31-10-2017 | Psoriatic arthritis | Gallery
Psoriatic arthritis image collection
Synovitis is defined as an area in the synovial compartment that shows increased post-gadolinium (Gd) enhancement of a thickness greater than the width of the normal synovium. Tenosynovitis is defined as increased water content or abnormal post-Gd enhancement adjacent to a tendon, in an area with a tendon sheath. Enhancement (signal intensity increase) is judged by comparison between T1-weighted images obtained before and after intravenous Gd contrast.
Whole-body magnetic resonance imaging (MRI) is a novel imaging method, which allows MRI of the whole body in one scanning session, but at the cost of lower image resolution than conventional MRI. Radiologists have applied whole-body MRI for screening for bone marrow malignancies and systemic muscle diseases [1]. Weckbach et al. reported the results of whole-body MRI in 30 patients with psoriatic arthritis, and found that the most often detected pathology was enthesitis [2]. Recently, seven clinical enthesitis indices were examined by whole-body MRI in patients with psoriatic arthritis, axial spondyloarthritis and healthy subjects and compared with entheseal tenderness [3]. A moderate agreement between MRI enthesitis and clinical examination was reported, suggesting a role for whole-body MRI in detecting subclinical inflammation. Furthermore, a new whole-body MRI enthesitis index was proposed, as a potential additional tool for assessing disease activity. An exciting possibility of whole-body MRI is the assessment of the distribution of inflammation and structural damage in the entire body, and the possibility of providing global scores of inflammation and damage in all peripheral and axial joints [4].
References
- Weckbach S. Whole-body MRI, for inflammatory arthritis and other multifocal rheumatoid diseases. Semin Musculoskelet Radiol 2012;16:377–388.
- Weckbach S, Schewe S, Michaely HJ et al. Whole-body MR imaging in psoriatic arthritis: additional value for therapeutic decision making. Eur J Radiol 2011;77:149–155.
- Poggenborg RP, Eshed I, Ostergaard M et al. Enthesitis in patients with psoriatic arthritis, axial spondyloarthritis and healthy subjects assessed by ‘head-to-toe’ whole-body MRI and clinical examination. Ann Rheum Dis 2014;74:823–829.
- Poggenborg RP, Pedersen SJ, Eshed I et al. Head-to-toe whole-body MRI in psoriatic arthritis, axial spondyloarthritis and healthy subjects: first steps towards global inflammation and damage scores of peripheral and axial joints. Rheumatology (Oxford) 2014;54:1039–1049.
The site of erosion can help differentiate peripheral joint psoriatic arthritis (PsA; around entheseal insertions and centrally resulting in 'pencil in cup') from rheumatoid arthritis (RA; marginal). Synovitis is generally the same between the two inflammatory arthritis conditions, but bone marrow edema may be more prominent and occurs at the bony corners of joints and at the entheseal sites in PsA (as in this slide). Magnetic resonance imaging (MRI) of the peripheral joint may also help to differentiate PsA from RA and from osteoarthritis (OA). Dynamic MRI can also detect increased vascularity compared with RA (this increased vascularity is also seen in biopsy samples of PsA). MRI can clearly depict the enthesitis at the distal interphalangeal joints, which occurs in PsA but not OA. Furthermore, whole body multi-joint MRI can be used to assess the extent of disease in joints and entheses.
Thickening of both the ventral and dorsal plates can form a wavy appearance in the late stages (see above) [1, 2]. These findings have also been divided into four types of morphological changes and were initially described with increasing severity by Worstman et al.: (1) focal hyperechoic areas of the ventral plate, without involvement of the dorsal plate; (2) loosening of the borders of the ventral plate, (3) wavy appearance of both plates; and (4) loss of definition of both plates [3]. Studies have noted that in psoriatic nails, the nail bed is typically thickened, reporting a thickness of either over 2.0 or 3.0 mm [2, 4].
References
- Gutierrez M, Wortsman X, Filippucci E, De Angelis R, Filosa G, Grassi W. High-frequency sonography in the evaluation of psoriasis: nail and skin involvement. J Ultrasound Med 2009;28:1569–1574.
