General Principles

  • Proper Patient Positioning
    • Patient comfort comes first, so may be difficult at times especially in cases of casting, fracture, or uncooperation
    • Allows for easier reformats
    • Reduces radiation dose to the patient
  • Reformats
    • Always include the entire field of view of the source images in the reformatted images
  • Soft tissue mass evaluation
    • Use palpable markers to bracket the area of palpable abnormality
    • Scan approximately 5 cm above and below the region of palpable abnormalit
    • If study is ordered noncontrast, please check if patient can get intravenous contrast
  • Arthrograms
    • Dilute iodinated contrast with sterile saline or water in a 50/50 ratio
  • Long Bone Protocol
    • Includes humerus, forearm, femur, and lower leg/extremity
    • Cover entire long bone in the field of view and surrounding soft tissues to the skin surface
    • Axial reformats perpendicular to the long bone diaphysis
    • Sagittal and coronal reformats parallel to the long bone diaphysis
    • Be sure to include entire source field of view in the reformats

MSK CT Protocols

Table of Contents

  • General Principles
  • Upper Extremity
    • Shoulder
    • Elbow (cast)
    • Elbow (no cast)
    • Wrist
    • DRUJ Instability

Table of Contents

• Lower Extremity • Pelvis/Sacrum

• Hip
• Hip – Anteversion • Knee
• Ankle
• Hindfoot/Midfoot • Midfoot/Forefoot

GENERAL PRINCIPLES

General Principles

• Proper Patient Positioning

  • Patient comfort comes first, so may be difficult at times especially in cases of casting,

    fracture, or uncooperation

  • Allows for easier reformats
  • Reduces radiation dose to the patient

    • Reformats
    • Always include the entire field of view of the source images in the reformatted images

    • Soft tissue mass evaluation
    • Use palpable markers to bracket the area of palpable abnormality

    • Scan approximately 5 cm above and below the region of palpable abnormality
    • If study is ordered noncontrast, please check if patient can get intravenous contrast

    • Arthrograms
    • Dilute iodinated contrast with sterile saline or water in a 50/50 ratio

• Long Bone Protocol

General Principles

  • Includes humerus, forearm, femur, and lower leg/extremity
  • Cover entire long bone in the field of view and surrounding soft tissues to the skin surface
  • Axial reformats perpendicular to the long bone diaphysis
  • Sagittal and coronal reformats parallel to the long bone diaphysis
  • Be sure to include entire source field of view in the reformats

UPPER EXTREMITY

Shoulder

• Positioning

Shoulder

• Patient supine with palm up

  • Ideally, affected arm by side with contralateral arm raised above head
  • If contralateral arm can’t be raised, position shoulder being scanned higher than other shoulder
  • If not possible (i.e. acute trauma), do what you can to keep patient comfortable

Shoulder

• Field of View

  • Above acromioclavicular (AC) joint to just

    below scapula

  • Medially to include scapula and laterally to skin surface
  • Do not need to include the whole clavicle
  • Include hardware if present

    • Scanning Parameters
    • 1.25 mm thick at 0.625 mm intervals

Shoulder

• Sagittal and coronal reformats

• 2 mm slice, 2 mm interval

• Find axial image that shows glenohumeral joint (dashed line)

Shoulder

• Coronal reformats

• 2 mm slice, 2 mm interval

• Slices perpendicular to the glenohumeral joint line

• Sagittal reformats

• 2 mm slice, 2 mm interval

• Slices parallel to glenohumeral joint line

Shoulder

  • Axial oblique reformats
  • 2 mm slice, 2 mm interval

Shoulder

  • Find coronal reformat image showing the acromion (red arrow)
  • Orient slices perpendicular to the glenohumeral joint (dashed line)

