This set of Clinical Science Multiple Choice Questions & Answers (MCQs) focuses on “FMRI”.
1. What does the ‘f’ in the fMRI stand for?
Explanation: MRI scans are currently the most advanced type of scans for the soft tissue. However, with MRI, you can only scan the body, i.e. get anatomical images but with fMRI, you can scan the metabolic functions happening within the body. Thus, the term Functional is added to the MRI.
2. What part of the body mostly scanned by fMRI?
Explanation: fMRI is in a way an exclusive way to scan for the brain. One of the main reasons is that fMRI does not require any dyes, even when doing a deep scan. Thus, it is a safer process for doing brain scan as compared to other scanning methodologies. Also, the brain is the most complex organ so using fMRI to get better details about the brain helps in a better study.
3. Which element does the fMRI target when taking the scan?
Explanation: In an MRI, the scans are taken with the help of the Hydrogen atom but in fMRI, the blood oxygen, i.e. the oxygen content of the blood is targeted. It measures the oxygen used up by the various tissues in the organs and images that as the Functional MRI.
4. fMRI is mostly dependent on which parameter?
a) T1 time
b) T2 time
c) T2* time
d) T1 + T2 time
Explanation: When the gradient and RF coils are powered off, the magnetized elements get demagnetized and this causes the image to be formed. T1 is the time for the elements to go back to the original, demagnetized state. T2 is the time needed for the elements to go out of phase. T2* is the time needed for the spin to dephase. T2* is important for fMRI because oxygenated haemoglobin is diamagnetic while deoxygenated hemoglobin is paramagnetic. Thus, the T2* star time will be different for the two of them and the amount of oxygen used by the brain can be mapped.
5. The underlying principle of fMRI is that ___________
a) cerebral blood flow and neuronal activity are not connected
b) cerebral blood flow and neuronal activity are connected
c) certain parts of the brain receive more blood
d) certain parts of the brain are more active than other parts
Explanation: The body functions with the help of oxygen. The oxygen supply allows glycolysis (the breakdown of the sugar molecules), the first step in generating ATP. Thus, when the brain has a good amount of oxygen supply, the neurons will work properly. The supply of oxygen may affect the activity levels of neurons. Maybe diseased neurons will show a different pattern of oxygen consumption. Since oxygen is provided by the blood, thus the researchers came to the conclusion that blood supply and neuronal activity are connected and thus it forms the underlying principle of fMRI.
6. fMRI images the brain tissues with respect to ______
d) blood flow
Explanation: A fMRI scan measures the amount of oxygen used by the body. In order to measure the oxygen used up, a continuous scan is done every few seconds, mostly within a span of 2 – 5 seconds. Thus, the images received are a function of time.
7. fMRI is mostly used for research than diagnosis.
Explanation: fMRI is an expensive process and the hardware and software needed are also very advanced. It is better to use fMRI for study and research purposes for this reason of expense. Also, the medical needs can be diagnosed with a simple MRI. As of now, no researches have not come up with any conditions that can be better diagnosed with a fMRI so it is better suited for research and study purposes.
8. In a transverse section of the CT of the brain, a ring of the cranium is seen which is absent or not so prominent in MRI. What is this reason?
a) The cranium is negated out while imaging
b) Cranial ring is made of bones which do not have water, so it cannot give an MRI
c) The EM waves received by MRI does not have sufficient magnetic strength to view the bones
d) MRI images soft tissues so it does not image the cranium properly. Thus, the cranial ring is more prominent in CT than in MRI
Explanation: The cranium is made of flat bones with spongy bones in between was shock absorbers. They are flat and thin and thus do not have bone marrow. Thus, the hydrogen content in these bones is less than those in long bones. Also, MRI mostly targets Hydrogen in water to get magnetized while the hydrogen in bones is arranged on another structure which restricts its mobility as well. Thus, bones normally don’t show up in an MRI but the bones with bone marrow can be imaged.
Sanfoundry Global Education & Learning Series – Clinical Science.
To practice all areas of Clinical Science, here is complete set of 1000+ Multiple Choice Questions and Answers.