Imaging Methods in Head and Brain Research Paper Example

The methods used for imaging of the head and brain are typically limited to MRI and CT. While MRI has a higher sensitivity when examining intracranial and spinal cord pathologies, due to pristine contrast and soft tissue resolution, CT is superior in the imaging of calcifications in lesions and cortical bone. 

In addition to MRI and CT, positron emission tomography, commonly referred to as PET, can be employed for brain imaging.

Brain

Magnetic resonance imaging and functional magnetic resonance imaging

Magnetic resonance imaging (MRI) and functional magnetic resonance imaging (fMRI) are abundantly applied in psychiatric medicine.

While classic MRI scans focus on the structure of the brain, fMRI also accounts for functional activity, specifically signal changes in the brain resulting from changing neuronal activity. In fMRIs, the patient may perform a mental task, such as reading. The blood then rushes to the utilized area of the brain, where neurons use oxygen, thus transforming oxyhaemoglobin into deoxyhaemoglobin. This change can consequently be detected due to their different magnetic susceptibility. 

Both, classic MRI and functional MRI are useful in the diagnosis and study of tumours, MS, metabolic disorder, psychiatric disorders, such as depression, and many more. 

Positron emission tomography (PET)

PET scans detect changes of glucose levels in the brain, for example in Alzheimer’s or brain tumours. The patient receives radioactively labelled tracers, which may need some time to entre the blood stream, depending on the route of administration. Once absorbed, the tracer (through the blood) travels to locations of high neuronal activity, which is picked up by detectors as visible spots. PET is limited due to its priciness and invasiveness. Its low degree of specific localisation is another contra. 

Head

Computed tomography (CT)

CT scans are the imaging technique of choice for (suspected) cranial fractures, calcifications, and haemorrhages. Moreover, unenhanced CT is the 1st line method in acute head trauma. 

Blood typically appears hyperattenuating and may compress or displace key structures.

Fractures ought to be viewed employing the “bone” window of the CT scan, rather than the “brain” window, as this allows a more detailed observance of the bone structure attributable to a wider CT window width.