Active inflammation and structural change in early active axial spondyloarthritis as detected by whole-body MRI.
OBJECTIVE
To evaluate active inflammatory lesions (AIL) and structural changes (SC) in patients with active non-radiographic axial spondyloarthritis (nr-axSpA) compared with patients with ankylosing spondylitis (AS) on whole-body MRI (wb-MRI).


METHODS
75 patients with active disease and a symptom duration of <5 years (39 with AS and 36 with nr-axSpA) were investigated with a comprehensive wb-MRI protocol and scored for AIL and SC in the spine, sacroiliac joints (SIJs) and non-axial manifestations.


RESULTS
92% of patients with AS showed active inflammation in the SIJ, 53% in the spine and 94% and 39%, respectively, in the nr-axSpA group. There was a non-significant trend towards more inflammation in patients with AS compared with patients with nr-axSpA in SIJs and spine. Peripheral enthesitis/osteitis was more common in patients with AS (n=22) than in those with nr-axSpA (n=12) (p=0.05). SC were more common in patients with AS than in those with nr-axSpA, with significantly higher scores for SIJ fatty bone marrow deposition (FMD) in patients with AS (4.8±3.2) compared with those with nr-axSpA (2.4±2.7; p=0.001) and more frequent bone proliferation in the spine and the SIJ (p=0.02 and p=0.005, respectively). SIJ erosions were more common in AS (score 4.2±2.3) than in nr-axSpA (score 3.8±1.8) patients (not significant).


CONCLUSIONS
Wb-MRI detects active inflammation and SC more frequently in the SIJs than in the spine. Half of the patients showed inflammation in non-axial sites. Active inflammatory and structural lesions were present both in patients with AS and those with nr-axSpA, being only slightly more common in patients with AS.
Department of Radiology, Charité Medical University, Campus Mitte, Berlin, Germany. christian.althoff@charite.de
Christian E
CE
Althoff
Joachim
J
Sieper
In-Ho
IH
Song
Hildrun
H
Haibel
Anja
A
Weiß
Torsten
T
Diekhoff
Martin
M
Rudwaleit
Bruce
B
Freundlich
Bernd
B
Hamm
Kay-Geert A
KG
Hermann
D000328:Adult; D001853:Bone Marrow / Q000473:pathology; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology; D007596:Joints / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D010000:Osteitis / Q000473:pathology; D012446:Sacroiliac Joint / Q000473:pathology; D058566:Sacroiliitis / Q000473:pathology*; D012720:Severity of Illness Index; D013131:Spine / Q000473:pathology; D025241:Spondylarthritis / Q000473:pathology; D013167:Spondylitis, Ankylosing / Q000473:pathology*; D013585:Synovitis / Q000473:pathology; D051598:Whole Body Imaging; D055815:Young Adult