MR findings that can be confused with spondyloarthritis lesions

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1 MR findings that can be confused with spondyloarthritis lesions Poster No.: C-1608 Congress: ECR 2014 Type: Educational Exhibit Authors: I. Zabala Martín-Gil, E. M. Ocón Alonso, N. Gómez León, P Largo Flores, S. Barker Tejeda, C. Laganâ ; Madrid, 28006/ES, 2 Madrid/ES Keywords: Edema, Diagnostic procedure, MR, Musculoskeletal spine, Musculoskeletal joint, Musculoskeletal bone DOI: /ecr2014/C-1608 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 43

2 Learning objectives To differentiate with MR (Magnetic Resonance) active inflammatory or structural lesions of axial spondyloarthritis from other entities. To evaluate MR findings toghether with clinical and analytical data. To identify other findings that may simulate spondyloarthritis injuries. Background Spondyloarthritis (SpA) refers to a group of diseases that originates inflammation of the axial skeleton and peripheral joints and usually exhibits specific clinical and laboratory features. There is a strong association with the genetically determined human leukocyte antigen B27 (HLA-B27) and other inflammatory markers are non-specific.spondyloarthropathy includes ankylosing spondylitis, reactive arthritis (Reiter syndrome), arthritis or spondylitis associated with inflammatory bowel disease, and psoriatic arthritis, as well as undifferentiated SpA (1). These diseases can be grouped based on common clinical and imaging features such as inflammatory back pain, sacroiliitis, spondylitis and enthesitis. The definition and subcategorization of the spondyloarthropathies has evolved over time (2,3). Nowadays the ASAS criteria define axial SpA as active sacroiliitis on imaging plus one or more clinical features of spondyloarthritis; or HLA-B27 positivity with two or more clinical features of spondyloarthritis (4,5). Page 2 of 43

3 Fig. 1: With permission. References: Rudwaleit M, et al. The development of assessment of SpondyloArthritis International Society classification criteria for axial spondyloarthritis (part II): validation and final selection. Ann. Rheum. Dis.68, (2009). The presence of radiological sacroiliitis in a patient with inflammatory back pain is sufficient to establish the diagnosis, but only 50% of patients with inflammatory back pain develop definite radiographic features of sacroiliitis at 10 years of follow-up (6). When radiographic findings are negative MR imaging may show signs of active disease (7). Preradiographic axial SpA refers to patients with SpA and acute bone marrow oedema on MR without visible findings on radiography (8). Fig. 2 on page 3 Images for this section: Page 3 of 43

4 Fig. 2: With permission Page 4 of 43

5 Findings and procedure details Spondyloarthropathies may involve the entire axial and appendicular skeleton, but the hallmark of all types of spondyloarthritis is sacroiliitis. Inflammation of one or both sacroiliac joints is the most characteristic and consistent feature of these disorders. The ASAS algorithm propose sacroiliac joint radiography as the first imaging method after evaluation of clinical and laboratory findings. The unequivocal presence of radiological sacroiliitis in a patient with inflammatory back pain is sufficient to establish the diagnosis. According to the modified New York criteria (2) there are different stages considering radiographic changes in the sacroiliac (SI) joints. These stages are: 1 (unclear), 2 (small erosions, sclerosis), 3 (definite erosions) and 4 (ankylosis). Fig. 3 on page Fig. 3: Sacroiliitis in Ankylosing Spondylitis(AS).(A) AP radiograph of the pelvis showing bilateral sacroiliitis stage 2-3(erosions and sclerosis).(b)ap radiograph of the Page 5 of 43

