2. • Cranial displacement of disk tissue in
spondylolisthesis
• is a common finding (a, b) that should not
• be mistaken for a true extrusion or protrusion.
3. MRI
MEGNETIC RESONANCE IMAGING
It is a radiological test that make pictures of organs and structures inside the body,
like
X-ray and ct scan
How it is different from:
x-ray AND CT scan
• It uses :
magnetic field and pulses of radio wave energy.
4. What is MRI
• Radiological technique that uses magnetism, radio waves and a computer to
produce images of body structures.
Equipment used for MRI
• Mri machine consist of:
• Mri scaner
• Pts tabel
5.
6. • Mri scanner is a tube surrounded by a giant circular magnet
• Creat a very strong magnetic field.
• The human body is mostly water.
• Water consist of hydrogen and oxygen atoms.
• At the centre of each hydrogen atom is an even smaller particle, called a proton.
Protons are like tiny magnets and are very sensitive to magnetic fields
7.
8.
9. Pt is placed on movable table that is inserted into this magnetic field.
Now the protons in the body line up in the same direction under the effect of
magnetic field in the same way that a magnet can pull the needle.
Short bursts of radio waves are then sent to certain areas of the body, knocking the
protons out of alignment.
10.
11. • When the radio waves are turned off, the protons realign.
• This realignment creat radio signals, which are picked up by receivers.
• Short bursts of radio waves are then sent to certain areas of the body, knocking
the protons out of alignment.
• These signals from the millions of protons in the body are combined through a
computer to create a detailed MRI image
• Because the protons in different types of tissue in the body realign at different
speeds therefore it produce distinct signals.
• Like bones soft tissues muscles etc
12.
13.
14. Strict contraindications
Implanted electric and electronic devices are a strict contraindication to the magnetic
resonance imaging including:
• heart pacemakers
• insulin pumps
• implanted hearing aids
• neurostimulators
• intracranial metal clips
• metallic bodies in the eye
15. Relative contraindications
• Metal hip replacements
• sutures or foreign bodies in other sites are relative contraindications to the MRI
• The first trimester of pregnancy is also a relative contraindication.
16. BASIC SEQUENCES OF MRI
• T1 AND T2
• ADDITIONAL
• FLAIR
• DWI
• ADC
T1 T2
FLUID low high
FAT high high
Air low low
22. Diffuse disc bulge
• Diffusely bulging disc extends symmetrically and circumferentially by more than 2
mm beyond the margins of adjacent vertbera.
• Protrusion:
• Focal assymetrical extension of the disc tissue beyond the verteberal margins .
• Base is broader than any other dimensions.
• Protruded disc does not extend in cranial or caudal direction.
• Bulging of the disk behind a intact annulus fibrosus.
• Displacement occurs within the disk tissue. (Contained disc)
• Often does not cause symptoms.
• Low signal intensity both on T1 and T2 WI.
23.
24. Extrusion:
• Herniation of the disk with perforation of the annulus fibrosis and extrusion of
disk tissue.
• Anteroposterior dimension is greater than base.
• Often symptomatic: radiculopathy.
• Extruded disc can extend in cranial or caudal directions, but maintain continuity
with parent disc.
• Typical appearance is low on all sequences .
• But There may be high signal on T2 and on post contrast images, in or surrounding
the disc because of the significant inflammatory reactions that may occur in
response to extruded disc material.
25.
26.
27.
28. Sciatica due to disk protrusion:
• Gradual onset
• Changing postural abnormality
• Proximal pain is most common
• Well controlled with medication
Sciatica due to disk extrusion
• Abrupt onset
• Constant postural abnormality
• Distal pain, paresthesia ,paresis
• Poorly controlled with medication
• Pain from the extruded disc is usually due to inflammatory changes rather than the
mass effect causing compression of the neural elements.
• There is spantanous regression of disc extrusion and protrusion with time.
