Musculoskeletal Imaging
Imaging modalities
• Conventional Radiography
• Computed Tomography
• Magnetic Resonance Imaging
• US
• Nuclear Medicine
Imaging modalities
Conventional Radiography
Plain films are the most frequently
obtained imaging studies for the bones evaluation.
Shoulder dislocation
Imaging modalities
Conventional Radiography
Some information about the soft tissues are also possible, i.e: gas or calcifications.
Gas collection lateral
to the hip arthoplasty infected prosthesis
developed abscesses
calcified parasital
cysts in muscle
wound calcifications
Imaging modalities
Conventional Radiography
There are standardized sets of views developed for evaluation specific
body areas in certain clinical settings, but in the most cases at least two
perpendicular views are demanded.
PA wrist
Lateral wrist
Imaging modalities
Conventional Radiography
Many lesions are invisible in one projection, even when they are
obvious in another view.
A
B
(A) Anteroposterior and (B) lateral views of a distal fibular
fracture. The fracture is displaced only in the sagittal plane.
Imaging modalities
Conventional Radiography
For example, if one sees a foreign metal object overlying a body part on a
single AP film, the object could actually lie on the skin surface, in the soft tissues of the
structure, imbedded in a bone, a visceral organ, or even on the X-ray table. A lateral view
can be lots of help in deciding among these many possibilities.
This construction worker was using
an explosive nail gun while driving
nails into concrete. With this film
alone, the nail could have been
almost anywhere in his knee.
The lateral view shows us that the nail
resided anteriorly, in the patellar tendon.
Imaging modalities
Conventional Radiography
Another case is when one is interested in looking at joint alignment. For
example, a posterior dislocation of the shoulder can be a hard diagnosis to make on a
single frontal view. An axillary view (taken parallel to the patient’s long axis) usually shows
these dislocations easily.
This patient suffered a gran mal
seizure. Sometime later, once he had
recovered from the seizure, he
complained of right shoulder pain,
and this radiograph was taken,
showing a shoulder joint that appears
to be in anatomic alignment.
An axillary view shows that the humeral
head is actually dislocated posteriorly
with respect to the glenoid fossa.
Imaging modalities
Conventional Radiography
If fracture fragments are only minimally displaced, spotting the fracture can be
a challenge. The reason for this is that fractures don’t show up well unless the X-ray
beam is parallel to the fracture plane. Since fractures don’t always align themselves in
convenient planes that parallel the X-ray beam, it can often be challenging to spot them.
This patient fell on her outstretched
hand, and now complains of snuffbox
tenderness. However, this AP view of
the wrist is normal. No fracture line is
visualized in the scaphoid.
A special scaphoid view clearly shows a
fracture across the waist of the scaphoid
(arrow).
Imaging modalities
Conventional Radiography
Different stress views - are primarily useful in looking at joints and spine
stability.
This patient with rheumatoid arthritis
is complaining of paresthesias with
neck flexion. This extension film
shows less than a millimeter between
the anterior margin of the dens and
the anterior arch of C1.
This flexion view of the lateral cervical spine shows that
the predental space has increased to about 7 mm in size - which is grossly abnormal. The normal upper limit for
this distance is about 3 mm. Since this one is way above
that upper limit, we know that the transverse ligament that
usually keeps the C1 and C2 vertebral bodies in
alignment with each other has ruptured - a known
complication of rheumatoid arthritis.
Imaging modalities
Conventional Radiography
Some examples of views in radiography of bones and joints.
Skull
Facial
AP
Lateral
Cervical
spine
AP
Waters view
AP external
rotation
AP internal
rotation
Shoulder
AP
Lateral
Axillary
Knee
Elbow
AP
Lateral
AP
Lateral
Tunnel view
Imaging modalities
Conventional Radiography
The importance of different time pictures - comparing an imaging study to
a prior examination.
This young patient fell on his
outstretched hand, and now
complains of wrist pain. This AP view
shows subtle cortical discontinuities
on both sides of the radius (arrows),
indicative of a torus fracture.
This wrist view was performed on the
same patient about 4 - 6 weeks later,
and now shows a subtle band of
increased opacity across the radius at
the site of the prior torus fracture
(arrows), consistent with interval callus
formation - a healing fracture.
Imaging modalities
Conventional Radiography
Normal radiographic and CT apperance of the bone - smooth, homogeneous
cortex surrounds the medullary space.
High resolution CT
The cortex is thicker along the shaft (diaphysis) of long bones and thinner
within their ends or in the small, irregular bones.
Imaging modalities
Conventional Radiography
Exceptions from that pattern are:
-roughening of the cortex at tendon or ligament insertion sites, and
-interruption of the cortex at the site of the nutrient arteries.
