Remy Mostard

Inflammatory activity assessment by F18 FDG-PET/CT in persistent symptomatic sarcoidosis

BACKGROUND Establishing inflammatory activity in sarcoidosis patients with persistent disabling symptoms is important. Whole body F(18)-FDG PET/CT (PET) appeared to be a sensitive method to detect inflammatory activity in newly diagnosed symptomatic sarcoidosis. The aim was to assess the presence of inflammatory activity using PET in sarcoidosis patients with unexplained persistent disabling symptoms and the association between PET findings and serological inflammatory markers. METHODS Sarcoidosis patients who underwent a PET between June 2005 and June 2010 (n = 89), were retrospectively included. All PET scans were examined and positive findings were classified as thoracic and/or extrathoracic. As serological markers of inflammatory activity angiotensin-converting enzyme (ACE), soluble interleukin-2 receptor (sIL-2R), and neopterin were considered. RESULTS In 65/89 (73%) of the studied patients PET was positive, 52 of them (80%) had serological signs of inflammatory activity. In 14/15 patients with a Chest X-ray stage IV PET was positive. In 80% of the PET positive patients extrathoracic inflammatory activity was found. Sensitivity of combined serological inflammatory markers for the presence of inflammatory activity as detected by PET was 80%, specificity 100%, positive predictive value 100%, negative predictive value 65%. CONCLUSIONS The majority of sarcoidosis patients with persistent disabling symptoms, even those with radiological stage IV, had PET positive findings with remarkably 80% extrathoracic lesions. In 20% PET was positive without signs of serological inflammatory activity. PET appeared to be of additional value to assess inflammatory activity in patients with persistent symptoms in the absence of signs of serological inflammatory activity and to detect extrathoracic lesions.

F-18 FDG PET/CT for Detecting Bone and Bone Marrow Involvement in Sarcoidosis Patients

Background: The prevalence of bone involvement in sarcoidosis has been estimated to be 3% to 5%, mostly affecting the phalanges. The aim of this study was to assess the prevalence and distribution pattern of bone and bone marrow involvement as detected by positron emission tomography/computed tomography (PET/CT) in sarcoidosis patients. Methods: Between June 2006 and September 2010, 122 patients suffering from severe sarcoidosis who underwent a PET/CT and met the inclusion criteria were studied. In 94 (77%) patients, the PET/CT demonstrated positive findings associated with sarcoidosis. The 94 PET/CTs were screened for the presence of bone/bone marrow localizations. Additionally, low-dose CT scans were screened for other causes of increased bone uptake. Relevant clinical data were gathered retrospectively. Results: Evidence for bone/bone marrow localizations was found in 34% of the 94 patients with PET/CT-positive findings. Of these patients, 60% showed obvious focal bone lesions at various localizations: axial skeleton (47%), pelvis (40%), extremities (34%), and skull (2%). In 40% of patients, diffuse increased uptake in both axial and peripheral bone marrow, without focal lesions, was found. Both diffuse and focal uptake were seen in 34%, whereas only focal lesions were observed in 25%. In all but 2 (6%) patients, no bone abnormalities on low-dose CT were found. Conclusions: More than one-third of PET/CT-positive sarcoidosis patients had osseous abnormalities on PET/CT. The majority of these lesions (94%) could not be detected on low-dose CT. No single localization of preference was found. These preliminary results stress the value of PET/CT imaging in the assessment of bone/bone marrow involvement in sarcoidosis patients.

The role of the PET scan in the management of sarcoidosis.

Purpose of review It is important to gain knowledge and understanding about the appropriate use of PET scan in the management of sarcoidosis patients. This means that, in view of the radiation dose and costs, defining appropriate indications for PET scanning in sarcoidosis patients is vital. Recent findings PET has been shown to be a very sensitive technique for the assessment of inflammatory activity in sarcoidosis by detecting and quantifying the degree of inflammatory and granulomatous reactions that occur in the lungs and elsewhere in the body. Summary PET is not indicated in the standard workup, but can be of great value to complement more routinely used techniques. On the basis of the current findings, PET offers added value in sarcoidosis patients with unexplained persistent disabling symptoms. PET appears especially helpful in those persistently symptomatic patients without serological signs of inflammatory activity, in patients with radiologic signs of fibrosis and in the detection of active cardiac sarcoidosis. The use of PET to assess the extent of disease can uncover a suitable location for biopsy to obtain histological evidence for the diagnosis or to explain the (mainly extrathoracic) symptoms. Furthermore, the detection of unexpected organ involvement may offer prognostic value.

