18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is a promising tool for diagnosing relapsing polychondritis (RP). However, its usefulness in assessing RP with airway involvement is unknown. This study aimed to further evaluate and confirm the potency of 18F-FDG PET/CT in diagnosing RP with airway involvement and monitoring response to steroid-based therapy. A total of 30 patients from a dedicated respiratory centre, diagnosed with RP in accordance with McAdam, Damiani or Levine criteria, were included in this study. All patients underwent baseline 18F-FDG PET/CT, and 10 patients underwent second scans after 2.5–15 months of steroid-based therapy. Visual scores (VS) and maximal standard uptake values (SUVmax) were analysed. In the initial scan, 83.3% (25/30) of patients were found to have FDG uptake in more than one cartilage. The median VS and SUVmax in the cartilages were 3 (range, 1–3) and 3.8 (range, 1.9–17.9), respectively. Positive rates for PET/CT-guided biopsy in nasal, auricular, and tracheal/bronchial cartilages were 100% (5/5), 88.9% (8/9), and 10.5% (2/19), respectively, but the positive biopsy rate in the auricular cartilage was 92.3% (12/13) even without PET/CT assessment. Based on biopsy-proven sites, the sensitivity of PET/CT was 55.6%, and the specificity was 5.3%. Compared with the baseline scan, the second scan showed much lower median VS (2 vs 3, respectively; p < 0.0001) and SUVmax (2.9 vs 3.8, respectively; p < 0.001). Of 10 patients who underwent second PET/CT, 8 had complete therapeutic response, while 2 had partial response. 18F-FDG PET/CT assists in identifying multiple cartilage involvement in RP, but it seems neither a sensitive nor specific modality in diagnosing RP with airway involvement. Moreover, PET/CT has limited utility in locating biopsy sites and monitoring therapeutic response to corticosteroids.

中文翻译：

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是¹⁸ F-FDG PET / CT用于诊断复发性多软骨气道参与和监控响应于基于类固醇治疗有用吗？

18F-氟脱氧葡萄糖（FDG）正电子发射断层扫描/计算机断层扫描（PET / CT）是诊断复发性多发性软骨炎（RP）的有前途的工具。但是，其在评估气道受累的RP中的作用尚不清楚。这项研究旨在进一步评估和确认18F-FDG PET / CT在诊断气道受累的RP和监测对基于类固醇的治疗中的反应的效力。这项研究包括来自专门的呼吸中心的30名患者，这些患者根据McAdam，Damiani或Levine标准诊断为RP。所有患者均接受了基线18F-FDG PET / CT，10例患者在接受类固醇激素治疗2.5–15个月后进行了第二次扫描。分析了视觉得分（VS）和最大标准摄取值（SUVmax）。在初始扫描中，为83。发现3％（25/30）的患者在一个以上的软骨中摄取了FDG。软骨中的VS和SUVmax中位数分别为3（范围为1-3）和3.8（范围为1.9-17.9）。PET / CT引导的鼻，耳和气管/支气管软骨活检的阳性率分别为100％（5/5），88.9％（8/9）和10.5％（2/19），但阳性即使不进行PET / CT评估，耳廓软骨活检率仍为92.3％（12/13）。根据活检证实的部位，PET / CT的敏感性为55.6％，特异性为5.3％。与基线扫描相比，第二次扫描显示中值VS（分别为2比3； p <0.0001）和SUVmax（分别为2.9 vs 3.8； p <0.001）更低。在接受第二次PET / CT的10例患者中，8例具有完全的治疗反应，2例具有部分反应。18F-FDG PET / CT有助于确定多发性软骨受累于RP，但在诊断气道受累的RP中似乎既不敏感，也不特定。此外，PET / CT在定位活检部位和监测对皮质类固醇的治疗反应方面的实用性有限。