Biophysics Week 1

Ottawa ankle rules- medial foot

Pain in MIDFOOT zone AND

-Bone tenderness at the Navicular OR

-Bone tenderness at the base of the 5th metatarsal OR

-Inability to bear weight: immediately and in ED

Ottawa Ankle Rules- lateral foot

Pain in MALLEOLAR zone AND:

-Bone tenderness in posterior edge of lateral malleolus OR

-Bone tenderness at the posterior edge of the medial malleolus OR

-Inability to bear weight: immediately and in ED

Ottawa knee rules (5)

-pt >55 y/o OR

-isolated tenderness of patella OR

-tenderness of the head of the fibula OR

-cannot flex to 90 degrees OR -unable to bear weight: immediately and in ED for 4 steps (2 weight shifts)

Canadian Cervical Spine Rules

1. High risk factors (age 65+ OR dangerous mechanism OR paraesthesia in extremities)
2. Not a simple rear end MVA OR cannot sit in ED OR not ambulatory at any time OR immediate pain OR presence of midline C-spine tenderness
3. Unable to rotate actively 45 degrees left and right

If yes to any of these, Radiograph

Why should PTs be able to order imaging (3)

-All other first contact providers can order imaging

-Reduces unnecessary delays

-We have an obligation to refer

PT utilization rates of imaging (all, DA)

All= 0.9%

DA= 7%

Overall appropriateness of PT imaging ordering (ordering based on ACR criteria)

91%

What percent of PT imaging referrals were reimbursed?

100% (No denials)

Emergent referrals (6)

-cauda equina

-infection

-myelopathy

-fracture

-stroke

-MI

Urgent referrals (3)

-some fractures

-cancer

-progressive neurological deficits

Abnormal imaging results are always the source of pt pain

FALSE (abnormal findings do not predict development of LBP)

What measure allows PTs to rule things out that we cannot treat?

Sensitivity

Osteoblastic

Bone building

Osteoclastic

Bone reducing

Radiopaque, opacity, sclerosis, and increased radiodensity are examples of

Osteoblastic terms

Radiolucent, lucency, osteopenia, decreased radiodensity, and lytic lesion/lysis are examples of

Osteoclastic terms

Less dense substances appear what color on radiographs

Black/darker

More dense substances appear what color in radiographs

White/lighter

What should you be looking for in a radiographic evaluation

Alignment Bone density Cartilage Spaces Soft Tissue

Contraindications for x-ray

None absolute

Precautions for x-ray

Pregnancy

Which kind of imaging is a continuous radiographic exam that is used to guide procedures and results in a higher radiation dose?

Fluoroscopy

In what procedure does fluoroscopy relate to PT

Lumbar epidural under fluoroscopy and percutaneous vertebroplasty

What non-PT treatment is given for vertebral compression fractures

Vertebroplasty

What kind of imaging consists of dye injected into the joint space and subsequent imaging

Arthrogram

What kind of imaging consists of contrast dye being injected into the subarachnoid space and imaging?

Myelography

What kinds of imaging can be used in a myelogram (4)

x-ray, CT, MRI, fluoroscopy

How often are MRI image slices taken?

3-5 mm

What are the 3 dimensions of an MRI

axial sagittal coronal

Which MRI view looks up through the patients feet

Axial (transverse)

Which MRI view is like looking at the patient from the side?

Sagittal (lateral)

Which MRI view is like facing the patient

Coronal (frontal, cross sectional)

Which kind of MRI has higher quality images and no real limitations related to the body region of interest?

Closed (traditional) MRI

What kind of MRI has a less quality image and limitations related to body region of interest but is ideal for pt with claustrophobia

Open MRI

What do you better visualize in a T1 MRI

Bone marrow

What do you better visualize in a T2 MRI (3)

healthy discs CSF boney edema

What color is fluid on a T2 weighted MRI

white

Are tattoos a contraindication for MRI

NO

Is pregnancy a contraindication for MRI

NO

What thickness are CT scan slices?

0.1-10 mm thick

Benefits of CT over MRI (2)

Less time consuming, claustrophobia friendly

Which has a higher radiation dose- x-ray or CT

CT

What structure does CT get an excellent view of?

Bone (cortical)

What is the best modality for evaluation of a loose body in a joint?

CT

What is the best modality for identifying subtle or complex fractures

CT

What can you see best via MRI (4)

-soft tissue -vascular/demyelinating dz -ligament/tendon injuries -neoplasms (spinal mets)

What can you see best via CT (4)

-cortical bone

-chest/abdomen/pelvis

-fractures/ loose bone

-bony stenosis

Radionucleide scanning and scintigraphy are also referred to as

Bone scan

What diagnoses are best for scintigraphy (3)

-stress fx

-infection

-tumor

What does a scintigraphy bone scan look for?

Increased metabolic activity/uptake

What are the absolute contraindications for scintigraphy bone scans?

Pregnancy

What are the limitations of scintigraphy bone scans

Lack of specificity in differential dx

Bone Density Scan DXA is also referred to as

Bone scan

What is the gold standard for measuring bone mineral density

DXA

What is the T score for healthy bone in a DXA

-1

What is the T score for osteopenia in DXA

-1 to -2.5

What is the T score for osteoporosis in DXA

< -2.5

Benefits of ultrasound imaging

image anatomy in real time with significant detail

Higher frequency on ultrasound have what effect on the resolution and depth?

resolution= better depth= decreased

What is the relationship between resolution and depth in ultrasound

inverse- increasing resolution accompanies decrease depth and vice versa

Which transducer for ultrasound has higher frequency and less depth

Linear

Which transducer for ultrasound has lower frequency and increased depth

Curvilinear

What is the importance of anisotropy in ultrasound

Better image results when perpendicular to the structure being evaluated

Hyperechoic structures will be what color?

White

Hypoechoic structures will be what color

Darker/black

What are three muscles that are helpful to visualize activation via ultrasound

Multifidi, transversus abdominis, and biceps long head