Class notes
Lecture notes Basics of MRI BMS24 Master Biomedical Sciences Nijmegen
- Course
- Institution
Lecture notes of all lectures about MRI for the course BMS24
[Show more]
Seller
Follow
kimbijl
Reviews received
Content preview
Lecture 1: MR modality overview- MRI in vivo measurement of the brain
2 types of tissues that can be differentiated in MRI white and gray matter and CSF
4 types of MRI
- Structural MRI image
- Diffusion MRI fiber tracks
- Functional MRI (task)
- Functional MRI (at rest)
T1-weighted = most often used, structural. Get signal from gray and white matter
T2-weighted = more signal from CSF
Proton density
- Gross brain anatomy
- Acquisition time depends on SNR and resolution
- Many different varieties of sequences to acquire these images
By changing timing and signals of MR sequence can null certain tissues or flows
Useful for highlighting lesions/pathologies
Give better sub-cortical contrast
, By sensitising the sequence to different properties can detect other features of tissue:
- Swi/qsi, S= susceptibility, magnetic field changes due to iron contect and myelin
- MT: magnetisation transfer: bound or free water
- Veno/Angio grams; flow blood iron/contract agent
Structural MRI
- Tissue types GM, WM, CSF
- Cortical surfaces and thickness
- Sub cortical structure and shape (limbic system as well)
- Local Gray matter changes
These pictures based on water and fat density (proton density), T1 relaxation time, T2
relaxation time.
- Relaxation times depend on many things but are sensitive to micro-environment and
tissue type.
- Intensity is usually a complicated weighting of different factors
Structural MRI is NOT A DIRECT MEASURE. Not counting axons, cell bodies etc.
- Only indirect measures that are influenced by the tissues such as water and fat
- Not quantitative
- T1 and T2 values vary withing GM and WM
- Doesn’t distinguish bone from air
- Contrast poor in subcortical regions
- Single sequences may miss certain things completely might not be able to see a
tumour
- Artefacts and noise MRI easily affected by external factors
o Hardware related (contrast noise, how well can you differentiate between
tissues)
o Resolution and partial voluming
For analysis contrast to noise ratio (CNR), often most important
Hardware related bias:
- RF Bias (B1 inhomogeneity)
o Non-uniform RF field causes smooth variations in intensity
o Can sometimes become very larger
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller kimbijl. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.95. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
77254 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now