Conventional
radiography is a well-established method for detecting permanent damage
(structural changes) in the sacroiliac joints.
For
all forms of spondyloarthropathy, the degree of severity is classified
according to the New York criteria for ankylosing spondylitis in 5 stages: https:/doi.org/10.1002/art.1780270401.
Grade 0: Normal findings.
Grade 1: Suspicious changes.
Grade 2: Minimal abnormality with small areas of erosions or
sclerosis without alteration in the joint width.
Grade 3: Unequivocal abnormality - moderate or advanced
sacroiliitis consisting of erosion, sclerosis, widening, narrowing, and/or
partial joint fusion (ankylosis).
Grade 4: Severe abnormality in the form of total ankylosis.
Grade 0
Normal findings
Grade 1
Suspicious changes at the left sacroiliac joint in the form of slightly irregular joint facets.
Grade 2
Minimal abnormalities in the form of small erosion (black arrow) and slightly condensed bone (sclerosis)(white arrow).
Grade 3
Manifest abnormalities in the form of erosion and sclerosis in addition to widening of the middle part of both sacroiliac joints.