Imaging approach to joint diseases

Imaging approach to joint diseases

Werner HarmseJuly 2010

ArthritisArthritis

• Indicates an abnormality of the joint as the result of a – degenerative, – inflammatory, – infectious, or – metabolic process.

• Affects articular surfaces on both sides of joint

• Results in joint space narrowing

Classification of arthritidesClassification of arthritides• Degenerative

– Osteoarthritis: Primary, Secondary• Inflammatory

– Rheumatoid arthritis– Seronegative spondyloarthropathies: AS, Reiter’s, Psoriasis, Enteropathic

arthropathies– Connective tissue disease: Scleroderma, SLE, Dermatomyositis – Erosive OA

• Metabolic– Crystal deposition: Gout, CPPD, etc– Other deposition: Hemochromatosis, Wilson’s, Alkaptonuria, Amyloidosis– Endocrine: Acromegaly, Hyper-parathyroidism– Haemophilia

• Infective– Pyogenic– TB– others

Imaging of joint diseaseImaging of joint disease

• X-ray

• Ultrasound

• MRI

• CT

• Arthrography

• Nuclear medicine

UltrasoundUltrasound

• Multiplanar real time soft tissue imaging

• Helpful in diagnosing joint effusions especially in septic arthritis, as well as other fluid collections

• Also used in evaluating for tendonitis and tendon rupture

CTCT

• Computed tomography (CT) is effective in evaluating degenerative and inflammatory changes of various joints

• Findings are similar to plain film radiography, only being able to demonstrate it more clearly

• Multiplanar reformations can be done with MDCT• Valuable in planning of surgery• In the assessment of spinal stenosis secondary to

degenerative changes, CT examination may also be performed after myelography especially if MRI is contraindicated

MRIMRI

• Excellent contrast between soft tissues and bone. • Articular cartilage, fibrocartilage, cortex, and spongy bone can be

distinguished • excellent for demonstrating synovial abnormalities in rheumatoid

arthritis. • Because synovitis is often accompanied by joint effusion, this too

can be effectively demonstrated by MRI • Occasionally, MRI may provide some additional information in

osteoarthritis and hemophilic arthropathy• Most important role is in evaluation of the spine.

– Demonstrate hypertrophy of the ligamentum flavum or the vertebral facets

– Grade foraminal and spinal stenosis – Evaluate degenerative and inflammatory disc disease

• Also very valuable in evaluating joint related injuries

Nuclear medicineNuclear medicine

• Used to evaluate the pattern of disease activity and monitor response– how many joints are affected, – which joints are the most affected, – are there unsuspected sites with disease involvement)

• Investigate sites of possible infection• A negative bone scan is reassuring and confirms the

absence of active arthritis, while a positive bone scan can demonstrate disease presence and activity before it becomes apparent on a radiograph.

• Bone scans have been used to predict erosions in rheumatoid disease and has also been shown to be a good predictor of disease progression in osteoarthritis

X-rays: what to look forX-rays: what to look for

• Alignment

• Bone

• Cartilage

• Distribution

• Soft tissues

X-rays: what to look forX-rays: what to look for

• Alignment– Subluxation and/or dislocation

• Common in RA and SLE• Bone

– Osteoporosis• Periarticular osteoporosis in RA

– Erosions• Aggressive with no sclerotis margin: RA, psoriasis• Non-aggressive (fine sclerotic border): gout, usually overhanging• Location: Marginal – inflammatory; Central – Erosive OA (gull wing)

– Bone production• Osteophytes: at sites of cartilage loss and degeneration typical in OA• Subchondral sclerosis: typical of OA• Ankylosis: seronegative inflammatory arthropathies eg AS• Periosteal reaction: psoriasis, Reiter’s (distinguish from RA)

– Subchondral cysts• OA and CPPD, also RA and AVN

X-rays: what to look forX-rays: what to look for

• Cartilage– Joint space

• Normal joint space: Gout; or any early arthropathy• Eccentric narrowing: OA• Uniform narrowing: All others• Wide joint space: early inflammatory process

– Calcification: CPPD

X-rays: what to look forX-rays: what to look for

• Distribution– Single joint: Infective; crystal deposition; post

traumatic– Hands and feet

• proximal: RA, CPPD, SLE• Distal: Reiter’s(feet), psoriasis(hands), scleroderma• Symmetrical: RA, SLE

