From the Guidelines
Brain compression on a CT scan is most accurately identified by signs such as midline shift, ventricular compression, sulcal effacement, loss of gray-white matter differentiation, cisternal compression, and herniation patterns, with the compression of basal cisterns being a key indicator of increased intracranial pressure, as noted in a study from 2018 1.
Key Signs of Brain Compression
- Midline shift: brain structures are pushed away from their normal central position due to pressure from one side
- Ventricular compression or effacement: normal fluid-filled spaces in the brain appear smaller or distorted
- Sulcal effacement: flattening of the normal grooves on the brain surface
- Loss of gray-white matter differentiation in the compressed areas
- Cisternal compression: CSF-filled spaces at the base of the brain appear narrowed or obliterated
- Herniation patterns: subfalcine, transtentorial, or tonsillar herniation where brain tissue is forced into adjacent compartments
Importance of CT Scan Findings
These findings may be accompanied by visible mass lesions like tumors, hemorrhages, or edema that are causing the compression. The severity of these signs correlates with the degree of increased intracranial pressure, which can lead to reduced cerebral blood flow, neurological deficits, and potentially life-threatening complications if not promptly addressed, as discussed in a study from 2015 1 and further emphasized in a study from 2018 1.
Clinical Assessment and CT Scan
Clinical assessment rather than CT scanning should be used to determine the safety of performing a lumbar puncture, with CT scans reserved for patients with specific clinical signs such as new seizures, focal neurological signs, or moderate to severe impairment of consciousness, as suggested in a study from 2012 1.
Radiological Assessment
Radiologists assess these features collectively to determine the urgency of intervention needed to relieve the pressure, with the goal of preventing further brain injury and improving patient outcomes, as highlighted in the studies 1.
From the Research
Signs of Brain Compression on a CT Scan
The following are signs of brain compression that can be identified on a computed tomography (CT) scan:
- Sulcal obliteration: This is a sign of elevated intracranial pressure (ICP) and is associated with measurements of ICP ≥20 mm Hg 2.
- Lateral ventricle compression: This is one of the five signs of elevated ICP measured in a study of traumatic brain injury patients 2.
- Third ventricle compression: This is another sign of elevated ICP and is associated with measurements of ICP ≥20 mm Hg 2.
- Midline shift: This is a sign of brain compression and is associated with abnormal pupillary light reflex findings 3.
- Herniation: This is a sign of severe brain compression and is one of the five signs of elevated ICP measured in a study of traumatic brain injury patients 2.
- Cisternal effacement: This is a sign of brain compression, but is not linked to changes in ventricular compression or sulcal effacement 3.
- Ventricular compression: This is a sign of brain compression, but is not linked to abnormal pupillary light reflex findings 3.
CT Scan Findings
CT scan findings can be used to identify signs of brain compression, including:
- Midline shift: This can be recognized by modeling brain deformation according to the estimated biomechanical properties of the brain and the cerebrospinal fluid spaces 4.
- Sulcal effacement: This is a sign of brain compression, but is not linked to changes in ventricular compression or abnormal pupillary light reflex findings 3.
- Ventricular compression: This is a sign of brain compression and is one of the five signs of elevated ICP measured in a study of traumatic brain injury patients 2.