Page 8 - BH-2-3

Brain & Heart Cerebral ischemia biomarkers

of mechanisms that lead to neuronal injury, cell death, and, useful in diagnosing diseases such as multiple sclerosis,
ultimately, neurological deficits. Early intervention to brain tumors, and neurodegenerative diseases such as
1
restore blood flow and prevent further ischemic damage Alzheimer’s disease (AD). MRI is also used to examine
is critical for improving outcomes in patients with cerebral the blood vessels in and around the brain, aiding in the
ischemia. diagnosis and management of conditions such as stroke
and arteriovenous malformations. 3
Despite advances in acute stroke management, the
timely diagnosis and prognosis of cerebral ischemia depend 2.1.1. Diffusion-weighted imaging (DWI)
largely on clinical assessment, radiological imaging,
and neurological examinations, which may have limited DWI is an important neuroimaging technique that
sensitivity and specificity. Therefore, the search for reliable measures the movement of water molecules in the brain,
1
biomarkers that facilitate early detection, risk stratification, providing information about the integrity of the white
matter and aiding in the diagnosis of acute stroke. DWI
and therapeutic monitoring remains a priority.
can detect regions of restricted diffusion that indicates
This review provides a comprehensive overview of ischemia or tissue damage. 5
the current state of knowledge on cerebral ischemia As an MRI technique, DWI provides crucial information
biomarkers, focusing on their potential role in early about ischemic lesions. The restricted diffusion observed
detection and prediction of clinical outcomes. It addresses in DWI images helps detect early ischemic damage,
various potential biomarkers for the diagnosis of cerebral facilitating therapeutic decisions and predicting treatment
ischemia, the methods of detection and monitoring, and outcomes. DWI detects ischemic damage within minutes
6
the translational challenges of these biomarkers in this and remains the most sensitive non-contrast MRI
complex and clinically important field. In addition, the technique. Restricted water diffusion identifies affected
review discusses several promising biomarkers at different tissue (hyperintense signal) due to cytotoxic edema and
structural levels, such as neuroimaging biomarkers, omics enables early detection and differential diagnosis of acute
data biomarkers, protein biomarkers, genetic biomarkers, stroke. 3
physiological biomarkers, neuroinflammatory biomarkers,
and blood-based biomarkers (Figure 1). 2.1.2. Perfusion imaging and cerebral blood flow
measurement
2. Neuroimaging biomarkers in cerebral
ischemia Perfusion imaging and cerebral blood flow measurement
techniques provide information about the blood supply
Neuroimaging plays a key role in detecting, characterizing, to the brain. These techniques are used to evaluate
and monitoring the progression of ischemic brain injury. patients with suspected ischemic stroke. They can help to
determine the extent of tissue damage and identify areas at
2.1. Computed tomography (CT) and magnetic risk of further damage. Perfusion imaging can also assist
resonance imaging (MRI) in treatment decisions, such as administering thrombolytic

CT and MRI are two commonly used neuroimaging therapy for acute stroke. Perfusion-weighted imaging
6
techniques that provide detailed images of the ischemic (PWI) assesses cerebral perfusion by detecting changes
brain. CT uses X-ray technology to create cross-sectional in regional cerebral blood flow. The discrepancy between
images of the brain, whereas MRI uses powerful magnets the affected region on DWI and the hypoperfused region
and radio waves to generate high-resolution images. 2,3 on PWI can be used to identify potential candidates for
reperfusion therapies. PWI helps assess the ischemic
4
CT scans are often used in emergency settings to quickly penumbra, which indicates potentially salvageable
assess patients with head trauma or suspected stroke. CT is tissue. Cerebral blood flow, cerebral blood volume, and
widely available and useful for early detection of ischemic mean transit time can be quantified to identify areas of
changes. Non-contrast CT is commonly employed to reduced perfusion. In combination with DWI, PWI helps
6
detect hyperacute ischemic lesions by visualizing neuronal characterize the ischemic core and penumbra.
hypodensity or loss of differentiation between gray and
white matter. CT angiography and CT perfusion provide 2.2. Magnetic resonance spectroscopy (MRS)
2
additional information on vascular occlusion and tissue MRS provides insights into the biochemical changes
viability, respectively. 4
associated with ischemia. For example, decreased
MRI, on the other hand, provides more detailed N-acetylaspartate and increased lactate levels correlate
images of the brain compared to CT scans. It can detect with ischemic injury and neuronal dysfunction. MRS can
7
subtle changes in brain anatomy and is particularly assess response to treatment and long-term outcomes.

Volume 2 Issue 3 (2024) 2 doi: 10.36922/bh.2750