6 pelvis in a 60-year-old woman with ankylosing spondylitis shows total ankylosis of both sacroiliac joints. Notice the typical bamboo spine of AS. References: RADIOLOGY RESIDENT, HOSPITAL UNIVERSITARIO DE LA PRINCESA - Madrid/ES CT is performed only in equivocal cases to confirm the presence of incipient erosions or intra-articular ankylosis. When the radiographic findings do not support the clinical diagnosis, additional imaging may provide more information. MR imaging may show early changes in the cartilage and acute inflammatory activity in the subchondral bone, ligaments, synovium, and capsular region. Of these findings, bone marrow oedema (BMO) is the first to appear (9,10). In addition, MR imaging has a similar sensitivity to CT in detecting early structural changes, a better sensitivity for assessing fatty deposits and, unlike CT, it involves no radiation exposure (11). MR is a new biomarker of disease activity because is able to quantify inflammatory activity which makes it ideal for monitoring disease activity and serves as a guide for treatment (12,13). Protocol Nowadays, the coronal oblique imaging parallel to the long axis of the sacrum is a standard MR imaging procedure. The entire sacral bone should be imaged from its anterior to its posterior border, which usually requires at least sections of 4mm with a matrix of 320x320 pixel acquiredin a 1,5T MR imager (GE). The protocol consists of coronal and axial oblique fast spin-echo T1-weighted sequences to detect structural changes, and coronal and axial oblique short inversion time inversion-recovery (STIR) or fat-saturated fast spin-echo T2-weighted sequences to detect acute inflammatory changes. The intravenous administration of gadolinium-based contrast material helps detect subtle osteitis, or BMO, and other imaging findings that are sometimes difficult to see without the administration of contrast material (eg, enthesitis and capsulitis) (14,15). However, but we do not routinely use it. The MR protocol for evaluating the spinal column comprises a sagittal T1-weighted turbo spin-echo sequence and a sagittal short inversion time inversion-recovery (STIR) sequence with an image matrix of 512 pixel. Administration of a paramagnetic contrast in spinal MR imaging is required only in certain cases. Descriptions of active inflammatory lesions in SI joints: Page 6 of 43

7 a) BMO/osteitis is depicted as a hyper-intense signal on STIR images and usually as a hypointense signal on T1 images. A hyper-intense signal on contrast-enhanced T1weighted fat-saturated images (T1 post-gd) reflects increased vascularization and is referred to as osteitis. Fig. 4 on page 11 b) Synovitis can be differentiated from joint fluid only after the administration of paramagnetic contrast medium and manifests as enhancement in the synovial part of the joint. Fig. 5 on page 12 c) Capsulitis has similar signal characteristics to synovitis but involve the anterior and posterior capsule. d) Enthesitis is depicted as a hyper-intense signal on STIR images and/or on contrastenhanced T1-weighted fat saturated images at sites where ligaments and tendons attach to bone, including the retroarticular space. Fig. 6 on page 13 Chronic or structural lesions in sacroiliitis: They are usually well depicted on T1-weighted images and include subchondral sclerosis, erosions, periarticular fat deposits, and ankylosis. These structuralchanges may coexist withactive lesions. Fig. 7 on page 13 According to the new ASAS criteria for axial spondyloarthropathy, the presence of subchondral or periarticular bone marrow edema is mandatory for the definition of sacroiliitis at MR imaging. If there is only one lesion, it should be present on at least two sections. Structural lesions are not a positive criterion on MR imaging examination (4). Page 7 of 43

8 Fig. 8: With permission. References: Rudwaleit M, et al. The development of assessment of SpondyloArthritis International Society classification criteria for axial spondyloarthritis (part II): validation and final selection. Ann. Rheum. Dis.68, (2009). Spinal changes: Arthritic lesions may affect the vertebrae and intervertebral disks, the synovial joints of the vertebral column, and the tendon and ligament attachments (entheses) but these are not ASAS criteria (16). Several vertebral lesions may ultimately lead to chronic abnormalities such as syndesmophytes or ankylosis. Spinal changes associated with spondyloarthritis are: a) florid anterior spondylitis (or Romanus lesion) Fig. 9 on page 14 b) florid diskitis (or Andersson lesion) Fig. 10 on page 15 Page 8 of 43

9 c) arthritis of the zygapophyseal joints (facet joints), costovertebral joints, and costotransverse joints joints Fig. 11 on page 16 Fig. 12 on page 17 d) enthesitis of the interspinal ligaments Fig. 13 on page 18 e) syndesmophytes and ankylosis Fig. 14 on page 19 Fig. 15 on page 20 An adequate interpretation of MR findings requires knowledge of the ASAS criteria. BMO at the sacroiliac joint may also be seen in patients with mechanical back pain, or even in healthy individuals (17). In this regard low-grade acute lesions of the sacroiliac joints on MR imaging should be interpreted with caution to avoid misclassifying young people with back pain as having spondyloarthropathy (18). Fig. 16 on page 21 Therefore, it is not the presence but the 'severity' of this lesion (which may be defined by the extent and intensity) that is specific of SpA and has prognostic validity (19,20). Differential diagnoses A number of other pathological or physiological conditions may mimic the inflammatory lesions seen in SpA. In sacroiliac joints : 1- Septic sacroiliitis is an inflammation due to infection, which often crosses anatomical borders of SI joints and spreads diffusely to soft tissues. Fig. 17 on page Insufficiency bone fractures are lesions in sacral bone that appear as active BMO/ osteitis, but in T1-weighted sequences an hypo-intense fine line may be seen and even confirmed in CT. Fig. 18 on page 24 Fig. 18 on page Bone tumours, such as metastasis, appear like BMO. However, they do not have the typical localization of inflammatory sacroiliitis lesions and are better demarcated with contrast-enhanced sequences. Furthermore there are often more lesions in other bones, and sometimes soft tissue masses. Fig. 19 on page Osteoarthritis, most often found in the elderly, may occasionally be associated with small areas of BMO along the SI joint and with articular cartilage degeneration. It is usually Page 9 of 43