• Manage non operatively : 90 % response
29. Sequestrated disc
When the extruded disc material loses its attachment with the parent
disc it is called the sequestrated fragment.
• Sequestrated disc fragment may migrate
• Cranially
• Caudally
• Usually remain within the 5mm of the parent disc.
30. But they may be located:
Between: posterior longitudinal ligament and bony spine.
• Anterior epidural space: Commonly
• Posterior epidural space :occasionally
• Dural sac: rarely
• Paraspinous soft tissues: rarely
Low signal like the parent disc.
Diffuse or peripherally high signal onT2 and post contrast images due to inflammatory
reaction.
31.
32. Quantifying the severity of disc
disease
Mild:
If the anterior epidural fat is not obliterated.
Moderate:
If the epidural fat is obliterated and thecal sac is displaced.
Severe:
If the cord is effaced and nerve roots are displaced.
33. • MR imaging studies to visualize spinal and vertebral structures early in the course
of low back pain with or without sciatica is generally not indicated
• Only if the symptoms fail to improve after a prolonged period—about four to six
weeks then a mri should be performed.
Early MRI or CT studies are indicated, in
the presence of
• Cauda equina syndrome
• Progressive neurological deficits paresis or sensory impairment
• Unbearable pain
• Signs of a tumor or inflammation.
34. • 23 years old lady presents with
complian of low back ache sine
3monts. Pain is not radiating and
relieve with rest and analgesics.
What are mri findings??
35.
36.
37. • This 32-year-old woman
complained of sacral pain
variably radiating into her left
and right legs, of three
months’ duration.
• What is diagnosis on mri???
38.
39. • Central disc protrusion at L5–S1. causing mild dural sac or thecal sac compresion.
• Treatment :????
Conservative therapy
40. • 55-year-old man complained of sciatica in the left S1
distribution, of six weeks’ duration, refractory to
spinal analgesics.
• There was an ipsilatral postural deformity on
forward bending.
41.
42. • Large left paracentral intervertebral disk extrusion at L5–S1 with compression of
the left S1 nerve root.
• Treatment: ??????
43. • This 32-year-old man complained of pain radiating into the right leg in an S1
dermatomal pattern, of several months’ duration. There was no significant
postural deformity.
Central and right para central extrusion causing mild thecal pressure.
Diagnosis on mri ??
44.
45.
46. • 50-year-old woman complained of low back pain radiating into the left leg, of two
months’ duration.
• There were no motor or sensory deficits.
• Treatment???
Conservative therapy
47.
48.
49. • 45 year old female presented with acute pain radiating into her left leg of one
week’s duration. The pain radiated across the buttocks to the posterolateral aspect
of the left high.
• Treatment ????
50.
51. • 37-year-old patient complained of severe pain in the left leg and less severe pain
in the right leg,
• radiating across the posterolateral aspect of the leg to the hee
Mri findings????
56. Focal or broad based disc bulge
• A segment of disc tissue that project s beyond the margin of vertbera but does
not involve the entire circumference of the disc
• This makes it difficult to differentiate
• between disk-level circumscribed protrusions and
• subligamentous extrusions
• peripheral portions of the annulus
• posterior longitudinal ligament
• dura mater.
• Mri cannot distinguish between these three structures
• .
57. • Disk extrusions develop laterally
• Because there is only the anterior epidural membrane.
• While posterior longitudinal ligament itself actually covers only the medial
portion of the posterior aspect of the vertebra.
58. Herniation with a subligamentous
fragment:
Sequestra that migrate beneath the anterior epidural membrane or
beneath portions of the posterior longitudinal ligament are referred to as
subligamentous or submembranous fragments.
Where the annulus fibrosus and anterior epidural membrane or posterior
longitudinal ligament are perforated, the displaced disk tissue will lie in
the epidural space.
• The extruded material may remain connected to the disk,and may migrate
upward or downward .
• or it may detache from parent disc and lie as a sequestrum in the epidural
space.
