Polymyalgia rheumatica and interspinous FDG uptake on PET/CT

Use of 18F-fluorodeoxyglucose positron emission tomography in the diagnosis of polymyalgia rheumatica-A prospective study of 99 patients

Objective

Previous studies have shown that the majority of patients with PMR have increased 18F-fluorodeoxyglucose (FDG) uptake around the shoulders, hips and processes of the cervical and lumbar spine on PET. The specificity of these findings for PMR is, however, not known.

Methods

We prospectively included 99 consecutive patients with a possible clinical diagnosis of PMR. All patients underwent 18F-FDG-PET scanning before treatment with glucocorticoids was started. The clinical suspicion of PMR was quantified by the treating physician on a scale from 1 to 5. FDG uptake was scored visually in 12 articular regions (scores 0-2) and a total skeletal score was calculated reflecting the FDG uptake in these 12 articular regions. Receiver operating characteristics analysis was performed to determine the optimal clinical and total skeletal score for diagnosing PMR. The gold standard for a diagnosis of PMR was the judgement of an experienced clinician after at least 6 months of follow-up.

Results

Sixty-seven patients were diagnosed with PMR while 32 patients got another diagnosis. A clinical score of 4 or more had a sensitivity of 67.2%, specificity of 87.5%, positive predictive value (PPV) of 91.8% and a negative predictive value (NPV) of 56.0% for the diagnosis of PMR. A total skeletal score of 16 or more had a sensitivity, specificity, PPV and NPV of, respectively, 85.1, 87.5, 93.4 and 73.7%.

Conclusion

18F-FDG-PET before starting glucocorticoid therapy improves the diagnostic accuracy compared with a clinical scoring system in patients with clinical suspicion of PMR.

Differences of articular and extra-articular involvement in polymyalgia rheumatica: A comparison by whole-body FDG-PET/CT

Objectives: To clarify differences in incidences of articular and extra-articular involvement in patients with polymyalgia rheumatica (PMR) using FDG-PET/CT.Methods: Twenty PMR patients were enrolled in this retrospective study. We compared frequency, degree, and patterns (diffuse or non-diffuse) of abnormal FDG accumulation in the proximal and distal articular structures (PAS, DAS), and extra-articular synovial structures (ESS). Regional analyses were performed for the large joints (shoulder, hip, and knee).Results: The incidences of positive FDG accumulation were significantly higher in the PAS (96.7%) and ESS (91.4%) than in the DAS (31.8%, p < .0001), although, the incidence in the knees (96.2%) was exceptionally high. PAS (2.79 ± 0.61) and ESS (2.52 ± 0.85) had significantly higher visual scores than DAS (0.89 ± 1.33, p < .0001). Shoulder, hip, and knee joints each had a different accumulation pattern. Strong FDG accumulation was frequently observed in the medial-to-subscapular part of the shoulder joints, the lateral part of the hip joints, and the medial part of the knee joints.Conclusion: ESS were found to be the main affected areas in PMR patients as well as PAS. DAS involvement occurred with low frequency except in the knee joints. Each large joint showed a different accumulation pattern and its own characteristically strongly affected areas.

Cervico-thoracic Interspinous Bursitis Associated with Bilateral Upper-extremity Numbness: A Case Report

The authors describe a 48-year-old woman suffering from bilateral upper-extremity numbness and axial radiating pain. Magnetic resonance imaging revealed soft-tissue edema and enhancement surrounding the dorsal tip of the C7 spinous process. Excisional biopsy of the lesion revealed a mildly inflamed bursa, with no evidence of an active infection. Removal of the inflamed bursa resulted in complete resolution of the upper-extremity numbness and improvement in her neck pain. Although similar cases have been reported to be associated with rheumatologic conditions, most notably polymyalgia rheumatica (PMR), the current report underlines the presentation of radicular-like complaints associated with interspinous bursitis in the absence of other conditions affecting the musculoskeleton.

Aortitis in giant cell arteritis: diagnosis with FDG PET/CT and agreement with CT angiography

OBJECTIVES

To assess the detection rate of aortitis in giant cell arteritis (GCA) with fluorodeoxyglucose positron emission tomography/computed tomography (PET) and to compare the findings with CT angiography (CTA).

METHODS

Fifty-two GCA patients and 27 controls were included. GCA patients had a PET scan at diagnosis (35/52) or during relapse (17/52). Concomitant CTA was performed in 35/52 patients. Aortitis was defined as FDG uptake higher than the liver for PET and wall thickness≥3mm for CTA. Agreement between PET and CTA was evaluated by the kappa coefficient and Spearman correlation coefficient.