10 accompanied by an overgrowth of bone (osteophytes), narrowing of the joint space and sclerosis. Fig. 20 on page Osteitis condensans ilii is typically seen in middle-aged women, in whom it manifests as sclerotic areas which previously could be associated with BMO. These occur mainly in the iliac bone, with relatively normal joint spaces. Fig. 21 on page 26 In vertebral spine: 1-Degenerative vertebral endplate and subchondral bone marrow changes. The intervertebral disk often appears normal or hypo-intense on T2WI because of desiccation and dehydration. -Type 1(Modic I) changes are hypo-intense on T1-weighted imaging (T1WI) and hyperintense on T2-weighted imaging (T2WI), and are shown to represent bone marrow edema and inflammation. Fig. 22 on page 26 -Type 2(Modic II) changes are hyper-intense on T1WI and iso-intense or slightly hyperintense on T2WI and are associated with conversion of normal red hemopoietic bone marrow into yellow fatty marrow as the structural changes in SpA. Fig. 23 on page 27 -Degenerative endplates accompanied by bony horizontal projections that develop along the edges of vertebra (osteophytes) must not be confused withsyndesmophytes. Fig. 24 on page Degenerative posterior elements often are associated with edema near the facet joints. Fig. 25 on page Schmorl's nodes are protrusions of the cartilage of the intervertebral disc through the vertebral body endplate and into the adjacent vertebra which may contact the marrow of the vertebra and sometimes lead to inflammation (BMO surrounding the protusion).such processes include juvenile kyphosis, trauma, metabolic and neoplastic disorders, and degenerative disk disease. Fig. 26 on page 30 3-Diskitisis is an intervertebral disk space infections which typically give rise to vertebral marrow edema, manifesting as areas of low signal intensity on T1WI and high signal intensity on T2WI. The vertebral endplates are usually eroded or destroyed and the presence of paraspinal or epidural inflammation and/or collection, which should guide the diagnosis towards an infectious process. Fig. 27 on page 31 Page 10 of 43

11 4- Trabecular insufficiency fractures in the spine are often related to osteoporosis. In case of acute fracture of the vertebral body, which is compressed and shows an intermediate intensity on T1WI and increased on T2WI or STIR sequences, reflecting the BMO. A fracture line can be seensometimes. Fig. 28 on page Bone tumours: The vertebras are a frequent place for metastasis, but apart from BMO, metastasis imaging is fairly well-known and can be distinguished from SpA, as described in the section relating to the sacroiliac area. Fig. 29 on page 33 Pitfalls These examples underline the need for experience in interpreting MR and the importance of making a correct diagnosis in order to initiate appropriate treatment. Equally, there are anatomical structures or technical artifacts than can simulate active or chronic inflammatory changes. For example ligaments, which are surrounded by blood vessels, may appear to be and may erroneously be interpreted as being inflamed on STIR images Fig. 30 on page 34, Fig. 31 on page 35. Furthermore, inadequate fat suppression may cause normal anatomic structures to appear hyper-intense, especially in the posterior part of the sacrum. In addition, the so called coil effect may result in brighter signal closer to the coil-body interface Fig. 32 on page 36. Similar effects on the adjacent soft tissue help distinguish these conditions from real alterations. The repetition artifact of vessels (aorta or iliacs) may also cause a hyper-intense image in normal anatomic structures Fig. 33 on page 37, Fig. 34 on page 39.Therefore, it is important to cross-reference between the axial and coronal plane Fig. 35 on page 39. Images for this section: Page 11 of 43

