ANKYLOSING SPONDYLITIS RADIOLOGIC MANIFESTATIONS.pptx

ANKYLOSING SPONDYLITIS RADIOLOGY

1. ANKYLOSING SPONDYLITIS

2. INTRODUCTION CLINICAL PRESENTATION PATHOLOGY WITH PATHOPHYSIOLOGY IMAGING COMPLICATIONS DIFFERENTIALS LABORATORY TESTS TREATMENT

3. INTRODUCTION Ankylosing Spondylitis is a chronic inflammatory rheumatological disorder that predominantly affects the axial skeleton Characterized by 1. SACROILITIS 2.SPONDYLITIS 3.ENTHESITIS Most common cause of seronegative spondylo arthritides a group of disorders that are rheumatoid factor negative and are frequently associated with the presence of HLA B - 27 antigen

4. Men > Women ( 15 -30 years ) Teen age to young adulthood Ankylosing Spondylitis affects both synovial and cartilaginous joints and entheses and is manifested by a combination of osseous erosions ,new bone formation and ultimately leads to ankylosis Previously known as Bechterew’s disease ,Marie Strumpell disease Other seronegative arthropathies include Psoriatic arthritis ,erosive arthritis ,reactive arthritis ,enteric arthritis

5. TYPES MOST COMMON( SKELETAL LOCATIONS) 1.SACROILIAC JOINT 2.SPINE OTHER COMMON SITES HIPS SHOULDER KNEE

6. CLINICAL PRESENTATION Characterized by insidious inflammatory low back pain worse in morning and after inactivity Improves with exercise Other clinical features are stiffness ,limited mobility and pain over protuberances secondary to enthesitis In advanced stage A thoracic kyphotic deformity with head and neck protruded forward and chest excursion due to ankylosis of chest Anterior uveitis – common association

7. ETIOLOGY Cause of disease is unknown, though interaction between infectious agent possibly Klebseilla and the HLA B -27 antigen( 90 % of patient )

8. PATHOGENESIS TNF alpha ,Bone morphogenetic proteins and prostaglandins contribute to the process PLASMA CELLS ,LYMPHOCYTES INFILTRATE JOINT AFFECT BOTH SYNOVIAL AND LIGAMENTOUS PORTION INITIALLY SUBCHONDRAL EDEMA ,SYNOVITIS , JOINT EFFUSION INFLAMMATORY INFILTRATES LEAD TO BONY EROSIONS HEALING WITH NEW BONE FORMATION ANKYLOSIS

9. PROGRESSION OF DISEASE AS typically begins at SI joints ,generally ascending through the spine from lumbar to cervical although it may skip levels Peripheral joints are less commonly involved ,with mainly the large joints , the HIPS AND SHOULDERS Small joint disease is uncommon ENTHESITIS – Hall mark pathological change in AS ,which is characterized by pathological cells causing inflammatory changes and finally destruction of the entheses ( the attachment of ligaments , tendons ,fascia and capsules to bone ) SCLEROSIS SYNDESOPHYTE FORMATION

10. SACROILIAC JOINT – AS

11. FINDINGS LOSS OF DEFINITION OF SUBCHONDRAL BONE PLATE SUBCHONDRAL EROSIONS A WIDENED JOINT SPACE( Initially there is widening of SI joint space which narrows as disease progresses) REACTIVE SCLEROSIS AROUND JOINT FINAL STAGE – ANKYLOSIS ( Joints may completely disappear in the final stage with ankylosis and remodelling ) Ligamentous compartment of SI joint affected by bony erosion and enthesial proliferation markedly made out in MRI

12. PLAIN RADIOGRAPH Sacrolilitis is the first manifestation, ( often first location involved in radiographs),symmetrical and bilateral KEY FEATURE- BILATERAL ,SYMMETRICAL INVOLVEMENT ILIAC side of joint shows changes first due to thinner cartilage compared to sacrum

13. XRAY VIEW FOR SI JOINT In plain XRAY – SI joint may be difficult to assess radiologically du to obliquity of the joint and obscuration by overlying soft tissues A modified FERGUSON AP view best depicts this articulation Patient positioned supine on the imaging tables with legs extended Elevate the side of interest approximately 25 to 30 degree FERGUSON VIEW FOR SI JOINT – A modified AP pelvis xray with the central xrays angled in a cephalad manner and directed at the midline 5 cm below the ASIS

