senior author, Qiyong Gong, M.D., Ph.D., from Huaxi MR Research Center at West China Hospital of Sichuan University in Chengdu, China.

The patients were initially evaluated using the Clinician-Administered PTSD Scale (CAPS) by trained earthquake support psychologists, and those with a CAPS score of ?50 were further evaluated by a psychiatrist to determine the presence or absence of PTSD and other psychiatric diagnoses. Patients with a history of psychiatric disorder before the earthquake, drug dependence or other relevant medical conditions were excluded from the study.

Ultimately, the study included 67 PTSD patients and a matched group of 78 healthy survivors. All participants underwent MRI scanning on a 3.0T MRI system.

The findings revealed the PTSD patients had greater cortical thickness in certain brain regions and reduced volume in other brain regions compared to healthy earthquake survivors. PTSD severity was positively correlated with cortical thickness in the left precuneus region of the brain.

Image shows brain scans with the cortical thickness mapped.

Maps of statistically significant cortical thickness differences between patients with PTSD and healthy survivors and of relationships between CAPS scores and cortical thickness in regions where significant cortical thickness changes were observed in patients with PTSD. Clusters of significantly increased cortical thickness were projected onto the inflated surface of the hemisphere. The first row shows the cluster located in the left precuneus, and second row shows the cluster located in right superior temporal gyrus extending to the inferior parietal lobule. Scatter plots show the averaged cortical thickness within the significant clusters and CAPS scores for patients with PTSD. Credit: Radiological Society of North America.

“Our results indicated that PTSD patients had alterations in both gray matter and white matter in comparison with other individuals who experienced similar psychological trauma from the same earthquake,” Dr. Gong said. “Importantly, early in the course of PTSD, gray matter changes were in the form of increased rather than decreased cortical thickness, as opposed to most reported observations from other studies of PTSD. This might result from a neuroinflammatory or other process that could be related to endocrine changes or a functional compensation.”

Dr. Gong added that the left precuneus is well known to be important in visual processing and is more active in PTSD patients during memory tasks. “It’s possible that changes in the precuneus may comprise a neural alteration related to visual flashback symptoms in PTSD,” he said.

According to the researchers, the study findings have important potential clinical value for identifying individuals who are likely to develop persistent PTSD after experiencing a devastating event.

About this neuroscience research

Funding: This work was supported by the National Natural Science Foundation, Program for Changjiang Scholars and Innovative Research Team in University.

Source: Linda Brooks – RSNA
Image Credit: Image is credited to Radiological Society of North America.
Original Research: Abstract for “Posttraumatic Stress Disorder: Structural Characterization with 3-T MR Imaging” by Shiguang Li, Xiaoqi Huang, Lingjiang Li, Fei Du, Jing Li, Feng Bi, Su Lui, Jessica A. Turner, John A. Sweeney, and Qiyong Gong in Radiology. Published online March 1 2016 doi:10.1148/radiol.2016150477


Abstract

Posttraumatic Stress Disorder: Structural Characterization with 3-T MR Imaging

Purpose
To explore cerebral alterations related to the emergence of posttraumatic stress disorder (PTSD) by using three-dimensional T1-weighted imaging and also to explore the relationship of gray and white matter abnormalities and the anatomic changes with clinical severity and duration of time since the trauma.

Materials and Methods
Informed consent was provided, and the prospective study was approved by the ethics committee of the West China Hospital. Recruited were 67 patients with PTSD and 78 adult survivors without PTSD 7–15 months after a devastating earthquake in western China. All participants underwent magnetic resonance (MR) imaging with a 3-T imager to obtain anatomic images. Cortical thickness and volumes of 14 subcortical gray matter structures and five subregions of the corpus callosum were analyzed with software. Statistical differences between patients with PTSD and healthy survivors were evaluated with a general linear model. Averaged data from the regions with volumetric or cortical thickness differences between groups were extracted in each individual to examine correlations between morphometric measures and clinical profiles.

Results
Patients with PTSD showed greater cortical thickness in the right superior temporal gyrus, inferior parietal lobule, and left precuneus (P < .05; Monte Carlo null-z simulation corrected) and showed reduced volume in the posterior portion of the corpus callosum (F = 6.167; P = .014) compared with healthy survivors of the earthquake. PTSD severity was positively correlated with cortical thickness in the left precuneus (r = 0.332; P = .008). The volumes of posterior corpus callosum were negatively correlated with PTSD ratings in all survivors (r = −0.210; P = .013) and with cortical thickness of the left precuneus in patients with PTSD (r = −0.302; P = .017).

Conclusion
Results indicate that patients with PTSD had alterations in both cerebral gray matter and white matter compared with individuals who experienced similar psychologic trauma from the same stressor. Importantly, early in the course of PTSD, gray matter changes were in the form of increased, not decreased, cortical thickness, which may have resulted from neuroinflammatory or other trophic process related to endocrine changes or functional compensation.

“Posttraumatic Stress Disorder: Structural Characterization with 3-T MR Imaging” by Shiguang Li, Xiaoqi Huang, Lingjiang Li, Fei Du, Jing Li, Feng Bi, Su Lui, Jessica A. Turner, John A. Sweeney, and Qiyong Gong in Radiology. Published online March 1 2016 doi:10.1148/radiol.2016150477

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