12 Fig. 4: Bone marrow oedema (BMO) in a 24-year-old woman with ankylosing spondylitis. Axial STIR (A) and coronal oblique contrast-enhanced fat-suppressed T1-weighted (B). RM image show bilateral hyperintense sacral and iliac areas consistent with BMO (arrows in A), which enhancing after the administration of paramagnetic contrast (osteitis)(arrows in B). Fig. 5: 44 year-old man HLA B27+ with suggestive clinic of ankylosing spondylitis. (A) Axial STIR RM image with small area of sacral bone marrow oedema(arrow) in 2 consecutives slices and sclerotic areas as low signal-free band (arrowhead). (B)Synovitis as an active inflammatory lesion appears as hyperintense signal on contrast-enhanced Page 12 of 43

13 T1-weighted fat-saturated image in the synovial part of the sacroiliac joints (arrow in B) (the signal intensity is similar to blood vessels). Fig. 6: 24 year-old woman with initial ankylosing spondylitis. Coronal oblique contrastenhanced fat-suppressed T1-weighted(A) MR image shows marked enhancement of the ligamentous aspect of the rigth sacroiliac joint (arrow), a finding that is consistent with enthesitis. Also synovitis is present (curved arrow).(b)capsulitis (arrow) has similar signal characteristics to those of synovitis (headarrow)but these changes involve the anterior and posterior capsule. Page 13 of 43

14 Fig. 7: MR images obtained of four different patients with structural damage lesions in sacroiliac joints. (A) Axial T1 sequence showing sclerotic areas (hypointense signal) (curved arrow). (B) Axial STIR sequence with erosions which are bony defects at the joint margin (short arrow). (C) Coronal T1 sequence with fat deposition may reflect previous inflammation of the SI joints (headarrow) with sclerotic. (D) Axial T1 image of a patient with advanced changes: bony bridges/ankylosis (long arrow). Page 14 of 43

15 Fig. 9: 51 year-old man with ankylosing espondylitis in treatment with salazopirine. Sagittal STIR (A) and T1-weighted (B) MR images showing active Romanus lesions at edges of the vertebral endplates (arrows) and postinflammatory fatty bone marrow degeneration of the anterior vertebral edges in L5 compatible with inactive Romanus lesions (arrowheads). Page 15 of 43

16 Fig. 10: Spondylodiskitis (inflammatory Andersson lesions) in a 34-year-old patient with ankylosing spondylitis.(a) Sagittal T1-weighted fast spin-echo image reveals erosive defects of the inferior endplate of L4 and superior endplate of L5(arrow), as well as signal loss in the surrounding bone marrow oedema (BMO). (B)Corresponding STIR image shows increased signal intensity (arrowheads) the intervertebral disk and BMO of the adjacent vertebras (florid Andersson lesion). Page 16 of 43

17 Fig. 11: Arthritis of the costo-transverse joints in a 42-year-old patient with ankylosing spondylitis. (A)In sagittal STIR sequences thoracic spine is seen high signal in the costoverbral joints which axial T2-weighted (B). In axial T2-weighted image shows a increased signal, erosions and synovial proliferations in joint (arrow). Page 17 of 43

18 Fig. 12: Arthritis of zygoapophyseal joints in lumbarspine (facet joints) in a 32-yearold woman.(a) Sagittal STIR image shows increased of space and fluid of the facet joint(arrow). (B) Sagittal contrast- enhanced fat-saturated T1-weighted image shows pronounced enhancement of articular process (arrowhead), findings suggestive of arthritis of apophyseal joints. Page 18 of 43

19 Fig. 13: 41-year-old patient with ankylosing spondylitis. Sagittal (A) and axial (B) STIR sequences in lumbar spine show bone medular edema in the pedicles and facet joints (line) with high intensity of paraspinal muscle (arrows). (C) Sagittal contrast-enhanced fat-saturated T1-weighted turbo spin-echo image shows pronounced enhancement in the spinous process (osteitis) and the area of the interspinous ligaments (headarrow), a finding indicative of enthesitis. Page 19 of 43

20 Fig. 14: 54-year-old patient with ankylosing spondylitis. (B) Lateral radiograph of the lumbar region shows syndesmophytes (headarrows) at L4 and L5.(A) On the corresponding T1-weighted fast spin-echo image, the syndesmophyte at L5 (arrow) is visible. Page 20 of 43

