1 Radiography in evaluating arthritic diseases Introduction The

Radiography inevaluating arthritic disease – Dr M Schranz 1 Radiography in evaluating arthritic diseases Introduction The plain radiograph is a central tool for evaluating arthritic diseases and often is useful in assessing the effectiveness of management. Soft tissue changes, bony abnormalities, and cartilage attenuation can be observed and often quantified. Indications for joint radiograph Assessment of joint space (cartilage) Identification of fractures Identification of indicators of inflammation (porosis, erosion) Assessment of effectiveness of treatments (protection from erosion or joint space loss) Identification of intra- or periarticular calcification (chondrocalcinosis or calcific periarthritis) Identification of specific clues to diagnosis (periostitis in enthesopathies, tophi, chondrocalcinosis) Rheumatologic conditons for which radiography is not required Condition Explanation Osteoarthritis Management is usually determined by amount of pain and disability, not by documenting progression on radiographs. Radiologic findings are nonspecific early in the course of the disease. Examination of synovial fluid for crystals is diagnostic. Early on, soft-tissue swelling is nonspecific. Synovial fluid analysis and culture are essential. Acute tendinitis or bursitis on clinical examination does not usually require radiography; it will not alter management. Radiographs are usually normal in young patients. Clinical diagnosis is more important than documenting radiographic abnormalities. Radiographs are needed only if surgery is contemplated. Once documented, radiography does not need to be repeated unless the symptom complex changes; it should not be repeated simply because the severity of pain has increased. Gout Early septic arthritis Rotator cuff syndromes Patellofemoral knee pain Bunions Chronic back and neck pain www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 2 Positioning during radiography is critical for detecting small amounts of knee joint fluid. The knee must be fully extended for the lateral projection; otherwise, small effusions are obscured. Nonweight-bearing radiograph of the ankle (below left) showing no major abnormalities. Standing view of the same ankle (below right) showing marked loss of joint space and angulation of the tibiotalar joint. Nodular swelling around joints may represent either nodules in rheumatoid arthritis or tophi in gout. Faint mineralization of such nodules favors gout. Periarticular swelling about finger joints is common in inflammatory arthritis. However, the finding of swelling has no diagnostic specificity. Calcinosis is characteristic of either scleroderma or CREST (calcinosis cutis, Raynauds phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia) syndrome may also be detected in soft tissues. The radiolucent space between bone ends is occupied by articular cartilage. Thus, joint space narrowing reflects loss of joint cartilage. Weight-bearing views often reveal or accentuate narrowing in knee radiographs. The responsible process may be either degenerative or inflammatory, and adjacent bony changes will frequently favor one or the other etiology. Mineralization of articular cartilages is characteristic of calcium pyrophosphate dihydrate crystal deposition (CPPD). In addition to involving hyaline articular cartilage, calcium pyrophosphate dihydrate crystal deposition often favors fibrocartilages, especially the menisci of the knee, triangular cartilage of the wrist, symphysis pubis, and anulus fibrosus of the intervertebral discs. Bony changes may be highly suggestive of specific classes of diseases or even specific types of arthritis. Osteoporosis is a common finding that occurs independently of arthritis. However, periarticular accentuation of osteoporosis is common in inflammatory forms of arthritis, most characteristically rheumatoid arthritis. www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 3 Erosions of bone represent breaches of cortex with replacement of bone by inflammatory synovium or fluid. The presence or absence of erosions helps us distinguish the possible cause of the arthritis. www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 4 The following is a plain radiograph of the hand in a patient with advanced rheumatoid arthritis Note: the soft tissues are clearly demonstrated, so the large rheumatoid nodules in the second and third fingers are readily apparent. Marginal erosions (arrowheads) at the proximal interphalangeal joints, as well as metacarpal phalangeal joints and wrist are well demonstrated as are the remodeling and sclerosis (open arrows) of postinflammatory degenerative change. If the purpose of the examination is to check for erosions in the hands of a patient with rheumatoid arthritis, either as a baseline assessment before second-line therapy or when a change in therapy is being considered, a single posteroanterior view is usually sufficient. Marginal erosions occur where the synovium abuts bare bone Subchondral erosions occur in bone beneath the hyaline articular cartilage. Erosions with periarticular osteoporosis signify an inflammatory process without specificity. Erosions without periarticular osteoporosis may be seen in spondyloarthritis or gouty arthritis. Periosteal reaction is seen in some instances of spondyloarthritis, especially psoriatic arthritis and Reiters syndrome, in hypertrophic pulmonary osteoarthropathy, and in some metabolic diseases of the bone Magnified view of a fine-detail radiograph shows intracortical tunneling and subperiosteal resorption (arrows) from hyperparathyroidism. These findings require careful attention to radiographic technique and instrumentation. www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 5 Contrast arthrography Contrast Arthrography involves filling a joint cavity with a radio-opaque contrast medium or air. It is less expensive than computed tomography or MRI but is uncomfortable for the patient, and results are not easily interpreted without considerable experience. Contrast arthrography allows • • • visualization of cysts that communicate with joints (eg, Bakers cysts) delineation of the cartilage surface assessment of the integrity of articular structures such as the meniscus or rotator cuff. Ultrasonography Ultrasonography is a useful noninvasive means of imaging soft tissues in or adjacent to joints. Ultrasound is inexpensive, more widely available than MRI and, like MRI, does not involve ionizing radiation. It can provide excellent spatial resolution of superficial structures, but its efficacy depends on the skill of the operator. Fluid collections such as Baker's (popliteal) cysts, ganglions and joint effusions are identified extremely well, and superficial tendons such as the rotator cuff, Achilles and patellar tendons can be studied for tears. This technique is excellent for guiding joint aspiration or injecting difficult-to-reach joints such as the hip. Some diagnostic information can be obtained with ultrasound-guided injections of local anesthetic into a joint to confirm that pain is actually arising from the joint identified by the patient. www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 6 High-resolution ultrasound (A) demonstrates a normal rotator cuff insertion into the greater tuberosity. The cortex of the humeral head is strongly echogenic. The greater tuberosity (curved arrows), articular cortex of the humeral head (open arrows), and the rotator cuff tendon (straight arrows) are shown. A complete tear of the rotator cuff is seen in the ultrasound labelled (B). The torn end of the cuff is apparent (solid arrows). The inferior surface of the deltoid muscle (open arrows) is dropping into the defect created by retraction of the more proximal portion of the rotator cuff and is nearly in contact with the humeral head. Computed tomography Although useful for evaluating traumatic or neoplastic lesions of the appendicular skeleton, computed tomography (CT) has limited application in studying peripheral joint disease. CT remains a very useful modality for evaluating the spine, particularly in complex or postoperative cases, but it is being rapidly supplanted by magnetic resonance imaging (MRI) as a primary diagnostic modality for spinal disease The following radiograph showing no significant arthritis in the hip (left). www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 7 Computed tomography scan (right) showing marked anterior and posterior joint-space loss (arrow heads) indicative of osteoarthritis. The following computed tomography image in soft-tissue settings shows the L5-Sl intervertebral disc with a large, right posterolateral disc herniation (arrowheads). The left and right Sl nerve root sheaths are shown. The right root sheath is displaced posteriorly by the herniated disc. www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 8 Magnetic resonance imaging Magnetic resonance imaging is an exceptional tool for defining structural abnormalities of appendicular or axial anatomy. Advantages include • absence of radiation exposure • favourable soft tissue discrimination Indications for magnetic resonance imaging of joints To identify nerve compression, especially in the axial skeleton To identify disruption of ligaments, tendons, or cartilage To identify early ischemic necrosis of bone Magnetic resonance imaging is useful for visualizing changes within the joint, in adjacent bone, and in the spine Intra-articular lesions that can readily be seen include • • • • • tears of tendons and cartilages, such as the rotator cuff and menisci of the knee chondral and osteochondral loose bodies synovial hyperplasia and tumors synovial fluid accumulations and Bakers cysts ligamentous injuries such as the medial, lateral, and cruciate ligaments of the knee. Subtle changes in cartilage contour and signal may occur in arthritic diseases or following trauma. Edema of subchondral marrow may be seen early in avascular necrosis of bone and in osteomyelitis. www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 9 The following sagittal magnetic resonance image of the cervical spine using a Tlweighted pulse sequence shows a herniated C5 -6 intervertebral disc displacing the spinal cord in a posterior direction (arrow). Radioisotopic scanning Radioisotopic scanning is considered nonspecific because if an abnormality is detected additional evaluation is often required to confirm a diagnosis. Technetium-99m methylene diphosphonate bone and joint scintigraphy has proved to be useful in detecting osteomyelitis, stress fractures, shin splints and tendon avulsions, as well as metastases and Paget's disease. However, radionuclide scintigraphy to assess inflammatory joint disease has been disappointing and is no longer widely used. Other radionuclides used for scintigraphy include gallium-67 citrate and indium-111 leukocytes. Gallium-67 citrate accumulates in inflammatory lesions and certain neoplasms, and an indium-111 leukocyte scan can be used to identify osteomyelitis, especially at a site that would take up technetium-99m methylene diphosphonate in the absence of infection (e.g., fractures or surgical incision). Single photon emission