A predictive tool for an effective use of 18F-FDG PET in assessing activity of sarcoidosis

Background18F-FDG PET/CT (PET) is useful in assessing inflammatory activity in sarcoidosis. However, no appropriate indications are available. The aim of this study was to develop a prediction rule that can be used to identify symptomatic sarcoidosis patients who have a high probability of PET-positivity.MethodsWe retrospectively analyzed a cohort of sarcoidosis patients with non organ specific persistent disabling symptoms (n = 95). Results of soluble interleukin-2 receptor (sIL-2R) assessment and high-resolution computed tomography (HRCT) were included in the predefined model. HRCT scans were classified using a semi-quantitative scoring system and PET findings as positive or negative, respectively. A prediction model was derived based on logistic regression analysis. We quantified the model’s performance using measures of discrimination and calibration. Finally, we constructed a prediction rule that should be easily applicable in clinical practice.ResultsThe prediction rule showed good calibration and good overall performance (goodness-of-fit test, p = 0.78, Brier score 20.1%) and discriminated between patients with positive and negative PET findings (area under the receiver-operating characteristic curve, 0.83). If a positive predictive value for the presence of inflammatory activity of ≥90% is considered acceptable for clinical decision-making without referral to PET, PET would be indicated in only 29.5% of the patients. Using a positive predictive value of 98%, about half of the patients (46.3%) would require referral to PET.ConclusionsThe derived and internally validated clinical prediction rule, based on sIL-2R levels and HRCT scoring results, appeared to be useful to identify sarcoidosis patients with a high probability of inflammatory activity. Using this rule may enable a more effective use of PET scan for assessment of inflammatory activity in sarcoidosis.

Metaiodobenzylguanidine scintigraphy in pulmonary and cardiac disease.

Purpose of review Nuclear medicine techniques have the capacity to investigate neuronal dysfunction at the synapse level. For instance, metaiodobenzylguanidine (MIBG) shows a similar uptake, storage and release as norepinephrine. Intravenously injected radiolabeled MIBG is able to reflect neuronal damage induced by inflammation and tumors. The purpose of this review is to evaluate the results and the limitation of these neuronal imaging techniques in patients with pulmonary and cardiac diseases and to give an opinion about the clinical value of these new diagnostic tools. Recent findings MIBG neuronal images of the lungs and heart can show heterogeneous distribution patterns with either diminished or increased MIBG uptake and/or washout. These changes reflect changes in endothelial integrity, neuronal innervations and clearance of norepinephrine. Interest in the role of neurotransmitter involvement and the relation between endothelial cell integrity and vascularization is growing and of utmost importance to understand the effect on pathophysiology of diseases. Summary At this moment, there is no added clinical value to routinely use MIBG scanning of the lungs and the heart. This is partly due to the many unresolved questions such as what actually happens and which factors influence MIBG uptake and washout under normal physiological circumstances. But the technique, if standardized and when dynamic time acquisition is performed with the latest equipment, such as PET and single photon emission computed tomography–computed tomography (SPECT–CT), has a tremendous potential. It can unravel upto now unknown relationships between innervation, vascularization and endothelial integrity. Other diagnostic tools such as MRI and CT do not have this capacity, so the future looks bright for these new neuronal imaging techniques.

Pet scan: Findings in a patient with severe cutaneous and systemic sarcoidosis

Sarcoidosis is a multisystem disease of unknown etiology characterized by the formation of noncaseating epithelioid-cell granulomas. We present a black female patient with severe cutaneous and systemic sarcoidosis. In the diagnostic work-up a F-18 FDG PET scan demonstrated the extensiveness of the disease. The scan was combined with a low-dose CT for attenuation correction and improvement of the localization of the identified abnormalities. The presented case showed that F-18 FDG PET scan is useful not only in the diagnostic work-up and the assessment of the extent of sarcoidosis activity but also in the follow-up.