Interrater reliability and radiation dosage of oblique coronal computed tomography for sacroiliitis in comparison with axial computed tomography

Computed tomography-based assessment of radiographic progression in spine and sacroiliac joints after pregnancy in women with radiographic axial spondyloarthritis

Background

Mechanical stress are one of the pathogenesis of axial spondyloarthritis (axSpA). During pregnancy, the mechanical overload on the spine and pelvis increases due to gravid uterus. We aimed to investigate whether pregnancy affects radiographic progression in patients with radiographic axSpA (r-axSpA) based on computed tomography (CT) evaluations.

Materials and methods

This retrospective study included women with r-axSpA aged 19-49 years who underwent at least two CT evaluations of the whole spine and/or sacroiliac joints (SIJs) at intervals of 2-4 years. To compare radiographic progression after delivery, we classified the patients into two groups: delivery group and controls. The delivery group was restricted to women who had the first CT ∼2 years before delivery and the second CT ∼2 years after delivery. The CT Syndesmophyte Score (CTSS) (0-522) and SIJ scores (0-40) were used to evaluate spinal syndesmophytes and erosion, joint space narrowing, and sclerosis of the SIJs.

Results

A total of 21 women in the delivery group and 38 women in the control group were included. The median (Q1-Q3) CTSS at baseline in the delivery group and controls was 19 (16-23) and 20 (13.25-27.75), and the median progression was 1 (0-3) and 0 (0-1) during the median 2.9-year follow-up, respectively. The median (Q1-Q3) SIJ score at baseline in the delivery group and controls was 13 (8-22) and 11 (6-22), and the median progression was 1.5 (0-3) and 1 (0-2), respectively. Using cut-off 0.5, 52.9, and 61.9% of r-axSpA patients and 39.3 and 44.4% of controls showed progression of whole spine and SIJs, respectively. However, no difference in proportion of spinal and SIJ progression and absolute score changes per time point was observed between two groups. Moreover, the SIJ score changes were comparable according to the delivery method.

Conclusion

Pregnancy and delivery do not affect the radiographic progression of the spine and SIJs in women with r-axSpA assessed by CT.

Computed tomography in axial spondyloarthritis

PURPOSE OF REVIEW

Computed tomography (CT) is increasingly being used in ankylosing spondylitis (AS) for imaging the spine and sacroiliac joint (SIJ). We review new insights to diagnosis and evaluation revealed by the use of CT.

RECENT FINDINGS

Studies using low-dose CT in AS to detect syndesmophytes can image the entire spine, but semiquantitative scoring of the scans by human readers decreases the reliability and validity of this method. The thoracic spine is the segment most involved with syndesmophytes. Syndesmophytes are not randomly distributed around the vertebral rim but have preferred locations, which vary with the vertebral level and may be related to biomechanics. Examination of SIJ on abdominal CT scans has found structural changes of sacroiliitis in up to 35% of patients with inflammatory bowel disease. The significance of monosodium urate crystal deposition in the pelvis of axial spondyloarthritis patients without coexisting gout is uncertain.

SUMMARY

Low-dose CT is a promising tool in AS. Studies of biomarkers or medications and their relations with syndesmophyte progression should take the thoracic spine into account. Abdominal CT scans are useful for detecting changes related to sacroiliitis.