Neuroimaging PDF Techniques

Neuroimaging pdf techniques allow scientists to visualize the brain’s anatomy, physiology and pharmacology in a noninvasive manner. The most advanced tools also capture the brain’s electrical and metabolic activity.

From intensive reading lessons to the reward systems of love, neuroimaging has helped scientists uncover the many ways that our brains work—and what goes wrong when they don’t.

Electroencephalography (EEG)

EEG gives us a window into your brain’s constant neural communication grid, detecting the tiny electrical impulses neurons send to one another as they coordinate essential functions life makes possible. These signaling activities get recorded as squiggly lines, or brain waves, and an eminent neurologist can scrutinize them to detect signs of trouble such as epilepsy.

EEG can reveal patterns of normal or abnormal brain activity, including rhythmic patterns such as alpha waves, beta waves and gamma waves. It can also identify transient features such as spikes and sharp waves, which may indicate seizure activity or a predisposition to seizures.

For an EEG, electrodes are placed on the head. Each electrode produces a voltage signal that is recorded by an electroencephalograph (EEG) machine. These signals are digitized and displayed for the reading neurologist in a display called a montage. Each channel in the montage represents the difference between the voltages at two adjacent electrodes. The neurologist can switch between montages as needed to highlight specific features of interest.

Computed tomography (CT)

Using computer processing, CT scans show cross-sectional pictures of internal organs, blood vessels and soft tissues. In addition to detecting abnormalities, CT is used to guide procedures such as biopsies and the placement of spinal implants.

CT is a valuable test to assess possible pathology in body cavities that are not easily viewed with ultrasound or conventional x-rays (for example, the skull, thorax, abdomen and pelvis). It is also useful for assessing musculoskeletal problems.

A CT exam is a non-invasive procedure that requires little or no preparation, depending on the area of your body being examined. Typically, you will lie on a table and the scanner will move around your body to generate images. A radiologist will interpret your CT scan and may inject you with a contrast dye to help identify certain areas of your body. The radiation from the contrast dye can increase your risk of developing cancer in the future, so you should talk to your doctor about this before getting a CT scan.

Magnetic resonance imaging (MRI)

MRI uses large magnets, radio waves and computer technology to create clear images of organs and structures inside the body without using radiation. It’s especially useful for studying soft tissues, such as those in the brain and spinal cord. MRI is also used to find tumors and other abnormalities, as well as guide biopsy procedures.

During an MRI scan, a person is enclosed in a narrow, cylinder-shaped tunnel. This can be uncomfortable for people who have claustrophobia or are extremely overweight. For certain types of MRI, doctors give patients a contrast dye to improve the clarity of images and help them better understand what the results mean. The dye can cause a metallic taste in the mouth.

MRI is one of the most powerful diagnostic tools in modern medicine, and it has contributed to advanced research and understanding of (patho)physiological processes. However, it is expensive and can drive up overall healthcare costs. Thus, demonstrating that MRI provides clinical value is an imperative for all stakeholders involved in patient care.

Diffusion tensor imaging (DTI)

DTI has opened new frontiers in the study of human brain anatomy and connectivity, enabling us to detect and noninvasively investigate microstructural changes in CNS diseases. It measures the microscopic diffusion of water molecules, allowing clinicians to visualize and evaluate white matter tracts and connectivity.

A matrix representation of the diffusion tensor yields three elements, called eigenvalues, that determine directionality. The largest eigenvalue, called the principal eigenvector, represents the preferred direction of diffusion in each image voxel. The principal eigenvector can be used to visualize white matter fiber tracts with color coding and to identify directional anisotropy using fractional anisotropy (FA) measurements.

DTI can help detect damaged axons in traumatic brain injury (TBI), as well as demyelination caused by axonal shear. It also has the potential to improve the diagnosis of refractory extratemporal neocortical epilepsy by identifying abnormalities that may be missed on conventional imaging. Moreover, it can differentiate between gliomas and solitary metastases in brain parenchyma by measuring FA.

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