computed tomography (SPECT) is useful in identifying avascular necrosis of the hip and in delineating specific facet joints involved in arthritis. A, Static image of the pelvis from a radionuclide bone scan shows abnormally increased uptake about the right hip. Radioisotope has accumulated on both sides of the joint, in a pattern typical for arthritis. B, Plain film of the hip shows moderately advanced osteoarthritis, accounting for the increased uptake on bone scan. There is narrowing and sclerosis of the hip joint, as well as appositional bone formation (buttressing) (arrow) of the femoral neck, a response to abnormal weight-bearing stress. www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 10 Ankylosing spondylitis Ankylosing spondylitis is, by far, the most common inflammatory arthropathy of the axial skeleton. This chronic inflammatory disorder of unknown etiology principally affects the axial skeleton. Alterations occur in synovial and cartilaginous articulations and in sites of tendon and ligament attachment to bone. Over 90 % of caucasian patients with ankylosing spondylitis are HLA-B27 positive. The following radiograph demonstrates bony ankylosis of both sacroiliac joints with flowing syndesmophytosis bridging multiple intervertebral joints www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 11 Sacroiliitis is the hallmark of ankylosing spondylitis. It occurs early in the course of the disease. Although an asymmetric or unilateral distribution can be evident on initial radiographic examination, roentgenographic changes at later stages of the disease are almost invariably bilateral and symmetric in distribution. This symmetric pattern is an important diagnostic clue in this disease and may permit it differentiation from other disorders that affect the sacroiliac articulation, such as RA, psoriasis, Reiter's syndrome, and infection. Changes in the SI joint occur in both the synovial and ligamentous (superior) portions, and predominate on the iliac side, for reasons that are obscure. Psoriatic arthritis This is a relatively uncommon arthropathy which occurs in about 2 to 6 % of patients with psoriasis. Approximately 25 to 60 % of patients with psoriatic arthritis are HLAB27 positive. Reiter's syndrome Reiter's syndrome is a relatively uncommon arthropathy of uncertain etiology with the classic triad of urethritis, arthritis, and conjunctivitis. Approximately 75 to 96 % of patients with Reiter's syndrome are HLA-B27 positive www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 12 Enteropathic arthropathy This arthropathy occurs in patients with ulcerative colitis or Crohn's disease. Approximately 90 % of patients with ulcerative colitis or Crohn's disease who develop spondylitis or sacroiliitis are HLA-B27 positive. Rheumatoid arthritis This is a disorder of unknown etiology characterized by synovial inflammation, pannus formation, and then destruction of bone and cartilage. Rheumatoid arthritis may involve the cervical spine, with apophyseal joint erosion and malalignment, intervertebral disc space narrowing with endplate sclerosis and without osteophytes, and with multiple subluxations, especially at the atlanto-axial junction. Diagram illustrating C1/C2 cervical instability in rheumatoid disease.(a) Anterior subluxation. (b) Posterior subluxation requires a co-existent fracture of the odontoid peg or its absence due to complete erosion. (c) Vertical subluxation with associated risk of cord compression and migration of the odontoid peg through the foramen magnum.(d) Lateral subluxation. All the above can co-exist and be associated with sub-axial instability. Rheumatoid arthritis is a systemic disease of unknown etiology. In the musculoskeletal system its presents as a chronic, symmetric and erosive synovitis which over time leads to joint destruction, deformity and disability. The joint space narrowing is typically uniform. www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 13 Most patients with rheumatoid arthritis have involvement of the hands and wrists. The earliest changes in the hand occur in the second and third metacarpophalangeal joints and in the wrist the earliest bony changes are seen as erosions in the ulnar styloid process. The disease also affects other joints, such as the small joints of the feet, elbow, shoulder, and hip. C1 C2 instability is best tested on lateral cervical spine with flexion and extension views. Normally the distance between the anterior arch of C1 and the dens should not exceed 3 mm in adults. In the following MRI note that the dens is eroded in this patient with rheumatoid arthritis. A mass of pannus is noted behind the dens and impinging on the thecal sac and cord. Osteoarthritis (OA) The term osteoarthritis is reserved for degenerative disease of synovial joints. OA can be idiopathic or primary or it can be secondary. The prevalence of OA increases with age. It is characterized by progressive loss of the articular cartilage, manifested radiographically by joint space narrowing, subchondral sclerosis, and osteophyte formation. The commonest joint involved is the knee followed by the hip. In the hands the distal interphalangeal joints and the basal joint of the thumb are also common sites for OA. Primary OA is not common in the ankles, shoulders, elbows and wrists. When the clinical diagnosis is osteoarthritis the physician would order radiographs of the painful joint itself (e.g., hip or knee). It is also generally helpful to obtain bilateral radiographs in these cases so the affected joint can be compared with the normal joint on the other side. If one of the