Elbow

University of Wisconsin CT Protocol Sheet
Elbow
Patient’s Name: _________________________ UW Med Rec #: _________________
Protocoled by: DB KD ADS RK KL HR KS MT Other: _______
Elbow Anatomy: Lateral View AP View
H
HUMERUS
U
M
ERUS
RADIUS
Coronoid
Fossa
Coronoid
Process
Olecranon
Fossa
Medial
Epicondyle
Trochlea
Lateral
Epicondyle
Capitellum
Radial
Head
ULNA
Radial Tuberosity
(Biceps Insertion)
Olecranon
R
A
U D
L I
N U
A S
Reformatting: ALL ELBOW REFORMATS ARE 2mm THICK, 2mm INTERVALS
4 reformats are made off SAGITTAL reference images
1
2
3
4
Sagittal
reference image
(1) Axial
to HUMERUS
(2) Axial
to FOREARM
(3) Coronal
to RADIUS
(4) Coronal
to ULNA
2 additional reformats are made off an AXIAL TO HUMERUS reference image
that passes through both EPICONDYLES
5 6
Inter-Epicondyle Line
(5) PARALLEL to
Inter-Epicondyle Line
(6) PERPENDICULAR to
Inter-Epicondyle Line
©Ken L Schreibman, PhD/MD www.radiology.wisc.edu/Divisions/MSK/Protocols 8/31/2011

University of Wisconsin CT Protocol Sheet
Elbow
Elbow CT Scanning Techniques
The elbow is the most difficult joint to scan.
‣ It is usually difficult to optimally position the elbow.
Particularly when the elbow is in a cast.
‣ It often requires 6 SETS of reformats.
3 relative to the distal humerus.
3 relative to the proximal forearm.
Extra care should be taken when positioning elbows.
‣ The better the elbow is positioned in the scanner:
The better the source data will be, and
The easier it will be to make the reformats!
Keys to Optimally Positioning the Elbow (Refer to the above photograph)
The arm MUST ALWAYS be raised above the patient’s head.
‣ This is usually best achieved with the patient laying supine on the table.
‣ Sometimes creative positioning (prone, decubitus) will be necessary.
This is crucial because:
‣ It puts the elbow near the center of the scanner (allowing use of “Small SFOV”).
‣ It avoids radiation to the head and torso.
It helps to have the patient bend their head away from the elbow (see photo).
Watch to make sure the patient’s head doesn’t hit the edge of scanner!
The arm MUST NEVER be across
the patient’s body.
‣ This yields undesirable beam
hardening artifacts from the torso,
while it also causes unnecessary
radiation to the torso.
‣ Respiratory motion will produce unacceptable reformatting artifacts
If the patient’s elbow is not in a cast: (this is uncommon for elbow CT)
‣ The elbow should be as straight as possible. (Fully extended)
‣ The arm should be supinated (palm up), causing the radius/ulna to be uncrossed.
If the patient’s elbow is in a cast: (this is common for most elbow CT)
‣ Obviously, the degree of elbow extension will be limited by the cast.
BUT EVEN WITH A CAST, MUST GET ELBOW ABOVE HEAD!
‣ Try to avoid positioning forearm bones parallel to scanning plane.
This causes beam hardening artifacts along entire length of radius & ulna.
‣ It is better to have forearm oblique to the scanning plane.
Try to avoid this
positioning
Scanning Plane
This positioning
is better
Scanning Plane
Scanning Parameters
‣ Small Scanning FOV. Slices 0.6mm Thick, 0.3mm Intervals (just like a wrist).
‣ “BonePlus” and “Standard” Algorithms
‣ IF THERE IS METAL: 140 kV, maximum mA
‣ Otherwise, use parameters optimized for your scanner.
‣ Cover distal humerus through proximal forearm.
©Ken L Schreibman, PhD/MD www.radiology.wisc.edu/Divisions/MSK/Protocols 8/31/2011