Isotopic scintigraphy coupled to tomodensitometry: Interest in the diagnosis of baclofen pump dysfonction

Introduction.– Intrathecal baclofen (ITB) infusion is an established method for the treatment of diffuse and disabling spasticity. The most frequent technical problems are due to catheter/pump dysconnections and diagnosis of dysfunction may be difficult. Observation.– We report the case of a 53-years-old woman suffering from multiple sclerosis with spastic paraplegia treated with ITB pump. Spasticity remained uncontrolled despite a gradual increase of ITB dosage up to 850 μg/day. Tests with baclofen infusion by lumbar puncture (150 μg) refuted any resistance to this drug. Plain films found a distal catheter directed downward with a catheter tip at L5 level without apparent disconnection or failure. An Indium 111 DTPA scintigraphy coupled with a tomodensitometry was performed. It was found that the activity of the radioisotope was maximal next to the first sacral vertebra related with the atypical orientation of the intrathecal catheter distal extremity. No leakage of the product was revealed. Very low activity of the radioisotope was observed above the lumbar level. The catheter was then replaced at T7 level. One month later, spasticity was well controlled. Six months later, a second Indium111 DTPA scintigraphy confirmed a high activity of intrathecal radioisotope up to the basal cisterns. Discussion.– This observation emphasizes the importance of Indium111 DTPA scintigraphy coupled with a tomodensitometry in the etiologic diagnosis of uncontrolled spasticity in patients with ITB pump. Baclofen stagnation in the dural sac shown in these investigations is related with the orientation of the catheter

American consensus recommendations for gastric scintigraphy: curve fitting with only a few points remains an easy and accurate method to obtain reliable and reproducible gastric emptying estimates.

International audienceBACKGROUND: In 2008, American consensus recommendations for performing gastric emptying (GE) scintigraphy were published. It was recommended that data are acquired only at 0, 1, 2, and 4 h and that the results are expressed as percentages of meal retention. Until now, it was established that the GE time-activity curves should have many points (every 10, 15, or 20 min) to reflect the GE process accurately and to be optimally adjusted by a mathematical model. In this study, we have evaluated the curve fitting using only a few points as proposed by the consensus protocol. MATERIALS AND METHODS: GE scintigraphy tests of 224 patients were retrospectively analyzed. Two curve fittings were done for each patient, either using data acquired every 20 min or using data acquired every hour. A comparison of these two methods was made based on the values of the computed GE parameters. RESULTS: We observed strong correlations between the two methods (r=0.81-0.99, P<0.05). Using the Bland-Altman analysis, more than 95% of the differences were included in the mean difference 95% confidence interval. The mean differences were weak with a relatively small SD and Cohen's k coefficients ranging from 0.84 to 0.93, indicating an excellent agreement between the two methods. CONCLUSION: Our results showed the feasibility and accuracy of curve fitting using only a few points. The curve fitting is easy to perform and allows the computation of reliable and reproducible parameters that reflect the whole GE process

Biodistribution et toxicité des nanocapsules chargées en 188Re après injection intratumorale par convection enhanced delivery chez la souris

Objectifs Déterminer la faisabilité, l’intérêt et la toxicité hématologique de l’administration intratumorale par convection enhanced delivery (CED) de nanocapsules chargées en 188Re (NCL-188Re). Matériels et méthodes L’étude de biodistribution des NCL-188Re vs perrhénate (188ReO4−) a été réalisée sur des souris nude (n = 30). Les animaux ont été séparés en 2 groupes : injection intratumorale de 188ReO4− pour le premier groupe (n = 15, 3 MBq) et de NCL-188Re pour le second groupe (n = 15, 3 MBq). Les animaux ont été sacrifiés à 1 h (n = 10), 24 h (n = 10) et 72 h (n = 10) après l’injection, les organes prélevés et comptés. La toxicité hématologique des NCL-188Re a été évaluée par prises de sang de 50 μL (sinus rétro-orbitaire) réalisées à j2, j7, j14 et j21 après traitement par NaCl (n = 4), NCL-188Re (3 MBq, n = 4), NCL-188Re (6 MBq, n = 4) et NCL-188Re (12 MBq, n = 4). Résultats La vectorisation par NCL a permis de limiter l’élimination urinaire du 188Re puisque dès 24 h post-IV 0,1 ± 0,1 % de la dose injectée (%D.I.) vs 81,9 ± 7,5 % D.I. sont retrouvés dans les urines pour les formes NCL188Re-SSS et 188ReO4-, respectivement, (p = 0,016). Celle-ci permet également de retrouver une activité significativement supérieure dans la tumeur à tous les temps de l’étude. L’administration unique de NCL-188Re a induit une toxicité modérée pour les activités injectées les plus élevées (12 MBq) se manifestant principalement par une thrombopénie transitoire de nadir j14–j18. Il n’a pas été observé de toxicité au niveau des autres lignées cellulaires pour les activités administrées de 3 et 6 MBq. Conclusions Les résultats obtenus montrent la faisabilité de l’injection intratumorale par CED et l’intérêt de la vectorisation du 188Re par les NCL. Les premiers signes de toxicité hématologiques sont en faveur du fractionnement des doses administrées et d’un meilleur ciblage par fonctionnalisation des NCL aux oestrogènes pour permettre une meilleure rétention tumorale

