Imaging modalities for the diagnosis and disease activity assessment of Takayasu's arteritis: A systematic review and meta-analysis

Early diagnosis of Takayasu's Arteritis (TAK) and detection of disease activity may reduce the risk of vascular complications. The objective of this study was to determine the effectiveness of imaging modalities for the management of TAK.MEDLINE and EMBASE were searched for studies of patients undergoing various imaging modalities for TAK diagnosis or to assess disease activity. We excluded case reports, reviews and case series with <10 patients. The methodologic quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). Random effects meta-analyses with inverse-variance weighting were performed.From the 1126 citations screened, 57 studies met our inclusion criteria. Many of the studies were of small sample size (average N=27), cross-sectional design and low methodological quality. Ultrasound (US) had a lower pooled sensitivity (SN) of 81% (95% CI: 69-89%) than Magnetic Resonance Angiography (MRA) with SN=92% (95% CI: 88-95%) for TAK diagnosis (by clinical criteria and/or X-Ray angiography). Both had high specificities (SP) of >90% for TAK diagnosis. Fewer studies investigated computed tomography angiography (CTA), but SN and SP for TAK diagnosis was high (>90%). The utility of vessel wall thickening and enhancement by MRA and CTA to predict disease activity varied across studies. The pooled SN and SP of 18F-fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) for disease activity was 81% (95% CI: 69-89%) and 74% (95% CI: 55-86%), respectively.US, CTA and/or MRA are effective for the diagnosis of TAK. The utility of these imaging modalities for assessing disease activity remains unclear.