Autoinflammatory & rare systemic diseases
[ 18 F]FAPI positron emission tomography (PET)/CT-based scoring systems for patient assessment in IgG4-related disease
Authors' conclusion
[18F]FAPI PET/CT could be a valuable tool for monitoring the activity of IgG4-RD, aiding in disease stratification.
Study context
- Population
- Patients with IgG4-related disease (IgG4-RD) and healthy individuals undergoing [18F]FAPI PET/CT64 lesions biopsied
- Comparison
- Patients with IgG4-RD vs healthy individuals; active vs inactive disease
- IgG4-RDn = 85
- Healthy individualsn = 10reference
- Outcome
- Diagnostic performance of [18F]FAPI PET/CT for detecting IgG4-RD based on organ-specific uptake thresholds (uptake > maximal SUV +3 SD of healthy individuals)
Methodological detailslogistic regression model with ROC curve analysis
- Logistic regression model with ROC curve analysis
Performance
As reported in the abstract
Detection of IgG4-RD based on organ-specific uptake thresholds
| Test or model | Sensitivity | Specificity | Accuracy |
|---|---|---|---|
| IgG4-RD | 86.2% | 83.3% | 85.9% |
IgG4-RD
Sensitivity86.2%
Specificity83.3%
Accuracy85.9%
Further findings
| Outcome | Active disease | Inactive disease | P value |
|---|---|---|---|
| FPAS-IgG4, active vs inactive diseaseHigher FPAS-IgG4 in active disease | 5.2 ± 3.0 | 1.7 ± 1.3 | P < 0.0001 |
FPAS-IgG4 >2 distinguishing active from inactive disease
- Sensitivity
- 93.2%
- Specificity
- 73.1%
Multivariable logistic regression: FPAS-IgG4 and active IgG4-RD
- FPAS-IgG4 strongly associated with active IgG4-RD
- P = 0.001
Original publication
[ 18 F]FAPI PET/CT-based scoring systems for patient assessment in IgG4-related disease. RMD Open. Published 4 March 2026. doi:10.
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