No abstract

BackgroundCardiac sarcoidosis (CS) is a potentially fatal condition lacking a single test with acceptable diagnostic accuracy. 18F-FDG PET/CT has emerged as a promising imaging modality, but is challenged by physiological myocardial glucose uptake. An alternative tracer, 68Ga-DOTANOC, binds to somatostatin receptors on inflammatory cells in sarcoid granulomas. We therefore aimed to conduct a proof-of-concept study using 68Ga-DOTANOC to diagnose CS. In addition, we compared diagnostic accuracy and inter-observer variability of 68Ga-DOTANOC vs. 18F-FDG PET/CT.MethodsNineteen patients (seven female) with suspected CS were prospectively recruited and dual tracer scanned within 7 days. PET images were reviewed by four expert readers for signs of CS and compared to the reference standard (Japanese ministry of Health and Welfare CS criteria).ResultsCS was diagnosed in 3/19 patients. By consensus, 11/19 18F-FDG scans and 0/19 68Ga-DOTANOC scans were rated as inconclusive. The sensitivity of 18F-FDG PET for diagnosing CS was 33 %, specificity was 88 %, PPV was 33 %, NPV was 88 %, and diagnostic accuracy was 79 %. For 68Ga-DOTANOC, accuracy was 100 %. Inter-observer agreement was poor for 18F-FDG PET (Fleiss’ combined kappa 0.27, NS) and significantly better for 68Ga-DOTANOC (Fleiss’ combined kappa 0.46, p = 0.001).ConclusionsDespite prolonged pre-scan fasting, a large proportion of 18F-FDG PET/CT images were rated as inconclusive, resulting in low agreement among reviewers and correspondingly poor diagnostic accuracy. By contrast, 68Ga-DOTANOC PET/CT had excellent diagnostic accuracy with the caveat that inter-observer variability was still significant. Nevertheless, 68Ga-DOTANOC PET/CT looks very promising as an alternative CS PET tracer.Trial registrationCurrent Controlled Trials NCT01729169.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-016-0207-6) contains supplementary material, which is available to authorized users.

Conventional 18F-FDG PET/CT is an accurate and reliable tool to diagnose cranial arteritis in glucocorticoid-naïve GCA patients. The high diagnostic specificity suggests that TAB can be omitted in patients with 18F-FDG uptake in cranial arteries. 18F-FDG PET/CT performed in patients with suspected vasculitis should always include the head and neck.

• Patients eligible for local treatment of colorectal liver-metastases require optimal imaging. • In 80 consecutive patients, MRI had superior per lesion diagnostic performance. • Findings were independent of prior treatment and type of planned local treatment. • Equally, MRI had superior diagnostic performance on per segment basis.

AbstrActbackground. The purpose of the study was to assess dose and time dependence of radiotherapy (RT)-induced changes in regional lung function measured with single photon emission computed tomography (SPECT) of the lung and relate these changes to the symptomatic endpoint of radiation pneumonitis (RP) in patients treated for non-small cell lung cancer (NSCLC). Material and methods. NSCLC patients scheduled to receive curative RT of minimum 60 Gy were included prospectively in the study. Lung perfusion SPECT/CT was performed before and three months after RT. Reconstructed SPECT/CT data were registered to treatment planning CT. Dose to the lung was segmented into regions corresponding to 0-5, 6-20, 21-40, 41-60 and  60 Gy. Changes (%) in regional lung perfusion before and after RT were correlated with regional dose and symptomatic RP (CTC grade 2-5) outcome. results. A total of 58 patients were included, of which 45 had three-month follow-up SPECT/CT scans. Analysis showed a statistically significant dose-dependent reduction in regional perfusion at three-month follow-up. The largest population composite perfusion loss was in 41-60 Gy (42.2%) and  60 Gy (41.7%) dose bins. Lung regions receiving low dose of 0-5 Gy and 6-20 Gy had corresponding perfusion increase (-7.2% and -6.1%, respectively). Regional perfusion reduction was different in patients with and without RP with the largest difference in 21-40 Gy bin (p  0.02), while for other bins the difference did not reach statistical significance. The risk of symptomatic RP was higher for the patients with perfusion reduction after RT (p  0.02), with the relative risk estimate of 3.6 (95% CI 1.1-12). conclusion. Perfusion lung function changes in a dose-dependent manner after RT. The severity of radiation-induced lung symptoms is significantly correlated with SPECT perfusion changes. Perfusion reduction early after RT is associated with a high risk of later development of symptomatic RP.