Source axial

Reformat axial oblique*

Reformat coronal oblique*

Reformat sagittal oblique*

Shoulder CT Summary for fracture and bone lesion

PLANE

SECTION THICKNESS

1.25 mm

2 mm

2 mm

2 mm

INTERVAL

0.625 mm

2 mm

2 mm

2 mm

OVERLAP

50%

None

None

None

WINDOW

SOFT TISSUE

SOFT TISSUE BONE

BONE

BONE

*All reformats should include ENTIRE field of view of the source images

Shoulder CT Summary for CT Arthrogramⱡ or soft tissue mass/infection

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW

Source axial

1.25 mm

0.625 mm

50%

SOFT TISSUE

Reformat axial oblique*

2 mm

2 mm

None

SOFT TISSUE BONE

Reformat coronal oblique*

2 mm

2 mm

None

SOFT TISSUE

Reformat sagittal oblique*

2 mm

2 mm

None

SOFT TISSUE

*All reformats should include ENTIRE field of view of the source images ⱡ Dilute iodinated contrast with sterile water or normal saline 50/50

Elbow (Cast)

• Most difficult to scan, particularly if in cast

  • Obviously can’t straighten elbow but must try to get arm above head
  • AVOID arm across chest
    • Causes beam hardening artifact, radiation to torso,

    and respiratory motion artifact

  • Scanning plane should be obliquely oriented towards the long axis of the radius and ulna (don’t scan parallel to radius and ulna)

Elbow (Cast)

• Positioning

Elbow (Cast)

• Field of View

• Distal humerus to proximal forearm (distal to radial tuberosity)

• Scanning Parameters

• 0.6 mm thick at 0.3 mm intervals

Elbow (Cast)

• Field of View

• Distal humerus to proximal forearm (past radial tuberosity)

• Scanning Parameters

• 0.6 mm thick at 0.3 mm intervals

• Reformats

• 2 mm slice, 2 mm interval

• Find sagittal image show elbow joint and olecranon (red arrow)

Elbow (Cast)

• Reformats

Elbow (Cast)

• 2 mm slice, 2 mm interval

• Axial images perpendicular to long axis of humerus

• Reformats

Elbow (Cast)

• 2 mm slice, 2 mm interval

• Axial images through long axis plane of forearm

Elbow (Cast)

• Reformats
• 2 mm slice, 2 mm interval
• Long axis images to plane of the radius

Elbow (Cast)

• Reformats
• 2 mm slice, 2 mm interval
• Coronal plane parallel to long axis of the ulna

Elbow (Cast)

  • From axial series through the humerus, find an image through the medial and lateral epicondyles
  • Note line parallel to the posterior border of the epicondyles

• Coronal reformats

• 2 mm slice, 2 mm interval

• Coronal to humerus, parallel to inter-epicondyle line

Elbow (Cast)

• Sagittal Reformats

• 2 mm slice, 2 mm interval

• Orient sagittal slices perpendicular to humerus and inter-epicondylar line

Elbow (Cast)

Cast Elbow CT Summary for fracture and bone lesion

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Reformat axial to long axis of humerus*

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat axial long axis plane of forearm*

2 mm

2 mm

None

BONE

Reformat long axis to plane of radius*

2 mm

2 mm

None

BONE

Reformat long axis to plane of ulna*

2 mm

2 mm

None

BONE

Reformat coronal to humerus, parallel to inter-epicondyle line

2 mm

2 mm

None

BONE

Reformat sagittal to humerus and inter- epicondylar line

2 mm

2 mm

None

BONE

*-All reformats should include ENTIRE field of view of the source images

Elbow (No Cast)

• Positioning
• Most difficult to scan

Elbow (No Cast)

  • Arm MUST be raised above patient’s head
  • Should be as straight as possible with palm up
  • If patient CAN’T straighten elbow, use CAST protocol
  • AVOID arm across chest
    • Causes beam hardening artifact, radiation to torso,

    and respiratory motion artifact

  • Scanning plane should be perpendicular to the CT scanning plane

    • Allows easier reformatting

• Positioning
• Most difficult to scan

Elbow (No Cast)

  • Arm MUST be raised above patient’s head
  • Should be as straight as possible with palm up
  • AVOID arm across chest
    • Causes beam hardening artifact, radiation to torso,

    and respiratory motion artifact

  • Scanning plane should be perpendicular to the CT scanning plane

    • Allows easier reformatting

Elbow (No Cast)

• Field of View

• Distal humerus to proximal forearm (distal to radial tuberosity)

