Update - Imaging of the Spondyloarthropathies Donald J. Flemming, M.D. Dept of Radiology Penn State Hershey Medical Center Spondyloarthropathies Family of inflammatory arthritides of synovium and entheses Axial and asymmetric peripheral arthritis Genetic predisposition - HLA B27 Infectious etiology Spondyloarthropathies psoriasis sacroiliitis carditis gut inflammation spondylitis arthritis HLA B27 enthesopathy Enteropathic arthritis Psoriasis Reactive arthritis Ankylosing spondylitis conjunctivitis genital inflammation
HLA B27 Normal population -USA ~0-8% Ankylosing spondylitis - >90% Reactive arthritis - 63-75% Psoriasis - not increased without arthritis with peripheral arthritis - 20% with axial arthritis - 50% IBD with axial arthritis - 50% Spondyloarthropathy (SpA) Peripheral SpA With psoriasis With IBD With preceding infection Without any above Axial SpA With radiographic SI disease Without radiographic SI disease Abnormal MRI HLA-B27+ and clinical findings Spondyloarthopathies Role of Imaging Demonstrate manifestations Characterize activity and extent of disease Appropriate imaging Understand limitations of techniques Differentiate arthropathies
Modalities Radiography Inexpensive; skill to interpret Specific but not sensitive; late findings CT Expensive, radiation Disease activity not studied Spectral CT?? Modalities Ultrasound Inexpensive, widely available More sensitive than x-ray Disease activity assessed Operator dependent MRI Expensive; time consuming Sensitive; too sensitive? Experience matters Nonaxial SpA - Psoriatic Arthritis Peak ages - 20-40 years M:F -1:1 Arthritis in 5-8% of patients with psoriasis Enthesitis hallmark of the disease Dactylitis
ASAS Criteria Peripheral SpA Ann Rheum Dis 2011;70:25 31 Non-axial SpA Radiographic Manifestations Fusiform soft tissue swelling Dactylitis Maintenance of mineralization Dramatic joint space loss Bone proliferation Marginal erosions predominate Pencil-in-cup erosions Bilateral asymmetric dz Sausage Digit 16-49% Pts with PsA Low sensitivity but high specificity
Sagittal T1 second toe Sagittal T1 first toe J Rheumatol 1997;24:926-30 MIP
Bone Production Reparative Response Whiskering / brush stroke erosions Osteitis Enthesopathy Periostitis Ankylosis
Enthesis Organ Tendon/ligament insertion Fibrocartilage Bursa Fat pad Cancellous bone Investing fascia Enthesitis Enthesitis triggers joint synovitis More peripheral joint damage Joint ankylosis Arthritis mutilans Poorer sleep/functional status Early detection critical MRI vs US
Enthesitis - MRI Thickening of tendon with T2 Insertional BME Not specific!! No BME? Not sensitive!! Field of view and cost Enthesitis-MRI New Techniques WBMRI Long scan time 61 min No reimbursement Inter/intraobserver reliability??? Ann Rheum Dis 2015;74:823 829 Enthesitis-US Patient comfort and low cost High spatial resolution Power doppler inflammation Operator dependent BMI>30 Lower specificity Seminars in Arthritis and Rheumatism 48(2018)35 43
Axial SpA Inflammatory Back Pain Age at onset <45 yr Duration > 3 mos Insidious onset Morning stiffness >30 min Improvement with exercise No improvement with rest Awaking from pain Alternating buttock pain 70-80% - Sens ASAS Criteria Axial SpA Ann Rheum Dis 2011;70:25 31 Imaging of Sacroiliitis Radiography initial evaluation Cross sectional imaging CT better for erosions MRI better for active disease high sensitivity/lower specificity Non-specific findings Older patients > 40 years Post partum females
AS-Radiographic Manifestations AP pelvis sufficient No benefit from 3 view sacral series Sacroiliac disease bilateral symmetric - same as enteropathic erosions predominate iliac vs sacrum sclerosis Ankylosis
SI Joint Anatomy
Sacroiliitis Differential Diagnosis Axial SpA Hyperparathyroidism Osteiitis Condensans Infection Osteoarthritis DISH
Radiography - Limitations Low sensitivity 30% vs MRI Very hard to read Poor inter/intraobserver reliability Experience matters FP rate 28-60% for local vs central read 1 Training may not improve results 2 1. Ann Rheum Dis 2018;77:e1. 2. Ann Rheum Dis 2003;62:519 525
Sacroiliitis - CT Gold standard for erosions Radiation in young patients Low dose techniques on horizon No assessment of BME, synovitis, capsulitis, enthesitis Spectral CT New technique quantify BME MRI still superior Br J Radiol 2016 89:20150196.
MRI of Sacroiliitis T1 structural abnormality Erosion, fat metaplasia, sclerosis T2 BME Disease activity, enthesitis Coronal/ Axial Oblique T1 and STIR Other sequences DWI Contrast not required MRI of Sacroiliitis Erosions better seen on T1 Active = BME or SC enhancement Single lesion on two or more slices Multiple lesions on single slice Capsulitis or enthesitis not sufficient Sclerosis - >5mm deep to SC bone Periarticular fat deposition Ankylosis 38M Active Sacroiliitis
Fat Deposition=Chronic 33M Active and Chronic 74M with OA
74M with OA MRI sacroiliac (SI) joints Osteitis Condensans Ilii (OCI). Osteochondral Injury 28F Postpartum Robert G W Lambert et al. Ann Rheum Dis 2016;75:1958-1963 2016 by BMJ Publishing Group Ltd and European League Against Rheumatism Sacroiliitis-MRI New Techniques Dynamic contrast enhancement (DCE) Quantitative assessment of dz activity Requires contrast and software Necessary?? Rheumatology International https://doi.org/10.1007 /s00296-018-4130-1
Sacroiliitis-MRI New Techniques Diffusion weighted imaging (DWI) Quantitative assessment of dz activity Necessary?? Rheumatology International https://doi.org/10.1007 /s00296-018-4130-1 AS-Radiographic Manifestations Spine Disease - ascends from lumbar to cervical Discovertebral destruction Romanus and Andersson lesions Shiny corner sign Squaring of vertebral body Syndesmophyte Bamboo spine Late findings
Normal Ank Spon
DISH Diffuse Idiopathic Skeletal Hyperostosis Common disease - 12% of elderly population Flowing bulky paravertebral ossification Four contiguous vertebral bodies Thoracic>lumbar>cervical Enthesophytes - particularly pelvis Absence of erosions/ joint abnormality DISH Ank S
DISH Ank Spon
Summary Imaging has significant role in SpA Enthesitis Probably best assessed by US Sacroiliitis AP pelvis avoid 3 view SI joint MRI for equivocal cases or disease assessment Contrast not required Hard to interpret - Sens but Spec Spine disease MRI for early disease Sens but Spec Hard to interpret