spondyloarthritides is suspected, radiographs of www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 14 the sacroiliac joints might be obtained because this is the most common and most important early finding in ankylosing spondylitis The initial radiographic abnormalities predominate in the pressure or stressed segments of the joint. In the knee, the medial joint compartment where about 60% of the weight bearing takes place would be the site that shows the earliest changes. Here, the cartilage is discolored, rough, cracked and thinned. The progressive cartilage loss leads the fundamental radiographic sign of OA: diminished joint space. In the interphalangeal, metacarpophalangeal and sacro- iliac joints the narrowing may be more uniform. With advancing disease sclerosis (eburnation) and cyst formation develop in the subchondral bone. Communication of these cysts with the joint is variable. Concurrent with these changes is the formation of marginal osteophytes that are excrescences of bone arising at the margins of the joint. In the distal, and proximal interphalangeal joints of the hands these osteophytes account for the clinically palpable Heberden and Bouchard nodes that are characteristic of this disease. On the medial aspect of the femoral neck, bone is formed resulting in thickening of the medial cortex; this is labeled buttressing, which is characteristic of OA of the hip. In the following radiograph there is ill-defined sclerosis centered over the right sacroiliac joint which could easily represent a sclerotic metastasis in the right clinical circumstances Axial CT clearly shows that this sclerotic focus is merely a large osteophyte bridging the sacroiliac joint and projecting anteriorly www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 15 Osteoarthritis of the spine looks much like osteoarthritis elsewhere in the body. Any of the spinal synovial joints can be affected, including the facet joints, the costovertebral joints, and the SI joints. Findings include osteophytosis, joint space narrowing, subchondral sclerosis, and subchondral cyst formation. Besides causing local joint pain, facet osteoarthritis may cause nerve root impingement or compression if the osteophytes are large enough to extend into the lateral recess of the spinal canal, as shown below. Marked osteophytosis is seen in the spine of a patient with osteoarthritis of the lumbar facet joints -- this osteophytosis is extending into the lateral recesses bilaterally and causing nerve root compression Intervertebral disc space narrowing, intradiscal gas, and osteophytosis are noted in this patient with predominantly degenerative disc disease www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 16 Extensive osteophytosis is noted in the thoracic spine in this patient with predominantly degenerative annular disease Diffuse idiopathic skeletal hyperostosis syndrome (DISH) Findings 1. Flowing ossification of the anterior longitudinal ligament, involving at least 4 adjacent disk spaces 2. Lack of intervertebral disk space narrowing Brief Discussion DISH syndrome is an idiopathic disorder, and therefore, by definition, a diagnosis of exclusion. In general, one must exclude 3 other entities that can commonly present with fairly large "phytes" in the spine: www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 17 1. ankylosing spondylitis 2. degenerative nuclear disease 3. degenerative annular disease With DISH, the flowing ossification seen is usually along the anterior longitudinal ligament. The following radiograph shows prominent, flowing ossification along the anterior margin of the cervical spine in this patient with DISH -- it is easy to see why such patients often complain of dysphagia. Flowing ossification is noted along the anterior margin of the thoracic and lumbar spine in these patients with DISH -- note that the disk spaces are preserved and that at least four contiguous bodies are involved www.e-radiography.org Society of Medical Radiography(Malta) Radiography inevaluating arthritic disease – Dr M Schranz 18 CONCLUSION Common conditions affecting joints and radiographic views helpful for diagnosis Common diagnostic possibilities Joint Radiographic views to order Hand and wrist Elbow Shoulder Neck Osteoarthritis, pseudogout, inflammatory arthritis* Post-traumatic osteoarthritis, inflammatory arthritis Rotator cuff syndrome, inflammatory arthritis Spondylosis, rheumatoid arthritis, physical trauma Osteoarthritis, osteonecrosis, inflammatory arthritis Osteoarthritis, inflammatory arthritis, ligament or meniscal injury, pseudogout Secondary osteoarthritis, inflammatory arthritis, "sprain" Osteoarthritis, inflammatory arthritis Spondyloarthritis,‡ osteoarthritis Spondylosis, compression fracture, spondylo-arthritis, diffuse idiopathic skeletal hyperostosis Single PA view Standard 3 views† Standard 3 views AP, lateral and oblique views (flexion–extension views if C1–C2 subluxation considered) AP pelvis and frog-leg lateral Standing AP and lateral Standing PA and lateral Standing PA and lateral 15° cranial-angled view of the pelvis AP and lateral Hip Knee Ankle Foot Sacroiliac Spine Note: AP = anteroposterior, PA = posteroanterior. *Inflammatory arthritis includes conditions such as rheumatoid arthritis, psoriatic arthritis and Reiter’s disease; Reiter’s disease is more likely to affect the joints of the lower extremities. †The standard 3 views are AP, lateral and oblique. ‡Includes ankylosing spondylitis, Reiter’s disease, psoriatic arthritis and arthritis with inflammatory bowel disease. www.e-radiography.org Society of Medical Radiography(Malta)