foundations of diagnostic imaging for physical therapist
TRANSCRIPT
Dana Tew PT DPT
Diagnostic Imaging for
Rehabilitation Professionals
Objectives
Become familiar with various medical imaging modalities
Demonstrate understanding of the advantages and disadvantages of different imaging modalities
Be able to recommend the correct modality given a case study
Integrate diagnostic imaging information into physical therapy practice
Why do physical therapist need
to understand medical imaging?
• Clinical Reasons?
How will it effect treatment?
How will it effect prognosis?
What about direct access?
• Research Implications?
Medical Imaging
•Radiography
• Plain Film/ X-Ray/ Roentgen Rays
• Computed Tomogaphy (CT Scan)
• DEXA
• Bone Scan
•Magnetic Resonance Image (MRI)
Radiography
Basic Concepts
What is an X-Ray?
Electromagnetic
Radiation - short
wavelength
Professor Roentgen
Discovered accidentally
in 1895
Experimenting with a
machine that, unknown
to him, was producing x-
rays
Saw the bones of his
hand in the shadow cast
on a piece of cardboard
in his lab
What Roentgen
saw Today's Image
Radiodensity
X-rays not absorbed,
screen produces
photons when struck,
and exposes the film,
turning it dark
When an object absorbs
the X-rays - fewer
protons produced, film
stays light
Radiopaque Radiolucent
Which one of the does not
belong?
The objects on the screen may
not be what they appear
Take a piece of paper and draw a geometric shape
on it. (Square, triangle, circle etc.)
Now take that shape and make it 3-D (square=cube)
What are you looking at?
Must be familiar with
the form of a
tissue/structures, if
not, you can not
anticipate it‟s
radiological
appearance, and can
not decipher normal
from abnormal
I feel
exposed!
A-B-C-D
A- Alignment- is the bone in good
general alignment
B- Bone- general bone density
C- Cartilage- sufficient cartilage space
D- Dee other stuff??
Muscles, fat pads and lines, joint
capsules, miscellaneous soft-tissue
findings, bullets
Alignment
Alignment
Bone
Bone
What do I need to look for?
Distal tibia and fibula
F- fifth metatarsal base
L- lateral process of the talus
O- os trigonum
A- anterior process of the calcaneus
T- talar dome
Cartilage
Dee other stuff
Dee other stuff
Dang
The role of imaging is to confirm the infection and show extent. Radiography will show the infection, however usually late. Radiography has a high specificity but low sensitivity.Ledermann HP, Morrison WB, Schweitzer ME. Pedal abscesses in patients suspected of having pedal osteomyelitis: analysis with MR imaging. Radiology 2002; 224(3):649-655
Viewing Images X-ray study named for the direction the beam
travels
AP
PA
Lateral
Orient film as if you were facing the patient, his/her
Left will be on your Right
Views
Lateral Oblique
Superior articulating facetTransverse processPedicleLaminaInferior articulating facet
Lumbar Spine, Oblique View
Lumbar Spine, Oblique View
“SCOTTY DOG”
Lumbar Spondylolysis
The defect„lysis‟ involves
the parsinarticularis
and can allowthe vertebra
above tosubluxforward
Views
AP Open Mouth
Dens
Still Alive?
Whew…That was close
Bullet can be in
any of these
places (anterior
to posterior at
same level)
1 - spinal cord
2 - trachea
3 – Superior Vena
Cava
4 - aorta
Viewing Images
A radiograph is a two dimensional
representation
Therefore, “One View is No View”
Two views are needed, ideally at
90 degress to one another for
proper 3-D like interpretation
How „bout some evidence Physical therapists in the military have been credentialed
to order various radiographic procedures, including plain film radiographs, bone scans, and magnetic resonance images (MRI), for over 30 years
PT‟s shown to be more cost effective than ortho surgeons in management of MSK disorders (with no difference in outcomes)
o Daker-White G et al., J Epidemiol Comm. Health, 1999
When given the opportunity, PT‟s order imaging up to 50% less, with no difference in outcomes
o Greathose DG et al., JOSPT, 1994
o James JJ et al., Phys Ther, 1981
o James JJ et al., Phys Ther, 1975
Diagnositic accuracy – No difference found between PT‟s and Ortho‟s
o Moore JH et al., JOSPT, 2005
Outcome of the modified Ottawa Ankle Rules for
identifying the need for radiographs when used by A
Physical Therapist
N = 157 Fracture No Fracture
(+) OAR 6 (a) 90 (b)
(-) OAR 0 (c) 61 (d)
Sensitivity= a/(a+)=0.99 Specificity= d/(b+d)=.40
PPV=a/(a+b)=.62 NPV=d/(c+d)= 1.0
Likelihood Ratio= +LR= Sens/(1-Spec)= 1.6
Likelihood Ratio= -LR= (1-Sens)/Spec= .025
Ankle radiographs account for
approximately 10% of all radiographs
ordered in the emergency room. Dunlop MG, Beattie TF, White GK, Raab GM, Doull RI. Guidelines for selective radiological
assessment of inversion ankle injuries. Br Med J (Clin Res Ed) 1986; 293(6547):603-605.
