Optimisation du protocole d’acquisition de la TEP à la fluorocholine dans la détection des lésions parathyroïdiennes

18F-Fluorocholine (FCH) PET/CT shows very promising potential for detection of hyperfunctioning parathyroid tumors. However, the optimal time to perform imaging after FCH administration has not yet been determined and protocols are highly variable. The aim of this study was to qualitatively and quantitatively compare 5, 10, 15, 20 and 60 min post-injection acquisition times in patients with primary hyperparathyroidism and equivocal traditional imaging. Thirty-one patients were included. Two observers retrospectively analyzed the five protocols. Any focal increase in FCH uptake was localized and graded on a discrete gradation scale between 1 and 5 to assess the likelihood of hyperfunctioning parathyroid tumors. Gold standard was histopathological findings for the 11 operated patients. Regarding quantitative analysis, ratio of SUVmax of parathyroid foci on SUVmean of thyroid background (as signal-to-noise ratio) were compared between protocols. After injection of 2.5 MBq/kg, FCH PET performed 60 min post-injection (2 min) had the best sensitivity and specificity by lesion (92% and 100% respectively and the best signal-to-noise ratio (median of 2). We suggest performing PET scan 60 min after injection, associated with early acquisition so as not to miss a wash-out hyperfunctioning parathyroid tumors.     

Fusion d’images en médecine nucléaire : des concepts à l’application clinique

In this paper, the authors propose a short overview of image fusion techniques in nuclear medicine. First, the methodological concepts of image fusion are discussed. Then, a sample of applications in nuclear medicine is presented. These applications ranging from diagnosis to guided therapy and monitoring clearly exemplify the challenges of image fusion in nuclear medicine.     

Intérêt de la TEP dans le bilan d’extension et l’évaluation de la maladie résiduelle des séminomes testiculaires : étude rétrospective

AimsTo evaluate the value of PET/CT comparatively to CT in staging and restaging after chemotherapy of testicular seminoma, to assess quantitative methods and prognostic value of PET in post-chemotherapy residual masses.MethodsThirty-two patients and a maximum of 65 targeted lesions visualized on PET-CT and CT performed for staging and therapeutic response assessment were analysed and compared. Each lesion was quantified according to miscellaneous SUV normalized methods. Optimal threshold of SUV for prediction of residual disease was obtained (ROC method). The prognostic value of PET/CT at the completion of treatment was determined with progression free survival study (Kaplan-Meier method).ResultsPET/CT exhibited higher accuracy than CT in the initial staging and assessment of therapeutic response, respectively 98% versus 83.3% and 95.1% versus 75.6%. Quantification, whichever method, was not more efficient than visual reading for prediction of residual disease. Progression-free survival was higher with negative than with positive PET/CT (P = 0.0033).ConclusionOur work demonstrates that PET/CT exhibits better accuracy than CT in both staging and restaging at the end of treatment. Quantification methods do not improve accuracy of PET/CT for prediction of viable residual disease. The prognostic value of PET/CT appears very promising and needs to be confirmed by large prospective studies. PET/CT appears to be a relevant method of prognostic stratification of the risk of relapse in seminoma.     

Segmentation des IRM cérébrales par une variante bootstrapée du HMRF-EM : étude préliminaire sur fantômes

This paper deals with global statistical unsupervised magnetic resonance image (MRI) segmentation based on a Markovian model combined with the family of mixture identification algorithms EM (Hidden Markov Random Field [HMRF-EM]) and using the Bootstrap sampling, which allows a greater respect to the data independence assumption and a reduction of algorithmic complexity. This leads not only to a flexibility in the control of running time but also an improvement in the classification quality relatively to the performance shown by an earlier version of the bootstrapped HMRF-EM.     

Tumeurs du grêle et du côlon : importance de l’anatomie en coupes

The aim of this article is to describe the anatomic specificities of each different digestive tumors in CT imaging and to show the interest of contrast-enhanced CT and bowel opacification. Some specific points about lymph nodes of the abdomen and peritoneum anatomy will be discussed.     

Le développement de l’inventaire de dépistage ERIraos: un outil global d’appréciation du risque d’évolution psychotique

Adequate identification of patients for early intervention programmes requires reliable and valid assessment tools. Within the German Schizophrenia Network (Kompetenznetz Schizophrenie) a set of schedules for early detection of schizophrenia has been proposed: the Early Recognition Inventory ERIraos. ERIraos is a two-step procedure with a 17-item checklist used at step 1 by GPs, psychologists, teachers, while a comprehensive 110-item symptom list is applied at early intervention centres at the expert level. In addition, ERIraos allows the assessment of several risk factors for psychosis such as familial load, childhood deficiencies, alcohol and drug use by special modules. Some preliminary results are presented here. The frequency of the 17 checklist symptoms increases from the early to the late prodrome, and more specific symptoms occur over time. The 17 checklist symptoms are grouped by factor analysis to 5 factors (psychotic, depressive, disorganised, withdrawn, dysphoric). In addition to prodromal symptoms, most patients (86.2%) report at least one additional risk factor (mean: 1.7 risks). 68% demonstrate some schizotypal features, 53% report alcohol and/or drug consumption, 24% demonstrate some deficiency or delay in childhood development, 21% report definite obstetric or birth complications, and 10% have a family history of schizophrenia or some schizophrenia-like diagnosis in first degree relatives. So far, the results are of a preliminary nature, and when sufficient information on psychotic transitions is available, the predictive value of ERIraos will be determined.     

Place de la tomographie d’émission de positons (TEP) pour l’évaluation thérapeutique et le suivi du cancer du sein

Positron emission tomography (PET) with fluorodeoxyglucose (FDG) is a nuclear imaging method whose interest in oncology has only grown over the past fifteen years. This article summarizes the results in monitoring and therapeutic evaluation of breast cancer. For the search of locoregional or distant recurrence, the performance of FDG-PET are very interesting. The impact of FDG-PET on the therapeutic management is undeniable. For therapeutic evaluation, this imaging is useful to evaluate the neoadjuvant chemotherapy and hormonotherapy efficacy. FDG-PET is indicated in cases of suspected recurrence (clinical, biological or imaging suspicious). It is the most sensitive exam for the detection of bone or visceral metastases. It allows the re-staging during a relapse proved whether local or remote, and can change the therapeutic management.