– SI joints• Asymmetrical: Reiter’s, Psoriasis• Symmetrical: AS, Enteropathic, Reiter’s, Psoriasis• Also DJD, infection, gout

X-rays: what to look forX-rays: what to look for

• Soft tissues– Swelling

• Symmetrical around joint: all inflammatory, but most common in RA

• Assymmetrical: most commonly d.t. osteophytes rather than true swelling in OA

• Lumpy, bumpy: gout (tophus)• Entire digit: Psoriasis, Reiter’s

– Calcification• Soft tissue: Gout• Cartilage: CPPD• Subcutaneous: Scleroderma, dermatomyositis

X-raysX-rays

• First important decision to make is if arthritis is present or not– Almost all arthritides lead to joint space

narrowing, except gout

• Then decide if it falls in the broader degenerative or inflammatory group as most a fall in one of these two.

Arthritis or notArthritis or not

AVNDJD

Inflammatory vs DegenerativeInflammatory vs Degenerative

• Joint inflammation is characterized by– bone erosions (marginal)– osteopenia– soft-tissue swelling– uniform joint space loss

• Degenerative cause of joint space narrowing is characterized by– osteophytes– bone sclerosis– subchondral cysts or geodes– asymmetric joint space narrowing– lack of inflammatory features such as bone erosions

InflammatoryInflammatory

InflammatoryInflammatory

• Evaluate the number of joints involved– If only a single joint is involved consider infective

arthritis• Features of any inflammatory arthritis• But erosions often not acutely present• Joint space may be initially widened due to effusion

– Seen easily with ultrasound

• Widening also seen in more indolent infections i.e. TB and fungal

• Phemister triad in TB arthritis– periarticular osteoporosis, – peripherally located osseous erosions, – gradual diminution of the joint space

Progression of TB of the knee over 1 year

InflammatoryInflammatory

• If multiple joints are involved consider a systemic arthritis

• Now evaluate hands and feet– If proximal with no bony proliferation consider

rheumatoid arthritis– If distal with features of bony proliferation

consider seronegative spodyloarthropathies eg. AS, Reiter’s, psoriasis and enteropathic arthropathies

Rheumatoid arthritisRheumatoid arthritis

• Women aged 30 – 60• Rheumatoid factor• General features of inflammatory arthritis• Additionally joint subluxation and subchondral

cysts may also be present• In the hands, target sites include the MCP, PIP,

midcarpal, radiocarpal, and distal radioulnar joints, with predilection for the ulnar styloid process

• Involvement is usually bilateral and fairly symmetric

• Ulnar deviation occurs at the MCP joints.• Swan neck and Boutonniere deformities. • In the feet, target sites include the MTP, PIP (incl 1st IP)

and intertarsal joints• Important to closely evaluate the lateral aspect of the

fifth metatarsal head – often 1st site of bony erosion• Also affects tendon sheaths and bursae like the

retrocalcaneal bursa:– Loss of the normal radiolucent triangle between the

posterosuperior margin of the calcaneus and the adjacent Achilles tendon suggests the presence of bursal fluid, with subjacent calcaneal erosions indicating inflammation

Rheumatoid arthritisRheumatoid arthritis

Rheumatoid arthritisRheumatoid arthritis

• Other peripheral joints also affected include the knees, the hips, the sacroiliac and glenohumeral joints.

• Spinal involvement affects the C1-C2 articulation– the odontoid process may be eroded– and the anterior atlantodens interval may be

abnormally widened (3 mm in adults), especially with neck flexion

Small erosions at the 5th MTP joint

a) Normal shoulder X-rays in patient with rheumatoid arthritis. (b) Ultrasound of same patient demonstrates 1.5 cm erosion.

Synovial enhancement with Gd-DTPA. (a) Three-dimensional gradient-echo image of a wrist following IV Gd-DTPA shows extensive enhancing synovitis and distention of the synovial cavity. (b) Repeat MRI with Gd-DTPA following 3 months of disease-modifying antirheumatic drug (DMARD) therapy shows marked reduction in the amount of enhancing tissue but similar distention of the synovial cavity (note the dorsally displaced extensor tendons).

Seronegative spondyloarhtropathies

Seronegative spondyloarhtropathies

• Psoriasis, AS, Reiter’s and enteropathic arthritides.