• Scanning Parameters

• 0.6 mm thick at 0.3 mm intervals

• Field of View

• Distal humerus to proximal forearm (distal to radial tuberosity)

• Scanning Parameters

• 0.6 mm thick at 0.3 mm intervals

Elbow (No Cast)

Elbow (No Cast)

  • From axial series through the humerus, find an image through the medial and lateral epicondyles
  • Note line parallel to the posterior border of the epicondyles

• Coronal reformats

• 2 mm slice, 2 mm interval

• Coronal to humerus, parallel to inter-epicondyle line (red lines)

Elbow (No Cast)

• Sagittal Reformats

Elbow (No Cast)

• 2 mm slice, 2 mm interval

• Orient sagittal slices perpendicular to humerus and inter-epicondylar line (red lines)

Noncasted Elbow CT Summary for fracture and bone lesion

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Axial

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat coronal to humerus, parallel to inter-epicondyle line

2 mm

2 mm

None

BONE

Reformat sagittal to humerus and inter- epicondylar line

2 mm

2 mm

None

BONE

*-All reformats should include ENTIRE field of view of the source images

Noncasted Elbow CT Summary for CT arthrogramⱡ and soft tissue mass/infection

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Axial

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat coronal to humerus, parallel to inter-epicondyle line

2 mm

2 mm

None

SOFT TISSUE

Reformat sagittal to humerus and inter- epicondylar line

2 mm

2 mm

None

SOFT TISSUE

*All reformats should include ENTIRE field of view of the source images ⱡ Dilute iodinated contrast with sterile water or normal saline 50/50

Wrist

Wrist

• Positioning • Prone

  • Arm over head and straight as possible with palm down
  • Wrist centered in gantry

    • Scanning Parameters

• 0.625 mm thick at 0.3 mm intervals

• Field of view
• Proximal-Radius/Ulnametaphysis

• Can scan more proximally to include extent of fracture

• Distal – Past metacarpal bases

• Positioning • Prone

Wrist

  • Arm over head and straight as possible with palm down
  • Wrist centered in gantry

    • Scanning Parameters

• 0.625 mm thick at 0.3 mm intervals

• Field of view
• Proximal-Radius/Ulnametaphysis

• Can scan more proximally to include extent of fracture

• Distal – Past metacarpal bases

• Axial reformats

Wrist

• 1.5 mm thickness, 1.5 mm interval

• Axial images through the radioulnar joint (red arrow)

• Sagittal reformats

Wrist

  • 2 mm thickness, 2 mm interval
  • Sagittal images through long axis of the wrist (perpendicular to axial reformats or along the long axis of the radius)

• Coronal reformats

Wrist

  • 2 mm thickness, 2 mm interval
  • Coronal images through long axis of the wrist (perpendicular to sagittal reformats)

Scaphoid Reformat

• ADD if clinical history includes scaphoid pathology

• oblique sagittal along long axis of scaphoid

• 1 mm slice thickness, 1 mm interval

Wrist CT Summary for fracture and bone lesion

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Reformat axial*

1.5 mm

1.5 mm

None

BONE SOFT TISSUE

Reformat coronal*

2 mm

2 mm

None

BONE

Reformat sagittal*

2 mm

2 mm

None

BONE

Reformat scaphoid oblique sagittal1

1 mm

1 mm

None

BONE

*-All reformats should include ENTIRE field of view of the source images 1-Perform if clinical history of scaphoid fracture

Wrist CT Summary for CT Arthrogramⱡ or soft tissue mass/infection

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Reformat axial*

1.5 mm

1.5 mm

None

SOFT TISSUE BONE

Reformat coronal*

2 mm

2 mm

None

SOFT TISSUE

Reformat sagittal*

2 mm

2 mm

None

SOFT TISSUE

*All reformats should include ENTIRE field of view of the source images ⱡ Dilute iodinated contrast with sterile water or normal saline 50/50

DRUJ INSTABILITY

DRUJ Instability

• DRUJ = distal radioulnar joint • Positioning

  • Prone with BOTH arms as straight as possible above head
  • 3 separate images obtained of BOTH wrists in neutral, supine, and prone
  • Keep both arms aligned with each other