Imaging modalities
Conventional Radiography
Five types of bones:
a Long – 2 ends and a shaft
(femur, humerus, phalanges)
b Short – Six sided
(carpals and tarsals)
c Flat – (ribs, sternum)
d Irregular – Many sides (vertebrae)
e Sesamoid – Lack periosteum
and develop in tendons
(The largest sesamoid is PATELLA)
Imaging modalities
Conventional Radiography
Bone regions:
– Epiphysis – bony ends
– Physis – Growth plate
– Metaphysis – Widened end of a tubular bone
– Diaphysis – Shaft of a tubular bone
• Proximal third
• Middle third
• Distal third
Imaging modalities
Conventional Radiography
In the medullary space there are
trabeculae witch are visible
as thin white lines.
Imaging modalities
Conventional Radiography
Because of the many anatomical variations the comparison with the
opposite extremity is helpful, especially in children, considering the open
physes and epiphyses or accesory centers of ossiification, which can mimic
injury.
accesory center of ossiification
open epiphysis
Unilateral bipartite hallux
epiphysis. If there is a history
of trauma to this area,
monthly radiographs over
several months may be
necessary to determine
whether or not it is a fracture
or variation of normal.
Imaging modalities
Conventional Radiography
Some other examples of normal variants.
Bone scintigraphy may be a valuable
diagnostic study for differentiation
between unilateral os trigonum and
patology. Focal intense uptake
suggests degenerative disease
and/or unhealed fracture.
Accessory sesamoids - best seen in the axial view.
Imaging modalities
Conventional Radiography
Fluoroscopy
-it supports positioning patients for unusual radiographic projection,
-used to monitor placement of hardware i.e. by orthopedic,
-evaluation of joint motion.
Postoperative fluoroscopic control of bone
fixation with plate and screws after a complete
fracture of the humerus.
Imaging modalities
Conventional Radiography
A simple way to approach the MS radiograph is to follow the ABC's:
A - Anatomy/Alignment:
Note the anatomy of the bones. Are they normal in size and relation to
other bones articulating with them.
Note the contour of the bones and joint surfaces.
Imaging modalities
Conventional Radiography
ABC's:
B - Bone Density:
Observe the bone for any changes in density. Normal is uniform in color
or milkiness. Abnormal density is representative of the degree of
mineralization.
Main conditions increasing density are: healing fractures or degenerative
joint disease.
Decreased bone density is mostly seen in osteoporosis or neoplastic
conditions.
Imaging modalities
Conventional Radiography
ABC's:
C – Cartilage (joint space):
Examine the spaces for uniformity in contour and size. In children the
epiphyseal plates are cartilaginous and can be mistaken for fracture
lines.
Obtain comparative films of the normal side.
Imaging modalities
Conventional Radiography
ABC's:
`s – Soft tissue:
Soft tissue does not distinctly illuminate well on X-Rays. Tissue lines
should be examined beginning from the periosteum to the skin lines.
Inflammation or swelling in soft tissues may be seen by displacement of
the surrounding fat pads.
Imaging modalities
Conventional Radiography
Cartilage
Articular cartilage is what separates the bones in a synovial joint. This space taken
up by the cartilage is termed the "joint space" on a plain radiograph.
When considering the joint space, one generally only sees one of the following
three findings: -decreased joint space, -increased joint space, -chondrocalcinosis.
The most common of these is decreased joint space, which usually implies some
form of arthritis.
A widened joint space can be seen in patients with acromegaly or in patients with a
large joint effusion.
Chondrocalcinosis has been reported in an number of entities, but over 95 % of
them will be due to calcium pyrophosphate deposition (CPPD) disease.
Imaging modalities
Conventional Radiography
Marked joint space
narrowing is noted in
the superior weightbearing portion of the
joint space in this
patient with
osteoarthritis.
Cartilage
Chondrocalcinosis (arrows) is noted in
the hyaline articular cartilage and
menisci of this patient with calcium
pyrophosphate deposition (CPPD)
disease.
Imaging modalities
Computed Tomography
It offers two major uses in musculoskeletal imaging:
1.
More precise than plain film evaluation of bone structure, which mostly
supports injury diagnosis - fractured fragment position.
Fractured left orbita.
2.
Evaluation of bone tumors.
Lipoma (F) of the femur.
Imaging modalities
Computed Tomography
It also offers quite good depicting of soft tissues.
Imaging modalities
Computed Tomography
Fracture evaluation - axial or frontal images
CT usually provides excellent delineation of fractures.
Axial scan. Broken fragment of cervical
vertebra.
Frontal scan. "Blow in" type
fracture of the left orbit. Small bone
fragment is in the left orbita.
Imaging modalities
Computed Tomography
Fracture evaluation - MPR images
Postprocessing MultiPlanar Reformations allow to see fracure in planes
perpendicular, oblique or even curved to primary section.
