Comparison of Sacroiliac Biopsies and Magnetic Resonance Imaging Examinations in Non-Radiographic Axial Spondyloarthritis


 Background : Early diagnosis and treatment are the key to improve the prognosis of axial spondyloarthritis (axSpA), therefore, we aimed to evaluate the diagnostic value of magnetic resonance imaging (MRI) and pathological examination of the sacroiliac joint (SIJ) for non-radiographic axSpA (nr-axSpA). Methods : Fine needle aspiration biopsy of bilateral SIJs was performed in 107 patients with nr-axSpA after MRI examination. The active inflammatory manifestations and chronic structural changes in SIJs were evaluated using MRI. The pathological changes of SIJ specimens were examined using microscopy. Results : Bone marrow edema (BME) was present in 67/214 joints on MRI (31.3%). The proportion of pannus formation and inflammatory cell infiltration were up to 63.8% and 53.4% in patients without BME on MRI, which were not significantly lower than 75.0% and 58.3% in patients with BME on MRI. The inflammatory infiltrating cells were mainly CD3 + T lymphocytes and CD68 + macrophages. In the group with normal cartilage on MRI, the proportions of chondrocytes and cartilage matrix degeneration were 22.2% and 44.9%，respectively, which was not significantly lower than those in the group with abnormal cartilage on MRI (35.7% and 46.4%). However, a significantly higher proportion of pannus invasion was observed in the latter (26.6% vs 57.1%, P =0.001). In the group with a normal bone plate on MRI, the incidence of subchondral pannus formation and bone plate destruction was as high as 74.0% and 71.7%, with no significant difference compared with that in the group with bone erosion on MRI (88.9% and 88.3%). Conclusions: Pathological examination is more sensitive for detecting inflammatory and structural changes in early sacroiliitis than MRI examination. Key words : non-radiographic axial spondyloarthritis, sacroiliac joint, aspiration biopsy, magnetic resonance imaging.

Page 2/6 Abstract Background : Early diagnosis and treatment are the key to improve the prognosis of axial spondyloarthritis (axSpA), therefore, we aimed to evaluate the diagnostic value of magnetic resonance imaging (MRI) and pathological examination of the sacroiliac joint (SIJ) for non-radiographic axSpA (nr-axSpA).
Methods : Fine needle aspiration biopsy of bilateral SIJs was performed in 107 patients with nr-axSpA after MRI examination. The active in ammatory manifestations and chronic structural changes in SIJs were evaluated using MRI. The pathological changes of SIJ specimens were examined using microscopy.
Results : Bone marrow edema (BME) was present in 67/214 joints on MRI (31.3%). The proportion of pannus formation and in ammatory cell in ltration were up to 63.8% and 53.4% in patients without BME on MRI, which were not signi cantly lower than 75.0% and 58.3% in patients with BME on MRI. The in ammatory in ltrating cells were mainly CD3 + T lymphocytes and CD68 + macrophages. In the group with normal cartilage on MRI, the proportions of chondrocytes and cartilage matrix degeneration were 22.2% and 44.9% respectively, which was not signi cantly lower than those in the group with abnormal cartilage on MRI (35.7% and 46.4%). However, a signi cantly higher proportion of pannus invasion was observed in the latter (26.6% vs 57.1%, P =0.001). In the group with a normal bone plate on MRI, the incidence of subchondral pannus formation and bone plate destruction was as high as 74.0% and 71.7%, with no signi cant difference compared with that in the group with bone erosion on MRI (88.9% and 88.3%).
Conclusions: Pathological examination is more sensitive for detecting in ammatory and structural changes in early sacroiliitis than MRI examination. Key words : non-radiographic axial spondyloarthritis, sacroiliac joint, aspiration biopsy, magnetic resonance imaging.

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However, the latest manuscript can be downloaded and accessed as a PDF.  The pathological changes and MRI of subchondral bone plates of SIJs.In the SIJ with bone plate erosion on MRI (A), lots of brous granulation tissues were formed and invaded into bone plates, resulting in disconnection of bone plates (B), accompanied by abundant neovascularization marked by CD34 (C) and large numbers of CD68+ osteoclasts in the absorption zone of bone plate (D). In the SIJ without bone plate erosionon MRI(E), there was a little pannusformation, and local disruption of trabecula (F), increased angiogenesis beneath the bone plate (G), and lots of CD68+ osteoclasts in ltration in the bone plateabsorption area (H). I-K were the specimens of non-SpA auto psycontrol.

Figure 3
The pathological changes and MRI of bone marrow of SIJs. In the SIJ with bone marrow edema (BME) on MRI (A), there were large numbers of in ammatory cells in ltration (B), most of which were CD3+ T lymphocytes (C) and CD68+ macrophages (D), accompanied by a high expression of TNF-α (E). In the SIJ without BME on MRI (F), there were less in ltration of in ammatory cells (G), but increased brous connective tissue rich in blood vessels marked byCD34belowthe boneplate (H), ndalsoincreasedCD68+macrophages and osteoclasts (I), accompanied byan increased expression of TNF-α in bone marrow (J). K-N were the specimens of non-SpA auto psycontrol.

Figure 4
The pathological changes and MRI of synovitis of SIJs. The MRI of bilateral SIJs showed a little bone marrow edema (BME) in the entheses and subchondral areas (A). The pathological studies revealed typical pannus formation invading into the cartilage (B, HE staining), excessive CD34+ neovascularization in the pannus (C), excessive CD68+ (D) and CD163+ macrophage in ltration, and a high expression of VEGF (F), TNF-α (G), MMP-3 (H), and RANKL (I).