    • Scanning Parameters

  • Same field of view as routine wrist
  • Only need axial images (but must be true axials as with routine wrist)

3 Separate Source axials (neutral/prone/supine)

Reformat axial NEUTRAL*

Reformat axial PRONE*

Reformat axial SUPINE*

Reformat bilateral coronal oblique

DRUJ Instability Summary

PLANE

SECTION THICKNESS

0.625 mm

2 mm

2 mm

2 mm

1 mm

INTERVAL

0.3 mm

2 mm

2 mm

2 mm

1 mm

OVERLAP

50%

None

None

None

None

WINDOW WIDTH/LEVEL

SOFT TISSUE

BONE

BONE

BONE

BONE

*-All reformats should include ENTIRE field of view of the source images

LOWER EXTREMITY

Pelvis/Sacrum

• Positioning
• Patient supine

Pelvis

• Legs flat on table, avoid cushions under legs or feet

• Field of View must include

  • Above iliac crests (white line)
  • Below lesser trochanter and ischial tuberosity (red line)
  • Skin to Skin

    • Scanning Parameters

• 1.25 mm thick at 0.625 mm intervals

• Axial reformats

• 2 mm slice, 2 mm interval

Pelvis

  • Coronal image that shows both femoral heads
  • Angle such that slice cuts evenly through both femoral heads (dotted line)
  • Coverage from iliac crests to below lesser trochanters ( solid lines)
  • FAI (FEMORAL-ACETABULAR IMPINGEMENT): Include angled oblique axials through femoral necks (three solid lines)

• Coronal reformats

  • 2 mm slice, 2 mm interval
  • Axial image that shows pubic symphysis (red arrow)
  • Angle evenly through ischial tuberosities (dotted line)

Pelvis

• Coverage from anterior aspect of the pubic symphysis to posterior to the musculature(solid lines)

• Sagittal reformats

  • 2 mm slice, 2 mm interval
  • Axial image that shows pubic symphysis (red arrow)

Pelvis

• Cover from hip to hip (solid lines)

Sacroiliac Joints

• Reformats

• 2 mm slice, 2 mm interval

• Oblique Coronal
• Mid-line Sagittal image through sacrum
• Angle slices parallel to the long axis of sacrum (top image) • Cover sacrum in entirety, including entire sacroiliac joints

• Oblique Axial

  • Same mid-line Sagittal image through sacrum
  • Angle slices perpendicular to the oblique coronals (bottom image)
  • Cover sacrum in entirety, including sacroiliac joints

Source axial

Reformat axial*

Reformat coronal*

Reformat sagittal*

Reformat axial oblique femoral neck1

Reformat oblique coronal sacroiliac joints2

Reformat oblique axial sacroiliac joints2

Pelvis CT Summary for fracture or bone lesion

PLANE

SECTION THICKNESS

1.25 mm

2 mm

2 mm

2 mm

2 mm

2 mm

2 mm

INTERVAL

0.625 mm

2 mm

2 mm

2 mm

2 mm

2 mm

2 mm

OVERLAP

50%

None

None

None

None

None

None

WINDOW WIDTH/LEVEL

SOFT TISSUE

BONE SOFT TISSUE

BONE

BONE

BONE

BONE

BONE

*-Should include ENTIRE field of view of the source images 1-Perform if clinical history of FAI or femoroacetabular impingement 2-Perform if clinical history of sacroiliac/sacral pathology

Pelvis CT Summary for soft tissue mass/infection

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

1.25 mm

0.625 mm

50%

SOFT TISSUE

Reformat axial*

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat coronal*

2 mm

2 mm

None

SOFT TISSUE

Reformat sagittal*

2 mm

2 mm

None

SOFT TISSUE

*-Should include ENTIRE field of view of the source images

Hip

Hip

• Positioning
• Patient supine

• Legs flat on table, avoid cushions under legs or feet

• Field of View must include

  • Superiorly above iliac crest (white line)
  • Inferiorly below lesser trochanter and ischial tuberosity (red line)
  • Laterally to the skin surface (green line)
  • Medially through the symphysis pubis (yellow

    line)