21 Fig. 15: Ankylosing spondylitis in very advanced stage without signs of inflammatory activity. Lateral(B) and AP (C) radiograph of the thoracic spine with an cifosis and syndesmophytes that conform a typical bamboo spine. (A) Sagittal T1-weighted turbo spin-echo image shows ankylosis which involves the vertebral edges with bony extension through the disk (arrow) and the interespinal ligaments (headarrow). These have the same signal intensity as normal bone on MR image. Page 21 of 43

22 Fig. 16: 25 year-old woman with low back pain without no more clinical or analitical datas. The presence of subchondral or periarticular bone marrow oedema (BMO) is mandatory for the definition of sacroiliitis at MR imaging. Only one signal is visible in this slice, the signal (BMO) should be visible on at least more than one adjacent slice in order to complete the definition of active sacroiliitis. Page 22 of 43

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24 Fig. 17: Septic sacroiliitis in a young woman. Axial T1-weighted (A), STIR (B) and contrast-enhanced fat-suppressed T1-weighted(C) MR images show bone marrow oedema (BMO) located in the left sacroiliac joint widely extends from bone to soft issue (headarrow), thus crossing anatomical borders. In STIR image, on the center of the BMO in the left part of sacro are seen several points of signal absence, corresponding in contrast T1 sequence with an annular enhancement which means that there is a bone abscesses.(courtesy of Juliana Marin Ocampo, Lenagés Hospital, Madrid, Spain ; with permission). Fig. 18: Insufficiency fractures of the sacral bone. The first patient (A,B,C) has a fracture on the right sacral bone. (A) Axial T1-weighted image shows low intensity signal in promontory and right sacral bone in which is seen a fine line of the fracture (arrow). (B) Axial T2-weighted image may see hight heterogeneus signal of bone marrow oedema (BMO), more intense near the sacroiliac right joint. (C ). CT coronal image show the line fracure on the sacral right bone(headarrow). (D) Another case of sacral contusion with Page 24 of 43

25 extensive BMO in areas of the sacral bone and also in iliac bones in a axial contrastenhanced fat-saturated T1-weighted turbo spin-echo image. Fig. 19: Avanced rectal cancer with bone metastases. Axial(A)and sagittal(b) contrastenhanced fat-saturated T1-weighted turbo spin-echo image. (A)Enhancement signal of marrow bone in right sacro and both iliac bones (headarrows).(b) In sagital image, there is no doubt of the multiple spinal metastasis and a metastatic compression fracture in L4 with focal paraspinal mass (arrow). Fig. 20: Degenerative sacroiliac joints of a 84 year-old man (osteoarthritis) with an decreased articular space, erosions, sclerosis, geodas and osteophytes. These features can be seen in structural changes in spondyloarthritis but often they are accompanied with others typical active inflammatory lesions. Page 25 of 43

26 Fig. 21: 41 year-old woman with a bilateral osteitis condensans ilii. It has quite a typical appearance on CT image in which it manifests as sclerotic areas, mainly in the iliac bone, with relatively normal joint spaces. Page 26 of 43

27 Fig. 22: 83 year-old woman with degenerative vertebral endplate and subchondral bone marrow changes in intervertebral spaces L4-L5. Sagittal T1-weighted (A) an fat-saturated T2 -weighted (B) MR images show the intervertebral disk has lost the height and the signal on T2WI because of desiccation and dehydration. Modic type 1 changes are hypointense on T1WI (A) and hyperintense on T2WI (B) (arrows). Page 27 of 43

28 Fig. 23: 80 year-old woman with intermittent sciatica and lumbar scoliosis. Sagittal T1weighted (A) an fat-saturatedt2 -weighted (B) MR images show a important degenerative changes in lumbar spine with Modic type 2 changes which are hyperintense on T1WI (A) and hypointense on T2WI (B) (arrows). Page 28 of 43

29 Fig. 24: Patient with low back pain with irradiation to the left side. Sagittal fat-saturated T2 -weighted (A) and T1-weighted (B) MR images show in intervertebral space L3-L4 a degenerative irregular vertebral endplate with osteophytes (arrow); subchondral bone marrow with changes Modic type 1 (headarrow) and heigh loss of the intervertebral disk. Page 29 of 43