Imaging modalities
Computed Tomography
Fracture evaluation - 3D images
Three-dimensional reconstructions are not a routine protocol, because
they are time-consuming and they do not contain any extra information
beyond the source axial scans, but they can:
-help to understand spatial relationships of the examined structures,
-support the surgeon to plan operative intervention.
Multifractured injuries of
the thoracic vertebra and
the face.
Imaging modalities
Computed Tomography
Fracture evaluation
The decision to use advanced CT imaging beyond conventional films
should be based on whether it change treatment or operative planning.
Injury of the left orbita in the conventional
and CT images: the inferior rectus muscle
is stacked in the fissure, which explains
the lack of downward movement of the
eye.
Imaging modalities
Computed Tomography
Evaluation of bone tumors
CT can show early periosteal new bone formation before it may be seen with
conventional radiography or MRI and supports biopsy.
Sarcoma of the tibia
(circle) and infiltration
of adjacent soft tissues
(arrows).
Biopsy of vertebral body
tumor.
Imaging modalities
Magnetic Resonance Imaging
The excellent contrast resolution of soft tissues makes it ideal for:
1.
Diagnosis of injuries to muscles, tendons or ligaments about joints.
2.
Evaluating disorders of bone marrow, such as neoplasm, osteomyelitis,
metabolic diseaes, avascular necrosis and even fractures.
Degenerative disease of left hip with loss of
joint space and damage to cartilage.
Tear of the left rotator tendon – high
signal (arrow).
Imaging modalities
Magnetic Resonance Imaging
Normal MRI apperance of the bone - smooth, with no signal (black)
cortex surrounds the medullary space. There is lack of trabeculae depiction,
but we can recognize the picture of „Bone Bruise” - trabecular microfractures
with blood and edema.
Imaging modalities
Magnetic Resonance Imaging
Evaluation of soft tissues.
MRI dynamic studies
depict phases of the
movement.
Liposarcoma of the left thigh (m).
Imaging modalities
Magnetic Resonance Imaging
Evaluation of bone marrow.
MR imaging is more often than CT used for staging, for its clear
delineation of tumor extent within bone marrow and muscle or other soft
tissues, altough it is non-specific.
Osteomyelitis of the right
femur – the lack of the normal
high signal of marrow.
Lymphoma of the left femur –
the same pattern of abnormal
marrow signal.
Imaging modalities
Ultrasonography
US may be quick and inexpensive technique to confirm or exclude
possible diagnoses from the clinical physical exam. This may then determine the
need for other investigations such as MRI, or invasive procedures such as
arthrography or biopsy.
Imaging modalities
Ultrasonography
The applications of US in the evaluation of musculoskeletal disorders
include muscle and tendon disease, soft tissue masses, identification of foreign
bodies, certain joint abnormalities, and infectious processes such as
osteomyelitis and subcutaneous abscesses.
Evaluation of tendons.
Left Achilles tendon (arrows): tendinitis hypoechoic and thickened part with loss of the
normal fibrillar pattern above the posterior
aspect of the calcaneus (arrowhead).
Contralateral normal Achilles tendon (arrows)
with a fine fibrillar texture; calcaneus pointed by
arrowhead.
Imaging modalities
Ultrasonography
Evaluation of tendons.
Imaging modalities
Ultrasonography
Evaluation of muscles and soft tissues.
gastrocnemius (G) tear with hematoma (arrow)
Imaging modalities
Ultrasonography
Dynamic studies
Ruptured rectus femoris muscle (arrows).
A - relaxed and
A
B - retracted
following contraction indicating a complete tear.
Surface of the femur (arrowheads).
B
Imaging modalities
Nuclear Medicine
Several types of scintigraphic studies are used for musculoskeletal
diseases, mostly more sensitive than X-rays or CT, but non-specific - most
osseous abnormalities will cause an increase in radiolabeling. They
are often used for screeening for metastases.
Bone scintigraphy scan
in Paget's disease.
Multiple bone
metastases.
Imaging modalities
Technique Selection
The plain radiograph is usually the initial imaging test, followed by the
others regarding not only medical need, but also availability and expense.
Trauma
radiograph
visible fracture
location of fragments
is desirable
CT
unvisible strongly
suspected fracture
next
radiograph
in 7 days
nuclear medicine
MRI
Imaging modalities
Technique Selection
Tumors
radiograph as screening
visible lesion
unvisible lesion
MRI for local staging
MRI as screening
CT for precise bone structure inspection
Imaging modalities
Technique Selection
Metastases
Symptomatic
bone sites
Overall survey for
metastases
radiographs
scintigraphic studies
CT for precise bone
structure inspection
Suspected soft-tissue
metastases
MRI
Imaging modalities
Technique Selection
Osteomyelitis
radiographs
normal
pathological
scintigraphic studies
MRI