AB1040 Clinical utility of bone scintigraphy for inflammatory arthritis
Authors: M Jiang, K Le Marshall, K Lim
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> Bone scintigraphy is often used in the workup of patients with rheumatological disease, in particular for the investigation of inflammatory arthritis. It also has a role in the investigation of malignancy and fractures. As an imaging technique, it is very sensitive but not specific for inflammation. The most common technique used is triple phase scintigraphy, with the 2nd phase (blood pool phase) being the most useful for identifying inflammation. <h3>Objectives</h3> To evaluate the clinical utility of bone scintigraphy in the workup of patients with rheumatological disease, in particular for inflammatory arthritis. <h3>Methods</h3> This was a retrospective study of patients seen in the rheumatology outpatients between January 2011 and July 2014, who had bone scintigraphy as part of their workup. Their clinical record was reviewed to obtain pre- and post-test clinical diagnoses, bone scintigraphy reports and investigations (ESR/CRP, rheumatoid factor/CCP antibodies). For patients who had followup at one year we recorded their clinical diagnosis at this time. <h3>Results</h3> A total of 226 patients had bone scintigraphy, with a median age of 54 years. 63% were female. The main indication for bone scintigraphy was to assess for inflammation in 194 patients. For this group, the most common pre-test diagnosis of inflammatory arthritis (41%), followed by degenerative arthritis (36%), unclear diagnosis (20%) and mixed inflammatory and degenerative arthritis (3%). Overall, 49% (n=95) of patients had their diagnosis changed after bone scintigraphy. The pre-test diagnosis was compared to bone scintigraphy findings with the highest confirmatory rate for degenerative arthritis (67%), followed by inflammatory arthritis (49%) and mixed arthritis (40%). Bone scintigraphy findings were also compared to post test diagnosis with the highest confirmatory rate for degenerative arthritis (91%), followed by inflammatory arthritis (70%) and mixed arthritis (14%). There was no significant association between patient factors (age, gender, ESR/CRP, RF/CCP) and having confirmatory or conflicting bone scintigraphy findings. The post test diagnosis was compared to the diagnosis at one year, with the diagnosis being unchanged in 84% for inflammatory arthritis and 45% for degenerative arthritis. <h3>Conclusions</h3> This study showed that bone scintigraphy lead to a change in diagnosis in a large proportion of patients and was better at confirming degenerative arthritis or ruling out inflammatory arthritis. <h3>References</h3> De Leonardis F, Orzincolo C, Prandini N, Trotta F. The role of conventional radiography and scintigraphy in the third millennium. Best practice &amp; research Clinical rheumatology. 2008;22(6):961–79. Kim JY, Cho SK, Han M, Choi YY, Bae SC, Sung YK. The Role of Bone Scintigraphy in the Diagnosis of Rheumatoid Arthritis According to the 2010 ACR/EULAR Classification Criteria. Journal of Korean Medical Science. 2014;29(2):204–9. Sudoł-Szopińska I, Ćwikła JB. Current imaging techniques in rheumatology: MRI, scintigraphy and PET. Polish Journal of Radiology. 2013;78(3):48–56. Al-Janabi M. Imaging modalities of the painful wrist: the role of bone scintigraphy. Rheumatology (Oxford, England). 2002;41(10):1085–7. <h3>Acknowledgements</h3> I would like to acknowledge Sara Vogrin (University of Melbourne) for her assistance with statistical analysis. <h3>Disclosure of Interest</h3> None declared