Home›Radiology & Imaging› FDG PET/CT positive in 94% of suspected relapsing polychondritis cases
FDG PET/CT positive in 94% of suspected relapsing polychondritis casesPET Scans Help Identify Hidden Cartilage Damage in Inflammation
Nuclear medicine communicationsPublished September 11, 2026Study authors: Malik Pareena, Saraswat Dhananjaya, Aggarwal Piyush, Singh Harmandeep, Sharma Ananya, Kumar Rajender…PubMed ↗DOI ↗Editorial oversight: Dr. Lars van Dijk, PhD · Surgical, Procedural & Diagnostic
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Key Takeaway
Consider FDG PET/CT for detecting cartilage involvement in suspected relapsing polychondritis, but await prospective validation.
This meta-analysis examined the diagnostic performance of 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) in patients with suspected relapsing polychondritis, pooling data from 97 patients. The primary outcome was the PET-positivity rate, which was 94% (95% CI 73-99%, I2=0%, P=0.76). The mean baseline SUVmax was 4.0 (95% CI 3.5-4.6, I2=32%, P=0.23).
The analysis also assessed secondary outcomes including identification of asymptomatic cartilage involvement and correlation with inflammatory markers. Asymptomatic cartilage involvement was detected in more than 25% of patients. The authors report that FDG PET had a higher positivity rate for inaccessible sites such as peripheral airways and was considered crucial in treatment monitoring.
Safety data, including adverse events, serious adverse events, discontinuations, and tolerability, were not reported. Follow-up duration and setting were also not reported. The comparator was not reported.
The authors acknowledge that prospective large-sample-size studies are required to explore diagnostic accuracy and prognostic implications. They caution that while the PET-positivity rate is high, more large-scale prospective studies are needed to establish diagnostic accuracy and prognostic implications. Funding and conflicts of interest were not reported.
In practice, these findings suggest that 18F-FDG PET/CT may identify cartilage involvement, including asymptomatic sites, in patients with suspected relapsing polychondritis, but the evidence base remains limited by the small sample size and lack of prospective validation.
How this fits prior evidence
Prior coverage described a scoping review of neurological involvement in relapsing polychondritis and VEXAS syndrome, noting significant knowledge gaps. This meta-analysis extends that picture by focusing on 18F-FDG PET/CT for detecting cartilage involvement, including asymptomatic disease in more than 25% of patients. It does not address neurological manifestations, so the knowledge gaps highlighted in the prior review remain. The high pooled PET-positivity rate (94%) contrasts with the limited evidence base noted previously, but the authors' call for prospective studies aligns with the prior review's emphasis on unmet research needs.
Researchers looked at how 18F-FDG PET scans work for patients with suspected relapsing polychondritis. This is a rare condition that causes inflammation of cartilage. The study looked at 97 patients to see if these scans could help identify active inflammation in areas that are hard to see or reach.
The results showed a high positivity rate of 94% for the scans. Importantly, the scans found that more than 25% of patients had cartilage involvement that was not showing symptoms. This means the imaging could find issues in areas like the peripheral airways that are difficult to examine with other methods.
Because this was a meta-analysis of a small group of patients, the results are not yet enough to change standard medical practice. More large-scale studies are needed to confirm how accurate these scans are for making long-term predictions. For now, the scan is seen as a helpful tool for monitoring treatment and finding hidden inflammation.
What this means for you:
PET scans can identify hidden cartilage inflammation in over 25% of patients with relapsing polychondritis.
Common questions
What did the PET scan find in patients with relapsing polychondritis?
The 18F-FDG PET scan showed a 94% positivity rate in patients with suspected relapsing polychondritis. It was particularly useful for finding inflammation in areas that are hard to reach, such as the peripheral airways, and helped doctors monitor how well a patient is responding to treatment.
Can these scans find issues that patients cannot feel?
Yes, the study found that more than 25% of patients had asymptomatic cartilage involvement. This means the scan can identify inflammation in cartilage even when the patient does not have symptoms in those specific areas.
Is this scan a proven way to diagnose the condition?
While the scan showed a high positivity rate, the study was small and the results are not yet enough to change standard medical practice. Larger studies are still needed to fully determine the diagnostic accuracy and long-term outlook for patients.
Relapsing polychondritis is a rare chronic autoimmune inflammation of the cartilage associated with life-threatening respiratory complications. Currently, no clear role of imaging modalities such as 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) is defined in the literature. This systematic review and meta-analysis provide current evidence on the PET-positivity rate and utility in relapsing polychondritis. Prospective or retrospective studies with more than five patients of suspected relapsing polychondritis who underwent 18F-FDG PET/CT during their management and reported a PET-positivity rate were included. Low-sample-size studies describing chondritis due to other aetiologies or utilizing PET-based radiopharmaceuticals other than FDG were excluded. A systematic search using relevant keywords was conducted across four databases (PubMed, Embase, Scopus and Web of Science) to include studies up to 25 April 2025. The Joanna Briggs Institute critical appraisal tools were used for risk-of-bias analysis. Data were analysed using the R software package (v4.3.1; 2023). Out of 962 articles, three with a total of 97 patients were included. With a pooled PET-positivity rate of 94% [95% confidence interval (CI): 73-99%, I2 = 0%, P = 0.76] and a pooled baseline SUVmax of 4.0 (95% CI: 3.5-4.6, I2 = 32%, P = 0.23), 18F-FDG PET identified asymptomatic cartilage involvement in more than 25% patients and PET parameters correlated well with inflammatory markers. It had a higher positivity rate for inaccessible sites, such as peripheral airways, and was crucial in treatment monitoring. The pooled PET-positivity rate of 18F-FDG PET in relapsing polychondritis is high but requires prospective large-sample-size studies to explore the diagnostic accuracy and prognostic implications of 18F-FDG PET in relapsing polychondritis.