    • Scanning Parameters

• 1.25 mm thick at 0.625 mm intervals

PROSTHESIS: Hip

• Positioning

• Patient supine

• Legs flat on table, avoid cushions under legs or feet

• Field of View must include

  • Superiorly above iliac crest (white line)
  • Laterally to the skin surface (green line)
  • Medially through the symphysis pubis (yellow line)
  • Scan below hardware (red line)

    • Scanning Parameters
    • 1.25 mm thick at 0.625 mm intervals

  • Axial and axial oblique reformats
  • 2 mm slice, 2 mm interval
  • Coronal image that shows femoral head
  • Straight Axial:
    • Angle such that slice cuts evenly through the

    superior femoral head (dotted line)

    • Coverage from above iliac crest to below lesser trochanters (red lines)

  • FAI (FEMORAL-ACETABULAR IMPINGEMENT): Include angled oblique axials through femoral necks (solid yellow lines)

Hip

  • 2 mm slice, 2 mm interval
  • Axial image that shows anterior acetabulum (red arrow)
  • Angle evenly through anterior acetabulum (dotted line)

Hip

• Coronal reformats

• Cover from skin to skin (red lines)

• Sagittal reformats

Hip

• 2 mm slice, 2 mm interval

  • Same axial image as the coronal reformats
  • Angle perpendicular to coronal plane (dotted yellow line)
  • Cover entire field of view (red lines)

Hip CT Summary for fracture or bone lesion

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

1.25 mm

0.625 mm

50%

SOFT TISSUE

Reformat axial*

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat coronal*

2 mm

2 mm

None

BONE

Reformat sagittal*

2 mm

2 mm

None

BONE

Reformat axial oblique femoral neck1

2 mm

2 mm

None

BONE

*-Should include ENTIRE field of view of the source images 1-Perform if clinical history of FAI or femoroacetabular impingement

Hip CT Summary for CT arthrogramⱡ or soft tissue mass/infection

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

1.25 mm

0.625 mm

50%

SOFT TISSUE

Reformat axial*

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat coronal*

2 mm

2 mm

None

SOFT TISSUE

Reformat sagittal*

2 mm

2 mm

None

SOFT TISSUE

Reformat axial oblique femoral neck1

2 mm

2 mm

None

SOFT TISSUE

*All reformats should include ENTIRE field of view of the source images ⱡ Dilute iodinated contrast with sterile water or normal saline 50/50 1-Perform if clinical history of FAI or femoroacetabular impingement

Hip – Anteversion

Hip – Anteversion

• Positioning
• Patient supine

  • Legs flat on table and as close together as possible
  • tape feet together with toes pointed straight up
  • avoid cushions under legs or feet

    • Scout
    • AP plane

    • Hips and Knees

    • Scanning Parameters

  • 5.00mmthickat5.00mmintervals
  • Hips – just above femoral heads and to just below lesser trochanters
  • Knees – just above femoral physis and thru tibial plateau

Hip – Anteversion

• Find slice that best reveals alignment of femoral neck • Measure the neck – horizontal angle (NH)

• Find the slice that best reveals alignment of femoral condyles

• Measure the condyle – horizontal angle (CH)
• Calculate angle of neck relative to condyle (NC = NH – CH)

Hip – Anteversion

• Find slice that best reveals alignment of femoral neck

• Measure the neck – horizontal angle (NH)

Hip – Anteversion

• Find the slice that best reveals alignment of femoral condyles

• Measure the condyle – horizontal angle (CH)

Hip – Anteversion

• Calculate angle of neck relative to condyle (NC = NH – CH)

Knee

Knee

• Positioning

• Patient supine

  • Slide patient so that knee being imaged is centered in the scanner
  • Tapping toes together may help positioning
  • Can scan both legs together, but if other leg has metal MUST bend so it is not in the scanning plane

• Field of View must include

  • Entire patella
  • Both femoral condyles
  • Proximal tibia to just past the fibular head
  • METAL PROSTHESIS: Must scan entire length of the femoral and tibial components

    • Scanning Parameters
    • 0.625 mm thick at 0.3 mm intervals

Knee

• Axial reformats

• 2 mm slice, 2 mm interval

  • Coronal image that shows tibial plateaus (solid line)
  • Angle such that slice cuts evenly through tibial plateaus (dotted lines)
  • Coverage from femoral metaphysis to below fibular head