14. GRADING OF SACROILITIS ACCORDING TO NEW YORK CRITERIA GRADE 0 – NORMAL GRADE I- SUSPICIOUS CHANGES (SOME BLURRING OF JOINT MARGIN) GRADE II- MINIMUM ABNORMALITY ( SMALL LOCALIZED AREAS WITH EROSION OR SCLEROSIS ,WITH NO ALTERATION OF JOINT WIDTH ) GRADE III – UNEQUIVOCAL ABNORMALITY ( MODERATE OR ADVANCED SACROILITIS WITH EROSIONS ,E/O SCLEROSIS ,WIDENING ,NARROWING,OR PARTIAL ANKYLOSOSIS) GRADE IV – SEVERE ABNORMALITY (COMPLETE ANKYLOSIS),Significant narrowing or complete loss of joint space

15. GRADE 1 – Some blurring of joint margin GRADE 2 – Minimal sclerosis with erosion s

16. Frontal xray in chronic b/l sacroilitis resulted in partial ankylosis

17. Frontal radiograph of SI joint showing b/l symmetric sacroiliitis with erosions creating a widened appearance of joints and subchondral sclerosis

18. SIGNS -SI ROSARY BEAD SIGN – EROSIVE APPERANCE OF SI JOINT STAR SIGN – FUSION /ANKYLOSIS OF THE SUPERIOR ASPECT OF SI JINT GHOST JOINT – COMPLETE SI JOINT FUSION ,NO VISIBLE JOINT

19. ROSARY BEAD SIGN – Small erosions lined up one behind the other at corresponding sites of ilium and sacrum , resembling a string of beads or rosary STAR SIGN – Fusion or ankylosos of the superior aspect of SI joint

20. CT of patient SI joint showing subchondral erosions and sclerosis Another patient CT with SI joint ankylosis

21. MRI MRI findings ( SI ) include MRI features of sacroiliitis can be divided into inflammatory and structural lesions inflammatory lesions M arrow oedema   (first to appear): high signal on water sensitive sequences,low on T1 and post contrast enhancement S ynovitis  and Capsulitis : thickening and contrast enhancement of the synovium and joint capsule E nthesitis :  thickening and contrast enhancement of ligaments and tendons at their attachments to bone S tructural lesions S ubchondral sclerosis: bands of low signal (on all sequences) parallelling the joint margins, at least 5 mm from the joint space E rosions : marginal foci of articular bone loss low T1 signal high T2/STIR signal if active more prominent anteroinferiorly and on the iliac side of the SIJ when confluent may appear as joint space widening Fat metaplasia : periarticular fat deposition A nkylosis

22. Acute SI in another young man , Gadolinium enhanced contrast fat Saturated Images showing enhancement of connective fibrous tissue

23. Another T2 axial image of patient showing subchondral erosions, joint space widening with effusion and subchondral sclerosis

24. Axial T1 and STIR images in a patient with AS – Post inflammatory fatty infiltration after acute sacroilitisT1 hyperintensity s/o fatty marrow infiltration

25. T2 W image showing b/l Symmetrical pattern of subchondral bone marrow edema and enthesitis at gluteus maximus attachments.T1 showing hypointense signal s/o marrow edema ,T2 showing erosions

26. ASAS CLASSIFICATION CRITERIA –ACTIVE SACROILITIS ON MRI ASSESSMENT IN SPONDYLOARTHRITIS INTERNATIONAL SOCIETY (ASAS) CLASSIFICATION CRITERIA REQUIRED CRITERIA NOT REQUIRED CRITERIA Bone marrow edema /osteitis on a T2 W or bone marrow enhancement on a T1 Inflammation must be clearly present and localized in a typical anatomical area (subchondral bone) MRI appearance must be suggestive of a spondyloarthropathy The sole presence of other inflammatory lesions like synovitis ,enthesitis or capsulitis without BMO is not sufficient for definition of active sacroiliitis in MRI In the absence of BMO ,presence of advanced signs like sclerosis ,erosion or ankylosis do not meet definition od sacroiliitis in MRI

27. AS -SPINE In spine involvement ,AS is characterized by osteitis , syndesmophyte formation , ,facet inflammation , and eventual facet joint and vertebral body fusion

28. AS - SPINE EARLY CHANGE – Early spondylitis is characterized by small erosions at the corners of vertebral bodies with reactive sclerosis – ROMANUS LESIONS ( It typically develops at the site of attachment of annulus fibrosis to the anterior corner of vertebral endplates ) SHINY CORNER SIGN Spinal finding in AS , associated with INACTIVE ROMANUS LESIONS ( HEALING STAGE ) – reactive sclerosis secondary to the inflammatory erosions at superior and inferior end plates

29. Next important radiological sign is squaring of vertebra Pathophysiology – The anterior borders of vertebra may appear squared due to periosteal proliferation of the new bone filling in the normal concavity or erosion at vertebral margins

