Japanese ver.
Radiopaedia (AP view)
Radiopaedia (PA view)
Purpose
Observation of the sacroiliac joint from the front and comparison of the left and right sides.
Diagnosis of sacroiliac joint fracture, dislocation, and sacroiliac joint tuberculosis.
If pelvic fracture is suspected, CT or MRI is recommended.
Prior confirmation
Choose to take the image in the 1. AP direction, or 2. PA direction. The PA direction allows for a wider projection of the joint space.
Remove any obstacles.
Positioning
Supine position (1. AP view) or prone position (2. PA view).
Align the mid-sagittal plane and the central axis of the cassette.
Extend both lower limbs (or slightly flex them).
To eliminate pelvic tilt, position both anterior superior iliac spines equidistant from the cassette.
Place the upper limbs away from the irradiation field.
Position the cassette to align the X-ray central ray and the center of the cassette.
Place R/L markers.
CR, distance, field size
CR :
1. AP view :
The incident point is directed cephalically, passing through a point three finger-width above the greater trochanter on the mid-sagittal plane (approximately 15° for males and 20° for females).
2. PA view :
The incident point is directed caudally, passing through a point three finger-width above the greater trochanter on the mid-sagittal plane (approximately 15° for males and 20° for females).
Distance : 100cm
Field size : Laterally from the anterior superior iliac spines, superiorly from the iliac crests to include the symphysis pubis (greater trochanter) inferiorly.
Exposure condition
75kV / 25mAs
Grid ( + ). *Pay attention to the direction of the grid for oblique incidence.
Suspend respiration.
Image, check-point
Normal (Radiopaedia)
Ensure the sacroiliac joints are projected symmetrically on both sides. (Normal joint space is 3-4 mm)
The field of view should include the iliac crests to the symphysis pubis.
The mid-sacral ridge and the symphysis pubis should be aligned in a straight line. Alternatively, the sacral foramina should be observed symmetrically, and there should be no pelvic rotation.
The sacrum should be centered within the irradiation field.
Soft tissues should be visible.
There should be no motion blur.
Videos
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