The role of ultrasonography in the investigation and management of rheumatic conditions

Aims: The importance of inflammation in the development of joint damage and
subsequent functional limitation, together with the increasing awareness that clinical
assessment is insensitive at detecting synovitis, has led to the use of modern imaging
modalities such as ultrasonography (US) in rheumatology. This with an emphasis on
improved detection of synovitis and earlier, more effective therapeutic intervention.
The aim of this thesis was to investigate the role of US in routine practice, by
validating its role in diagnosis, prognosis and therapeutic intervention, across a
range ofcommon rheumatological clinical scenarios.
Methods: Construct validity for US-detected synovitis in knee arthritides was
examined by comparison with clinical assessment and arthroscopy. In order to
examine the benefits of US-guided joint injections, the accuracy of guided shoulder
injections was observed. As well, the efficacy of US-guided corticosteroid injections
in hip osteoarthritis and predictors of outcome were also assessed. The sensitivity of
US over clinical examination was assessed in a cohort of rheumatoid arthritis patients with low disease activity levels. The diagnostic and therapeutic predictive
value of US-detected synovitis in inflammatory hand pain was examined in a large
cohort. Finally the clinical utility of US at altering diagnosis and management in
clinical rheumatology practice was prospectively examined.
Results: For detection of knee synovitis, using arthroscopy as the gold-standard, US
had higher sensitivity (98 vs 85%) and specificity (75 vs 25%) than clinical
assessment. Kappa values for inter- and intra-reader reliability of US were 0.71 and
0.85 respectively. In the shoulder US-guided injections were 100% accurate, but 55% had evidence of extrabursal contrast limited to the tissue planes adjacent to the
bursa. Outcome following hip injection was poor, but synovitis without osteophytes
on US was the best predictor of short term benefit. In rheumatoid arthritis patients in
clinical remission, the majority satisfying established remission criteria, US detected
gray-scale and power Doppler (PD) synovitis in 85% and 60% patients respectively.
The kappa value for inter-reader reliability was 0.60 for gray-scale, and intra-reader
reliability was 0:60 for gray-scale and 0.62 for PD.Most inflammatory hand pain
patients without clinical evidence of an inflammatory arthritis had US synovitis
(55%); and US (p<O.OOl), but not clinical, synovitis was significantly associated
with response to parenteral corticosteroid therapy. The site-specific diagnosis (53%)
and management (53%) was altered in most patients referred for US in a routine
clinic.
Conclusion: Ultrasonography is now well validated in synovitis detection in small
and large joints, and this has substantial implications for the accurate and early
diagnosis of inflammatory arthritis, as well as in monitoring outcomes to therapy in
rheumatoid arthritis. Ultrasonography can aid prognosis as well as improving
placement of guided intra-articular therapies. This work has demonstrated that US
has a significant role to play in rheumatology practice.