Brain Imageries Flashcards
What are the different types of brain imagery?
CT Scans Positron emission tomography (PET) scans Single-photon emission tomography (SPECT) scans Magnetic Resonance Imaging (MRI) scans Functional MRI (fMRI) Regional Cerebral Blood Flow (rCBF) Magneotoencephalography (MEG)
What is a CT scan?
Computerized Tomography
A CT scan uses a computer that takes data from several X-ray images of structures inside a human’s or animal’s body and converts them into pictures on a monitor.
The CT scanner uses digital geometry processing to generate a 3D image of the inside of the subject.
Although CT is a useful tool for assisting diagnosis in medicine, it is a source of ionizing radiation and can cause cancer.
A CT scanner emits a series of narrow beams through the human body as it moves through an arc, unlike an X-ray machine which sends just one radiation beam. The final picture is far more detailed than an X-ray image.
Inside the CT scanner there is an X-ray detector which can see hundreds of different levels of density. It can see tissues inside a solid organ.
Sometimes a contrast dye is used because it shows up much more clearly on the screen.
CT scanning is useful to get a very detailed 3D image of certain parts of the body, such as soft tissues, the pelvis, blood vessels, the lungs, the brain, abdomen, and bones.
A radiologist who is trained in supervising and interpretingradiologyexaminations will analyze the images and send his/her report to the patient’s doctor. A radiologist is a doctor.
A CT scan uses X-rays. AnMRIdoes not use X-rays; it uses magnets and radio waves.
A CT scan shows organ tear and organ injury more quickly - so it may be the best choice for accident victims.
What is a PET scan? (might not be on the test)
A positron emission tomography (PET) scan is an imaging test that helps reveal how your tissues and organs are functioning. A PET scan uses a radioactive drug (tracer) to show this activity.
The tracer may be injected, swallowed or inhaled, depending on which organ or tissue is being studied by the PET scan.
The tracer collects in areas of your body that have higher levels of chemical activity, which often correspond to areas of disease. On a PET scan, these areas show up as bright spots.
A PET scan is useful in revealing or evaluating several conditions, including some cancers, heart disease and brain disorders.
What is a SPECT scan? (might not be on the test)
A single-photon emission computerized tomography (SPECT) scan lets your doctor analyze the function of some of your internal organs.
A SPECT scan is a type of nuclear imaging test, which means it uses a radioactive substance and a special camera to create 3-D pictures.
While imaging tests like X-rays can show what the structures inside your body look like, a SPECT scan produces images that show how your organs work.
For instance, a SPECT scan can show how blood flows to your heart or what areas of your brain are more active or less active.
What is a MRI?
Magnetic resonance imaging (MRI) is a technique that uses a magnetic field and radio waves to create detailed images of the organs and tissues within your body.
Most MRI machines are large, tube-shaped magnets. When you lie inside an MRI machine, the magnetic field temporarily realigns hydrogen atoms in your body.
Radio waves cause these aligned atoms to produce very faint signals, which are used to create cross-sectional MRI images — like slices in a loaf of bread.
The MRI machine can also be used to produce 3-D images that may be viewed from many different angles.
What is the difference between and MRI and a CT scan?
A CT scan uses X-rays. An MRI does not use X-rays; it uses magnets and radio waves.
A CT scan does not show tendons and ligaments, an MRI does.
MRI is better for looking at the spinal cord.
A CT scan is better for looking at cancer,pneumonia, abnormal chest x-rays, bleeding in the brain (especially from injury).
A brain tumor is better seen on MRI.
A CT scan shows organ tear and organ injury more quickly - so it may be the best choice for accident victims.
CT scans are better at visualizing the lungs and organs in the chest cavity between the lungs.
What is a fMRI?
A functional MRI measures the changes in blood flow that occur when specific parts of your brain are working.
Why would a Dr. us a fMRI?
To identify the exact locations of critical functions, such as speech and movement, so that surgeons can avoid injuring those places while operating.
What is the difference between structural MRI and Functional MRI?
Structural reveals brain anatomy and functional reveals brain function.
What is rCBF and what does it measure? (might not be on the test)
Regional Cerebral Blood Flow.
Measures theamountofbloodflowtoaspecificregion
ofthebrain.
What is an EEG? (might not be on the test)
An electroencephalogram (EEG) is a test that detects electrical activity in your brain using small, flat metal discs (electrodes) attached to your scalp.
Your brain cells communicate via electrical impulses and are active all the time, even when you’re asleep.
This activity shows up as wavy lines on an EEG recording.
An EEG is one of the main diagnostic tests for epilepsy.
An EEG may also play a role in diagnosing other brain disorders.
