Imaging in PT

Question 1

Academy of Orthopedics in 2016 stated that PTs:

Answer 1

• are capable of recognizing the need for imaging
• are capable of incorporating imaging results into initial and
  subsequent clinical reasoning processes
• can provide expert clinical examinations to determine wether imaging
  is necessary
• are capable of utilizing imaging in a safe and efficient manner to
  reduce potential risks….lower costs…and minimize risks of
  unnecessary early imaging in the course of a condition

Question 2

Expanding use of imaging decision making in PT

Answer 2

• Facilitate interprofessional practice and communication * Expansion of direct access
• Screening
• Referral for conditions outside scope of PT practice * Patient education/ therapeutic alliance
• Treatment planning and progression
• Therapeutic PNE

Question 3

Referral for imaging

Answer 3

Directly refer a patient for imaging without going through another provider

Question 4

Recommend for imaging

Answer 4

Suggest or request imaging through another provider who then orders the imaging

Question 5

Integration of imaging

Answer 5

Using imaging results to make well-reasoned decisions regarding individual patients

Question 6

is referral for imaging dependent on direct access?

Answer 6

no

Question 7

physical therapists should:

Answer 7

○ Understand the role of imaging
○ Idenfity when imaging is indicated
○ Idenfity what type of imaging is most appropriate
○ Obtaining necessary diagnostic imaging
○ Integrating imaging results into patient/client management
○ Effective communication strategies between providers and with patients/clients

Question 8

Providers who sign the referral for imaging…

Answer 8

assume responsibility to manage the patients subsequent care

Question 9

purpose of clinical decision tools for imaging

Answer 9

○ Identify when imaging is indicated
○ Specify the most appropriate type of imaging

Question 10

available clinical decision tools for imaging

Answer 10

○ Clinical Decision Rules (e.g. Ottawa Ankle Rules, Canadian C-spine
rules etc.)
○ American College of Radiology (ACR) Appropriateness Criteria

Question 11

benefits of clinical decision rules

Answer 11

○ Clear and simplified indications for imaging
■ Radiographs: knee, ankle, foot
■ CT: c-spine
○ Not medical specialty dependent

Question 12

limitations of clinical decision rules

Answer 12

○ Acute trauma only; limited to assessment for fracture
○ All developed based on patients presenting to ED
○ Does your patient meet the “inclusion” criteria?
○ No indication about how to manage patients outside the research protocol

Question 13

ACR Appropriateness Criteria - What

Answer 13

○ A set of of evidence-based imaging guidelines for specific clinical conditions
○ Expert consensus, reviewed annually

Question 14

ACR Appropriateness Criteria - Purpose

Answer 14

○ Recommend type and sequence of imaging modalities
○ Optimize patient / client safety

Question 15

ACR Appropriateness Criteria - Clinical Hypothesis Variants

Answer 15

○ Detailed variants based on clinical hypotheses
○ Primary focus is appropriate imaging modality

Question 16

ACR Appropriateness Criteria - Author Narratives

Answer 16

○ Explains rationale
○ Captures clinical essence of imaging recommendations
○ Patient summaries

Question 17

How is ACR Appropriateness Criteria helpful to us even though we can’t order imaging?

Answer 17

• Improve understanding of imaging terminology
• Facilitate integrating imaging report information into patient care
• identify conditions or situations outside the scope of PT practice
• Improve communication and recommendations to referral sources

Question 18

Radiograph - Physical Position

Answer 18

• supine, upright, etc

Question 19

Standard radiograph position

Answer 19

describes the body part closest to the image receptor

Question 20

Radiograph - projections describe the path of the x-ray beam

Answer 20

• A-P, P-A, lateral, oblique etc.
• Lateral are defined by the side closest to the image receptor/plate
• Oblique views necessary to image specific structures

Question 21

MRI

Answer 21

• Utilizes magnetic field physics
• Differences in magnetic field strengths
• Provides excellent tissue contrast and a means to evaluate brain, spinal cord, discs, ligaments, vertebral bodies, vascular structures, organs, tumors, muscle, and facet joints
• Significant contraindications exist (e.g., pacemaker, metal in the body, claustrophobia etc.)

Question 22

MRI - TE

Answer 22

• TE (time to echo) is the time between application of
  the RF pulse and the peak of the signa

Question 23

MRI - TR

Answer 23

• TR (repetition time) is the time from application of
  excitation pulse to the application of the next pulse

Question 24

MRI - T1 and T2

Answer 24

• T1 and T2 are different processes related to the return of protons to alignment with the main magnetic field
• T1 weighted image: early part of the decay signal
• T2 weighted image: late stage of the decay signal

Question 25

T1 Weighted images

Answer 25

* short TR and TE times * signal is caught early when the difference in relaxation characteristics for fat and water is most noticeable and tissues that rapidly recover their longitudinal magnetization, such as fat, give rise to high signal intensity (create a bright image) * short TE --> tissues that are slow to regain longitudinal magnetization, such as tissues with high free-water content, render low signal intensity and appear dark on T1-weighted images

Question 26

T1 provides images of ...

