The technical challenge of Functional 18F-FDG-PET Brain imaging in paediatric epilepsy

Epilepsy is a chronic brain disease, characterized by the appearance of crisis (whit or without convulsions), caused by abnormal electric activity on brain cells. Neuroimaging might be necessary in the work-up of epilepsy for localisation of the seizure focus for possible surgical cure. In our department, we started performing inter-ictal 18F-2-deoxyglucose (FDG)-PET/TC Brain imaging in 2009, in paediatric patients, following EANM procedure guidelines. Aim: the aim of the study was to retrospectively review all the performed inter-ictal 18F-FDG-PET/TC brain imaging, to assess the difficulties found during these procedures and the deviation according to guideline recommendations. We also intend to focus on the major importance of an optimal cooperation with other departments, such as anaesthesiology and neurophysiology. Material and Methods: between 2009 and 2012, eleven patients (pt) were referred for an 18F-FDG-PET-TC brain study, with ages between 10 months - 18 years old all with medically intractable epilepsy. The exams were performed with different conditions according to the needs of each patient, because we know that exceptional procedures call for special conditions. Results: All files were review for pt information pertinent to performance of the procedure, pt pre-arrival preparation, pt pre-injection preparation, pt monitoring for ictal crises before injection (EEG), pt sedation, variability of radiopharmaceutical administration and data acquisition parameters. 8 of the pt were performed with anaesthesia while 3 without since the pediatric patient were cooperative. All of the pt were monitored under parental surveillance, one with additional movie recording and other with EEG. Conclusion: We found that this process of retrospective review of this pool of paediatric patients with epilepsy enhanced the learning curve in this very specific procedure. We also found it critical to request the collaboration of the departments of anaesthesiology and neurophysiology

Comparação de dois tipos de colóides tecneciados na detecção de gânglio sentinela

Introdução: O gânglio sentinela define-se como o primeiro gânglio detectado numa via de drenagem linfática do tumor primário. O marcador ideal para pesquisa de gânglio sentinela deve apresentar: retenção persistente neste gânglio, reduzida acumulação de radiofármaco nos gânglios satélites e depuração rápida do local de injecção. Há dois tipos de colóides tecneciados que são frequentemente utilizados em linfocintigrafia – colóides de albumina humana e colóides de sulfureto de rénio. Objectivo: Comparar os dois radiofármacos tecneciados - colóides de albumina humana e colóides de sulfureto de rénio – quanto a: 1) tempo de migração e visualização do gânglio sentinela e 2) incidência de gânglios satélites, quando utilizados em linfocintigrafias para pesquisa de gânglio sentinela em doentes com carcinoma da mama. Material e Métodos: Analisaram-se os estudos de pesquisa de gânglio sentinela de 138 pacientes com carcinoma da mama. Em 63 doentes a linfocintigrafia foi realizada com colóides de albumina humana (Nanocoll®) e em 75 doentes o radiofármaco utilizado foi colóides de sulfureto de rénio (Nanocis®). Procedeu-se à aquisição de imagens iniciais após administração do radiofármaco e foram sendo adquiridas imagens seriadas aos 60min, 90min, 120min, 180min, 240min, 300min e 360min até aparecer o gânglio sentinela. Considerou-se como término do estudo o momento de visualização do gânglio sentinela. Em 5 pacientes não se visualizou gânglio sentinela; 3 correspondiam a colóides de albumina humana e 2 correspondiam a colóides de sulfureto de rénio. Estes 5 casos foram excluídos deste estudo. Resultados: Verificou-se que no grupo de doentes a quem foi administrado colóides de albumina humana, o intervalo de tempo para visualização do gânglio sentinela foi de; 130’ (média), 120’(mediana), com um tempo mínimo de 10’ e máximo de 330’. Neste grupo não foram visualizados gânglios satélites. No grupo de doentes a quem foi administrado colóides de sulfureto de rénio o intervalo de tempo para visualização do gânglio sentinela foi de; 145’(média) 150’(mediana), com 10’ de mínimo e 360’ de tempo máximo. Neste grupo de doentes foram observados gânglios satélites em 2 casos. Conclusão: Nesta amostra não foi observada diferença significativa entre os dois radiofármacos utilizados quanto a: taxa de detecção e tempo para visualização do gânglio sentinela, assim como quanto à incidência de visualização de gânglios satélite

