Is 18F-FDG PET/CT useful for diagnosing relapsing polychondritis with airway involvement and monitoring response to steroid-based therapy?

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Chronological assessment of airway lesions in relapsing polychondritis by positron emission tomography.

A 40-year old woman presented with pyrexia, productive cough, and bilateral precordial pain. Positron emission tomography (PET)-computed tomography (CT) showed high, diffuse F-18 deoxyglucose accumulation in the tracheal, peribronchial, and bilateral costal cartilage. We diagnosed her with relapsing polychondritis (RP) based on McAdam's criteria. Airway lesions are a major prognostic indicator of RP, and so chronological assessment and control is essential. In this patient, PET-CT accurately reflected both the location and severity of the inflammation and helped to guide treatment decision-making and facilitated early detection of recurrence. However, its high cost is prohibitive to frequent use, making it necessary to comprehensively evaluate serum C-reactive protein levels, bronchoscopy, spirometry, and 3D-CT.

F-18 FDG PET/CT in relapsing polychondritis.

We report a case of relapsing polychondritis for which fluorodeoxyglucose (FDG) positron-emission tomography/computed tomography (PET/CT) showed increased FDG accumulation in all rib cartilages, as well as in the larynx, trachea, and major bronchi. Contrast-enhanced CT during PET/CT showed smooth tracheal and bronchial wall thickening with calcification and airway narrowing. After steroid therapy, clinical symptoms and laboratory data were improved and cartilaginous FDG accumulation had completely disappeared. FDG PET/CT is considered to be a powerful radiological tool to assess the disease activity of relapsing polychondritis.

Involvement of nonarticular cartilage, as demonstrated by release of a cartilage-specific protein, in rheumatoid arthritis.

Analysis of human cartilage extracts by radioimmunoassay showed that the noncollagenous 148-kd cartilage matrix protein was present in extracts of tracheal cartilage but was undetectable in normal or arthritic joint cartilage, corroborating previous results with bovine cartilage samples. Concentrations of the protein in the circulation, as studied by radioimmunoassay, were greatly elevated in patients with rheumatoid arthritis and polyarticular juvenile rheumatoid arthritis. In contrast, patients with reactive arthritis and oligoarticular juvenile rheumatoid arthritis, as well as rheumatoid arthritis patients treated with low-dose glucocorticoids, had levels similar to those in healthy controls. The serum concentrations were not related to age. A patient with polychondritis and tracheal involvement had a high serum concentration of the protein, which decreased during plasma exchange and cyclophosphamide treatment. Studies of the release of this cartilage matrix protein, which is present in nonarticular cartilage but not in articular cartilage, should aid in the understanding of the mechanisms of cartilage involvement in disease, and the protein may become a clinically useful marker.

[Relapsing polychondritis. Histochemical, histoenzymological, immunoflourescent and ultrastructural studies of ear cartilage in three cases (author's transl)]. / La polychondrite chronique atrophiante. Etude du cartilae auriculaire par histochimie, histoenzymologie, immunoflourescence et microscopie électronique. (A propos de 3 observations).

Ear cartilage has been studied by histochemistry, histoenzymology, immunofluorescence and electron microscopy in three cases of relapsing polychondritis. The most significant lesions have been observed at the cellular level, both by enzymology and electron microscopy : chondrocytes of peripheral zones seem to be first hypertrophic and then necrotic ; at the opposite, there is no correlation between histochemical and electron microscopic studies about the chondroid intercellular substance whose lesions are probably secondary to the cellular ones. A few chondrocytes are positive with antiimmunoglobulins sera (IgM and IgA) ; this fact could be a proof of the dysimmune nature of this disease.

[Relapsing polychondritis. Histochemical, histoenzymological, immunofluorescent and ultrastructural studies of ear cartilage in three cases (author's transl)]. / La polychondrite chronique atrophiante. Etude du cartilage auriculaire par histochimie, histoenzymologie, immunofluorescence et microscopie électronique. (A propos de 3 observations).

Ear cartilage has been studied by histochemistry, histoenzymology, immunofluorescence and electron microscopy in three cases of relapsing polychondritis. The most significant lesions have been observed at the cellular level, both by enzymology and electron microscopy: chondrocytes of peripheral zones seem to be first hypertrophic and then necrotic; at the opposite, their is no correlation between histochemical and electron microscopic studies about the chondroid intercellular substance whom lesions are probably secondary to the cellular ones. A few chondrocytes are positive with antiimmunoglobulins sera (IgM and IgA); this fact could be a proof of the dysimmune nature of this disease.

[Clinical-biochemical study of systemic panchondritis]. / Klinisch-biochemische Studie zur Panchondritis systemica

With the help of a casuistic and the results of own investigations clinical, differential-diagnostic, biochemical, pathogenetic and therapeutic aspects of panchondritis systemica are described. The very rare clinical picture, which coincides with chondrolysis and perichondritis, manifests itself intermittently in the region of the auricles, the nose, the cartilaginous parts of the ribs as well as of the chondroskeleton of the respiratory system and in most cases has a fatal termination. Probably on the basis of the pathogenetically decisive changes of the basic substance in addition to this arthritic symptoms, symptoms similar to Bechterew's disease, carditic as well as ocular and internal ear symptoms may appear. Results of own investigations refer to considerable abnormalities in the glucosamine glycan metabolism, in which case the question must remain open, whether these biochemical and immunologic factors are to be regarded as the primary pathogenetic cause. For avoiding irreparable and dangerous defects of the cartilage a sufficiency dosed treatment with corticoids is necessary.