30. ANDERSON LESIONS - INFLAMMATORY LESIONS at the junction of intervertebral disc and the vertebral endplate can lead to interbody ankylosis (Non infectious spondylodiscitis )

31. ANDERSON LESION - MRI T1 ,STIR and T1 PC FAT SAT images shown below, we can see high signal intensity of hemispherical shape involving the central portion of vertebra and the discs showing hyperintense signal in STIR ,hypointense on T1 and post contrast enhancement

32. BAMBOO SPINE BAMBOO SPINE APPEARANCE- Diffuse syndesmophytic ankylosis Syndesmophytes are vertically oriented projection of bone that develop due to ossification within the outer fibers of annulus fibrosis Syndesmophytes are radiologically visible on anterior and lateral aspects of spine starting from corner of vertebra The progressive growth of syndesmophyte bridge the intervertebral disc causing ankylosis Peripheral ankylosis resulting from the syndesmophytes and spinal ligament ossification and central ankylosis through disc and facet joints ,cause appearance of spine as a fused osseous column – BAMBOO APPEARANCE

33. SYNDESMOPHYTE Paravertebral ossification ,caused by ossification of annulus fibrosis Oriented vertically USUALLY SYMMETRICAL- Origin at the edge of one vertebral body extending to the margin of adjacent vertebral body However , bridging osteophytes and large syndesmophytes can appear similar OSTEOPHYTE Paravertebral ossification , horizontal orientation Marginal osteophytes are horizontal bony extension of vertebral endplate and non marginal are horizontal extension of vertebral body 2-3 mm away from endplate

34. PARA SYNDESMOPHYTES Aka Non marginal bulky syndesmophytes or floating syndesmophyte are paravertebral dystrophic soft tissue calcifications or heterotopic ossifications Known to be seen in Psoriatic arthritis or reactive arthritis Often asymmetrical On radiography , initially parasyndesmophytes begin at a distance from the vertebral body and intervertebral space Ultimately they increase in size to form large and bulky masses ,merging with the underlying bones and disc

35. DAGGER SPINE- Linear ossification along the central spine ,representing the interspinous ligament can give a dagger spine appearance Combination fo Bamboo spine and dagger spine called as trolley track sign

36. ROLE OF MRI IN SPINE M ay have a role in early diagnosis of sacroiliitis; MRI is more sensitive than CT or plain radiography in detecting inflammatory changes (which precede structural changes) such as  bone marrow oedema  (best demonstrated on STIR sequences), synovitis and capsulitis (on gadolinium enhanced T1 weighted sequences)  S ynovial enhancement on MR correlates with disease activity measured by inflammatory mediators E nhancement of the interspinous ligaments is indicative of enthesitis S uperior to CT in the detection of cartilage inflammation and destruction U seful in following treatment results in patients with active ankylosing spondylitis

37. Another young man with AS .MRI showing Romanus anterior spondylitis ,Anderson spondylodiscitis , hyperintensity of facet joint s/o edema and arthtritis Post contrast image showing discrete enhancement of interspinal and supraspinal ligaments

38. Another CT image of AS patient showing Romanus anterior spondylitis ,Anderson spondylodiskitis ,zygapophyseal joint arthritis ,sclerosis and erosions of vertebral endplates

39. Another AS patient Cervical spine xray (lateral xray ) showing posterior vertebral body syndesmophytes ,ankylosis of the facet joints from C2 to T1 and interlaminar and interspinous ankylosis

40. OTHERS Apophyseal and costovertebral arthritis and ankylosis Enthesiophyte formation ( bony proliferations that can occur at entheses , Can be mistaken for osteophytes Ankylosed spine susceptible to fractures Pseudoarthroses aka false joint ( mobile fracture non union ) can occur at fracture sites Dural ectasia- Ballooning or widening of the dural sac which can result in posterior vertebral scalloping and associated with herniation of nerve roots

41. BASRI SCORING (BATH ANKYLOSING SPONDYLITIS RADIOLOGY INDEX SCORE ) 0- Normal 1- Suspicious ( No definite change) 2- Mild – (Any number of erosions ,squaring , or sclerosis, with or without syndesmophytes ( on more than or equal to 2 vertebra) 3- Moderate – ( Syndesmophytes on more than or equal to 3 vertebra ,with or without fusion involving 2 vertebra) 4- Severe – fusion involving more than 3 vertebra

42. AS -PELVIS WHISKERING of the pelvic bones mainly the ischial tuberosity resulting from ossification of ligamentous origins There can be bridging and fusion of pubic symphysis

43. AS - HIP Hip involvement is generally b/l and symmetric Uniform joint space narrowing Axial migration of femoral head sometimes reaching a stage of protrusion acetabuli,and a collar of osteophytes at the femoral head –neck region

