Dual energy CT in diagnosis of Gout Poster No.: R-0060 Congress: RANZCR ASM 2013 Type: Educational Exhibit Authors: F. Tabatabaie Moghadam, A. Moghaddam, F. Ghazanfari ; 1 1 1 2 2 Brisbane/AU, Melbourne/AU Keywords: Musculoskeletal joint, CT, Computer Applications-3D, Arthritides DOI: 10.1594/ranzcr2013/R-0060 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 RANZCR's endorsement, sponsorship or recommendation of the third party, information, product or service. RANZCR 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 RANZCR 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,.doc documents and any other multimedia files are not available in the pdf version of presentations. www.ranzcr.edu.au Page 1 of 9
Learning Objectives To appreciate the implication of Dual energy CT (DECT) in diagnosis of Gout, a highly accurate noninvasive imaging tool, and to show case examples of patients imaged with this technique. Background Gout is a common crystalline arthropathy of metabolic origin, triggered by crystallization of Monosodium urate (MSU) within the joints(1). A definitive diagnosis of gout is based upon the identification of monosodium urate crystals in synovial fluid or a tophus, which demonstrate a needle-like morphology and strong negative birefringence. Nonetheless, in clinical practice, only 11% of patients undergo arthrocentesis and the vast majority of cases of gout are diagnosed on clinical grounds (2). Up to 42% of patients with gout have normal serum uric acid levels. Bony alterations occur only years into the illness and even then, only 45% of patients have radiographic findings (3,4). Due to these difficulties in diagnosing gout, many physicians manage gout without confirming the diagnosis with joint aspiration. Thus, a highly accurate non-invasive imaging tool to confirm the presence of gout is desirable. Imaging Findings OR Procedure Details DECT can accurately characterise MSU deposition and improve clinical diagnosis of unclear arthropathies (5). The dual source scanner is equipped with two x-ray tubes and allows simultaneous acquisition at two different energy levels (80 and 140 kvp) and subsequent creation of two different datasets that are loaded into the post processing software on a Multi technique CT workstation. A material decomposition algorithm is then able to differentiate the soft tissue material based on its chemical composition. This allows accurate and specific characterisation of MSU deposition which could subsequently be colour-coded, usually green in our institute. We describe and illustrate imaging findings in four patients who were either clinically diagnosed with or suspected of having gout(6). Case 1: DECT scan of a 70 year old man with the background of Gout who developed severe knee and ankle pain following coronary angiogarm. It depicted Uric acid deposition in green at the knee and ankle joint and tendons.(fig 1,2) Page 2 of 9
Case 2: DECT scan of a 50 year old man with longstding polyarticular tophaceous gout in elbow, MCPs, Wrists, knees and ankles which demonstrates green MSU depostis within the joints and tendons.(fig 3) Case 3: DECT scan of the wirst in a 65 year old man with severe pain and swelling in right wrist, raised WCC. The diagnosis was confirmed with identification of the MSU deposits in wrist joint aspirates.(fig 4) Case 4: 80 years old man who presented to Emergency Department with fever, diffuse ankle swelling and neck tenderness, with no history of trauma. He had confirmed diagnosis of gout in previous admissions, however given the severity of the fever and the other symptoms, there was clinical concern of osteomyelitis. Ankle washout and Arthroscopy was done in the operation room, and large amount of MSU crystal within the synovium was detected. A cervical spine MRI was ordered by the neurosurgens for chronic neck pain. Sagittal T1 post contrast image showed C3/4 disc height attenuation with abnormal enhancement extending to the epidural and prevertebral spaces, highly suggestive of discitis. This patient was a case of polyarticular gout, including cervical spine, with evidence of MSU depostis in cervical spine detected by DECT scan.(fig 5) Images for this section: Page 3 of 9
Fig. 1: Dual energy CT of the knee(3d) Page 4 of 9
Fig. 2: Dual Energey CT of the ankle(3d and axial) Page 5 of 9
Fig. 3: DECT scan of the hands and wrists(3d) Page 6 of 9
Fig. 4: DECT scan of the wrist (3D). Page 7 of 9
Fig. 5: DECT scan of Cervical Spine. Page 8 of 9
Conclusion DECT provides a noninvasive imaging modality for: Diagnosing gout by demonstrating uric acid deposition. Differentiating gout from other infalmmatory arthropathies. Quantifying and depicting distribution of MSU in multiple joints. Monitoring disease progression or response to therapy. Potentially reducing the burden of chronic complications associated with gout and possibly obviating asthrocentesis. limited abvailability will likey confine the role of DECT to those individuals with diagnostic uncertainty and access to larger imaging centers. Personal Information References 1. Lawrence RC, Felson DT, Helmic CG et al (2008) Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II. Arthritis rheum 58:26-35 2. Underwood M (2006) Diagnosis and managemet of gout. BMJ 332: 1315-1319 3. Schlesinger N, Baker DG, Schumacher HR Jr. Serum urate during bouts of acute gouty arthritis. J Rheumatol.1997:325-341 4. Brower AC, Flemming DJ. Gout. In: Arthritis: In Black and White. 2nd ed. Philadelphia, Pa: WB Saunders;1997:325-341 5. Thiele RG, Schlesinger N (2007) Diagnosis of gout by ultrasound. Rheumatology 46: 1116-1121 6. Manger B, Lell M, Waker J et al (2011) Detection of periarticular urate deposits with CT dual energy in patients with acute gouty arthritis. Page 9 of 9