30 Fig. 25: A 74-year-old man with a history of prostate carcinoma and left lower lumbar mechanical pain. Sagittal fat suppression FSE T2-weighted image (A) demonstrates bone marrow edema in the left L4 pedicle (arrow) and also bone marrow edema in superior endplate of L5 vertebra (Modic I changes) (headarrow); Osteoarthrosis facet joint L4-L5 is seen (long arrow in B) with osteophytes, facet synovitis from the left superior articular facets at L4 and L5 with periarticular soft tissue inflammation (in A). Page 30 of 43

31 Fig. 26: Patient with renal insufficiency with Schmorl's nodes in the L1 and L2 vertebras(arrows). Sagittal STIR (A) and T1WI MR images. In A image is seen bone medular edema in the vertebral body surrounding these nodes. Page 31 of 43

32 Fig. 27: Spondylodiscitis in a 83 year old patient with acute myeloid leukemia on chemotherapy with low back pain in the last month. Sagittal T1W (A), fat sat T2W (B) and contrast enhanced T1W (C) MR images of the spine. Vertebral bone erosions on the inferior aspect of D12 and superior L1 and bone marrow low signal in D12 and L1 (A) with signal fluid in the D12-L1 intervertebral disk (B) and enhancement in adyacent vertebral bodies (C). Page 32 of 43

33 Fig. 28: 55-year-old patient with ankylosing spondylitis and low back pain after a car accident. Sagittal T1WI (A) and fat-sat T2WI (B) MR images show active Romanus lesions at superior and inferior vertebral endplates in L5. In B is seen bone marrow edema in the vertebral body L2 (headarrow) and in T1 sequence is distinguished a fine line of low signal in this vertebra that correspond with a trabecular fracture. Page 33 of 43

34 Fig. 29: Two middle age women with breast cancer and bony metastasis. Patient 1 (A and B): sagittal T1WI and fat-sat contrast enhanced T1 MR imaging sequences demonstrate metastatic lesions within vertebral body (headarrows in D5, D10) and in pedicles (arrows) that are hypointenses in T1 with and annular or heterogeneos or well defined contrast enhancement lesions with contrast. Patient 2: Sagittal fat-sat contrast enhanced T1 (C) is seen a contrast enhacement in postero-inferior area of bone marrow in vertebral body L4 (arrow). Page 34 of 43

35 Fig. 30: Sagittal STIR MR imaging sequences of two patients who show blood vessels (arrows) surrounding the thoracic spinal apophysis and may appear to be, and may erroneously be interpreted as being, actively inflamed lesions of spondyloarthritis. Page 35 of 43

36 Fig. 31: Blood vessels mimicking bone marrow oedema(bmo). A hyperintense signal in both iliac bones (arrows) due to a blood vessels is seen in STIR sequence. This hyperintense signal was visible on one slice only and not on consecutive slices and should not be misinterpreted as BMO. Page 36 of 43

37 Fig. 32: Axial STIR (A) MR image shows the coil effect or inadequate fat suppression (headarrows) with false-positive (hyperintense) signals in the lower sacral part of the right sacroiliac joint in A.in sagital STIR sequences in thoracic spine. In B, it show the so called coil effect may result in brighter signal closer to the coil-body interface (headarrow) in sagital STIR sequence in thoracic spine. Page 37 of 43

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39 Fig. 33: A repetition artefact of the signal of aorta and a iliac vessel produces hyperintense images (headarrows) in normal anatomic structures in lumbar spine in sagittal STIR sequence. Fig. 34: Axial fat-sat T2WI MR imaging sequence(b) show a bilateral repetition artefact of the signal of iliac vessels in the lower sacral part (headarrow) that disappears in coronal fat-sat T2WI MR imaging sequence(a). ( Anyway, notice in A there is bone marrow edema and sclerotic areas in right sacroiliac joint because is a patient with known ankylosing spondylitis). Page 39 of 43

40 Fig. 35: Axial (A) and coronal (B)fat-sat T2WI MR imaging sequences can be crossed to confirm the findings. We check the high signal in right sacro in axial plane does not appear in the sacral bone in coronal plane, and probably is a blood vessel. Page 40 of 43

