What is structural magnetic resonance imaging (MRI) in PTSD?

The technology of structural MRI is based on the magnetisation properties of cellular protons. The application of a strong magnetic field causes the protons within cells to shift direction, which will return to their original position over time (“precession”). The rate of precession differs across tissue types (such as grey matter and white matter in the brain), which can be interpreted by specialised programs to represent a 3D image. Many mental disorders have shown brain structural changes investigated with MRI, including schizophrenia and bipolar disorder.

What is the evidence for changes in brain structure in PTSD?

Moderate quality evidence found small to medium-sized reductions in total brain volume, intracranial volume, left insula, right insula, total insula, superior frontal gyrus, left middle temporal gyrus, inferior temporal gyrus, left anterior cingulate, total anterior cingulate, rostral anterior cingulate, lateral orbitofrontal cortex total amygdala, left hippocampus, right hippocampus, and total hippocampus in people with PTSD compared to controls.

Moderate to low quality evidence found medium-sized effects of reduced hippocampus volume and large effects of reduced amygdala volume in people with PTSD who were exposed to childhood abuse compared to controls.

Moderate quality evidence found small to medium-sized reductions in grey matter, cerebral volume, temporal lobe, hippocampus, and vermis in children with PTSD compared to controls. There were also non-significant, small reductions in the amygdala.

Moderate to low quality evidence found increased PTSD symptom severity was significantly associated with decreased volume of the left, but not the right, hippocampus.

Compared to people with major depressive disorder, people with PTSD had reduced total brain volume and increased thalamus volume. Both PTSD and depression patients had significantly smaller hippocampal volume compared with controls, with no difference between the patient groups in this brain region.

August 2021

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Last updated at: 3:01 am, 11th October 2021
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