Evaluating Residual Activity in 18F-FDG administration

The Positron Emission Tomography (PET) is an imaging technique, based on functional, biochemical and molecular information. It is also a useful tool in oncological examination. 18F-FluoroDeoxyGlucose (FDG) is a radiopharmaceutical widely used in nuclear medicine departments with PET facilities. FDG’s corrects administration is very important in order to achieve good images and correct Standard Uptake Values (SUV). The aim of this study was to evaluate the residual activity, according to the method used in our department. Materials & Methods: Residual activities of the syringes used to administer FDG to 125 patients were measured and recorded, during one month. The intravenous administration was always performed by the same four nuclear medicine technologists. These technologists are trained in this procedure, according with the developed technique, based on the procedure guidelines for PET imaging. This technique consists in administering FDG in a catheter with a triple channel system (standard system with three-way tap to enable saline flush); the syringe is always filled to its maximum capacity (5cc) and rinsed once, including needle rinsing. Registered time in every procedure was calibrated, in order not to include bias. Results: according to the analysis of the registered data, less than 1% of the activity calculated and measured for each patient remained on the syringe. Conclusions: regarding the search for the best administration procedure, we conclude that the technique used in our department results in a very low residual activity, meaning that it is an accurate technique that leads to reliable SUV values

Comparing two pharmacological stress tests: adenosine vs ATP infusion – patient’s tolerance and image quality

Aim: Adenosine and Adenosine Triphosphate (ATP) are vasodilator agents that are used for pharmacologic stress testing in Myocardial Perfusion Imaging (MPI). Both pharmaceuticals may cause side-effects that are similarly described in the literature. Although, the half-life of these molecules are slightly different and patient’s tolerance might be different. These molecules have also been associated to an increase in the sub diaphragmatic tracer uptake that may reduce image quality, interfering with image interpretation. The aim of this study was to compare pharmacologic stress tests induced by adenosine infusion and by ATP infusion in terms of side-effects referred by patients and the corresponding image quality. Materials & Methods: Two hundred and forty eight (248) patients that underwent MPI were divided in two groups: Group 1 – Adenosine infusion (n=157); Group 3 – ATP infusion (n=91). Each group was further divided according to the presence or absence of side effects, their number and the need to administer pharmacological therapy to control symptoms: A- No side-effects; B - One side-effect; C – Two side-effects; D – Three or more side-effects and/or pharmacologic therapy needed. Image quality was evaluated according to the requirement of a new stress acquisition due to extra-cardiac activity that interfered with image quality and interpretation. Microsoft ExcelTM and SPSSTM were used in this analysis. We also correlated the two populations (Adenosine and ATP) according to the risk factors for cardiac events and the MPI result (normal or pathologic), in order to ensure that uniformity between both groups. Results: The most common effects were facial flushing, abdominal/throat pressure and discomfort in the arms. (See Table 1). Conclusions: The group with the highest percentage of no side-effects and the smaller percentage of three or more side-effects was group 2. However, in spite of the higher percentage of one side effect for group 2 (group 2=38% vs group 1=34%), the difference between them is not statistically significant (p=0,065), so we can assume that both groups had the same percentage of only one side-effect. Additionally, this group had less acquisition repetition, if compared to group 1 (acquisitions repeated: group 1=19,9%, group 2= 9,9%, p= 0,001). So, the group that had better results in terms of patient’s tolerance and image quality was group 2 – ATP infusion

Thermal annealed silk fibroin membranes for periodontal guided tissue regeneration

Guided tissue regeneration (GTR) is a surgical procedure applied in the reconstruction of periodontal defects, where an occlusive membrane is used to prevent the fast-growing connective tissue from migrating into the defect. In this work, silk fibroin (SF) membranes were developed for periodontal guided tissue regeneration. Solutions of SF with glycerol (GLY) or polyvinyl alcohol (PVA) where prepared at several weight ratios up to 30%, followed by solvent casting and thermal annealing at 85 °C for periods of 6 and 12 h to produce high flexible and stable membranes. These were characterized in terms of their morphology, physical integrity, chemical structure, mechanical and thermal properties, swelling capability and in vitro degradation behavior. The developed blended membranes exhibited high ductility, which is particular relevant considering the need for physical handling and adaptability to the defect. Moreover, the membranes were cultured with human periodontal ligament fibroblast cells (hPDLs) up to 7 days. Also, the higher hydrophilicity and consequent in vitro proteolytic degradability of these blends was superior to pure silk fibroin membranes. In particular SF/GLY blends demonstrated to support high cell adhesion and viability with an adequate hPDLs’ morphology, make them excellent candidates for applications in periodontal regeneration.info:eu-repo/semantics/publishedVersio