RESULTS

Aortitis was diagnosed using PET in 40% (14/35) of patients at diagnosis and in 0% of controls (0/27). Agreement was perfect between PET and CT at a patient-based level, and very good at a vascular segment-based level (kappa: 0.72 to 1). PET was positive in 35% (6/17) of patients scanned during GCA relapse, showing aortitis (n=4) and/or articular uptake (n=4). Discrepancies between PET and CT were observed only in relapsing GCA (n=3). Correlation between the maximum standardized uptake value and wall thickness was moderate at diagnosis (r: 0.57 to 0.7) and not statistically significant during relapse.

CONCLUSIONS

The detection rate of aortitis in GCA patients using PET is 40%, approximately in the range of CTA rates, suggesting that the two techniques have similar sensitivity. PET seems valuable in relapsing GCA, allowing the detection of vascular and articular activities.

Imaging in systemic vasculitis

PURPOSE OF REVIEW

Imaging is becoming a relevant tool for the assessment of patients with systemic vasculitis. This review focuses on recently generated data with potential clinical impact in the diagnosis, evaluation of disease extent and management of systemic vasculitis.

RECENT FINDINGS

Temporal artery examination by color duplex ultrasonography (CDUS) is a valuable approach to the diagnosis of giant-cell arteritis. Evaluation of additional arteries may increase its diagnostic performance. However, CDUS-specific findings may not be detected in arteries with early inflammation and CDUS-guidance of temporal artery biopsy does not seem to significantly increase its diagnostic yield. Large-vessel involvement detected by computed tomography angiography occurs in two out of three of patients with giant-cell arteritis at diagnosis. Furthermore, significant ascending aortic dilatation can be observed in one out of three of patients after long-term follow-up. Objective cut-offs for detecting large-vessel inflammation by positron emission tomography (PET) are trying to be established through prospective studies. PET may also contribute to the assessment of disease extent in patients with ANCA-associated vasculitis or Behçet's disease.

SUMMARY

Data generated by existing and emerging imaging techniques are expected to have a major impact in the diagnosis, appraisal of disease extent, evaluation of disease activity and response to treatment in patients with systemic vasculitis.

The role of 18F-FDG PET/CT in large-vessel vasculitis: appropriateness of current classification criteria?

Patients with clinical suspicion of large-vessel vasculitis (LVV) may present with nonspecific signs and symptoms and increased inflammatory parameters and may remain without diagnosis after routine diagnostic procedures. Both the nonspecificity of the radiopharmaceutical ¹⁸F-FDG and the synergy of integrating functional and anatomical images with PET/CT offer substantial benefit in the diagnostic work-up of patients with clinical suspicion for LVV. A negative temporal artery biopsy, an ultrasonography without an arterial halo, or a MRI without aortic wall thickening or oedema do not exclude the presence of LVV and should therefore not exclude the use of ¹⁸F-FDG PET/CT when LVV is clinically suspected. This overview further discusses the notion that there is substantial underdiagnosis of LVV. Late diagnosis of LVV may lead to surgery or angioplasty in occlusive forms and is often accompanied by serious aortic complications and a fatal outcome. In contrast to the American College of Rheumatology 1990 criteria for vasculitis, based on late LVV effects like arterial stenosis and/or occlusion, ¹⁸F-FDG PET/CT sheds new light on the classification of giant cell arteritis (GCA) and Takayasu arteritis (TA). The combination of these observations makes the role of ¹⁸F-FDG PET/CT in the assessment of patients suspected for having LVV promising.

Advances and challenges in the diagnosis and treatment of polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is a common inflammatory condition that often affects people over the age of 50 years. Characteristic symptoms are shoulder and hip girdle pain and prolonged morning stiffness. Markers of inflammation are often elevated. Clinicians are often faced with the challenge of distinguishing PMR from other conditions, particularly rheumatoid arthritis and spondyloarthropathy that can mimic symptoms of PMR in older people. Additionally, there is an association between PMR and giant cell arteritis, a common large-vessel vasculitis which also affects people over the age of 50 years. Imaging of the large vessels in asymptomatic patients with PMR often reveals findings of subclinical vasculitis. Presently, there are no tests that are specific for the diagnosis of PMR and clinicians rely on a combination of history, physical examination, laboratory tests and imaging studies to make a diagnosis. A recent undertaking by the European League Against Rheumatism/American College of Rheumatology has led to the publication of provisional classification criteria of PMR. Ultrasonography, which is being increasingly used by rheumatologists, can greatly aid in the diagnosis of PMR and often shows changes of synovitis and tenosynovitis. Treatment consists of low doses of glucocorticoids which are associated with morbidity. Evaluation of newer biologic therapies targeting inflammatory cytokines is underway. Despite treatment, relapses are common.