Less than 25% of ankle fractures have
adequate physical examinations, and
more than 99% had radiographs. Vargish T, Clarke WR, Young RA, Jensen A. The ankle injury--indications for the selective
use of X-rays. Injury 1983; 14(6):507-512
Case Study Smith & Cleland
PTJ 2004
9 year old female patient carried by her father to PT clinic direct access.
Heard pop in anterior knee while attempting a backward flip the previous night.
Unable to fully weight bear since injury.
Physical Exam: isolated tenderness of the patella and unable to fully weight bear on the effected side. Unable to flex knee.
What is your recommendation? What clinical exam/ imaging modality do you want to order? What do you think is problem? Why?
Ottawa Knee Rules
Are 55 years of age or older; No Have palpable tenderness over the head of
the fibula; No Have isolated patellar tenderness; Yes Cannot flex the knee to 90°; Yes
Cannot bear weight immediately following the injury; Yes
Cannot walk in ED Yes Pooled Sensitivity = 100%
Case Study Smith & Cleland
PTJ 2004 Cont.
Radiograph revealed horizontal fracture of the lower patalla
To sum it up It is however,
relatively much more important for a physical therapist to recognized the indications for diagnostic imaging, to select the most appropriate imaging study, and to image the appropriate area(s) than it is to interpret the image
o Deyle GD JOSPT, 2005
Computed Tomography (CT)
•X-Ray beam moves 360 around the patient
•Consecutive x-ray “slices” around the patient
•Computer can recreate 3D image of the body
•Best for evaluating bone and soft tissue tumors, fractures, intra-articular abnormalities, and bone mineral analysis
Computed Tomography (CT)
LV
VERTEBRAL BODY
SPINALCANAL
TRANSVERSEPROCESS
RIB
LUNGRA
LA
RV
AORTA
Magnetic Resonance Imaging
(MRI)
What is a MRI?
The use of a High Power Magnet (.3 -
2.0 Teslas) To align hydrogen atoms in
the body to which a radio wave
frequency is applied to produce an
image
Higher Tesla level= increased resolution
No standardization among imaging centers
Indications for MRI
Diagnosing multiple sclerosis (MS)
Diagnosing tumors of the pituitary gland and brain
Diagnosing infections in the brain, spine or joints
Visualizing torn ligaments in the wrist, knee and ankle
Visualizing shoulder injuries
Diagnosing tendonitis
Evaluating masses in the soft tissues of the body
Evaluating bone tumors, cysts and bulging or herniated discs in the spine
Diagnosing strokes in their earliest stages
T1 Vs T2
T1
Tissue with high
water content will
apear dark (grey)
Fat, edema,
infection
Tissue with low
water content will
appear white/
brighter
Bone, lungs
T2
Tissue with high
water content will
appear white/
brighter
Tissue with low
water content will
appear darker (grey)
World War II
Water is white on
T2
T1 vs. T2
T1 image of knee T2 image of knee
Gastrocnemius
Semimembranosus
Popliteal vein
Quad TendonSemimembranosus
ACL
Semitendonosus
Knee - MRI Sagittal
ANTERIORCRUCIATE LIGAMENT
POSTERIORCRUCIATE LIGAMENT
PATHOLOGY
ACL Tear
Meniscus
Bow Tie Sign
Knee
Meniscus
Knee - MRI Sagittal
TORN POSTERIOR MEDIAL MENISCUS
Meniscus
Torn Meniscus- Double PCL Sign
Your MRI is showing
humerus
Scapula
supraspinatus
Deltoid
Clavicle
Glenoid labrum
Long Head of Triceps
Shoulder - MRI – Axial Plane
SupS
D
D
IS
Shoulder - MRI – Axial Plane
Shoulder - MRI – Coronal Plane
Supraspinatus
Rotator CuffSS Tendon