Knee

Knee

• Coronal
• 2 mm slice, 2 mm interval
• Axial image that shows distal patella

• Angle such that slice are parallel to a line connecting the posterior aspect of the femoral condyles (dotted line)

• Sagittal

• 2 mm slice, 2 mm interval

Knee

  • Axial image that shows distal patella (same image as for coronal reformats)
  • Angle such that slice are parallel to the coronal reformats

Knee CT Summary for fracture or bone lesion

PLANE

SECTION THICKNESS

INTERV AL

OVERLA P

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Reformat axial*

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat coronal*

2 mm

2 mm

None

BONE

Reformat sagittal*

2 mm

2 mm

None

BONE

*All reformats should include ENTIRE field of view of the source images

Knee CT Summary for CT arthrogramⱡ or soft tissue mass/infection

PLANE

SECTION THICKNESS

INTERV AL

OVERLA P

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Reformat axial*

2 mm

2 mm

None

SOFT TISSUE

Reformat coronal*

2 mm

2 mm

None

SOFT TISSUE

Reformat sagittal*

2 mm

2 mm

None

SOFT TISSUE

*All reformats should include ENTIRE field of view of the source images ⱡ Dilute iodinated contrast with sterile water or normal saline 50/50

Ankle

• Positioning
• Patient supine

Ankle

  • Use foot holder
  • Feet together, centered in scanner
  • Toes pointing straight up
  • Typically scan both feet together (if can’t bring feet together, ensure imaged foot is centered in gantry)

    • Scanning Parameters
    • 0.625 mm thick at 0.3 mm intervals

Ankle

• Field of View must include • Start above ankle joint just

above tibial metaphysis

• Include calcaneus and metatarsal bases

• Axial reformats

• 2 mm slice, 2 mm interval

  • Find sagittal image of tibiotalar joint (dotted yellow line)
  • Orient slices parallel to the tibiotalar joint (solid yellow lines)

Ankle

• Coronal reformats

• 2 mm slice, 2 mm interval

  • Find tibiotalar joint on axial image (same level as sagittal reference image)
  • Orient slices parallel to the joint

Ankle

• Sagittal reformats

• 2 mm slice, 2 mm interval

  • Find tibiotalar joint on axial image (same level as sagittal reference image)
  • Orient slices perpendicular to the joint

Ankle

Ankle CT Summary for fracture or bone lesion

Source axial

Reformat axial*

Reformat coronal*

Reformat sagittal*

PLANE

SECTION THICKNESS

0.625 mm

2 mm

2 mm

2 mm

INTERV AL

0.3 mm

2 mm

2 mm

2 mm

OVERLA P

50%

None

None

None

WINDOW WIDTH/LEVEL

SOFT TISSUE

BONE SOFT TISSUE

BONE

BONE

*All reformats should include ENTIRE field of view of the source images

Ankle CT Summary for CT arthrogramⱡ or soft tissue mass/infection

PLANE

SECTION THICKNESS

INTERV AL

OVERLA P

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Reformat axial*

2 mm

2 mm

None

SOFT TISSUE BONE

Reformat coronal*

2 mm

2 mm

None

SOFT TISSUE

Reformat sagittal*

2 mm

2 mm

None

SOFT TISSUE

*All reformats should include ENTIRE field of view of the source images ⱡ Dilute iodinated contrast with sterile water or normal saline 50/50

Hindfoot/Midfoot

Hindfoot/Midfoot

• Appropriate for Hindfoot fractures (calcaneus, talus), subtalar joint evaluation, tarsal coalition

• Positioning

  • Patient supine
  • Use foot holder
  • Feet together, centered in scanner
  • Toes pointing straight up
  • Typically scan both feet together (if can’t bring feet together, ensure imaged foot is centered in gantry)

    • Scanning Parameters
    • 0.625 mm thick at 0.3 mm intervals

Hindfoot/Midfoot

• Field of View must include • Start above ankle joint just

above tibial metaphysis

• Include calcaneus and metatarsal bases

• Axial reformats

  • 2 mm slice, 2 mm interval
  • Find sagittal image of tibiotalar joint (dotted yellow line)
  • Orient slices parallel to the tibiotalar joint (solid yellow lines)

