foundations of diagnostic imaging for physical therapist

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