New starch-based radiotracer for lung perfusion scintigraphy

PURPOSE: In order to avoid the microbiological risks linked to human serum albumin macroaggregates (MAA) used for lung perfusion scintigraphy, we developed a new starch-based Tc-99m potential radiopharmaceutical. METHODS: Microparticles were prepared from oxidised starch coupled to natural polyamine for Tc-99m complexation. Suspensions were formulated as ready-to-use kits for easy one-step labelling procedures. RESULTS: Particle-size analysis, electron microscopy, and confocal microscopy were performed for microparticle characterisation, and gave a typical size distribution ranging from 7 to 63 microm, with a homogenous population of spherical or oval-shaped microparticles. Radiochemical purity exceeded 95%, and was stable for at least 8 h. When challenged with histidine and human plasma, labelling was also stable. Dynamic scintigraphic acquisitions and biodistribution studies conducted on healthy Wistar rats showed a tracer accumulation with more than 80% of the ID in the lungs after 15 min. CONCLUSIONS: With clinically significant characteristics such as a lung half-life of 3 h, a lung-to-vascular ratio of 900, and a lung-to-liver ratio of 90, starch-based microparticles exhibit all the qualities for an effective new lung perfusion agent

Evaluation of immune responses after nanovectorized internal radiotherapy for glioblastomas

Contribution issue du 4e Workshop européen, orgnaisé par le Cancéropôle Grand-Ouest du 22 au 25 septembre 2010 à l'Ile de Berder en France, autour du thème "Biology of ionizing radiation".International audienc

2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) can identify chronic lymphocytic leukaemia (CLL) stage A et stage B patients

Purpose: There is no data in the literature concerning the utility of 2-[18F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) in chronic lymphocytic leukaemia (CLL), except for the diagnosis of Richter\u27s transformations. The purpose of this study was to assess the potential role of FDG-PET in CLL stages A and B. Materials and methods: Thirty-five patients (61 ± 9 years; 11 women, 24 men; 8B and 27A) have benefited of a FDG-PET scan at baseline, for example, before an eventual treatment. FDG-PET scans were analyzed visually and the maximum values of the Standardised Uptake Value (SUVmax) were measured in the main lymph nodes areas. The ability of FDG-PET to differentiate stages A and B patients was evaluated by Student\u27s tests and Receiver Operating Characteristics (ROC) analysis. Results: All patients with a normal FDG-PET (n = 18) were stages A. The remaining 17 patients (9A and 8B) showed hypermetabolisms in nodal areas above (n = 17) and below (n = 9) the diaphragm, and no visceral involvement. The lymph nodes hypermetabolisms were always bilateral, and of low intensity (≤ mediastinum; 9A), or of higher intensity (≥ liver, 8B). The SUVmax of stage B (n = 8) were significantly higher than those of the 27 stages A, in all lymph nodes areas except in mediastinum. The highest intensity of FDG uptake was observed in axillary area in stages B patients (SUVmax = 2.74 ± 1.03). An axillary SUVmax of 1.33 is the most suitable value for the discrimination between stages A and B patients (ROC; AUC = 0.968; sensitivity 1.00; specificity 0.91). Conclusion: Lymph nodes hypermetabolisms are constant in the B stage, and more intense than in stage A. These anomalies are always bilateral, unlike what is observed in Richter\u27s transformation. The intensity of axillary lymph nodes FDG uptake can distinguish CLL stages A and B