Hindfoot/Midfoot

Hindfoot/Midfoot

• Axial oblique reformats

  • 2 mm slice, 2 mm interval
  • Find sagittal image of posterior facet subtalar joint (dotted yellow line)
  • Orient slices parallel to the posterior facet subtalar joint (solid yellow lines)

Hindfoot/Midfoot

• Coronal oblique reformats

• 2 mm slice, 2 mm interval

• Orient slices perpendicular to axial oblique reformats

Hindfoot/Midfoot

• Straight sagittal reformats
• 2 mm slice, 2 mm interval
• Orient parallel to axial reformats

Hindfoot/midfoot CT Summary for fracture or bone lesion

Source axial

Reformat axial*

Reformat axial oblique*

Reformat coronal oblique*

Reformat sagittal*

PLANE

SECTION THICKNESS

0.625 mm

2 mm

2 mm

2 mm

2 mm

INTERV AL

0.3 mm

2 mm

2 mm

2 mm

2 mm

OVERLA P

50%

None

None

None

None

WINDOW WIDTH/LEVEL

SOFT TISSUE

BONE SOFT TISSUE

BONE

BONE

BONE

*All reformats should include ENTIRE field of view of the source images

Hindfoot/midfoot CT Summary for soft tissue mass/infection

Source axial

Reformat axial*

Reformat axial oblique*

Reformat coronal oblique*

Reformat sagittal*

PLANE

SECTION THICKNESS

0.625 mm

2 mm

2 mm

2 mm

2 mm

INTERV AL

0.3 mm

2 mm

2 mm

2 mm

2 mm

OVERLA P

50%

None

None

None

None

WINDOW WIDTH/LEVEL

SOFT TISSUE

BONE SOFT TISSUE

SOFT TISSUE

SOFT TISSUE

SOFT TISSUE

*All reformats should include ENTIRE field of view of the source images

Midfoot/Forefoot

Midfoot/Forefoot

• Appropriate for Lisfranc fracture/dislocation, metatarsal fractures

• Positioning

  • Patient supine
  • Use foot holder
  • Feet together, centered in scanner
  • Toes pointing straight up
  • Typically scan both feet together (if can’t bring feet together, ensure imaged foot is centered in gantry)

    • Scanning Parameters
    • 0.625 mm thick at 0.3 mm intervals

Midfoot/Forefoot

• Field of View must include

• Start from distal talonavicular joint to beyond the toes

Midfoot/Forefoot

• Reformats (2 mm slice, 2 mm interval) • Relative to 2nd Metatarsal
• LONG AXIS OBLIQUE

Midfoot/Forefoot

• Reformats (2 mm slice, 2 mm interval) • Relative to 2nd Metatarsal
• SHORT AXIS OBLIQUE

Midfoot/Forefoot

• Reformats (2 mm slice, 2 mm interval) • Relative to 2nd Metatarsal
• SAGITTAL

Midfoot/forefoot CT Summary for fracture or bone lesion

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Reformat long axis oblique*

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat short axis oblique*

2 mm

2 mm

None

BONE

Reformat sagittal*

2 mm

2 mm

None

BONE

*All reformats should include ENTIRE field of view of the source images

Midfoot/forefoot CT Summary for soft tissue mass/infection

PLANE

SECTION THICKNESS

INTERVAL

OVERLAP

WINDOW WIDTH/LEVEL

Source axial

0.625 mm

0.3 mm

50%

SOFT TISSUE

Reformat long axis oblique*

2 mm

2 mm

None

BONE SOFT TISSUE

Reformat short axis oblique*

2 mm

2 mm

None

SOFT TISSUE

Reformat sagittal*

2 mm

2 mm

None

SOFT TISSUE

*All reformats should include ENTIRE field of view of the source images

References

• University of Wisconsin CT protocols https://www.radiology.wisc.edu/sections/msk/protocols.php

• Thomas Jefferson University http://www.bone.tju.edu/protocols.htm