MRI - MIDTERM L1 Flashcards
MRI is used to visualize the _______ structures of the body in _________
- Internal
- High Detail
MRI is valuable for imaging soft tissues like the ______, ______, ______, and ________
- Brain
- Spinal Cord
- Muscles
- Organs
What type of MRI uses different tissue properties to generate detailed images of soft tissues, and visualize anatomic structures such as the brain, spinal cord, and joints to verify diseases such as Brain Tumors, Stroke, or Spinal Cord injuries ?
Structural MRI (Anatomical MRI)
A Structural MRI variant which produces high-resolution images where fat appears bright, and white fluid appears dark
T1-Weighted Imaging (T1W1)
A Structural MRI variant sensitive to fluid and is often used to detect pathology wherein fluid appears bright, useful for identifying edema or tumors
T2-Weighted Imaging (T2W1)
It is an MRI classification which measures and maps beam activity by detecting changes in blood flow, based on the principle that brain areas with higher activity require more oxygen.
Functional MRI (fMRI)
The acronym BOLD stands for ________
Blood Oxygen Level Dependent
(Umayos ka hindi to ano)
fMRI is commonly used for research of neurological conditions such as ______ and _____
- Epilepsy
- Alzheimer’s Disease
This MRI measures and assesses movement of water molecules within tissues to visualize the orientation and integrity of white matter pathways and for imaging white matter tracks in the brain
Diffusion MRI (Diffusion Tensor Imaging, DTI)
The common applications for Diffusion MRI include the following EXCEPT:
A. Multiple Sclerosis
B. Traumatic Brain Injury
C. Stroke
D. Surgery Planning
E. NOTA
E. NOTA
It is a non-invasive technique used to visualize blood vessels and assess conditions such as aneurysms, blockages, or arterial malformations.
Magnetic Resonance Angiography
TRUE OR FALSE
MR Angiography can only be performed if there is a contrast agent.
FALSE
MR Angiography can be performed WITH OR WITHOUT CONTRAST AGENTS.
What MR Angiography variant is used to visualize arteries without the need of a contrast agent ?
Time-of-Flight (TOF)
This MR Angiography variant uses a contrast agent to enhance the visualization of veins and smaller vessels
Contrast-enhanced MRA
It measures the chemical composition (concentration) of metabolites within tissues, giving insights into the metabolic changes in the body
Magnetic Resonance Spectroscopy
It specializes in imaging the heart and blood vessels, particularly for assessment of the structure and function of the heart, including the myocardium, blood vessels, and heart valves.
Cardiac MRI
What are the common applications of Cardiac MRI (4):
- Cardiomyopathy
- Myocardial Infarction
- Congenital Heart Defects
- Valve Disorders
It involves the use of an oral contrast agent to highlight the intestines, along with MRI to capture detailed images of the GI tract.
MR Enterography
The following are the clinical indications of MR Enterography EXCEPT:
A. Crohn’s Disease
B. Inflammatory Bowel Disease
C. Multiple Sclerosis
D. Bowel Obstructions
C. Multiple Sclerosis
The MRI machine generates a strong magnetic field which aligns the hydrogen nuclei in the body along the direction of the field.
Magnetic Field Application
A _______ is applied which temporarily disrupts the alignment of the hydrogen nuclei
Short RF Pulse
The strong magnet is defined as the __________
Core of the MRI System
These coils create varying magnetic fields, allowing for spatial encoding of the MR signals and enabling the creation of detailed, cross-sectional images.
Gradient Coils
These coils transmit the RF pulses and receive the signals emitted by the hydrogen nuclei as they relax
RF Coils
It controls the sequence of pulses, processes the signal data, and reconstructs it into images
Computer System / Computer
It is considered as the Heart of the MR System
Magnet
The Performance Criteria for any Particular Magnet Type include (3):
Bonus Q: All of these are affected by _________
- Field Strength
- Temporal Stability
- Field Homogeneity
Bonus : All of these are affected by MAGNET DESIGN.
These are magnets made of wire-wrapped cylinders of 1m diameter and greater, where the magnetic field is produced by an electric current in the wires
Air-core Magnets
Air-core magnetic fields run ______ to the long axis of the cylinder
Parallel
Air-core magnetic field is _______ and runs along the ______ axis of the patient lying _____
- Horizontal
- Cranial-caudal
- Supine
The Solid Core magnetic field runs ______ the poles of the magnet, most often in a _______ direction
- Between
- Vertical
These are constructed from permanent magnets, a wire-wrapped iron core “electromagnet” or a hybrid combination
Solid Core Magnets
These magnets are constructed in either an air core or solid core configuration, using continuous electric power to produce the magnetic field necessary for a significant amount of heat.
Resistive Electromagnets
What are the three (3) Main Types of Designs for MRI Machines ?
- Resistive Electromagnets
- Permanent Magnets
- Superconductive Magnets
These magnets rely on the ferromagnetic properties of iron, nickel, cobalt, and alloy
Permanent Magnets
Some early permanent magnets weigh over _______
100 tons
The Magnetic Field of Resistive Electromagnets ranges from ____ to ____
0.1 T to about 0.3 T
What is the main advantage of Resistive Electromagnets ?
Ability to Turn Off the Magnetic Field in an Emergency
These are magnets that typically use an air core electromagnet configuration and consist of a large cylinder of approximately 1 m in diameter and 2-3 m in depth
Superconductive Magnets
It is a characteristic of certain materials (metals) to exhibit NO RESISTANCE to electric current when kept at extremely low temperatures.
Superconductivity
TRUE OR FALSE
Operational costs of systems with permanent magnets are the HIGHEST of all MR systems
FALSE
Operational costs of systems with permanent magnets are the LOWEST of all MR systems (no major electric or cooling requirements).
After initialization (________), by an external electric source, current ______ to flow as long as the wire temperature is kept at _________
- Ramp Up
- Continues
- Liquid Helium Temperature
__________ cause the loss of superconductivity and resistance heating ______ the magnetic field
- Higher Temperatures
- Quenches
Field strengths of Superconductive Magnets range from _____ to _____ for CLINICAL SYSTEMS
0.3 T to 3.0 T
TRUE OR FALSE
Superconductive Magnets are considered as the most widely used magnet type for clinical imaging
TRUE
Field strengths of Superconductive Magnets range from _____ to _____ for CLINICAL LARGE BORE MAGNETS
4.0 T to 7.0 T
What are the Integral Parts of the Magnet System (4):
- Gradient
- Shim
- RF Coils
- Cryogenic Liquid Containment Vessels
Among the three types of magnets for MRI machines, which has the lowest cost ?
A. Resistive Electromagnet
B. Permanent Magnet
C. Superconductive Magnet
D. NOTA
B. Permanent Magnet
TRUE OR FALSE
Superconductive Magnets can have instances of explosive boiling of liquid helium
TRUE
Explosive boiling of liquid helium and severe damage to magnetic winding is POSSIBLE due to UNCONTROLLED QUENCHING,
