Results of the meta-analysis (pooled estimates) for ultrasound and MRI signs of vasculitis in comparison with clinical diagnosis or temporal artery biopsy as reference standard for giant cell arteritis (GCA)
| Index test | Reference standard | Number of patients (number of studies) | LR+ (95% CI) | LR– (95% CI) | Sensitivity (95% CI) | Specificity (95% CI) |
| Ultrasound | ||||||
| ‘Halo’ sign* | Clinical diagnosis | 605 (eight studies)17 19 20 23 25 28 30 31 | 19 (4.8 to 75.5) | 0.2 (0.1 to 0.4) | 77 (62 to 87) | 96 (85 to 99) |
| ‘Halo’ sign±stenosis±occlusion† | Clinical diagnosis | 560 (three studies)6 17 22 | 6.9 (3 to 16.1) | 0.3 (0.1 to 0.6) | 78 (57 to 90) | 89 (78 to 95) |
| ‘Compression’ sign‡ | Clinical diagnosis | 140 (two studies)30 32 | ‡ | ‡ | ‡ | ‡ |
| ‘Halo’ sign* | TAB | 289 (seven studies)17–21 23 27 | 4.3 (2.4 to 7.8) | 0.4 (0.2 to 0.6) | 70 (56 to 81) | 84 (73 to 91) |
| ‘Halo’ sign±stenosis† | TAB | 50 (two studies)18 27 | 8.4 (2.4 to 30.1) | 0.3 (0 to 1.6) | 77 (23 to 97) | 91 (75 to 97) |
| ‘Halo’ sign±stenosis±occlusion* | TAB | 611 (five studies)6 17 22–24 | 8.3 (2.5 to 27.4) | 0.2 (0.1 to 0.7) | 78 (48 to 93) | 91 (70 to 98) |
| MRI | ||||||
| MRI* | Clinical diagnosis | 509 (six studies)33–35 38–40 | 5.9 (3.4 to 10.3) | 0.3 (0.2 to 0.5) | 73 (57 to 85) | 88 (81 to 92) |
| MRI* | TAB | 443 (six studies)33–35 37 38 40 | 5 (3.2 to 7.8) | 0.1 (0.1 to 0.1) | 93 (89 to 96) | 81 (73 to 87) |
*Bivariate random-effects binomial generalised mixed model.
†Univariate random-effects models.
‡Model fails to converge with both analytical methods.
‘halo’ sign ±stenosis, combination of ‘halo’ sign±stenosis as ultrasound signs suggestive for vasculitis; ‘halo’ sign±stenosis±occlusion, combination of halo±stenosis±occlusion as ultrasound signs suggestive for vasculitis; MRI, magnetic resonance imaging; wall thickening+contrast enhancement as MRI signs suggestive for vasculitis.
ACR, American College of Rheumatology; CI, confidence interval; clinical diagnosis, final diagnosis made according to the ACR criteria or physician diagnosis; LR, likelihood ratio; TAB, temporal artery biopsy.