Imaging and intervention of sacroiliac joint

Imaging and intervention of

sacroiliac joint

Dr Ryan Lee Ka Lok

Associate Consultant

Prince of Wales Hospital

Introduction

• 15%-25% of low back pain is related to

sacroiliac joint (SIJ) pain

• SIJ pain is usually under-diagnosed

clinically

Sacroiliac joint

Anterior : Synovial joint

Posterior : ligamentous connection

Ant

Post

Sup

Inf

Sacroiliac joint

Iliac side

AntPost

Sacral side

Ant Post

Imaging modalities

• XR

• USG

• CT

• NM – Bone scan

• MRI

MRI

Oblique coronal Oblique axial

Sagittal planning

Oblique axial

Oblique coronal

True axial

True coronal

SIJ pathology

1. Inflammatory sacroiliitis

2. Infective sacroiliitis

3. Osteoarthrosis

4. Stress reaction/insufficiency fracture

5. Osteitis condensan ilii

6. Others : tumour

Rheumatic

Non-Rheumatic

Sacroiliitis on

imaging Plus

>1 SpA feature

HLA-B27 plus

>2 other SpA featuresor

Sacroiliitis on imaging:• Active(acute) inflammation on MRI highly suggestive of

sacroiliitis associated with SpAor

• Definite radiographic sacroiliitis according to modified New York

criteria

Assessment in SpondyloArthritis international society (ASAS) classification

criteria for axial spondyloarthritis (SpA) 2009

1. Inflammatory sacroiliitis

A. Active (acute) sacroiliitis

• Bone marrow edema (BME)/osteitis

• Capsulitis

• Enthesitis

• Synovitis

Bone marrow edema / osteitis

Bone marrow edema /

Osteitis

T2W STIR

T2W STIR Contrast T1W FS

Contrast T1W FS

? Bone marrow edema / osteitis

T2W STIR Contrast T1W FS

Bone marrow edema/osteitis

At least one signal on

consecutive slice

Bone marrow edema/osteitis

Or more than one signal on single slice

Capsulitis

Posterior capsulitisAnterior capsulitis

Enthesitis

T2W STIR Contrast T1W FS

Enthesitis

Synovitis

B. Definite radiographic sacroiliitis

• According to modified New York Criteria

Subchondral sclerosis

Subchondral periarticular erosion

Periarticular fat deposition

Bony bridges / ankylosis

Grade Radiographic findings

0 Abnormalities are present

1 Suspicious areas are noted

2 Minor erosions

3 Unequivocal abnormalities in the joint

4 Severe change in the joint

Low back pain for at least 3 months improved by exercise and not relieved by rest

Limitation of lumbar spine in sagittal and frontal planes

Reduced chest expansion relative to normal values for age and sex

Bilateral sacroiliitis grades 2-4

Unilateral sacroiliitis grades 3-4

Modified New York criteria for the classification of ankylosing spondylitis

Radiographic

sacroiliitis +

one clinical

symptoms

= AS

Subchondral sclerosis

T1W

Subchondral periarticular

erosion

Pseudo-wideningErosion

Peri-articular fatty infiltration

T1W T2W STIR

T1W

Bony bridges / Ankylosis

Radiograph

Subchondral sclerosis and erosion Ankylosis

Radiographic involvement of sacroiliac joints in different conditions

Bilateral, symmetric Bilateral,

asymmetric

Unilateral

Ankylosing spondylitis

Juvenile

spondyloarthropathy (SpA)

Osteitis condensus ilii

Psoriatic

arthropathy

IBD-associated SpA

Reactive

arthropathy

Undifferentiated

SpA

Infection (including TB)

Malignancy

2. Infective

sacroiliitis

Joint fluid

Iliacus muscle involvement Gluteal muscle involvement

Infective sacroiliitis

Iliacus and gluteal muscle

involvement

Infective sacroiliitis

Abscess

T2W STIR Contrast T1W FS

TB sacroiliitis

Infective or inflammatory sacroiliitis ?

3. Osteoarthritis

Osteoarthritis

4a. Stress reaction

4b. Stress fracture

Honda sign

4c. Insufficiency fracture

4d. Stress related

5. Osteitis

condensans ilii

Osteitis

condensans ilii

Image guided intervention

• CT guided biopsy/aspiration

• CT guided injection

• USG guided injection

• Floroscopic guided injection

CT guided aspiration

Joint fluid

CT guided biopsy

Bone

CT guided pig tail insertion

Needle Guidewire

Dilator Pigtail

CT guided injection

CT guided injection

Ultrasound guided injection

2nd sacral foramen

Floroscopic guided

Take Home Message

• MRI is imaging of choice to diagnosis

different SIJ pathology

• CT is useful for SIJ related diagnostic

and therapeutic intervention

End

Thank You