Evolution of the Diagnostic Paradigm for Giant Cell Arteritis: From Histopathology to Multimodal Imaging Integration
Jiajia Song1, Haibo Jiang1, Xiaoyin Wang2
1J. Song, MD, H. Jiang, MD, K. Gong, MD, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing.
Insights
Non-invasive imaging, like ultrasound, significantly improves giant cell arteritis (GCA) diagnosis, reducing delays and preventing vision loss. This approach is now comparable to traditional biopsy methods for accurate GCA detection.
Area of Science:
- Rheumatology
- Vascular Medicine
- Diagnostic Imaging
Background:
- Giant cell arteritis (GCA) is a serious vasculitis affecting large arteries, with delayed diagnosis risking blindness or stroke.
- Temporal artery biopsy (TAB) is the traditional standard but suffers from low sensitivity (40-70%) and procedural risks.
- Non-invasive imaging offers a promising alternative for timely and accurate GCA diagnosis.
Purpose of the Study:
- To compare the diagnostic accuracy of non-invasive imaging modalities against TAB for GCA.
- To evaluate the prognostic significance of imaging findings in GCA patients.
- To assess the effectiveness of imaging-first clinical pathways in managing GCA.
Main Methods:
- A systematic review following PRISMA 2020 guidelines, searching PubMed and Embase for relevant studies (n=36).
- Analysis included studies on diagnostic accuracy, guideline updates, and fast-track clinic (FTC) models.
- Focus on Colour Doppler ultrasound (CDUS), MRI, 18F-FDG PET/CT, and CT angiography (CTA).
Main Results:
- CDUS with the "halo sign" showed high pooled sensitivity (88-93%), now recognized by ACR/EULAR criteria.
- High-resolution MRI allows quantitative assessment of arterial wall changes.
- 18F-FDG PET/CT aids in evaluating systemic inflammation and relapse risk; CTA visualizes structural damage.
- FTC pathways utilizing imaging reduced diagnostic time to 24-72 hours and visual loss risk by 60-80%.
Conclusions:
- Non-invasive, multimodal imaging has revolutionized GCA diagnosis and risk stratification.
- Imaging enables personalized management strategies for GCA patients.
- Standardized protocols and AI-assisted analysis are future directions for improved early detection and reduced operator dependence.
Abstract:
Giant cell arteritis (GCA) is a systemic vasculitis that predominantly affects medium- and large-sized arteries. Delayed diagnosis may result in irreversible blindness or stroke. Temporal artery biopsy (TAB), historically regarded as the diagnostic gold standard, has limited sensitivity (40-70%) due to the segmental distribution of inflammatory lesions and risk of procedural complications and diagnostic delay. This systematic review aims to (1) compare the diagnostic accuracy of noninvasive imaging modalities with TAB, (2) assess the prognostic value of imaging findings, and (3) evaluate the implementation of imaging-first clinical pathways. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement, PubMed and Embase were searched for high-impact studies (n = 36) addressing diagnostic accuracy, guideline updates, and the effectiveness of the fast-track clinic (FTC) model. Color Doppler ultrasound (CDUS) demonstrating the halo sign achieved a pooled sensitivity of 88-93%. Accordingly, the 2022 American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) classification criteria assign CDUS findings a diagnostic weight equivalent to those of a positive TAB. High-resolution magnetic resonance imaging (MRI) enables quantitative evaluation of cranial arterial wall thickening and contrast enhancement. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is particularly useful for assessing systemic inflammatory burden and identifying large-vessel involvement associated with higher relapse risk, whereas CT angiography (CTA) delineates structural vascular damage. Implementation of FTC pathways reduces diagnostic latency to 24-72 hours and lowers the risk of permanent visual loss by 60-80%. Noninvasive, multimodal imaging has redefined the diagnostic paradigm of GCA. By enabling accurate diagnosis and risk stratification, it informs personalized management strategies. Future directions should emphasize standardized acquisition protocols and artificial intelligence-assisted analysis to reduce operator dependence and further enhance early detection.
