Q 1.35. Neuroimaging Techniques

1. Neuroradiology:

  • Neuroradiology is a specialized field within radiology that focuses on imaging the central nervous system (CNS), including the brain and spinal cord.
  • It encompasses various imaging modalities, such as X-rays, computed tomography (CT), and magnetic resonance imaging (MRI).
  • Neuroradiologists interpret these images to diagnose neurological conditions, tumors, vascular abnormalities, and traumatic injuries.


2. CT Imaging Technique

Computed Tomography (CT) is a non-invasive diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images of the body. During a CT scan, the patient lies on a bed that moves through the gantry while an X-ray tube rotates around them, capturing multiple images from different angles. These images are then processed to create detailed pictures of the bones, blood vessels, and soft tissues inside the body.


Use of CT in Diagnosing Brain Diseases

CT scans are pivotal in neurology for diagnosing various brain diseases. They can quickly provide detailed information about brain tissue and structures, making them especially useful in emergency situations. CT imaging can detect conditions such as:

  • Brain tumors
  • Hemorrhages
  • Strokes
  • Skull fractures
  • Intracranial bleeding
  • Hydrocephalus
  • Infections


Indications and Contraindications for Contrast CT

Contrast agents in CT scans enhance the visibility of certain tissues or blood vessels and can be crucial for diagnosis. However, there are specific indications and contraindications for their use:


  • To enhance the visualization of tumors, infection, or blood clots
  • To guide biopsies or other procedures
  • To assess blood flow and detect abnormalities.


  • Known allergies to contrast agents
  • Renal impairment or failure
  • Pregnancy
  • Recent radioactive iodine treatment for thyroid disease
  • Metformin use in diabetic patients due to the risk of lactic acidosis.


3. Magnetic Resonance Imaging (MRI):

  • MRI is a noninvasive imaging technique that uses strong magnetic fields to create detailed images of soft tissues, including the brain.
  • It provides exquisite anatomical information, allowing visualization of brain structures, white matter tracts, and abnormalities.
  • MRI is widely used for diagnosing conditions like strokes, tumors, multiple sclerosis, and neurodegenerative diseases.


4. Positron Emission Tomography (PET):

  • PET scans involve injecting a small amount of radioactive material (a radiotracer) into the patient’s body.
  • The radiotracer emits positrons, which collide with electrons in the tissue, producing gamma rays.
  • These gamma rays are detected by PET scanners, creating functional images that reveal metabolic activity.
  • PET is valuable for assessing brain function, blood flow, and glucose metabolism. It aids in diagnosing Alzheimer’s disease, epilepsy, and brain tumors.


5. Functional Magnetic Resonance Imaging (fMRI):

  • fMRI measures changes in blood oxygen levels to infer neural activity.
  • It captures brain activation patterns during specific tasks or at rest.
  • Researchers use fMRI to study cognitive processes, memory, language, and emotions.
  • Clinical applications include preoperative mapping and assessing brain disorders.


6. SPECT Imaging Studies

Single Photon Emission Computed Tomography (SPECT) is a nuclear medicine imaging technique that provides three-dimensional images of the body’s internal functions. Unlike other imaging modalities that primarily show the structure of internal organs, SPECT can demonstrate how well organs are working by measuring blood flow and metabolic processes.

How SPECT Works

SPECT involves the use of radiotracers, which are radioactive substances that accumulate in specific organs or tissues based on their function. These radiotracers emit gamma rays, which are detected by a gamma camera as the patient lies within the scanner. The camera rotates around the patient, capturing multiple images from different angles, which are then reconstructed into 3D images.


7. DaT Scan Technique

A DaTscan is a specialized imaging technique used to diagnose Parkinson’s disease and other forms of parkinsonism. It involves the injection of a radioactive substance called Ioflupane (123I), which is taken up by dopamine transporters in the brain. The patient then undergoes a SPECT scan to produce images of the striatum, a part of the brain involved in movement. In Parkinson’s disease, the striatum will show reduced uptake of the tracer, indicating a loss of dopamine-containing nerve cells, which is a hallmark of the condition.

The DaTscan is particularly useful in differentiating Parkinson’s disease from conditions with similar symptoms, such as essential tremor. In essential tremor, the DaTscan would appear normal because there is no loss of dopamine transporters.

It’s important to note that while a DaTscan can support the diagnosis of Parkinson’s disease, it is not used as a preliminary screening tool and is typically only employed after classic motor symptoms are present. The diagnosis of Parkinson’s disease is primarily clinical, based on physical examination findings, and a DaTscan is used to confirm the diagnosis in uncertain cases.


Key Takeaways:

  • Neuroimaging techniques provide insights into brain structure, function, and pathology.
  • Structural imaging (e.g., MRI) visualizes brain anatomy, while functional imaging (e.g., fMRI, PET) reveals brain activity.
  • These tools aid in diagnosis, research, and treatment planning.

Remember, the brain’s mysteries unfold through these remarkable imaging methods! 



1 technologynetworks.com

2 cambridge.org

3 academic.oup.com

4 assets.cambridge.org

5 radiopedia.org




Verified by Dr. Petya Stefanova