From:  Advances in the validation of lung ultrasound for the detection of interstitial lung disease associated with rheumatoid arthritis

 Case-control studies on the accuracy of LUS.

Author, year of publicationStudy characteristicsLUS protocolResults
Tüzün et al., 2025 [30]Monocentric, case-control study
RA with ILD (n = 35) and RA without ILD (n = 34)		Multifrequency linear probe (6–18 MHz)
12 ICS
Coalescent LUS score*

  • Significant correlation between coalescent LUS score and Warrick score (r = 0.838)

Gutierrez et al., 2022 [29]Multicenter (2 centers), case-control study
RA patients, regardless of symptoms (n = 74) and healthy controls (n = 74)		Linear probe (5–13 MHz and 4–12 MHz)
14 ICS
Semiquantitative BL score&

  • Significantly higher LUS signs of ILD in patients than in controls

  • Positive correlation between US and HRCT findings

  • LUS for ILD diagnosis: Se 92%, NPV 95%

Mena-Vázquez et al., 2021 [28]Monocentric, case-control study
RA patients with (n = 35) and without ILD (n = 36)		Convex probe (1–8 MHz)
72 ICS
Total number of BL and PI

  • The number of BL and PI is significantly higher in patients with RA-ILD than in controls

  • LUS cutoffs and accuracy for different LUS scores

  • Positive correlation of BL with ACPA, DAS28, and HAQ, and negative association with DLCO

Fotoh et al., 2021 [27]Monocentric, case-control study
RA patients with (n = 75) and without ILD (n = 75)		Linear probe (4–13 MHz)
14 ICS
Total number of BL
Semiquantitative BL score&

  • LUS score and serum KL-6 were significantly higher in RA-ILD than in controls

  • Positive correlation between LUS, KL-6, and HRCT. Negative correlation with PFT

Moazedi-Fuerst et al., 2014 [26]Monocentric, case-control study
RA patients without respiratory symptoms (n = 64) and healthy controls (n = 40)		Convex probe (3.5 MHz) and linear probe, 18 ICS
LUS positive if BL in > 2 locations, pleural line thickening or fragmentation, subpleural nodules, and negative lung sliding

  • ILD diagnosis in 26.5% of patients

  • LUS accuracy: Se 97.1%, NPV 98.6%

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*: coalescent LUS score: score 0: presence of A lines or BL ≤ 2; score 1: BL ≥ 3; score 2: coalescent BL; score 3: tissue-like pattern; &: semiquantitative BL score: 0 = normal (≤ 5 BL), 1 = mild (≥ 6 and ≤ 15 BL), 2 = moderate (≥ 16 and ≤ 30 BL), and 3 = severe (≥ 30 BL); ACPA: anti-cyclic citrullinated peptide antibodies; BL: B lines; DLCO: carbon monoxide diffusion capacity; HAQ: Health Assessment Questionnaire; HRCT: high-resolution computed tomography; ICS: intercostal spaces; ILD: interstitial lung disease; KL-6: Krebs von den Lungen-6; LUS: lung ultrasound; NPV: negative predictive value; PFT: pulmonary function tests; PI: pleural ultrasound irregularities; RA: rheumatoid arthritis; Se: sensitivity.