- 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
Archives: Wikis
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 thesuperior 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