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Basic Understanding on Magnetic Resonance Imaging (MRI) & Interpretation of MRI Images
By : QF Gan, PT, MSc Human Anatomy (Batch 3)
Is MRI Important I am a Physiotherapist. During my student years, I used to think that MRI is totally not important for a Physiotherapist. The reason behind this is because in every patient with MRI, there is a interpretation sheet that comes along to tell the clinician exactly what exactly is the findings from MRI.
However, there are times where some patient’s who walk in for treatment with his/her MRI but forgotten the MRI interpretation sheet. Without the knowledge, how am I to interpret those MRIs images given in order to confirm my assessment? Of course, everything I see is blank and white images not knowing what are those, where to start and how it goes.
Hence, the question is, ‘Is the basic understanding and ability to interpret MRI images important for physiotherapist?’
Content Brief History Introduction to MRI MRI Machine Principles of MRI Advantages & Disadvantages Indications for MRI Contraindications Types Of MRI Machine Strength of Magnetic Field Used in MRI MRI Contrast Agent Types of MRI Images Basic Interpretation of MRI Q & A Session
By: Gan Quan Fu, PT
Brief History
Invented by Paul C. Lauterbur in September 1971
Paul Lauterbur of the University of Illinois at Urbana-Champaign & Sir Peter Mansfield of the University of Nottingham were awarded the 2003 Nobel Prize in Physiology or Medicine for their discoveries of MRI.
By: Gan Quan Fu, PT
Introduction to MRIUses magnetic field & radio
waves to create detailed images of organs & tissues within the body.
Also known as nuclear magnetic resonance (NMR).
No ionizing radiationEmploys radiofrequency pulse
ranging from 1 to 80MHz
By: Gan Quan Fu, PT
MRI Machine
By: Gan Quan Fu, PT
MRI Machine
By: Gan Quan Fu, PT
By: Gan Quan Fu, PT
Principles of MRIHuman body made up of chemical
composition (ie: hydrogen, carbon, nitrogen sodium, phosphotus, potassium etc.)
Atoms these elements have different number of protons in their nucleus and possess different magnetic property.
Protons of hydrogen atom are the most abundant in the body in the form of water.
Magnetic properties of these atoms have been utilized to produce magnetic resonance signals and images.
By: Gan Quan Fu, PT
Principles of MRIWhen a patient is placed in a strong
magnetic field in MR scanner, hydrogen nucleus in the body align with the applied external magnetic field.
Hydrogen nuclei in the patients body absorbs the energy and then generates the MR signal when exposed to short bursts of electromagnetic energy in form of radio frequency pulse.
By: Gan Quan Fu, PT
Principles of MRIThe magnet creates a strong magnetic
field which aligns the protons of hydrogen atoms which are then exposed to a beam of radio waves.
This spins the various protons of the body and produce a faint signal which is detected by receiver portion of the MRI scanner.
The receiver information is processed by computer and image is produced.
By: Gan Quan Fu, PT
Advantages & Disadvantages
Advantages Disadvantages
1. Excellent soft tissue contrast resolution
2. Ability to obtain direct transverse, sagittal, coronal and oblique images
3. Does not use ionizing radiation
4. Does not produce bone/air artefacts
1. Longer imaging time
2. Complexity of the equipment and scan acquisition
3. High Cost
4. Inability to demonstrate calcification or cortical bone details
5. Bullet shrapnel and metallic fragments may move and become projectile (Contraindicated for patients with Cardiac pacemakers, dental implants, heart valve prosthesis and aneurysm clips)By: Gan Quan Fu, PT
Indications for MRIPlease contact the Author to view
this PageE-mail: [email protected]
By: Gan Quan Fu, PT
ContraindicationsCardiac pacemakersBrain aneurysm clipAortic clipArtificial heart valve Insulin pump IUD Joint replacementProstheses (such as cochlear implant)Wire suturesDentures (Must be Removed)Claustrophobia (Can be sedated or use open
MRI)By: Gan Quan Fu, PT
Types of MRI MachineMost MRI scanners, patient examination
table fits inside a long cylindrical tube.3 Common Types of MRI Machine:
◦ Open MRI Units Patient placed between two plates Early versions had low magnetic field strength, gave
poorer image quality Required longer examination times.
◦ Closed MRI Units Short magnets and wide bore tubes offer improved
comfort. Alternative to open scanners. Gives better Image than open MRI units.
◦ High field MRI Uses very strong magnet Higher picture resolution, fast scans, and ability to
visualize physiological processes.By: Gan Quan Fu, PT
By: Gan Quan Fu, PT
Strength of Magnetic Field Used in MRIMeasured in Tesla (T)
[Developed by Nikola Tesla]
Open MRI units ◦0.1T to 0.3 T
Closed MRI unit ◦0.5 T to 0.6 T
High field MRI ◦1.0 T to 3.0 T or
higherBy: Gan Quan Fu, PT
MRI Contrast AgentGroup of contrast media used to improve
visibility of internal body structures in magnetic resonance imaging (MRI).