Answer 26

good anatomic detail, displaying the tissues in a fairly balanced manner

Question 27

T2 Weighted images have

Answer 27

long TR and TE times

Question 28

How does T2 imaging work

Answer 28

* signal is measured late in the decay process so tissues that are most reluctant to give up energy are selectively imaged * Free water is slow to give up its energy = high signal intensity on T2 sequences * Fat, which gives up energy rapidly = low intensity on T2

Question 29

T2 images

Answer 29

* T2 images are grainier and display less spatial resolution since they are made at lower energy levels

Question 30

What is T2 imaging valuable for

Answer 30

detecting inflammation

Question 31

what does MRI excel in

Answer 31

display of soft tissue detail

Question 32

what is MRI the best movability for

Answer 32

evaluation of disk herniation and other potential causes of nerve root impingement

Question 33

MRI sensitivities

Answer 33

* very sensitive for detecting changes and variations in bone marrow * can stage neoplasms in bone and soft tissues as well as evaluate the extent of tissue invasion * more sensitive than bone scans for detecting bone metastases (although bone scan is more effective as a screening technique)

Question 34

Computed Tomography

Answer 34

* Merges x-ray and computer technology to create cross sectional slices

Question 35

major advantage of CT

Answer 35

demonstration of subtle bony abnormalities

Question 36

major disadvantage of CT

Answer 36

10-100 x increase in radiation exposure to the patient

Question 37

CT is standard modality in...

Answer 37

ED for head trauma, CVA, abdominal trauma

Question 38

what is bone scan

Answer 38

A nuclear imaging technique that shows areas of increased bone activity as the marker or tracer is taken up in the bone tissue as increased mineral turnover

Question 39

What is bone scan useful for

Answer 39

Useful for detecting subtle fracture, stress fracture, infections, various types of arthritis, avascular necrosis, primary and secondary metastatic tumors, and can be used in diagnosing CRPS

Question 40

what is the most commonly used radionuclide in bone scan

Answer 40

Technetium-99

Question 41

are bone scans sensitive

Answer 41

yes but not specific not usually used alone

Question 42

DEXA/DXA

Answer 42

* used to determine the density of bone to assess its strength. * a standard method for diagnosing osteoporosis; used in combination with risk factors it is also considered an accurate way to estimate fracture risk

Question 43

see the supplemental table

Question 44

Advantages of Xray

Answer 44

- familiarity - readily available - inexpensive - quick

Question 45

disadvantages of x ray

Answer 45

radiation exposure availability may cause over use

Question 46

CT advantages

Answer 46

- superior anatomic detail, improved fracture sensitivity - transverse (axial) images - computer storage

Question 47

CT disadvantages

Answer 47

- radiation exposure - expensive - artifacts - reactions to contrast

Question 48

MRI advantages

Answer 48

- excellent anatomic detail, especially of soft tissue - no radiation exposure

Question 49

MRI disadvantages

Answer 49

- expensive - lengthy study - limited visualization of cortical bone - no ferromagnetic objects

Question 50

Nuclear studies advantages

Answer 50

- very sensitive - identify extent of process - low radiation exposure

Question 51

nuclear studies disadvantages

Answer 51

- lack of specificity - low resolution - expensive

Question 52

US advantages

Answer 52

- safe during pregnancy (no radiation) - intermediate cost - high sensitivity and specificity

Question 53

US disadvantages

Answer 53

- poor screening tool; best when site of disease is known - image deterioration; sound blocked by air - operator dependent

Question 54

Review Ottawa knee rules

Question 55

review Ottawa ankle/foot rules

Question 56

Pittsburg decision rule (knee pain following an injury)

Answer 56

Conventional radiographs when a patient has had "blunt trauma or a fall as a mechanism of injury" plus either or both of the following: * Age < 12 years or > 50 years * Inability to walk four weight-bearing steps in the ED

Question 57

review Canadian c spine rules

Question 58

what does NEXUS low risk criteria identify

Answer 58

patients following trauma who DO NOT need diagnostic imaging

Question 59

NEXUS low risk criteria

Answer 59

Radiography is indicated following trauma unless a patient meets all five criteria: 1. No posterior midline cervical tenderness 2. No evidence of intoxication 3. Normal level of alertness and consciousness 4. No focal neurological deficit 5. No painful distracting injuries (for example, an injury in an area other than the cervical spine that may distract the patient from neck pain)

Question 60

risk factors for cervical instability

Answer 60

* Rheumatoid arthritis * Ankylosing spondylitis * Os Odontoideum * Klippel-Feil syndrome * Down syndrome * Morquios syndrome * Ehler-Danlos syndrome * Marfan syndrome * Other hereditary connective tissue disorders * Post-fusion

Question 61

radiography cervical spine

Answer 61

* A-P allows visualization of C3-7 vertebra * A-P odontoid (“open mouth”) for visualization of C1-2 * Oblique views to visualize IV foramen

Question 62

should you do imaging for low back pain within the first six weeks?

Answer 62

no unless there are red flags

Question 63

imaging guidelines for acute LBP in primary care settings

Answer 63

1. For adults younger than 50 years of age with no signs or symptoms of systemic disease, symptomatic therapy without imaging is appropriate. 2. For patients 50 years and older or those whose findings suggest systemic disease, conventional radiography and simple laboratory tests can almost completely rule out underlying systemic disease. 3. Advanced imaging should be reserved for patients who are considering surgery or those in whom systemic disease is strongly suspected.