• HLA B27 usually positive• Hands and feet show more distal involvement.• Osseous attachment sites of ligaments and

tendons are more involved than in RA.• Entheseal involvement leads to increased

density and irregular bone proliferation (perisotitis).

• Ankylosis more common

Psoriatic arthritisPsoriatic arthritis• Hallmarks

– signs of inflammatory arthritis combined with– periostitis, enthesitis, and a distal joint distribution in the extremities

• Findings may be bilateral or unilateral and symmetric or assymmetric

• Hands more than feet• Involvement of several joints in a single digit, with soft-tissue

swelling, produces what appears clinically as a “sausage digit”• Aggressive erosions leading to “Pencil in cup” appearance and

resorption of terminal tufts• Fuzzy/fluffy bony proliferation and periostitis • Ivory phalanx• Mouse ears: Bone production adjacent to erosions• SI joint involvement usually bilateral – may be symmetrical or

not

Psoriatic arthritis. Dorsovolar radiograph of the hand of a 57-year-old woman shows the typical presentation of psoriatic polyarthritis. The “pencil-in-cup” deformity in the interphalangeal joint of the thumb is characteristic of this form of psoriasis.

Psoriatic Arthritis. A. Cartilage loss at the PIP joints of the 3rd, 4th, and 5th digits in this hand is apparent, with erosions noted most prominently in the 4th digit (arrow). These erosions are not sharply demarcated but are covered with fluffy new bone. Note also the periostitis along the shafts of each of the proximal phalanges. B. Advanced psoriatic arthritis. Fusion across the PIP joints of the 2nd to 5th digits. Several of the DIP joints are also ankylosed. Severe joint space narrowing at the metacarpophalangeal joints is noted.

Reactive arthritis (Reiter’s)Reactive arthritis (Reiter’s)

• Sterile inflammatory arthritis following an infection at a different site

• Young men aged 25-35

• Similar to psoriasis in inflammation, proliferation, periostitis and ethesitis

• Feet more than hands – particularly MTP joints and heels

• Axial skeleton may also be affected

A CT scan through the SI joints shows unilateral SI joint sclerosis and erosions (arrows), typical for psoriatic arthritis or Reiter disease.

Ankylosing spondylitisAnkylosing spondylitis

• Idiopathic inflammatory arthritis• 96% are HLA B27+, Men aged 20 – 40• More commonly affects axial skeleton• Spine involvement is characterized

– by osteitis, syndesmophyte formation, facet inflammation, and eventual facet joint and vertebral body fusion.

• Sacroiliac joint disease is bilateral and symmetric.

• Other peripheral joints, such as the hips and glenohumeral joints, may be involved.

Ankylosing spondylitisAnkylosing spondylitis

• SI joints show early erosions best seen at inferior aspects

• Sclerosis follows with eventual ankylosis• Spine involvement usually centered at

thoracolumbar or lumbrosacral junction• Osteitis at anterior discovertebral junctions with

erosions, sclerosis “shiny corner” and squaring of vertebral bodies

• Syndesmophytes form with eventual fusion of the vertebral bodies (bamboo spine).

• Also interspinous ligament calcification

Enteropathic arthritisEnteropathic arthritis

• Occur with Crohn’s disease, Ulcerative colitis and Whipple disease

• Spine and sacroiliac and peripheral joints may be affected.

• Spine: squaring of the vertebral bodies and the formation of syndesmophytes are common features.

• Sacroiliitis, usually bilateral and symmetric– radiographically indistinguishable from ankylosing spondylitis

• In addition, patients may also exhibit a peripheral arthritis, the activity of which generally approximates the activity of the bowel disease.