- Marina ME, Jid CB, Roman II, Mihu CM, Tataru AD. Ultrasonography in psoriatic disease. Med Ultrason 2015;17:377–382.
- Wortsman X, Jemec GB. Ultrasound imaging of nails. Dermatol Clin 2006;24:323–328.
- Sandobal C, Carbo E, Iribas J, Roverano S, Paira S. Ultrasound nail imaging on patients with psoriasis and psoriatic arthritis compared with rheumatoid arthritis and control subjects. J Clin Rheumatol 2014;20:21–4.
Three-dimensional (3D) ultrasound (US), since its first application in medical practice, appeared to be a useful tool to carry out diagnosis and follow-up in various medical areas including the musculoskeletal diseases. 3D US image is acquired automatically using a volumetric probe in few seconds, due to the automatic sweeping scan movement of the piezoelectric crystals located inside the volumetric probe [1]. It can be performed in both grayscale and power Doppler (PD) mode. Moreover longitudinal, transverse, and coronal planes (by producing a 3D reconstruction of the anatomic area) can also be accurately obtained.
References
- Meenagh G, Filippucci E, Abbattista T et al. Three-dimensional power Doppler sonography in short-term therapy monitoring of rheumatoid synovitis. Rheumatology (Oxford) 2007;46:1736.
Elastosonography (ES) is an imaging technique that allows a non-invasive evaluation of tissue elasticity in addition to information obtained from conventional B-mode. It is based on the principle that the compression of tissue produces different degree of tissue displacement according to the stiffness of each tissue. The degree of the tissue displacement is calculated in real-time and the elasticity information can be displayed as color-coded elasticity map, so-called elastograms, superimposed on the B-mode images, in which each color is representative of a different level of elasticity.
The most prominent lymph node was a 2 cm in the short axis left level 2 lymph node with a SUVmax of 6.9. Several hypermetabolic lymph nodes were also noted in the axillae, subpectoral space and mediastinum. For example, a left axillary node measured 7 × 14 mm with a SUVmax of 2.7, a right axillary node cluster measured 13 × 26 mm with a SUVmax of 4.3, and multiple left axillary and left subpectoral nodes measured up to 1.5 cm with SUVmax values up to 4.7. The lungs were clear. Also, multiple hypermetabolic iliac lymph nodes were seen (whole-body MIP image shown in a). Interestingly, the scan also showed an abnormal, heterogeneous, patchy pattern of fludeoxyglucose (FDG) activity in the muscles of the upper extremities, chest wall, and lower extremities, with a serpiginous appearance more prominent in the thighs, where the patient experienced his main area of weakness and pain. This was a very atypical pattern of FDG uptake different from the typical pattern observed in normal up-regulation of metabolism in the muscle groups due to exercise, muscle strain or as frequently observed in the postprandial state. This pattern was also different from prior case reports of lymphoma in the muscles and local myositis. In fact, in the thighs the FDG activity seemed to clearly favor localization in the intermuscular fascia consistent with fasciitis (b).
In early stages erosions occur in the joint margins, resembling “mouse ears” and are different from the central erosion (“gull wings”) of erosive osteoarthritis (EO). Erosions progress over time and may affect the central area. If they are extensive, the subchondral bone can be destroyed, leading to joint space widening. The ends of the bones can become pointed, resulting in the image of “pencil in cup”. This appearance is not specific for psoriatic arthritis or any of the other spondyloarthritis, but it is most commonly seen in these conditions.
One characteristic feature of PsA in the foot is the “ivory phalanx,” which classically involves the distal phalanges (especially in the first digit) with sclerosis, enthesitis, periostitis, and soft-tissue swelling [1]. Joint subluxation and luxation may also be present.
References
- Torre Alonso JC, Rodriguez Perez A, Arribas Castrillo JM, Ballina Garcia J, Riestra Noriega JL, Lopez Larrea C. Psoriatic arthritis (PA): a clinical, immunological and radiological study of 180 patients. Br J Rheumatol 1991;30:245–50.