Each sacroiliac joint is divided into quadrants that are scored separately:
(I) upper sacral aspect (at levels above the caudal aspect of the first neural foramina)
(II) lower sacral aspect (at levels below the causal aspect of the first neural foramina)
(III) lower ilial aspect opposite the lower sacral aspect
(IV) upper ilial aspect opposite the upper sacral aspect
Left and right sides are score separately, giving 8 evaluation zones.
Lesions scored:
(1) fatty lesions (increased signal on unenhanced T1w MR images in a para-articular locaion within the bone marrow)
(2) bony erosions (bony defects located at the subchondral plate of the joint with a clearly visible cortical break on at least 2 adjacent slices)
Scoring for each type of lesion in each quadrant on both sides:
|
Percent Involved
|
Points
|
|
0% (no lesions)
|
0
|
|
1 to 33%
|
1
|
|
33.1 to 66%
|
2
|
|
> 66%
|
3
|
Interpretation:
• minimum score for fatty lesions: 0
• maximum score for fatty lesions: 24
• minimum score for bone erosions: 0
• maximum score for bone erosions: 24