DegenerativeDegenerative

• Joint space narrowing, Osteophyte formation, Bone sclerosis and Subchondral cysts are seen in the absence of inflammatory changes

• Consider age, joints involved and x-ray appearance to distinguish between– Typical osteoarthritis– Atypical osteoarthritis

Typical osteoarthritisTypical osteoarthritis

• Result of articular cartilage damage and wear and tear from repetitive microtrauma that occurs throughout life, although genetic, hereditary, nutritional, metabolic, pre- existing articular disease, and body habitus factors may contribute in some cases. Usually after 4th or 5th decade

• Typical sites– AC joints – small osteophytes from 4th decade– 1st CMC joint, IP joints of hands, MCP to a lesser degree, 1st

MTP(joint space narrowing may be symmetrical in hands, unlike larger

joints)– Knee – medial joint space as well as patellofemoral. Often

formation of osteochondral bodies– Hip – superior migration

(A) Sagittal PD of pt with OA of the right knee shows involvement of the femoropatellar compartment. Note joint space narrowing, subchondral cyst (arrow), and osteophytes (open arrows). (B) Coronal T2 fatsat image shows complete destruction of articular cartilage of the lateral joint compartment (arrows), subchondral edema (open arrows), and tear of the lateral meniscus (curved arrow). (C) Sagittal T2-fatsat in another patient shows osteoarthritis of the knee complicated by multiple osteochondral bodies (arrows).

Atypical osteoarthritisAtypical osteoarthritis

• Osteoarthritis, but – involved joint is not one commonly affected by osteoarthritis,– the severity of the findings are excessive or unusual, or – the age of the patient is unusual,

• then other less common causes for cartilage damage and osteoarthritis should be considered.– Trauma,– Crystal deposition disease, – Neuropathic joint, – Hemophilia. – Other possible causes include congenital and developmental

anomalies, such as dysplasia, that disrupt normal biomechanics.

Atypical osteoarthritisAtypical osteoarthritis

• Trauma (injury or repetitive stresses) – most common cause, – usually relatively young patient, with marked

asymmetric involvement• CPPD

– Atypical in joint distribution, excessive subchondral cyst formation and calcium deposition (chondrocalcinosis)

– Knee most commonly affected– Radiocarpal and 2nd & 3rd MCP joints– Chondrocalcinosis of triangular fibrocartilage and

menisci (also pubic symphysis and hip labrum)

• Haemochromatosis– Also chondrocalcinosis, with overlap of CPPD findings– More extensive MCP involvement– Metacarpal radial hooklike or drooping osteophytes are more

common

• Neuropathic joint– Late disease is characteristic with severe joint destruction

• sclerosis, fragmentation, subluxation, heterotopic new bone formation

– Early disease is similar to OA but distribution is characteristic• Midfoot and hips in DM• Bilateral shoulder joints in a syrinx or spinal tumour• Hips in tertiary syphilis

Atypical osteoarthritisAtypical osteoarthritis

Lisfranc Charcot Joint. Dislocation of the second and third metatarsals along with joint destruction and large amounts of heterotopic new bone are present in the foot of this diabetic patient. These findings are classic for a Charcot joint

• Haemophilia– Repetitive intra-articular haemorrhage may cause cartilage damage– Young patients– Osteophytes, sclerosis and subchondral cyst, but also erosions– Joint space narrowing is more symmetrical– Epiphyseal overgrowth– Knees – squaring of patella and widening of the intercondylar notch– Repeated hemorrhage may produce a large expansile and

destructive abnormality known as hemophiliac pseudotumor, most commonly involving the femur and pelvis

– overlap between of hemophilia and juvenile chronic arthritis; however, knee, ankle, and elbow involvement are more common in hemophilia.

• Remember: Any cause of arthritis can eventually end in secondary or atypical osteoarthritis

Atypical osteoarthritisAtypical osteoarthritis

Advanced haemophilic arthropathy in the elbow

OthersOthers

• Juvenile Idiopathic Arthritis (previously known as JRA)– Soft tissue swelling and osteopenia– Delayed joint space narrowing and erosive changes– Possible periostitis and later joint fusion– Osseous overgrowth of the epiphyses due to chronic

hyperemia and – Bone undergrowth due to premature growth plate

fusion.– Three sub types:

• Oligo articular (Prev. pauci articular) • Poly articular• Systemic disease

JIAJIA

• Oligo-articular– Affects 4 or fewer joints in the first 6 months of

illness. – Often ANA positive– 50% of JIA cases. – Usually involves the knees, ankles, and

elbows but smaller joints such as the fingers and toes may also be affected. The hip is not affected unlike polyarticular JRA.

– Usually asymmetrical

JIAJIA

• Poly-articular– Affecting 5 or more joints in the first 6 months of disease. – More common in small girls to that of boys. – Usually the smaller joints are affected, such as the fingers and

hands, although weight-bearing joints such as the knees, hips, and ankles may also be affected. Can include neck and jaw as well.

