Concomitant Polymyalgia Rheumatica and Large-Vessel Vasculitis Visualized on 18F-FDG PET/CT

[Polymyalgia rheumatica in 18-fluorodeoxyglucose-positron-emission-tomography/computed tomography : Improvement in diagnostic accuracy and differentiation from rheumatoid arthritis]

BACKGROUND

The diagnosis of patients with polymyalgia rheumatica (PMR) has relied upon the clinical examination of symptoms and laboratory parameters of inflammation until now. Currently, the use of different imaging modalities is being explored, including ultrasound, MRI and PET.

OBJECTIVES

The aim was to evaluate the diagnostic value of 18-fluorodeoxyglucose-positron-emission-tomography/computed tomography (18F-FDG-PET/CT) for PMR, in order to improve the sensitivity and specificity of diagnosing PMR and to improve the differential diagnosis of rheumatoid arthritis (RA).

MATERIALS AND METHODS

Examinations using 18F-FDG-PET/CT of 284 rheumatological patients, including 97 patients with PMR, were retrospectively evaluated over a 44-month period. Furthermore, 13 regions changed by inflammation were analysed via a three-dimensional region of interest (ROI) measurement with determination of maximum standardized uptake values (SUVmax), followed by statistical analyses.

RESULTS AND DISCUSSION

Patients with PMR presented significantly elevated uptake in all regions examined (p < 0.001), compared with a control group treated for rheumatological diseases. The method with the highest diagnostic relevance was represented by the combination of four SUVmax values of both anterolateral hip capsules and both ischial tuberosities, reaching a sensitivity of 91.3% and a specificity of 97.6% with a cut-off of 11.0 SUV at the initial diagnosis of PMR patients who had not yet received any immunosuppressive therapy. Patients with RA could be significantly distinguished from those with PMR at initial diagnosis in the same anatomical regions (p < 0.001).

Comparison of Shoulder Ultrasonographic Assessments between Polymyalgia Rheumatica and Frozen Shoulder in Patients with Bilateral Shoulder Pain: A Comparative Retrospective Study

This study aimed to assess and compare the ultrasonographic (US) pathologic findings in patients with polymyalgia rheumatica (PMR) and bilateral frozen shoulder (FS). We included 19 patients with clinically diagnosed PMR and 19 patients with stage II bilateral FS. The US evaluation included the assessment of subacromial-subdeltoid (SASD) bursitis, long head of biceps (LHB) tenosynovitis, and posterior and inferior glenohumeral (GH) synovitis. Unilateral SASD bursitis was noted significantly more frequently in PMR patients than in bilateral FS patients (p = 0.001). There were no significant differences in the incidence of unilateral LHB tenosynovitis and posterior GH synovitis between PMR and bilateral FS patients (p = 0.108 and p = 0.304, respectively). Unilateral inferior GH synovitis was more common among bilateral FS patients than among PMR patients (p < 0.001). Bilateral SASD bursitis and LHB tenosynovitis were noted significantly more frequently in PMR patients than in bilateral FS patients (p < 0.001 and 0.049, respectively). Significant differences were not observed in the incidence of bilateral posterior GH synovitis between PMR and bilateral FS patients (p = 0.426). Bilateral inferior GH synovitis was more common among bilateral FS patients than among PMR patients (p = 0.044). The US evidence for bilateral inferior GH synovitis without bilateral SASD showed high specificity (94.7%) with sensitivity (78.9%) for the diagnosis of bilateral FS. SASD bursitis, representing periarticular synovial inflammation, was more common among the patients with PMR than among the patients with bilateral FS. Inferior GH synovitis without SASD bursitis suggests FS rather than PMR in patients with bilateral shoulder pain.

Diagnosis of giant cell arteritis

GCA is the most common form of primary systemic vasculitis affecting older people. It is considered a clinical emergency because it can lead to irreversible blindness in around 20% of untreated cases. High doses of glucocorticoids should be initiated promptly to prevent disease-related complications; however, glucocorticoids therapy usually results in significant toxicity. Therefore, correct diagnosis is crucial. For many years, temporal artery biopsy has been considered the diagnostic ‘gold standard’ for GCA, but it has many limitations (including low sensitivity). US has proven to be effective for diagnosing GCA and can reliably replace temporal artery biopsy in particular clinical settings. In cases of suspected GCA with large-vessel involvement, other imaging modalities can be used for diagnosis (e.g. CT and PET). Here we review the current evidence for each diagnostic modality and propose an algorithm to diagnose cranial-GCA in a setting with rapid access to high quality US.

An update on the role of 18F-FDG-PET/CT in major infectious and inflammatory diseases

For decades, conventional nuclear medicine techniques have been utilized for the assessment of many infectious and inflammatory diseases. Most of these techniques have limitations such as the relatively low spatial resolution, being time consuming and low sensitivity or specificity. In recent years, FDG-PET/CT has shown promising role in the management of such diseases. An expanding set of studies illustrate the multifarious roles of FDG-PET/CT in the assessment of these conditions, both systemic diseases and more regional. Specifically, PET can provide vital information at a molecular level and consequently detect the disease activity at their earliest manifestation. With the continuing research on the diagnosis and treatment monitoring of patients with infectious and inflammatory diseases, the role of PET/CT can be further extended.