Fluorine-18 deoxyglucose uptake in sarcoidosis measured with positron emission tomography

Abstract

Regional pulmonary glucose metabolism (MRglu; mumol h-1 g-1), extravascular lung density (D(EV); g cm-3) and vascular volume (VB; ml cm-3) were measured in a single midthoracic transaxial slice (approximately 2 cm thick) using position emission tomography (PET) in seven patients with histologically proven sarcoidosis. The measurements were repeated 1-7 months later after steroid therapy (in two cases, no treatment) in order to assess MRglu as an index of inflammation and relate it to routine pulmonary function tests, chest radiography and serum angiotensin converting enzyme (SACE) levels. MRglu was computed from serial lung scans and peripheral venous blood samples for 60 min following an i.v. injection of 18F-2-fluoro-2-deoxy-D-glucose (18FDG). Both MRglu (which was increased in six of seven patients) and elevated SACE levels returned to normal in those patients treated with high-dose steroids. Regional vascular volume was normal in six of seven cases and did not change significantly with therapy. The high tissue density measured in all patients decreased significantly in two of three patients treated with 40 mg prednisolone daily. The abnormal MRglu observed in active sarcoidosis becomes normal pari passu with SACE levels during high-dose steroid therapy. We conclude that MRglu measured with 18FDG and PET may reflect "disease activity" in sarcoidosis in quantitative terms (per gram lung tissue) and in respect of disease distribution.

Caseating lymphadenopathy at imaging: When ethnicity is deceptive

“…[11] 18 FDG accumulating within the sarcoid granuloma show the classical presence of a rich infiltrate of lymphocytes and macrophages [12,13] even if 18 FDG-PET/CT is not specific for sarcoidosis, and other pathological benign thoracic lesions showing 18 FDG uptake include infection, inflammation, granulomatosis and sarcoidosis. [14,15] The appearance of lymph nodes at thoracic computer tomography is quite characteristic of sarcoidosis and in our case, multiple enlarged lymph nodes at the mediastinum were found, the majority being confluent which was compatible with sarcoidosis, but some lymph nodes were colliquate and this was not typcal of the disease. Thus, the findings of the…”

Fluorodeoxyglucose PET Scan in Pulmonary Sarcoidosis during Treatment with Inhaled and Oral Corticosteroids

“…So far, sarcoid activity has been demonstrated by FDG-PET in the hilar and mediastinal lymph nodes, in the lungs and in the bones [2, 3, 4, 5, 6]. In the individual patient, FDG-PET can probably be employed to evaluate the extent of sarcoid organ involvement, i.e.…”

“…However, FDG-PET can also be used as a marker of inflammation, e.g. to visualise inflammatory granulomatous disorders such as sarcoidosis [2, 3, 4, 5, 6]. The objective of the present case study was to study changes in FDG-PET in pulmonary sarcoidosis prior to and during treatment with inhaled as well as oral corticosteroids.…”

Granulomatosis and Cancer

“…Metabolic imaging with 2-(18F)-fluoro-2-deoxy-D-glucose positron emission tomography (PET) is being used more and more to differentiate benign from malignant focal lesions and it has been shown to be more efficious than conventional chest CT. Howewer, fluorodeoxyglucose (FDG) is not a cancer-specific agent, and false positive findings in benign diseases have been reported in active inflammation or infection, causing false-positive results. Active granulomatous conditions with agregation of inflammatory cells in sarcoidosis results in accumulation of FDG and it has been suggested that the intensity of FDG uptake may reflect disease activity (Brudin et al, 1994). A retrospective study was conducted by Chowdhury et al to evaluate the prevalence of sarcoid-like reaction to malignancy detected using integrated 18 FDG PET/CT in patients undergoing staging or restaging of solid-organ malignancy (Chowdhury et al, 2009).…”