41 Conclusion - The spondyloarthritis has MR characteristic findings in sacroiliac joints and the spinal column which may appear as active inflammation changes, the most typical of which is the bone medular oedema, or as structural changes. - The use of MR imaging in the context of the ASAS criteria is the most current breakthrough and the most important development with respect to the previously established diagnostic criteria. MR imaging can reveal pre-radiographic disease, allowing early diagnosis of sacroiliitis. - As MR is increasingly used, it is important to know other differential diagnoses and pitfalls in relation to axial spondyloarthritis injuries. Personal information References 1.Kimberly K. Amrami, MD. Imaging of the Seronegative Spondyloarthopathies.Radiol Clin N An 2012;50: Van Der Linden S, Valkenburg H, Cats A. Evaluation of diagnostic criteria for ankylosing spondylitis. A proposal for modification of the New York criteria.arthritis Rheum 1984;27: Amor B, Dougados M, Mijiyawa M. Criteria of the spondyloarthropathies. Rev. Rhum. Mal. Osteoartic1990;57: classification of 4. Rudwaleit M, Landewé R, van der Heijde D et al. Defining active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis: a consensual approach by the ASAS/OMERACT MRI group. Ann Rheum Dis 2009; 68: Page 41 of 43

42 5. Rudwaleit M, van der Heijde D, Landewé R et al. The development of assessment of SpondyloArthritis International Society classification criteria for axial spondyloarthritis (part II): validation and final selection. Ann. Rheum. Dis 2009; 68: Mau W, Zeidler H, Mau R, et al. Clinical features and prognosis of patien with possible ankylosing spondylitis. Results of 10-year foll up. J Rheumatol 1988, 15: Hermann Kay-Geert A, Althoff C, Schneider U, et al. Spinal changes in patients with spondyloarthritis: comparison of MR imaging and radiographic aparences. Radiographics 2005; 25: Rudwaleit M, et al.the change of diagnosis and classification in early ankilosing spondylitis: do we need a new criteria?. Arthri Reu 2005;52: Braun J, Bollow M, Eggens U, et al. Use of dynamic magnetic resonance imaging with fast imaging in the detection of early and advanced sacroiliitis in spondylarthropathy patients. Arthritis Rheum 1994; 37: Colbert R A. Early axial spondyloarthritis. Current Opinion in Rheumatology 2010,22: Weber U, Østergaard M, Lambert R & Maksymowych W.The impact of MRI on the clinical management of inflammatory arthritides. Skeletal Radiol 2011; 40: Bollow M, Fischer T, Reisshauer H, et al. Quantitative analyses of sacroiliac biopsies in spondyloarthropathies: T cells and macrophages predominate in early and active sacroiliitis - cellularity correlates with the degree of enhancement detected by magnetic resonance imaging. Ann Rheum Dis 2000;59: Appel H, Loddenkemper C, Grozdanovic Z, et al. Correlation of histopathological findings and magnetic resonance imaging in the spine of patients with ankylosing spondylitis. Arthritis Res Ther 2006;8:R Althoff CE, Feist E, Burova E, et al. Magnetic resonance imaging of active sacroiliitis: do we really need gadolinium? Eur J Radiol 2009;71: Madsen KB, Egund N, Jurik AG. Grading of inflammatory disease activity in the sacroiliac joints with magnetic resonance imaging: comparison between short-tau Page 42 of 43

43 inversion recovery and gadolinium contrast-enhanced sequences. J Rheumatol 2010; 37: Bennett AN, Marzo-Ortega H, Rehman A, Emery P, McGonagle D. The evidence for whole-spine MRI in the assessment of axial spondyloarthropathy. Rheumatology 2010; 49: Marzo-Ortega H, McGonagle D, O'Connor P, et al. Baseline and 1-year magnetic resonance imaging of the sacroiliac joint and lumbar spine in very early inflammatory back pain: relationship between symptoms, HLA-B27 anddisease extent and persistence. Ann Rheum Dis 2009; 68: Weber U, Lambert RG, Østergaard M, Hodler J, Pedersen SJ, Maksymowych WP. The diagnostic utility of magnetic resonance imaging in spon-dylarthritis: an international multicenter evaluation of one hundred eighty-seven subjects. Arthritis Rheum 2010;62: Aydingoz U, Yildiz AE, Ozdemir ZM, Yildirim SA, Erkus F, Ergen FB. A critical overview of the imaging arm of the ASAS criteria for diagnosing axial spondyloarthritis: what the radiologist should know. Diagn Interv Radiol 2012;18: Navallas M, Ares J, Beltrán B, Lisbona MP, Maymó J, Solano A. Sacroiliitis associated with axial spondyloarthropathy: new concepts and the latest trends. RadioGraphics 2013;33: Page 43 of 43