44. Bilateral enthesitis manifested by the subchondral bone marrow edema within each greater trochanter and edema within enthesis of gluteus medius tendons

45. SHOULDERS Glenohumeral joint involvement is not uncommon , and demonstrates a large erosion of the anterolateral aspect of the humeral head ,producing a HATCHET DEFORMITY Marrow edema of the acromion process ,at the site of origin of deltoid muscle ,has been described very specific for the disease

46. CHEST -THORACIC MANIFESTATION OF AS It can affect tracheobronchial tree and lung parenchyma and disease spectrum includes Upper lobe fibrocystic changes – fibrobullous disease Early involvement may be unilateral or asymmetrical Most cases eventually consist of bilateral apical fibrobullous lesions Most can be progressive with coalesecence of nodules Formation of cysts and cavities ,fibrosis and bronchiectasis occur Uncommon findings – Pleural thickening ,chest wall restricted mobility

47. CARDIOVASCULAR MANIFESTATIONS Aortic root dilatation Aortitis AR Pericarditis Myocardial involvement – Left and right ventricular dysfunction Cardiomegaly Conduction disturbances especially AV node

48. OTHER ASSOCIATIONS WITH AS 1.ANTERIOR UVEITIS- MC 2.PSORIASIS 3.INFLAMMATORY BOWEL DISEASE 4.OSTEOPENIA 5.SECONDARY AMYLOIDOSIS ( RARE) 6.CAUDA EQUINA SYNDROME ( RARE )

49. COMPLICATIONS Fractures Patients with AS with diffuse paraspinal ossification and inflammatory osteitis creates a fused brittle spine ,which has risk of fracture even with trivial trauma More common at the cervicothoracic and thoracolumbar regions CHALK STICK FRACTURE OR CARROT STICK FRACTURE Fractures of fused spine ,usually occur at the discoveretbral junction in lower cervical or upper thoracic spine Chalk stick fracture can also be seen in other conditions of fused spine like DISH ,PLL ossification ,surgical spine fusion Anderson lesion ( Inflammatory spondylodiscitis can further result in pseudoarthrosis Rare neurological complications like Transverse myelitis and cauda equina syndrome

50. DIFFERENTIALS GENERALIZED SPINE – ENTEROPATHIC ARTHRITIS CERVICAL SPINE – JUVENILE RHEUMATOID ARTHRITIS DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS OPLL ( Ossification of PLL ) 5.Hyperparathyroidism ( SI joint space widening more marked)

51. DISH( DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS ) Pathological process characterized by diffuse calcification and ossification of ALL RADIOLOGICAL Frequently involve the cervical and thoracic spine FLOWING OSSIFICANS Florid ,flowing ossification along the anterior aspect or right aspect of at least five contiguous vertebra Left lateral aspect usually spared thought due to aortic pulsation inhibiting ossification Disc spaces are usually preserved Ankylosis is more common in thoracic than cervical or lumbar spine’ No sacroiliitis or facet joint ankylosis noted

52. ANKYLOSING SPONDYLITIS DISH OPLL Both anterior and posterior longitudinal ligaments are involved Thin calcifications contiguous with ‘ SYNDESMOPHYTES ‘ Diffuse Anterior longitudinal ligament only Prominent flowing anterior osteophytes involving > 4 joints Most common in lower thoracic spine PLL only Thin or thick linear sheet of calcification Cervical or upper thoracic spine

53. PSORIATIC ARTHRITIS Also a seronegative arthropathy Involves SI joint – however asymmetrical Other radiographic features Acroosteolysis Periositis – Enthesitis and marginal bone erosions – pencil in cup deformity ( Pathognomonic ) Bone proliferation around joint Ivory phalanx Arthritis mutilans Sausage digit – dactylitis can present as sausage digit refers ti soft tissue swelling of entire digit Spondylitis – asymmetric paravertebral ossification and relative sparing of digits

54. REACTIVE ARTHRITIS Tends to involve distal lower extremity more commonly( knee > metatarsophalangeal joint > calcaneus >ankle > SI) Enthesitis may develop at the calcaneus at the site of achilles tendon and plantar fascia attachment A large bulky paravertebral area of ossification – :” Floating osteophytes” often seen Sacroiliitis –asymmetrical

55. BRUCELLOSIS Another miscellaneous condition that can affect spine It causes unilateral sacroiliitis Can also cause spondylodiscitis,bursitis and osteomyelitis

56. CLINICAL TEST AND MANGEMENT Schober's test – A useful clinical measure of flexion of lumbar spine performed during examination Medications used are NSAIDS ,DMARDS TNF alpha blockers Surgical management – Osteotomy for marked deformities or occasionally arthtroplasty may be used