Fluid inJoint
Glenoid
Shoulder
Supraspinatus Tear Subdeltoid Bursa
Lumbar Spine - MRI
Coronal T1 Sagittal T1 Sagittal T2
Axial T1body
Axial T1disc
Axial T2body
Axial T2 disc
Lumbar Spine – MRI Axial
Body
Psoas
Spinal Canal
Herniated disc
Lumbar Spine – MRI Sagittal T2
Things that make you go Hmm
20-year-old male collegiate athlete who was
referred to physical therapy for left knee pain
Subjective: patient reports insidious onset of
knee pain 1 yr. prior, but pain was exacerbated 3
weeks ago when he was tackled while playing
football
Things that make you go Hmm
Physical Exam:
ataxic gait with a widened, base of support
single-limb balance > 1 second bilateral
MMT non-specific weakness
Reflexes present
Clonus present on L (4 beats)
Extension reflex with Babinski
Recommendations?
What is your recommendation? What
clinical exam/ imaging modality do
you want to order? What do you think
is problem?
Walk JOSPT 2008
Insert case study by
Matt Walk
Walk JOSPT 2008
DEXA SCAN
Looks at bone mineral densities
The “image” however, is secondary the important
information gathered is the bone mineral density
Skeletal Scintigraphy
(Bone Scan)
Indication:
Cancer,
stress or
hidden
fractures
Ankle Radiograph- 20 views
Tibia Radiograph- 6 views
Knee Radiograph- 2 views
Chest Radiograph- 4 views
Hand Radiogpraph- 2 views
Finger Radiograph- 2 views
CT chest
Ultrasound
Doppler
Abdominal aortogram
Angiogram
Fluroscopy
Did you see that?
Good Websites
•http://www.freitasrad.net/index.html
•http://www.gla.med.va.gov/mriatlas/index.html
•http://www.mypacs.net
•http://www.info-radiologie.ch/index-english.php
•http://medinfo.ufl.edu/year1/rad6190/
•http://www.physio-
pedia.com/index.ph?title=Lectures_and_Presentations
•http://www.mskcases.com/
•TWU- anatomy tv
INTEGRATION A 54-year-old male safety consultant
Mechanism of injury: The patient sustained a knee injury at the age of 17 and has periodically experienced varying levels of pain for 37 years.
Subjective: He began to experience intermittent medial left knee pain about 4 months prior to seeking treatment. The pain worsened when he climbed up or down stairs and by twisting when weight bearing. Knee occasionally gives out.
1st imaging option, 2nd option
Case #1
Case #1
INTEGRATION A 54 y.o. female school teacher
Recently experienced sever headache and difficulty speaking
Exam- presents with aphasia , dysarthria and coughs when eating. She has decreased strength and coordination in her left arm.
1st imaging option, 2nd option
Case #2
Case #2
INTEGRATION
3.
30 y.o. male who works as a construction worker
with acute back pain when he lifted a jack hammer.
Patient reports numbness and tingling present
down the back of his left leg and into his left foot
Exam reveals weakness of dorsiflexion and great
toe extension, (+) SLR and (+) slump, (+) cough/
sneeze
1st imaging option, 2nd option
Explain what might be the problem and why you
chose the modality
Case #3
Case #3
INTEGRATION
Case 4.
17 y/o female student who plays club volleyball with complaints of weakness of plantar flexion and plantar foot pain with prolonged gait. Patient reports she feels a little weak when jumping and also walking
Exam reveals:No lumbar painWeakness of S1 myotome testingNo lateral shiftPain free in supine; even with exerciseNo pain with cough or sneeze• Antalgic gait due to weaknessBMI below normal, overall excellent health
Case 4