– Usually symmetrical

• Systemic JIA– Characterized by arthritis fever and rash – Affects males and females equally.– Systemic JIA may have internal organ involvement and lead to

serositis

11-year-old girl with juvenile idiopathic arthritis. Anteroposterior radiograph of both knees shows bones are osteopenic. Overgrowth of medial femoral condyles and widened intercondylar notch are both recognized features of juvenile idiopathic arthritis.

8-year-old girl with juvenile idiopathic arthritis. Right hand reveals severe changes: marked osteopenia, erosions (arrows), ankylosis of carpal bones and some interphalangeal joints, and subluxation of proximal interphalangeal joints of index and little fingers.

OthersOthers

• Erosive osteoarthritis– Distribution similar to OA in hands (IP joints)– Osteophytes– Central gullwing erosions– May end in ankylosis

• SLE– Joint space narrowing and erosions are rare– Commonly reducible MCP subluxations

Central gullwing erosions in erosive

osteoarhtritis

Systemic lupus erythematosus. (A) Typical appearance of the thumb in a 43-year-old woman with systemic lupus erythematosus. Note subluxations in the first carpometacarpal and metacarpophalangeal joints without articular erosions. (B) In anther patient, a 32-year-old woman with SLE, the oblique radiograph of her left hand shows dislocation at the first carpometacarpal joint (arrow) and subluxations in the metacarpophalangeal joints of the index and middle fingers associated with swan-neck deformities (open arrows).

OthersOthers

• Gout– Joint space narrowing only occurs late– Characteristic erosions – Punched out, overhanging

edges, sclerotic margins, near joint but not specifically marginal

– Marked soft tissue swelling due to tophi– Most common in 1st MTP– Also IP joints and tarsal bones– Soft tissue swelling from bursitis as in olecranon

bursitis– Radiographic findings may at times be confusing and

appear quite unusual, thus it may be helpful to remember, “When in doubt, think gout.”

Other diseases involving jointsOther diseases involving joints

• Synovial osteochondromatosis– caused by a metaplasia of the synovium– results in deposition of foci of cartilage in the joint– mostly deposits calcify and are seen on X-ray– knee, hip, and elbow

• Pigmented villonodular synovitis– rare chronic inflammatory process of the synovium that causes synovial

proliferation– swollen joint with lobular masses of synovium occurs and causes pain

and joint destruction – rarely calcifies– Joints with PVNS look radiographically identical to noncalcified synovial

osteochondromatosis– Erosion in 50%: cyst-like defects of varying sizes are present which

show sclerotic margins. – PVNS has a characteristic appearance on MR, with low-signal

hemosiderin seen lining the synovium on both T1WIs and T2WIs

Synovial Osteochondromatosis. Anteroposterior view of the hip in this patient with left hip pain shows multiple calcified loose bodies in the hip joint, which is virtually diagnostic of synovial osteochondromatosis.

Pigmented Villonodular Synovitis (PVNS). Sagittal T1W (A) and fast spin-echo T2W (B) images of an ankle with PVNS show a soft tissue mass emanating from the ankle joint, which is low signal on both sequences and has very low signal hemosiderin lining parts of the synovium, which is characteristic for PVNS.

Joint space narrowing

Inflammatory

1 joint > 1 joint

Infection

RheumatoidArthritis

Seronegativespondyloarthropathies

Degenerative

Typical OA

Atypical OA

TraumaCrystal deposition

NeuropathicHaemophilia

SymmetricErosions

Soft tissue swelling

Asymmetric OsteophytesSclerosis

UnusualDistributionSeverityAge

Prox

imal

No

bony

pro

lifer

atio

n

Distal

Bony proliferation

Others: JRA, Gout, SLE, erosive OA,PVNS, Synovial osteochondromatosis

ReferencesReferences

1. Jacobson et al. Radiographic evaluation of arthritis: Inflammatory conditions. Radiology 2008; 248:378–389

2. Jacobson et al. Radiographic evaluation of arthritis: Degenerative Joint Disease and Variations. Radiology 2008; 248:737–747

3. Weisleder. Primer of Diagnostic Radiology4. Brandt & Helms. Fundamentals of Diagnostic

Radiology5. Greenspan. Orthopaedic Imaging: A ractical

approach. 4th Ed