Imaging in diagnosis, monitoring and outcome prediction of large vessel vasculitis: a systematic literature review and meta-analysis informing the 2023 update of the EULAR recommendations

Abstract

ObjectivesTo update the evidence on imaging for diagnosis, monitoring and outcome prediction in large vessel vasculitis (LVV) to inform the 2023 update of the European Alliance of Associations for Rheumatology recommendations on imaging in LVV.MethodsSystematic literature review (SLR) (2017–2022) including prospective cohort and cross-sectional studies (>20 participants) on diagnostic, monitoring, outcome prediction and technical aspects of LVV imaging. Diagnostic accuracy data were meta-analysed in combination with data from an earlier (2017) SLR.ResultsThe update retrieved 38 studies, giving a total of 81 studies when combined with the 2017 SLR. For giant cell arteritis (GCA), and taking clinical diagnosis as a reference standard, low risk of bias (RoB) studies yielded pooled sensitivities and specificities (95% CI) of 88% (82% to 92%) and 96% (95% CI 86% to 99%) for ultrasound (n=8 studies), 81% (95% CI 71% to 89%) and 98% (95% CI 89% to 100%) for MRI (n=3) and 76% (95% CI 67% to 83%) and 95% (95% CI 71% to 99%) for fluorodeoxyglucose positron emission tomography (FDG-PET, n=4), respectively. Compared with studies assessing cranial arteries only, low RoB studies with ultrasound assessing both cranial and extracranial arteries revealed a higher sensitivity (93% (95% CI 88% to 96%) vs 80% (95% CI 71% to 87%)) with comparable specificity (94% (95% CI 83% to 98%) vs 97% (95% CI 71% to 100%)). No new studies on diagnostic imaging for Takayasu arteritis (TAK) were found. Some monitoring studies in GCA or TAK reported associations of imaging with clinical signs of inflammation. No evidence was found to determine whether imaging severity might predict worse clinical outcomes.ConclusionUltrasound, MRI and FDG-PET revealed a good performance for the diagnosis of GCA. Cranial and extracranial vascular ultrasound had a higher pooled sensitivity with similar specificity compared with limited cranial ultrasound.

Ultrasound intima-media thickness cut-off values for the diagnosis of giant cell arteritis using a dual clinical and MRI reference standard and cardiovascular risk stratification

“…In the case of a negative ultrasound, other diagnostic tests such as cranial MRI, TA biopsy or FDG-PET-CT can be performed, and we have been using this stepwise approach successfully in clinical practice for several years ( 6 ). The measures of diagnostic accuracy from our study compare well to recent pooled estimates for the T1-BB MRI (sensitivity of 82%, specificity of 92%) ( 6 , 35 ). Since a relevant proportion of patients with GCA do not have vasculitis of the TAs, the maximum attainable sensitivity of any diagnostic test for the TAs is expected to lie below 100% with an expected ceiling effect ( 34 , 36 ).…”

Multimodality Imaging in Cranial Giant Cell Arteritis: First Experience with High-Resolution T1-Weighted 3D Black Blood without Contrast Enhancement Magnetic Resonance Imaging

“…The reported pooled sensitivity and specificity for MRI with contrast in diagnosing cranial GCA, using the clinical diagnosis as the standard reference, were 81% and 96%, respectively. Regarding 2-[ 18 F]FDG PET/CT, the reported sensitivity and specificity were 76% and 96%, respectively [ 26 ].…”

両下腿の安静時痛が初発症状であった巨細胞性動脈炎の1例(Giant cell arteritis presenting as bilateral calf rest pain: a case report)

“…GCAの診断は，アメリカリウマチ学会の分類基準（以下の5項目のうち，3項目以上を満たせばGCAとする；1：年齢が50歳以上，2：新規の頭痛，3：側頭動脈の異常，4：赤沈の亢進，5：側頭動脈生検の異常）を参考になされてきた 12)。このような古典的な基準があるにも関わらず診断に難渋することが多い。実際に，本症例では，画像上は浅側頭動脈に炎症を認めたが，それに伴う症状はなく，生検も陰性であり，この基準を満たしていない。側頭動脈生検は侵襲度が高く，かつ偽陰性となる可能性もあり 13)，最近では，画像検査でも下肢に限局しているGCAも報告されており，より診断を難しくしている 9), 14)。このような背景から，2022年にGCAの分類基準が改訂（10項目の合計点が6点以上であればGCAと分類）され，側頭動脈生検に加えて，超音波検査やCTなどの画像所見も基準項目に入った 15)。血管造影検査では，両側性の滑らかで長く，徐々に狭小化していく内腔が特徴とされる。下肢の動脈で最も影響を受けるのは浅大腿動脈と膝窩動脈とされ 4), 10), 11)，本症例の造影CTでも同部位の動脈壁肥厚と周囲の脂肪織濃度の上昇を認めた。侵襲度の低い動脈超音波検査の有用性も報告されており 13), 16)，本症例でもGCAに特徴的な側頭動脈のcompression sign（圧迫でも内腔が完全に虚脱しない所見）やhalo sign（炎症による動脈壁肥厚を反映した動脈周囲の低エコー領域の所見）を認めていた。側頭動脈に加えて腋窩動脈まで評価することで，動脈超音波検査の感度は高くなるとされる 16)が，下肢の動脈の評価については報告が少ない。本症例では，大腿・膝窩動脈にも壁肥厚を認めたが，小規模な後方視研究では，超音波検査による大腿動脈のhalo signの感度は低いと報告されており，必要に応じてMRIやPET–CTなどの画像検査を追加で評価しなければならない 17)。一方で，halo signの診断特異度は高く，改訂された分類基準でも，生検での陽性所見と同等の5点の重み付けとなっている。本症例では，超音波所見（halo sign；5点）と高炎症所見（ESR≧50mm/h；3点）で分類基準は満たしており，側頭動脈生検までは不要であったかもしれない。…”