Examples are:◦ Gadolinium◦ Paramagnetic agent
Shortens the T1 relaxation time and produces increased signal intensity on T1W images.
Dose 0.1 to 0.2 mmol/kg body weight.Side Effect:
◦ Nausea◦ Vomiting, ◦ Headache,◦ Seizures,◦ Anaphylaxis
By: Gan Quan Fu, PT
Types of MRI ImagesPlease contact the Author to view
this PageE-mail: [email protected]
By: Gan Quan Fu, PT
Basic Interpretation of MRIT1
◦Bright Fat Blood Contrast
◦Dark Fluid Cortical Bone
T2 ◦Bright Fluid
◦Dark Cortical bone
By: Gan Quan Fu, PT
T1W MRI Image Interpretation (Neuro)T1
◦Bright Fat Blood Contrast
Dark Fluid Cortical Bone
Skull Bone
Fat in SCALP Fluid CSF
By: Gan Quan Fu, PT
T2W MR1 Image Interpretation (Neuro)
T2 ◦Bright Fluid
◦Dark Cortical bone
Skull Bone Fluid CSF
By: Gan Quan Fu, PT
T1W Image vs T2W Image (Neuro)
By: Gan Quan Fu, PT
Multiple SclerosisUseful for
diagnosis and to assess progress of the disease.
Plaques of demyelination are seen in the white matter.
By: Gan Quan Fu, PT
Magnetic Resonance Angiogram (MRA)Type of MRI scan which
uses a magnetic field and pulses of radio wave energy to provide pictures of blood vessels inside the body.
Images are generated in which only structures containing flowing blood are visualized.
Can demonstrate:◦ Occlusions◦ Stenosis ◦ Aneurysms. By: Gan Quan Fu, PT
Right MCA Infarct
By: Gan Quan Fu, PT
MRI Interpretation (Abdomen)Please contact the Author to view
this PageE-mail: [email protected]
By: Gan Quan Fu, PT
Liver Cirrhosis
Small, Nodular in liver showing cirrhosis.
Spleen is enlarged possibly due to portal hypertension.By: Gan Quan Fu, PT
History of cirrhosis, rule-out Hepatocellular Carcinoma
T1 Weighted Image
T2 Weighted Image
By: Gan Quan Fu, PT
Following Gadolinium Administration
By: Gan Quan Fu, PT
Magnetic Resonance Cholangiopancreatogram (MRCP)Technique uses magnetic resonance
imaging to visualize the biliary and pancreatic ducts in a non-invasive manner.
Can be used to determine if gallstones are lodged in any of the ducts surrounding the gallbladder.
Excellent for demonstration of: ◦Biliary tract ◦Pancreatic duct ◦Gallbladder
By: Gan Quan Fu, PT
Advantages & Disadvantages MRCP
Advantages Disadvantages
► Rapid imaging-single breath hold
► Noninvasive vs. Endoscopic retrograde cholangiopancreatography (ERCP)
► No complications ► No IV or PO contrast ► Less expensive than
ERCP ► Sensitivity &
specificity comparable to ERCP
►Purely diagnostic ►Does not provide
access for treatment ►ERCP better at
demonstrating bile duct leaks – Contrast introduced
directly into ducts
By: Gan Quan Fu, PT
Choledochal cyst on MRCP
Common Bile Duct
Gall Bladder
By: Gan Quan Fu, PT
MRI of PancreasPlease contact the Author to view
this PageE-mail: [email protected]
By: Gan Quan Fu, PT
MRI of BreastPlease contact the Author to view
this PageE-mail: [email protected]
By: Gan Quan Fu, PT
MRI Breast Cancer
Very large lymph node (arrow) in Patient with breast cancer
By: Gan Quan Fu, PT
MRI in MusculoskeletalTo demonstrate disc herniation and
spinal cord or nerve root compressionTo diagnose bone metastasisExtent of primary bone tumour and to
demonstrate myeloma and lymphomaTo image soft tissue massesTo image OsteomyelitisJoint pathologies and injuries to
cartilages and ligaments
By: Gan Quan Fu, PT
SpineMRI is a better way of looking in
detail at the inner ear, cranial and spinal nerves.
MRI also looks at the state of vertebrae and discs.
By: Gan Quan Fu, PT
Herniated Disc
By: Gan Quan Fu, PT
Joints Tendon and LigamentsMost accurate examination
available for joints and the surrounding tendons, ligaments and cartilage.
Helpful for sports related injuries.
By: Gan Quan Fu, PT
Ligament Tear Examples (MRI)
By: Gan Quan Fu, PT
Meniscus Tear
By: Gan Quan Fu, PT
Muscle Tear Examples (MRI)
By: Gan Quan Fu, PT
Pelvis Male & Female (Sagittal)
Male Female
By: Gan Quan Fu, PT
Full Body MRIAllows high resolution
regional MRI scans to be added creating a composite study.
Purpose:◦Search for tumors or
secondary spread. ◦ Ideal for follow up of
systemic disease.Head, chest, abdomen
and pelvis are zipped together.
By: Gan Quan Fu, PT
Q & A Session
THANK YOU
By: Gan Quan Fu, PT
